GroupDIY

Project Specific Discussions => Microphones => Topic started by: poctop on September 29, 2012, 03:25:12 PM

Title: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 29, 2012, 03:25:12 PM
D-U67 Build Thread

Let's get those Electron flowing.
All of the info: http://www.groupdiy.com/index.php?topic=49675.0 (http://www.groupdiy.com/index.php?topic=49675.0)

The D-U67 Tube Mic

Mic Assembly Tutorial
https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0351f.pdf

PSU Assembly and Tips
https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03549.pdf




(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0355a.jpg)

http:// Check this First: Project Files for The D-U67 Build   :)
https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0356c.zip


The Safety Manual and Considerations.
https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0357d.pdf

IMPORTANT:
You Should always have the SHLF Jumper in position in the PSU PCB ,  this will ensure that your cable shield is tied at both end of the cable and connect to 0V
you Should Also have the 0V star grounded to your case and then from there to you IEC earth ground ,


For More Information on Grounding
https://www.dropbox.com/s/6y121dasm3iw4ba/Sound_System_Interconnection.pdf?dl=0

Best,
Dan,


D-U67 Mic Parts: http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=83ad963d23  (http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=83ad963d23)
Note: BOM include 56R For R20

D-U67 PSU Parts :  http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=b5c122b4d0  (http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=b5c122b4d0)     
Note: BOM include 560R for R9

OK , here is the briefing

For More Information on Grounding
https://www.dropbox.com/s/6y121dasm3iw4ba/Sound_System_Interconnection.pdf?dl=0

i always have the habit of never float 0V on a PSU i always star ground it to the chassis and then IEC plug , 
about the shield it is imperative at all time that the shield has a path to the chassis as well so it will protect YOU and Your investment. in the mic PCB the shield and 0v are on the same level meaning they are connected togheter and the mouting hole of the pcb are connected to the chassis , this lead to always have the shield protecting you because i ALWAYS star Ground 0V to the power supply case so in all everything always goes to the earth no matter what , So in essence this SHLF is somthing i wanted to implement as a ground lift but it was not done properly and i am glad it turned that way because it is safe this way ,
i guess i am an habit person i always did it like this and never had any problem.

if you have hum problem  you can start floating thing arroundb like the 0V from PSU to in respect to Chassis or the shield but it is very something of last resort and i dont recommend it as it is to me potentially unsafe to do so ,
Hope this helps,  above is a good read about how to properly ground the equipment togheter,

best,
Dan,


Important Note


Update on PSU Power Specification

Problem : R2 is getting way too hot
it has been brought to my attention that the PSU Power Supply (R2) Power was out of tolerance and heating passed its
ratings. this has been very isolated case only.

Do Not Use More than 6VA for the 20V transformer

Explanation: the Hammond transformer in the BOM was specified at 300ma 6VA , some DIYER used higher power supply rating cause a bigger Voltage drop in R2 than anticipated supplying more current to it causing the resistor to get too hot and melt the solder on the pcb. those who have used the Specified Hammond transformer can go ahead and only upgrade R2 for the new higher power resistor if needed. Those who have the old hammond transformer should be ok as it cannot outpout enough power to go past 2W specified, only a resistor upgrade is need in this case.

Solution: After Analysis of the power dissipation required on R2 to provide with the Heater Voltage. it has been found that
 new higher power R2 Resistor 22ohm 5W to alleviate this as well and it will run cooler. it is also recommended that R2 and the Zener diode shall be lifted a little bit from the PCB to permit better heat disspipation to run even cooler :[/b]

Now Included in the BOM

Here is the 2 suggested part for R2  5Watt as well updated in the BOM

http://ca.mouser.com/Search/ProductDetail.aspx?R=RWHSE09TU025R0FSvirtualkey58440000virtualkey605-RWHSE09TU025R0FS

or

http://ca.mouser.com/Search/ProductDetail.aspx?R=AC05000002209JAC00virtualkey59420000virtualkey594-AC05W22R00J

Many Thanks To TLRT for catching those potential issues.
Best,
Dan,


The only 2 parts that is not (Europe 230V) compatible is the hammond 20VAC and the PSU pilot Lamp wich is 120V everything else is fine except the fuse will need to be 0.1A instead of a 0.2A for north America, you will need a minimun 6VA traffo for the filament side,
alternative part number are discussed in this thread here :
http://www.groupdiy.com/index.php?topic=49675.20 (http://www.groupdiy.com/index.php?topic=49675.20)
http://www.groupdiy.com/index.php?topic=49675.40 (http://www.groupdiy.com/index.php?topic=49675.40)



PSU Schematic
https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0358d.pdf




Errata Feedback winding polarity  http://groupdiy.com/index.php?topic=50021.800 reply # 814

AMI T67 Corrected Wiring to main microphone pcb

From transformer board to mic PCB

Pad 5 ----->  mic pcb pad T1212
Pad 12 -------> mic pcb pad T55
Pad 1 --------> mic pcb pad T44
Pad 4 --------> mic pcb pad T11
Pad 7 --------> mic pcb pad T1010
Pad 10 ------> mic pcb Pad T77


(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0359a.jpg)




Here is the correspondance on the pcb pad for the U67 Mic pcb


(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a035a6.jpg)


AMI sent me the updated schematic with these details below.

The circuit:
(http://i1300.photobucket.com/albums/ag85/rjuly/imagejpg1_zps7ff60568.jpg)

... and the reference image:
(http://i1300.photobucket.com/albums/ag85/rjuly/imagejpg1_zpsfa3e1910.jpg)

Best,
Rich

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a035b4.jpg)

 :)
yes i got it this morning , cant wait to start a new build with this traffo. i really like my D-EF47 with the BV8 classic series.
let get this bv12 classic series going :)
the 2 black wire are actually shiedling of the core, take those 2 wires to a gnd pad onm the pcb,
Also note that the Blue wire (4) is the +audio out and the White (3) is - audio out

https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a035c5.pdf
best,
Dan.

See here for complete relationship between pad and transfomer on the AMI mic pcb,
http://groupdiy.com/index.php?topic=50021.msg720336#msg720336


BOM Annexe
https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a035d6.doc



Not inclued in the Mouser Bom are:

Styroflex Capacitor Available Here :http://dl.dropbox.com/u/43869772/U67/Picture%20Tron/orderformDU67.xls (http://dl.dropbox.com/u/43869772/U67/Picture%20Tron/orderformDU67.xls)
 

Microphone Body and accessories Available Here :http://www.groupdiy.com/index.php?topic=50015.0 (http://www.groupdiy.com/index.php?topic=50015.0)

Bellow Basic Setup for Different Version , different folks different strokes  8)

I have been working on validating the last details regarding mouting the AMI boards and last fine tuning regarding the Clearance of the track pad in respect to th railing and position,  fit in the mic boady and hole tolerance ,  I am pleased to annonce that all my concerns on this have been validated ,

here some
AMI  or External Board Mounting Hints and clearance railing test,  :)

and Yes this is My favourite Celebration beers the Boddingtons  ;D

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0360d.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0361f.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03631.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03643.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03655.jpg)


(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03667.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03678.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0368a.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0369b.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a036ab.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a036bd.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a036ce.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a036e0.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a036f2.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03706.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03713.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0373f.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03751.jpg)



The D-U67 Build

All Of it, 100% original Circuit , No Exception  :) Include Calibration Check Port & Internal LC shift Switch ;)
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03765.gif)
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03776.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03787.jpg)

External Transformer Such As Tabfunkenwork AMI T67 PCB shown in Photo Build ,  Ioaudio BV 12 on the left,

PSU thanks To  DanDeurloo
Dan's Case Available here : http://www.collectivecases.com/ (http://www.collectivecases.com/)
or Here: http://www.groupdiy.com/index.php?topic=41963.0 (http://www.groupdiy.com/index.php?topic=41963.0)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0379a.jpg)
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a037ab.jpg)
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a037be.jpg)
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a037cf.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a037e0.jpg)
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a037f1.jpg)

The Build of the HZ floating Bridge uses all the existing resistor and capacitor leads  ;)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03805.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03816.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03828.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03839.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0384b.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0385e.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0386f.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03881.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03893.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a038a6.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a038b7.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a038d8.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03902.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0391e.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03942.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03971.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0397e.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0398f.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a039a5.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a039b2.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a039c3.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a039d4.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a039e6.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a039f9.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03a0a.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03a17.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03a28.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03a3c.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03a4d.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03a5e.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03a70.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03a81.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03a94.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03aa5.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03ab7.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03ac8.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03adb.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03ae8.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03af9.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03b0a.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03b1b.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03b2f.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03b41.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03b6f.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03b7c.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03b89.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03b98.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03ba9.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03bba.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03bcb.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03bdf.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03bec.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03bfd.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03c0e.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03c1f.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03c32.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03c44.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03c55.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03c66.jpg)

The D-U67 and the D-M269 Share the same  pattern switch , low cut switch, and pad switch wiring. the only difference is for Pattern Swich Pin 1 For A complete switch connection tutorial see here in build Part 2 : http://www.groupdiy.com/index.php?topic=51350.0 (http://www.groupdiy.com/index.php?topic=51350.0) 


(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03c7a.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03c8c.jpg)

AMI T67 Example.

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03c9d.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03caf.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03cc1.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03cd6.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03ce3.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03cf6.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03d08.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03d1c.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03d2e.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03d41.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03d6d.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03d7f.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a03d8f.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d02819938f7.jpg)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on October 01, 2012, 08:24:48 AM
First post! And perhaps the most useless...   :)

http://www.crameda.com/pdf_files/eng/multiswitch/MS-L-E-060915.pdf

If one was willing to go the extra mile and mount these to Chungers u67 will it work electricaly with the circuit? Not sure what current and voltage flows through the pattern switch. It's possible to get custom markings on the thumb wheel so if well mounted they would look pretty nice. Or? I might be in over my head here.. =)


/
Emil
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: HellfireStudios on October 01, 2012, 09:24:28 AM
First post! And perhaps the most useless...   :)

http://www.crameda.com/pdf_files/eng/multiswitch/MS-L-E-060915.pdf

If one was willing to go the extra mile and mount these to Chungers u67 will it work electricaly with the circuit? Not sure what current and voltage flows through the pattern switch. It's possible to get custom markings on the thumb wheel so if well mounted they would look pretty nice. Or? I might be in over my head here.. =)


/
Emil

That switch seems very complicated. The switch you would need requires that at least one position is "off." A simple SPDT on-off-on switch would be easier to implement, but I believe Chunger's U-67 body already has the right switches. I hope that helps.

-James-
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on October 01, 2012, 09:44:51 AM
Of course it's complicated! Even fitting it/them to body is probably close to impossible due to the size of them. Would look cool though, and closer to original Neumann design.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 01, 2012, 09:55:08 AM
Of course it's complicated! Even fitting it/them to body is probably close to impossible due to the size of them. Would look cool though, and closer to original Neumann design.

you would be able to Set "5"-"6" for cardiod mode tough.  ;D ;)
Best
Dany,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: JessJackson on October 03, 2012, 06:38:14 AM
Had the body powder coated almond.

Interested in the above switches or other cosmetic improvements

Need a new grill built the same contour lines as mic body / original 67. Back side of grill to be black wire (like elam). Probably going to go for open weave one layer c12 type. Anyone here messed with different mesh sizes and types on 67/87 types? Even contemplating buying head assembly from sennheiser.

Polish grill holder to chrome.

Need to source touchel connector.

Probably wont stick those flags on there... was just messing around with a pin.

(http://www.jessjackson.com/sessions/Jessu67powdercoated.JPG)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Dylan W on October 03, 2012, 04:35:22 PM
Had the body powder coated almond.

Interested in the above switches or other cosmetic improvements

Need a new grill built the same contour lines as mic body / original 67. Back side of grill to be black wire (like elam). Probably going to go for open weave one layer c12 type. Anyone here messed with different mesh sizes and types on 67/87 types? Even contemplating buying head assembly from sennheiser.

Polish grill holder to chrome.

Need to source touchel connector.

Probably wont stick those flags on there... was just messing around with a pin.

Jess,

That looks great. I'm planning on getting a powder coating gun to do mine.

Haven't ordered my body yet, think a Binder 7 pin connector will fit?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 03, 2012, 06:17:47 PM
Hey guys, I just bought some gac7 cable from redco, and a have a couple questions before I start assembling it. Is there a specific color to pin number orientation? I noticed that the blue wire is a thicker gauge. I am also unsure as to what I should do with the shield. I'm having trouble loading some of the build docs on my ipad  >:(

By the way, that powder coated body looks excellent, I might have to do something similar
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on October 03, 2012, 06:27:31 PM
There should be two thicker wires for the heater
Two thin wires in a twisted pair for the audio
The mogami tube mic cable datasheet is good to look at to get an idea what to use for what
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 03, 2012, 06:29:02 PM
Hey guys, I just bought some gac7 cable from redco, and a have a couple questions before I start assembling it. Is there a specific color to pin number orientation? I noticed that the blue wire is a thicker gauge. I am also unsure as to what I should do with the shield. I'm having trouble loading some of the build docs on my ipad  >:(

By the way, that powder coated body looks excellent, I might have to do something similar

Hope this helps , Red and Blue Wire are bigger because more current goes trough them so less voltag drop long run ,

in my example the Red is filament and Blue the ground ,

Shield question =
Basically your cable is not using the black wire incsde it uses the shield instead  Just Leave out the black wire inside the cable , and both will connect in position # 3 at both ends,
Note: there is a SHLF jumper on the PSU pcb this is the Starground point of the Shield
So if you cont connect it to the microphone position #3 make sure you have this jumper installed refer to the PsU schematic for details,
Hope that  Helps,

PS: i did not know IStuff could actually have an error  ;D
Dany,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 03, 2012, 06:35:20 PM
Thanks Dany, that's everything I needed to know and more. Thanks for the explanation. I get an error when I try to load the build docs. The safety one loads fine every time.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 03, 2012, 06:46:25 PM
Thanks Dany, that's everything I needed to know and more. Thanks for the explanation. I get an error when I try to load the build docs. The safety one loads fine every time.

You are very Correct to Remind Everyone that this project uses 200VDC, wich is Lethal SO... safety is everything before everything. please Read the Safety Manual.

Dan,

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: mrcase on October 04, 2012, 06:03:27 AM
Hey All!

As already asked in the whitemarket thread, I was wondering which (brand) tubes everyone is using?
Is it really worth to invest in an Telefunken EF806s? see
http://www.gearslutz.com/board/high-end/130060-u67-tube.html

thanks
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Sredna on October 04, 2012, 06:35:14 AM
Depends on your budget, you have to buy several to test for noise and microphony.

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: kpearsall on October 04, 2012, 06:40:00 AM
www.tubedepot.com you can ask them to select for low noise + microphonics from there. Always great quality from that store.

That's the route I'll be going for my tubes. Going to try the EF86 and EF806. And whatever else I can dig up out of my collection. I don't have any pairs at the moment though, and i'm building two, so I'll have to buy a set somewhere. Beezneez capsule and IOAudio transformer are priority right now though.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Sredna on October 04, 2012, 07:44:59 AM
Keep in mind that in a microphone circuit the tube is working outside is normal parameters,
most selection/matching is done for "normal" applications (ie preamp stages).

The "selected" tube may or may not work well in your microphone.

Finding a seller who is willing to take back/replace a noisy tube may be practical....
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: kpearsall on October 04, 2012, 07:21:26 PM
All good points Sredna. Yea, I wouldn't just "trust" anything. I'm gathering as many tubes, bought and borrowed, as I can to do a listening test with a friend who has two 67's. I'm going to try out the selected ones from that link so I know if it's going to be sufficient or not for future tube mic builds. :)

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 04, 2012, 07:25:47 PM
All good points Sredna. Yea, I wouldn't just "trust" anything. I'm gathering as many tubes, bought and borrowed, as I can to do a listening test with a friend who has two 67's. I'm going to try out the selected ones from that link so I know if it's going to be sufficient or not for future tube mic builds. :)

+1 for the experiment.  ;)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 05, 2012, 05:01:10 PM
Hey guys, a couple more newbie questions for you.
First, I am a little confused as to where I should hook up the primaries on the 20v transformer. Do they both go to the switch, or one to the switch and the other to neutral, neither of those?

Also, I have holes on the front and back of my psu case, so I was thinking of just putting in two LEDs. Where's a good place to draw power for them from?

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on October 05, 2012, 05:08:29 PM
Curious about your  "EXCEPTION 1" pic. What am I missing?                                                           
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on October 05, 2012, 05:31:00 PM
The exceptions are the holes you actually dont solder to. If you follow Poc's pictures it will be more clear. The leads of thos components are only solderd to one side. Or none at all. Its for the Hi z section.

Eric
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 05, 2012, 06:19:08 PM
Hey tskguy, do you mind helping me with my question a couple posts back? I have my psu almost completely finished, I'm just unsure of the 20v transformer , and led wiring.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on October 05, 2012, 06:52:36 PM
 mmm its the square one right? If so there are 5 tabs 3 on top and 2 on the bottom. The 2 on the bottom go to your switch and power inlet. Its the same connections as the other transformer. So power switch on sends AC to both TX's
The outer 2 tabs on the top go to the pcb. Again study the pictures in Poctops build docs. With this info it should be more clear.

Eric ;D
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 05, 2012, 07:07:17 PM
Yeah the square one. I have the top connections correct, going to the pcb, but the bottom ones I am confused about. Do they both go to the switch, or does one go to the switch and the other to the neutral on the iec plug? I tried to look at all of Danny's pic and your pics and I can't see this part of the psu on any of them. I looked over the schematic several times but I only understand the secondary side of it, unfortunately. I am also unsure where to connect the positive lead of my LEDs. Thanks for your response  :)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on October 05, 2012, 09:13:27 PM
Ok so first off be carefule!! there is 200volts in this PS and it can kill you! Both transformers are connected the same way.  So both tx's have a pimary wire conected to one of the hot iec connections (not the earth) the other primary wire for both tx's goes to one leg of the power switch. then the power switch open leg goes to the open hot iec conection. PCB and Earth go to start ground.(connected to chassis) I attached a very crude drawing hope it clears it up for you.

(http://i280.photobucket.com/albums/kk187/tskguy/wirediagram.jpg)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 05, 2012, 09:19:32 PM
Ok, so I have tab 2 on the transformer going to the switch and  tab 3 going to the neutral on the input.  I get a 20v reading between 5 and 8 on the small transformer, but I am getting a reading in the 300s between the yellow and black output wires on the big transformer that are going to the 210v pcb section ???
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 05, 2012, 09:24:06 PM
Ok so first off be carefule!! there is 200volts in this PS and it can kill you! Both transformers are connected the same way.  So both tx's have a pimary wire conected to one of the hot iec connections (not the earth) the other primary wire for both tx's goes to one leg of the power switch. then the power switch open leg goes to the open hot iec conection. PCB and Earth go to start ground.(connected to chassis) I attached a very crude drawing hope it clears it up for you.

(http://i280.photobucket.com/albums/kk187/tskguy/wirediagram.jpg)

Aaah, I almost have it exactly like this. I have 2 and 3 reversed on the small transformer. Should I change them, or does this have the same effect? Thanks for drawing this up, I really appreciate it
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on October 05, 2012, 10:09:33 PM
I am not sure what you mean by 2 and 3? Are you referring to the primary? That’s the bottom 2 connections on the small square TX. Those don’t matter, the 2 wires connected on the top need to be the outer 2 connections and either can be connected to the pcb.

And I forgot to mention that I wouldn’t use a led...I am using a 120 v lamp right off the IEC and switch.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 05, 2012, 10:19:27 PM
I am not sure what you mean by 2 and 3? Are you referring to the primary? That’s the bottom 2 connections on the small square TX. Those don’t matter, the 2 wires connected on the top need to be the outer 2 connections and either can be connected to the pcb.

And I forgot to mention that I wouldn’t use a led...I am using a 120 v lamp right off the IEC and switch.
Ok, that's kind of what I figured. Thanks for the tip on the light, and for all of your help  : :D
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on October 05, 2012, 11:13:21 PM
Glad to help out
 ;D
Eric
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 07, 2012, 05:15:01 PM
Curious about your  "EXCEPTION 1" pic. What am I missing?                                                         

The Exception picture is actually the component you have to take care in the second step of the build so basically all of those exception will have a link to another component via a flotating connection , so it reminds you not to cut the lead from those until you actually use them in the HZ bridge,
hope this helps,
dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: JessJackson on October 08, 2012, 08:06:27 AM
an interesting mod I came across.

http://repforums.prosoundweb.com/index.php/topic,36020.0.html
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on October 09, 2012, 08:48:46 PM

Jess,

That looks great. I'm planning on getting a powder coating gun to do mine.

Haven't ordered my body yet, think a Binder 7 pin connector will fit?

Dylan,
Implementing a Binder will require a considerable modification to the bottom of the mic. You will probably not be able to use a screw on type shockmount either. It's for this reason that we are using the Amphenol 7 pin connectors. they drop in the bottom with minor boring and give you the ability to use a screw on Amphenol female cable end as well as a screw on shockmount.

Dave

p.s. AMI version build manual coming soon complete with pics of how to use the Amphenol end. Stay tuned
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: burglar on October 10, 2012, 07:37:07 AM


p.s. AMI version build manual coming soon complete with pics of how to use the Amphenol end. Stay tuned

Looking forward to it.  Will it include a step by step build manual for the PSU?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on October 10, 2012, 11:22:08 AM
Yes
We will have instructions for the PSU

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 10, 2012, 01:15:36 PM
Quote
Dylan,
Implementing a Binder will require a considerable modification to the bottom of the mic. You will probably not be able to use a screw on type shockmount either. It's for this reason that we are using the Amphenol 7 pin connectors. they drop in the bottom with minor boring and give you the ability to use a screw on Amphenol female cable end as well as a screw on shockmount.

Dave

p.s. AMI version build manual coming soon complete with pics of how to use the Amphenol end. Stay tuned

Why would you use a screw on shockmount? Are you referring to ChuckD's U67/87 body? Is the amphenol connector a screw on type, or is it more like the neutrik type?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on October 10, 2012, 02:03:13 PM
Here is a pic of  what Wave is talking about.

(http://i280.photobucket.com/albums/kk187/tskguy/20120903_114318.jpg)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: burglar on October 10, 2012, 05:25:29 PM

Not sure if they're of any value to anyone but I have a NOS Haltron EF86 & a used Philips Miniwat EF86.  No idea what they're worth.  Probably not a lot.  My grandad has a huge collection of old tubes and having shown him Poctops white market thread he managed to dig these out along with 2 old EF86 mullards.  :)

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 10, 2012, 05:26:25 PM
Here is a pic of  what Wave is talking about.

(http://i280.photobucket.com/albums/kk187/tskguy/20120903_114318.jpg)
Aw damn, I jumped the gun on this build. It would be a total pain for me to go back and redo my cable and mic jack. Looking forward to the build instructions though. Will they include the calibration part of the build?  That would be great, since it's my next step.  ;D
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 10, 2012, 05:39:34 PM
Here is a pic of  what Wave is talking about.

(http://i280.photobucket.com/albums/kk187/tskguy/20120903_114318.jpg)
Aw damn, I jumped the gun on this build. It would be a total pain for me to go back and redo my cable and mic jack. Looking forward to the build instructions though. Will they include the calibration part of the build?  That would be great, since it's my next step.  ;D

Please note that this modifcation is not needed ,  the U67 mic body is supplied with a 7 pin connector,
the modification is needed if you prefer a Tuchel connector version ,
this is just to clear up some confusion ,
cheers,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on October 10, 2012, 05:54:56 PM
Yes I am referring to Chuck's body. His shockmount is the clamping style. While it's a good solid mount, I like to hang my mics for doing VOX and ACG (just my preference) and I feel like the mic can slide out of the mount. I have a screw on mount that came with my T-Bone SCT700 which works for the U67 style body as well.

Here are some pics of the Amphenol 7 pin implemented on my MK47 (which I used the T-Bone SCT700 for) It's got the same sized end as the ChuckD/Chunger U67 body. It requires minor boring to implement. it's MUCH easier than throwing a Binder on there and you get the screw on cable capability which i like way more than a clip in 7 pin XLR

(http://farm9.staticflickr.com/8467/8075196985_6f4dc42a1c.jpg) (http://www.flickr.com/photos/wavedealer/8075196985/)

(http://farm9.staticflickr.com/8324/8075197059_090c6214a0.jpg) (http://www.flickr.com/photos/wavedealer/8075197059/)


Here is a shot of the U67 body in a screw on shockmount

(http://farm9.staticflickr.com/8330/8075191480_ca002d7a41.jpg) (http://www.flickr.com/photos/wavedealer/8075191480/)


Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on October 10, 2012, 06:04:41 PM
 ;D Wow Dave it almost looks finished! :P

Much better pics then mine by they way! Very clear.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Dylan W on October 10, 2012, 06:59:30 PM
Thanks for the pics everyone, the Amphenol seems nice. Glad there's a screw-on option available. This build is looking better and better--can't wait to start mine.

Dylan
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 10, 2012, 07:08:46 PM
Just added the picture from from the WM in term of railing validation, it explains a bit better the basic board setup,

Thanks,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on October 10, 2012, 11:29:28 PM
Hi all, I posted this in my capsule thread awhile back but I thought it may be valuable here as well.
So I have been lucky enough to be the very first Poctop u67 builder, Let me say a big thanks to Poctops tireless efforts the guy is truly a freak and deservers nothing but our admiration!! So as soon as I finished my 67 build I started work on tweaking my capsule. After a good week of effort I feel I have what I think is pretty close to the original sound of the Neumann k67 capsule. The first is me playing guitar pretty badly  :P I am a drummer by trade! 312 pre amp in to my fireface at 24 bit 44.1. Second is my very nice wife. Same setup with a pop screen, the third is a voice over test I did again same 312 to fireface setup. I also have some build pics as well. Enjoy!!

https://dl.dropbox.com/u/55530129/acoustic.wav
https://dl.dropbox.com/u/55530129/female%20vocal.wav
https://dl.dropbox.com/u/55530129/voiceover.wav

(http://i280.photobucket.com/albums/kk187/tskguy/20120902_084016.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120902_084039.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120902_084103.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120902_084122.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120902_084208.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120902_084242.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120902_084352.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120903_114135.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120903_114203.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120903_114219.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120903_114233.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120903_114304.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120903_114318.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120903_114338.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120903_114709.jpg)
(http://i280.photobucket.com/albums/kk187/tskguy/20120903_114727.jpg)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: burglar on October 13, 2012, 11:15:14 AM
What a great sounding mic you have there TSKGUY.  Really picks up the body of everything effortlessly.  Great clarity in the mid range and low mids without being peaky.  Sounds expensive!

Very impressed

Big respect you you as well poctop!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: adeptusmajor on October 13, 2012, 11:32:36 AM
Looks great, Sounds great....

Nice work.

Hopefully I can get around to building my pair before too long.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on October 13, 2012, 12:03:02 PM
Thanks for the kind words guys,  I am very happy with the way it sounds. I can't wait to see some more folks finishing these up!
I am feeling a bit lonely.
Eric :)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: burglar on October 13, 2012, 03:06:58 PM

Does anyone know if you can build the U67 into a Behringer B2?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 13, 2012, 03:17:04 PM

Does anyone know if you can build the U67 into a Behringer B2?

Yes, No you can't,
D.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on October 15, 2012, 05:23:19 PM
I have a Neumann k67. I would have to strap the backplates together, right?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 15, 2012, 05:28:33 PM
I have a Neumann k67. I would have to strap the backplates together, right?

If you have a K67 the 2 individual backplate are short togheter ( you can actually test this with a DMM) and that is what you need for the U67 project
So only 3 connection ( backplate - front D and Back D,)
Hope this helps,
dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on October 16, 2012, 01:35:43 PM
Finished the first one! The 30 dollar Tungsol tube from thetubestore.com turned out to be dead quite and has been burning all night. The Telefunken that has been rolling around in a drawer for years had me thinking I had done something wrong at first. I think I may want to increase the feedback a bit but have to do some recordings first. I will follow up with my impressions soon. I really need to find a counter weight for that old Atlas stand because the mic is heavy enough to kill normal stands.
Thanks again for all your work Dan!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 16, 2012, 02:43:43 PM
 :)Cool , any pic in the pipe
Dan
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: kpearsall on October 16, 2012, 07:19:33 PM
I noticed this was brought up, but never directly addressed in the thread. I've finished my power supply, and it seems to be working great. Testing it unloaded gets me over 300VDC with the B+ trimmer all the way down. Can anyone verify this as normal? Still waiting on capsule and transormer for the mic, so nothing to hook it up to as of yet. Thanks


Ken
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on October 16, 2012, 07:39:36 PM
Sounds like you may not have that 56k resistor installed in series with the pot.
Mine is running 245v unloaded.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: kpearsall on October 16, 2012, 07:43:40 PM
DOH! you're right. For some reason I spaced it. Will throw that in and clean up my wiring a bit.

Beezneez capsule on it's way, I'll order Max's transformer soon and start the testing with pics and sound samples



Ken
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 16, 2012, 07:59:08 PM
Mine was running 320 vdc unloaded so it seems fine to me
Happy to see that some of you will have a 67 running soon
You can tweak that serie resistor to get what you need but the 56k should do the trick
Dan
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on October 17, 2012, 12:14:28 AM
Did a shootout  between the 67 and one half of my sm2 tonight. The competition was fierce! Both great tools, the sm2 was smokey and the 67 was much more articulate, more air. Just what I wanted! But they were out of phase. Have to find out which one now. I'll put the 67 up against a bunch more mics tomorrow - majority rules.
I found that a 47k resistor on the series plate pot put the pot in a more useful position, but it might just be my tube.
Dan, there are two post sets labeled LC and IS, LC is a switch hookup. Does IS represent S2 on the Neumann schematic? Should IS be open or closed.
Keep up the good work, this is a great project,
Pete
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 17, 2012, 12:35:10 AM
I noticed this was brought up, but never directly addressed in the thread. I've finished my power supply, and it seems to be working great. Testing it unloaded gets me over 300VDC with the B+ trimmer all the way down. Can anyone verify this as normal? Still waiting on capsule and transormer for the mic, so nothing to hook it up to as of yet. Thanks


Ken

yeps ,  if you have used the Triad 230V I had close to 320VDC with the pot in one direction dont recall wich one tough,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 17, 2012, 12:58:42 AM
Did a shootout  between the 67 and one half of my sm2 tonight. The competition was fierce! Both great tools, the sm2 was smokey and the 67 was much more articulate, more air. Just what I wanted! But they were out of phase. Have to find out which one now. I'll put the 67 up against a bunch more mics tomorrow - majority rules.
I found that a 47k resistor on the series plate pot put the pot in a more useful position, but it might just be my tube.
Dan, there are two post sets labeled LC and IS, LC is a switch hookup. Does IS represent S2 on the Neumann schematic? Should IS be open or closed.
Keep up the good work, this is a great project,
Pete
Thanks Pete Glad this is coming along
Question 1) What is a half of a SM2 ?  i am not sure i know which mic it is Let me know ,

And the LC is indeed the Low Cut Switch hookup and the IS = internal switch S2 you are correct ,
i think it linerarise when out, the low cut region for broadcast app , according to the schemo it is close by defautls, know i have tried it in the validation and it works,  here is the comments from the U67 manual regarding this,  So Basically if you need less bass and steeper low cut behavior make sure you have the jumper in , if not leave it open ,
Let me know if it helps,
Best,
Dan,




Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 17, 2012, 01:01:06 AM
Here is the Doc in question,
Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dandeurloo on October 17, 2012, 01:40:49 AM
Dan, I take it the 560R in the BOM is for R9 (536r) on the PSU.

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 17, 2012, 01:57:38 AM
Dan, I take it the 560R in the BOM is for R9 (536r) on the PSU.

Correct,
Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on October 17, 2012, 06:18:36 AM
Quote
So Basically if you need less bass and steeper low cut behavior make sure you have the jumper in , if not leave it open

This, along with de-emphasis of the pre-emphasized capsule, separate feedback winding etc., is one of those things that make a U67 what it is. After the U47, there was demand for a studio LDC with less proximity and less popping. The built-in 40Hz low cut (not to be confused with the 200Hz low cut switch on the body), among other things, makes it a singer's microphone. Without the jumper, it will be more suited for orchestral work, or recording a large pipe organ for instance, but it will be less what a U67 is typically known for IMO. And for the other purposes, many would likely pick a couple of omni Schoeps or something of the sort, anyway.
But yes, it's nice to have the option.  :)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on October 17, 2012, 12:35:41 PM
Thanks guys, that's what I thought.
The SM2 is an early Neumann stereo sdc tube mic.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 17, 2012, 01:09:04 PM
What value did you guys use for r20? I didn't have a 60 ohm in my mouser order and I don't see one in the bom. I did have an extra 60m though. Maybe a mistake in the bom? Anyone have a part number? I did a quick search and it turned up a bunch of values around 60r, nothing spot on though.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 17, 2012, 02:38:58 PM
What value did you guys use for r20? I didn't have a 60 ohm in my mouser order and I don't see one in the bom. I did have an extra 60m though. Maybe a mistake in the bom? Anyone have a part number? I did a quick search and it turned up a bunch of values around 60r, nothing spot on though.
Use the 56r in the mic bom this resistor is in the calibratio line so it will not have any impact on the sound more like the reference preamp data checks
It should be in the BOM
Hope this helps
Dan
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 17, 2012, 03:13:17 PM
What value did you guys use for r20? I didn't have a 60 ohm in my mouser order and I don't see one in the bom. I did have an extra 60m though. Maybe a mistake in the bom? Anyone have a part number? I did a quick search and it turned up a bunch of values around 60r, nothing spot on though.
Use the 56r in the mic bom this resistor is in the calibratio line so it will not have any impact on the sound more like the reference preamp data checks
It should be in the BOM
Hope this helps
Dan
Ok, thanks again Dany
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 19, 2012, 04:17:16 PM
Any Build  O uthere  :-X ?
 :) ;)

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on October 19, 2012, 09:25:06 PM
This has been a gripping thread the last couple of days hasn't it? :P
I'll contribute; I have found that my du67 is out of phase with the rest of my mics but I haven't spent any time to try to figure it out other than recheck the xlr.  Just mentioning so everybody checks.
To anybody that thinks they will save some time and use the swithc PCB that came with the case - don't. That grounding on Dan's PCB is needed. It's easy enoung to jump one in but it's not as clean.
I've ordered some telefunkens from Germany, Mouser is sending me another Triad, (first one was bad) so in a week or two I'll have my pair. Tomorrow night marks the first session with the first one and I'm excited to hear it in the mix. From all the testing I've done so far the thing that stands out the most in the mic is the sound stage clarity. It seem to have more than it's mono send.
After the session I might decide to increase the feedback or pull the switch 2 jumper. I love that there is so much you can do to tune this mic.
Hope all the builds are going well,
Pete
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: kpearsall on October 19, 2012, 10:01:38 PM
My build is going great, just on hold waiting for capsule and transformer to show up. All wire used is silver teflon, AC input and trimmers wired with cloth covered silver teflon because it looks cool, and was nice and thick  ;D

Mic PCB itself was quite fun to build! I'm even a little proud of how neat I was able to keep it following Dany's pictures. Looking forward to building the second one, but next time I'll be ording the cap and transformer FIRST! haha

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on October 19, 2012, 10:10:19 PM
Can I ask what cap you selected?
I don't know what silver teflon is but it sounds cool.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: kpearsall on October 19, 2012, 10:14:03 PM
I'm getting the BeezNeez capsules for my 67's. They haven't shipped yet but I know they will be worth the wait.

The wire I'm speaking of, is silver coated copper wire, with a teflon insulation. Expensive, but if you only need a few feet of it, why use the cheap stuff?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 19, 2012, 10:47:55 PM
This has been a gripping thread the last couple of days hasn't it? :P
I'll contribute; I have found that my du67 is out of phase with the rest of my mics but I haven't spent any time to try to figure it out other than recheck the xlr.  Just mentioning so everybody checks.
To anybody that thinks they will save some time and use the swithc PCB that came with the case - don't. That grounding on Dan's PCB is needed. It's easy enoung to jump one in but it's not as clean.
I've ordered some telefunkens from Germany, Mouser is sending me another Triad, (first one was bad) so in a week or two I'll have my pair. Tomorrow night marks the first session with the first one and I'm excited to hear it in the mix. From all the testing I've done so far the thing that stands out the most in the mic is the sound stage clarity. It seem to have more than it's mono send.
After the session I might decide to increase the feedback or pull the switch 2 jumper. I love that there is so much you can do to tune this mic.
Hope all the builds are going well,
Pete

Thanks Guys For all your inputs,  can't wait to see more and hear more about ya  ;D

Regarding the out of phase thingy ,  must be a simple thing ,
the only confusing part but you probably check that already is that the german pin 2 is our pin 2 and the german pin 1 is our pin 3 and the german pin 3 is our pin 1 ,
check the Schemo of the power supply it actually show the inversion already made and mic togheter and trace those to the Transfo to make sure it is in the right order, the tuchel and cannon are not the same and depending on number and times also the hot and cold differs also,
Keep us posted,

thanks Again Guys,
Dan.,  :)

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 20, 2012, 12:23:49 AM
What value did you guys use for r20? I didn't have a 60 ohm in my mouser order and I don't see one in the bom. I did have an extra 60m though. Maybe a mistake in the bom? Anyone have a part number? I did a quick search and it turned up a bunch of values around 60r, nothing spot on though.

how many 60M had you , there is 3 used in the mic , R2, R9, R16,
also In the PSU  there is one of 56R For R20 Best,
Cheers,
Dan,
 
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on October 20, 2012, 01:34:49 AM

Thanks Guys For all your inputs,  can't wait to see more and hear more about ya   

Regarding the out of phase thingy ,  must be a simple thing ,
the only confusing part but you probably check that already is that the german pin 2 is our pin 2 and the german pin 1 is our pin 3 and the german pin 3 is our pin 1 ,
check the Schemo of the power supply it actually show the inversion already made and mic togheter and trace those to the Transfo to make sure it is in the right order, the tuchel and cannon are not the same and depending on number and times also the hot and cold differs also,
Keep us posted,

thanks Again Guys,
Dan., 

Thanks for this Dan,
Check it out! I didn't know that! As soon as my reading mind comes back I'll look into it.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 21, 2012, 03:31:13 PM
Merged info tht was on wM ,
Thanks, :)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 23, 2012, 08:50:04 PM
What value did you guys use for r20? I didn't have a 60 ohm in my mouser order and I don't see one in the bom. I did have an extra 60m though. Maybe a mistake in the bom? Anyone have a part number? I did a quick search and it turned up a bunch of values around 60r, nothing spot on though.

how many 60M had you , there is 3 used in the mic , R2, R9, R16,
also In the PSU  there is one of 56R For R20 Best,
Cheers,
Dan,

Just noticed this question. I will check first thing tomorrow and post back.

I am surprised that no one has posted any build pics yet. I found a local powder coating company that quoted me $15-40 for two mikes, depending on the colors I choose. I'll post some pics as soon as I get them done. Hopefully by then the capsules will arrive. I'm thinking of maybe getting the head baskets and retainer rings chromed as well.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 24, 2012, 12:23:53 AM
Quote
I am surprised that no one has posted any build pics yet.
+1  ;)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 24, 2012, 02:13:08 PM
Just added a note on using the aMI adaptor board to avoid any confusion look a the picture on the first page ,
Dany,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on October 24, 2012, 04:01:11 PM
Waiting for capsules (beesneez), transformers ( Bv-12),
bodies (chugger), parts (mouser), Got the PS cases ( grand master )

what tubes are you using?
I've been looking at old NOS telsa and telefunkun ef806(s)
matcheded pairs at 25 days delivery.

Wanna see my empty P.S.B.'s
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 24, 2012, 04:51:41 PM
Waiting for capsules (beesneez), transformers ( Bv-12),
bodies (chugger), parts (mouser), Got the PS cases ( grand master )

what tubes are you using?
I've been looking at old NOS telsa and telefunkun ef806(s)
matcheded pairs at 25 days delivery.

Wanna see my empty P.S.B.'s

I have been happpy with those
http://www.ebay.com/itm/Vintage-Amperex-Electron-Vacuum-Tube-EF86-6267-No-Reserve-/300801068578?pt=Vintage_Electronics_R2&hash=item4609240e22 (http://www.ebay.com/itm/Vintage-Amperex-Electron-Vacuum-Tube-EF86-6267-No-Reserve-/300801068578?pt=Vintage_Electronics_R2&hash=item4609240e22)
and those,
http://www.economik.com/tung-sol/ef806s-gold-ef86-6267/ (http://www.economik.com/tung-sol/ef806s-gold-ef86-6267/)

Thanks For the Offer  :),
Best,
Dan,

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: imo on October 24, 2012, 06:27:50 PM
hello,
Just jumping into first steps of power supply build.
Curious as to why the heater voltage is run on a negative rail. I understand that the tubes don't care regardless, as long as they get the right amount, but just hadn't seen that before
Thanks
Ian
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on October 24, 2012, 07:07:29 PM
I asked the same question, and the answer is. Because Neumann did it that way!! The microphone and power supply are 100% true to the original circuit.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 24, 2012, 07:15:58 PM
hello,
Just jumping into first steps of power supply build.
Curious as to why the heater voltage is run on a negative rail. I understand that the tubes don't care regardless, as long as they get the right amount, but just hadn't seen that before
Thanks
Ian

It is just a matter of reference,  the only answer i could figure out to this question was to permit the electron to say hello to each other travelling down the line  8), or .......
Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ioaudio on October 24, 2012, 07:30:37 PM
Actually the biasing of the tube is derived from the negative voltage, so yes, it's important.

-max
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 24, 2012, 08:10:33 PM
Actually the biasing of the tube is derived from the negative voltage, so yes, it's important.

-max

Indeed ,  ;)
 
thanks Max
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: imo on October 26, 2012, 12:44:10 PM
Its funny. In looking at the schematic, i didn't even notice the negative heater rails until i was about to start building. My eyes saw what they wanted to see.
My power supply seems to be in good working order. I put some test points on the back panel.
I am around 250V B+, and -9V H unloaded. Does anyone know what the load of the mic circuit is, and for grins, how to figure that? would we just be looking at the plate load of the EF86 through the BV12?
Ian
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 26, 2012, 01:09:50 PM
Its funny. In looking at the schematic, i didn't even notice the negative heater rails until i was about to start building. My eyes saw what they wanted to see.
My power supply seems to be in good working order. I put some test points on the back panel.
I am around 250V B+, and -9V H unloaded. Does anyone know what the load of the mic circuit is, and for grins, how to figure that? would we just be looking at the plate load of the EF86 through the BV12?
Ian

Might be something wrong with you H-  there is a Zener over there in that section and if i remember well when there is no load the we should see the Zener regulated voltage trough it at about -16V ,  did you use   check back the schemo just to make sure,
Thanks
Dan,

Edit: Just Measured my power Supply to give you an idea , so 250VDC unloaded for the plate is what i have when my conditions are met with the mic eventually plugged in,

Regarding the Heater Voltage it should read -16V ish when no mic is connected,
I attached a picture of my psu just so you can have a visual cue if somthing is not right,




Title: Re: D-U67 Tube Microphone Build Thread.
Post by: imo on October 26, 2012, 02:02:03 PM
I did the 56k series. Using the Triad. Actually getting closer to 240v unloaded with the pot opened up. I can trim it down from there. The heater voltage is around -16. Sorry. I wrote that on memory, which was a bit off. I am not able to trim the heater voltage without a load. Is that ok?
Do you know the load of the circuit?
Thanks
Ian
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 26, 2012, 02:09:46 PM
I did the 56k series. Using the Triad. Actually getting closer to 240v unloaded with the pot opened up. I can trim it down from there. The heater voltage is around -16. Sorry. I wrote that on memory, which was a bit off. I am not able to trim the heater voltage without a load. Is that ok?
Do you know the load of the circuit?
Thanks
Ian

Ouff ! , Memory can play tricks isnt

Quote
I am not able to trim the heater voltage without a load. Is that ok?
Correct you need the mic ( Load)  plugged in for that , it draw about 200ma for heater current ,


 
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 26, 2012, 03:27:07 PM
Here is a great post from Gus, ( thanks Gus).
basically you follow ohms law and power law  ;)

http://www.groupdiy.com/index.php?topic=21696.msg256063#msg256063 (http://www.groupdiy.com/index.php?topic=21696.msg256063#msg256063)

http://www.groupdiy.com/index.php?topic=37428.0 (http://www.groupdiy.com/index.php?topic=37428.0)

Just make sure you get the right Wattage with the resistor you are using if any, but it looks like your allset to go

Quote
People

This is a very short example.  Building a load for a power supply should be a meta or sticky better written than this.

  I often power up a just built or worked on  power supply on a simple resistive load bank.  This can save the circuit that you just built  from overvoltage 

  You need to know how to use ohms law and DC power.

Lets say a G7 go to the spec sheets and find the fil current and voltage
Use Voltage 6.3 VDC and current .2 amps to start

a resistor to sub for the heater would be 6.3/.2 for 31.5 ohms use a 33ohm it is close enought.
Next you know the current and voltage so voltage  X current = DC power
6.3VDC X .2amps =1.26watts

33 ohms at 2 watts
 or three 100 ohm in parallel at .5watts for 33.3 ohms at 1.5watts.

Now if you underheat the voltage and current will be a little different but this should be close  for a load test of the power supply

Simple stuff

Then do the B+.  One way, Look at the cathode voltage divide the cathode resistor voltage by the resistor value this should be very close to the plate current.  Or you could use the voltage drop across the plate R

Then calculate the capsule voltage divider and pattern resistors total value and then that value current at the rated B+

Add up the currents and calculate the needed resistor value and wattage.


Ripple you will need a scope for.

Hope this helps,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dandeurloo on October 27, 2012, 06:14:45 PM
Hey Guys I have the first of 2 PSU's built up.  I am getting -16v on the heaters and a range about around 250v on the B+.  So I think I am as far as I can go on this until I get some bodies and capsules. 

Here is a picture of how I did mine with one of my cases.  The mounting brackets are just some stuff I picked up a while ago at home depot for something else.  Those even had holes in them already so I didn't have to do to much drilling.  Seems to work nicely.


(http://www.collectivecases.com/images/Vintage%20PSU/1000w/DU67-PSU.jpg)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: bkbirge on October 28, 2012, 02:38:53 PM
^------- nice mounting solution for the trimmers, that would give me confidence in trimming while it's turned on.

Is everyone using the capsule mounts from Peluso? I've got everything to start a pair of builds but the mounts. Was there a group buy for mounts somewhere?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on October 29, 2012, 08:20:12 AM
These look nice as well but may be a bit pricey,

http://www.thiersch-mic.de/en/estm_produkte.html
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dandeurloo on October 29, 2012, 11:46:23 AM
I used the Peluso for my 87's and I have original capsule in those.  It worked great.  I have a pair of BeesNeez coming and I am not sure what will work with those for mounting.  If they don't come with one I will be getting Peluso mounts.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 29, 2012, 01:26:05 PM
I used the Peluso for my 87's and I have original capsule in those.  It worked great.  I have a pair of BeesNeez coming and I am not sure what will work with those for mounting.  If they don't come with one I will be getting Peluso mounts.

All of our capsules come with capsule saddle and mounting post, which are usually valued at $79. The Capsules will ship in a hard plastic case to protect them during shipping.  As with all of the BeesNeez Microphones they are manufactured in the BeesNeez Microphones factory on our property in NSW Australia.

In order to view and purchase the above options. Please visit our secure page attached to our facebook page. I have set up a category just for you, showing your reduced rates. Please feel free to email or PM me if you have any questions.

http://www.facebook.com/BeesNeez?v=app_139114646178872&app_data={%22transaction%22:%22viewcategory%22,%22id%22:%2201e59bdb-2a8f-503d-ae30-7270a877f16f%22}

Kind Regards,
Veronica Sneesby
Beesneez Microphones
www.beesneezmicrophones.com.au
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 30, 2012, 03:10:53 PM
What value did you guys use for r20? I didn't have a 60 ohm in my mouser order and I don't see one in the bom. I did have an extra 60m though. Maybe a mistake in the bom? Anyone have a part number? I did a quick search and it turned up a bunch of values around 60r, nothing spot on though.

how many 60M had you , there is 3 used in the mic , R2, R9, R16,
also In the PSU  there is one of 56R For R20 Best,
Cheers,
Dan,

Just noticed this question. I will check first thing tomorrow and post back.

I am surprised that no one has posted any build pics yet. I found a local powder coating company that quoted me $15-40 for two mikes, depending on the colors I choose. I'll post some pics as soon as I get them done. Hopefully by then the capsules will arrive. I'm thinking of maybe getting the head baskets and retainer rings chromed as well.

Ok, everything was correct in my order and builds, so far. I combined the psu, d67, and 87 into one mouser order, and it made things a little confusing. Thanks!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on October 30, 2012, 10:48:30 PM
Hello fellow builders,
I still have to build my PSU but I wanted to let everyone know that Eric (tskguy) came by with his PSU and my AMI DU67 is ALIVE!!!!!
It works perfectly (all patterns) and sounds great except for the fact that I'm still waiting for my HK-67 capsule so I have a Chinese K-67 in there for testing that has way too mush 4-7K response.
PSU components are on the way. I'll have it built up this weekend and then I'll be able to finish up my build manual.

Great project but not the easiest one to do. It's very satisfying to have the mic work right out of the block tho.

Dave

pics and sound samples coming...
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on October 31, 2012, 02:40:16 AM
Awesome! Are you guys still thinking of doing a build guide?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on October 31, 2012, 09:12:34 AM
What is the calibration input used for?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: bkbirge on October 31, 2012, 10:15:39 AM
Awesome! Very much looking forward to the build guide, my understanding is that correct component placement is critical for the sound on this build. Going to have to make sure my wiring is extra pro on this one.

Hello fellow builders,
I still have to build my PSU but I wanted to let everyone know that Eric (tskguy) came by with his PSU and my AMI DU67 is ALIVE!!!!!
It works perfectly (all patterns) and sounds great except for the fact that I'm still waiting for my HK-67 capsule so I have a Chinese K-67 in there for testing that has way too mush 4-7K response.
PSU components are on the way. I'll have it built up this weekend and then I'll be able to finish up my build manual.

Great project but not the easiest one to do. It's very satisfying to have the mic work right out of the block tho.

Dave

pics and sound samples coming...
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on October 31, 2012, 01:28:22 PM
What is the calibration input used for?

It's for checking the frequency response of the amplifier. You feed a 600ohm 1K tone at -18 into it and measure the output.
The old owner's manual has the info in it.

bkbirge - it's def necessary in the HiZ section to make sure your work is nice and tidy. There's a lot of floating components and not much space up there in the AMI build (there's much more room in the ioaudio build)

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on October 31, 2012, 01:53:01 PM
Quote
It's for checking the frequency response of the amplifier. You feed a 600ohm 1K tone at -18 into it and measure the output.
The old owner's manual has the info in it.

Thanks - it's not for calibration as much as a test, apparently. A BNC jack would make the most sense if installing, I suppose.
I found this info in the manual for others who are interested:

"For purposes of checking the frequency response of the amplifier, a test signal may be fed to the instrument jack marked "calibrating input" at one end of the power supply. Proceed as follows: From the 600 ohm output of a signal generator, feed a 1000 cps tone at a level of -18 dbm to the calibrating input. You may use the model z-58 dummy head or can proceed with the regular head assembly plugged in. The three switches are set for "omni", full sensitivity, and linear frequency response. The following output levels are to be observed at the output of the 150/250 ohm impedance, using a vacuum tube voltmeter:

1000 cps:    -38dB     1dB
40 cps:        -43dB     1dB
1500 cps:   -48dB      1dB
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 31, 2012, 02:00:06 PM
Quote
It's for checking the frequency response of the amplifier. You feed a 600ohm 1K tone at -18 into it and measure the output.
The old owner's manual has the info in it.

Thanks - it's not for calibration as much as a test, apparently. A BNC jack would make the most sense if installing, I suppose.
I found this info in the manual for others who are interested:

"For purposes of checking the frequency response of the amplifier, a test signal may be fed to the instrument jack marked "calibrating input" at one end of the power supply. Proceed as follows: From the 600 ohm output of a signal generator, feed a 1000 cps tone at a level of -18 dbm to the calibrating input. You may use the model z-58 dummy head or can proceed with the regular head assembly plugged in. The three switches are set for "omni", full sensitivity, and linear frequency response. The following output levels are to be observed at the output of the 150/250 ohm impedance, using a vacuum tube voltmeter:

1000 cps:    -38dB     1dB
40 cps:        -43dB     1dB
1500 cps:   -48dB      1dB

That is correct , they remove it at some point after 1963.  here is the 1963 Manual with  info about the U67  Preamp Checkup.
Thanks Guys,
Dan, 

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: kante1603 on October 31, 2012, 02:49:29 PM
1963.....hmmmmmm....must be a good piece of gear.......the year I was born....... ;D
Even the month is correct......
Udo.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: franckboxe on October 31, 2012, 03:09:19 PM
i have an original power supply  NU 67 Neumann (but not the mic) ,
do you think i could use it with the D-U67 Tube Microphone ??

thanks
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 31, 2012, 03:35:41 PM
i have an original power supply  NU 67 Neumann (but not the mic) ,
do you think i could use it with the D-U67 Tube Microphone ??

thanks

Absolutely  ;)  Just make sure to check the cable configuration from the psu to the mic
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on October 31, 2012, 03:49:18 PM
Congrats to Wave for is really nice build 8) , Dave was involved at the very first stage of the developpment of the D-U67 microphone as you can see that he has etched his own adaptor board,  I was allowed to post picture of his new toy,  Keep us posted,  I do like the AMI transformer look  8)

(http://dl.dropbox.com/u/43869772/U67/AMIA.JPG)
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993933.jpg)
Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on November 01, 2012, 04:30:15 PM
D-U67 Build Folder.zip updated. added document manual 1963 and some tube socket suggestion in the U67doc
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on November 02, 2012, 05:28:59 PM
Hello peoples,
So I've got all my PSU parts. I had forgotten to add a power switch to my BOM (I'm using a custom BOM which differs slightly form the one Dany posted on page one)
SO I ran over to the shack and got one. It was only $3.20 and comes with that cool metal on/off label.

I am using the Hammond 513-0900
http://www.mouser.com/Search/ProductDetail.aspx?R=513-0900virtualkey54600000virtualkey546-513-0900

I decided to machine my own case instead of buying the collective cases PSU box because I want to use the amphenol connectors on the mic, cable, and PSU. Also because while doing the machining is a pain in the arse, I can do the layout of the components however I want, and I want to have the power transformer mounted vertically on the back panel.

So all that being said do you guys want me to include a layout template for the PSU components in the build manual?

Let me know what you think
Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on November 02, 2012, 08:15:05 PM
Hey guys, I thought that I'd share my unfinished builds. Just waiting on caps and calibration.
Some pics are blurry, sorry.

(http://i875.photobucket.com/albums/ab314/Volume11/694EA9BF-1494-4DBE-89A1-BA619FF656AC-1236-0000025D134308E5.jpg)

(http://i875.photobucket.com/albums/ab314/Volume11/45DFD56B-38E6-4CCC-884A-F12EB77CE17C-1236-0000025D2081C15D.jpg)

(http://i875.photobucket.com/albums/ab314/Volume11/F4365DC1-48C5-4B85-BD48-21A83B14D9C6-1236-0000025D2FC1CB0A.jpg)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on November 02, 2012, 08:19:35 PM
(http://i875.photobucket.com/albums/ab314/Volume11/ED733C83-B815-49BB-9899-9FA494ADFE30-1236-0000025D4870082F.jpg)

(http://i875.photobucket.com/albums/ab314/Volume11/834FB294-CDF2-4EB7-8FD8-39834A92AC44-1236-0000025D3DA49E59.jpg)

(http://i875.photobucket.com/albums/ab314/Volume11/823B802E-EED4-4304-A4ED-5DB6E86AB216-1236-0000025D532C8F3A.jpg)

(http://i875.photobucket.com/albums/ab314/Volume11/CAFD483A-0A48-419B-AE4B-0F1176FCE156-1236-0000025D6545595F.jpg)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on November 03, 2012, 01:54:12 AM
Awsome Duo of Lolly-pops, Kudos  8),  congrats for the build very nice  ;) ,
Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on November 06, 2012, 06:29:35 PM
All Pcb available now,
Thanks ,
dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on November 07, 2012, 06:10:34 PM
beware of this , it has been discussed earlier in the thread and just want to warn again everybody on this,

Important Note
The only 2 parts that is not (Europe 230V) compatible is the hammond 20VAC and the PSU pilot Lamp wich is 120V everything else is fine except the fuse will need to be 0.1A instead of a 0.2A for north America, you will need a minimun 6VA traffo for the filament side,
alternative part number are discussed in this thread here : http://www.groupdiy.com/index.php?topic=49675.20 (http://www.groupdiy.com/index.php?topic=49675.20)

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on November 07, 2012, 09:01:54 PM
I thought I would throw up a photo of my PSU

(http://farm8.staticflickr.com/7108/8165637536_6dbf97f082.jpg) (http://www.flickr.com/photos/wavedealer/8165637536/)

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on November 07, 2012, 09:48:07 PM
Tease  ;)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on November 08, 2012, 04:04:40 PM
I thought I would throw up a photo of my PSU

(http://farm8.staticflickr.com/7108/8165637536_6dbf97f082.jpg) (http://www.flickr.com/photos/wavedealer/8165637536/)

Dave

Hey Wave ,  awsomely clean build here , your are not raising the bar you are the bar ,
nice stand for the pots   8)

best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on November 08, 2012, 07:38:51 PM
Thanks Dany!
I plan on working on the build manual this weekend. I have around 220 pics of my build.

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on November 09, 2012, 11:05:02 PM
Got to say that pot holder/shield idea is inspired.
I have been experimenting with tubes and different sides of my k67's. My gosh, those 2 items are supper critical. The best combo I have is a Tungsol with a Steven Paul reskin. All the tubes have a big difference, not counting the noise. It's like how many doors are between you and the source.  I've tried 3 nos Telefunken tubes and they are all bad, money down the drain. Maybe they have been all picked through. Thinking I got to pull the trigger on some $65 tubes with the return option or maybe another Tunsol.  I'm trying to decide about new Neumann caps or a reskin of my old Neumann's. I feel like I'm almost there. The amp is fine, I only need to compliment them with a great tube/cap duo to reach the promise land. Luck to all!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on November 10, 2012, 05:22:57 AM
Thanks KFH.
Good to hear your opinion about the Tung-Sol tubes. I was thinking of getting one of those myself.
Have you considered Eric (tskguy) for you reskin? Eric's current production capsules are looking great. He showed me one the other day that was freshly finished and it was, for lack of a better term, a work of art. F***in beautiful. I'm anxiously awaiting mine!

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on November 10, 2012, 01:30:22 PM
I,ve been hearing good things about Eric. Thanks for that vote.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: pasi_k on November 11, 2012, 05:11:28 AM
Does anyone have a list of suitable donor bodies?
How about t-bone sct700? for example.
there is plenty of them offered as second-hand.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on November 12, 2012, 10:17:23 AM
Hello fellow builders,
So yesterday I went over to Eric's (tskguy) house. He was kind enough to do some machining to a front panel for a 500 series module racking project I'm doing. We had a period of time where we couldn't run the CNC because of his daughter's nap. So Eric said "sit down and check this out"
He then proceeded  to skin 2 of his HK-67 backplates and then assemble a capsule for me. I had brought my DU67 over so we could do some test recordings shootout style (his DU67 and mine).
First let me say again that his capsules are works of art. To sit and watch while he skinned and tuned them by hand was super cool. We had already done some test recordings of my mic with an ISK K67 capsule in it (I had this from gutting a BM-600 for a DU87 project)
The ISK capsule, for lack of a better description, sounded "Chinesey". Loads of hi mid response - very essey and would probably need some band compression in a mix to sit right.
We then installed his capsule in the mic. It's night and day. The HK-67 sounds absolutely amazing. Rich lows and silky highs with the sweetest midrange. A very good match to my AMI transformer.

I couldn't be happier with my mic. It looks and sounds wonderful - it's a great DIY project. Not something I would recommend for a new builder, but not super difficult either.
If anyone is on the fence about whether or not to invest in one of Eric's capsules, don't be. For $200 it's a steal. You won't be disappointed.

Dave
p.s. For the record, while Eric might be my friend, I wouldn't endorse anything that didn't meet my standards. This is the best compliment I can give.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on November 12, 2012, 12:42:35 PM
I would have loved to be there. I have always wanted to know what involved in tuning a cap, or a ribbon.  How long did it take?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Delta Sigma on November 14, 2012, 12:26:37 AM
Waiting on my capsule, body and a few resistors that were back-ordered from Mouser.

In the meantime I thought I'd post a photo of my mostly completed power supply. I made quite a few mistakes on this one since I'm trying to get renos done and when I should be sleeping, I find myself soldering.

I didn't think when I positioned the low voltage transformer and ended up having to turn the IEC housing upside down (no big deal). I then decided just to mount the toroidal transformer to the case (just to get it done), only to find an unused rack ear to mount it to, leaving me with a hole on the side of the case. Lastly, I only realized after I took a photo of this thing, that I put the lamp on the power switch side instead of the mic connector side. If I'm ambitious when I calibrate this thing I move it over.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Delta Sigma on November 14, 2012, 12:35:18 AM
Since I've made enough mistakes on the power supply, I suppose I should post a photo of my in-progress mic so you guys can set me straight!

Am I on the right track with the hi-Z section? I haven't been reading the forums as close as I should be for this build but I did read that the hi-Z section should be suspended above the circuit board. I did not read the theory on this so I'm not confident that I did it correctly.

I'm waiting on a tube socket and will place the remaining components once the socket and my back-ordered resistors arrive.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Delta Sigma on November 14, 2012, 12:45:46 AM
Another view of the mic in yet another post. I don't have a clue on how to post multiple pictures in one post.

One more question: I have been using Teflon that I've stripped from wire to insulate the leads of the floating components. Can this cause any problems?

I read on another forum that using solid wire can cause microphonic noise, I assume the writer was referring to the leads to the capsule but they made reference to a stubborn tech that still uses solid Teflon-coated wire in mics even though it's well known that it is not a good choice. The wording they used made me think that the Teflon could also be a problem.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on November 14, 2012, 11:12:08 PM
I think I read that. Klaus talking about a picture of a mic with solid wire to the capsule!  That is not referring to the mic build itself. I wouldn't worry solid strand in  the hi-z, I didn't. I also have teflon in those positions. Looks to me like your doing fine. But I'm not Klaus. I am trying to decide whether to get a re skin of my k67's or pull the $1400 trigger for Neumann skins because Klaus said there is no substitute. :-X
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on November 14, 2012, 11:59:19 PM
ktfstudio

By the way I am thee American microphone guru and you should for sure have your capsule reskined by me!! I will do it for the low price of 600 dollars.

I am kidding of coarse but I hope you get my point, Klaus has a good reputation but please keep in my mind your ears are the ultimate decider.  Let me reskin it, I am pretty sure you will be satisfied. PM me I will give you a price. And trust me its way under 1400!!!

tskguy
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Delta Sigma on November 15, 2012, 12:18:19 AM
$1400? If it were me I'd rather do another DU67 build for that much money! I think my total build costs are roughly around $1300 CAD, using the Beesneez capsule. You could put the money you save towards another build using a Beesneez capsule or one from tskguy.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on November 15, 2012, 07:33:19 PM
Waiting on my capsule, body and a few resistors that were back-ordered from Mouser.

In the meantime I thought I'd post a photo of my mostly completed power supply. I made quite a few mistakes on this one since I'm trying to get renos done and when I should be sleeping, I find myself soldering.

I didn't think when I positioned the low voltage transformer and ended up having to turn the IEC housing upside down (no big deal). I then decided just to mount the toroidal transformer to the case (just to get it done), only to find an unused rack ear to mount it to, leaving me with a hole on the side of the case. Lastly, I only realized after I took a photo of this thing, that I put the lamp on the power switch side instead of the mic connector side. If I'm ambitious when I calibrate this thing I move it over.


Wow very neat build , Kudos,   

it seems you are doing very fine ,
keep on the good work can't wait to see more of those baby's for sure,

Such of a treat for me ,
Thanks ,
Best,
Dan,


Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on November 16, 2012, 12:19:55 PM
Built up the mic this weekend. Really a fun project!
I was wondering if a chassis ground connection is required? Should the chassis tab on the xlr be connected to pin 7 or 3? Using a multimeter, 7 and 3 seem to connect on the pcb.
And second question: what size screws are needed for connecting the pcb to the mic body with the cathedral pipes body? I found two that fit to get it together, but I want to order some.
Finally, the mic tube is a tight fit going on with the pcb in (I'm using max's bv12). The body is hitting the bv12. Anyone else have this problem?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on November 16, 2012, 12:43:55 PM
Built up the mic this weekend. Really a fun project!
I was wondering if a chassis ground connection is required? Should the chassis tab on the xlr be connected to pin 7 or 3? Using a multimeter, 7 and 3 seem to connect on the pcb.
And second question: what size screws are needed for connecting the pcb to the mic body with the cathedral pipes body? I found two that fit to get it together, but I want to order some.
Finally, the mic tube is a tight fit going on with the pcb in (I'm using max's bv12). The body is hitting the bv12. Anyone else have this problem?

pin 7 is 0V and pin 3 the cable and mic body shield   they join to the psu pcb only if SHLF jumper is installed on the pcb if not then you need to connect the shield pin 3 to the mic pcb this permits having 2 diefferent grounding scheme, 
Check the schematic here to better understand 

as per the xlr grounding tab it is already connected to the psu pcb at the connector (XLR-OUT pin 1) and then the PsU pcb 0V connector is to chassis so no need of soldering the chassis tab, 

the transformer should not hit the mic body, check the position of the transformer.

here is the schematic to help

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993942.jpg)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on November 16, 2012, 12:57:51 PM
regarding the hitting : sometime i had that happen where those screws get a little loose and give the impression that the transfo is stuck in the mic body but it is not ,
hope this helps,
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993955.jpg)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on November 16, 2012, 01:45:35 PM
Quote
pin 7 is 0V and pin 3 the cable and mic body shield   they join to the psu pcb only if SHLF jumper is installed on the pcb if not then you need to connect the shield pin 3 to the mic pcb this permits having 2 diefferent grounding scheme,
Check the schematic here to better understand 

OK - that makes sense. So I can choose to connect 7&3  on the mic pcb by wiring xlr p3 to the pcb (7 and 3 are always connected on the mic pcb) OR not wire p3 to the mic pcb, and install the jumper to connect 7&3 at the psu pcb. Two options for connecting audio ground to chassis ground. The original u67 schematic shows them connecting in the mic, and that p3 is connected to the casing (gehause). How does pin 3 connect to the mic body in this build? The xlr tab I was talking about was the tab on the 7p xlr in the mic. That tab connects to the body.

I did think that the screws on the sides were rubbing, but when I took the mic back apart the copper foil on the transformer had been ripped at the back corners. I'll check it's installation and see if it can go down further.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on November 16, 2012, 01:50:12 PM
Quote
pin 7 is 0V and pin 3 the cable and mic body shield   they join to the psu pcb only if SHLF jumper is installed on the pcb if not then you need to connect the shield pin 3 to the mic pcb this permits having 2 diefferent grounding scheme,
Check the schematic here to better understand 

OK - that makes sense. So I can choose to connect 7&3  on the mic pcb by wiring xlr p3 to the pcb (7 and 3 are always connected on the mic pcb) OR not wire p3 to the mic pcb, and install the jumper to connect 7&3 at the psu pcb. Two options for connecting audio ground to chassis ground. The original u67 schematic shows them connecting in the mic, and that p3 is connected to the casing (gehause). How does pin 3 connect to the mic body in this build? The xlr tab I was talking about was the tab on the 7p xlr in the mic. That tab connects to the body.

I did think that the screws on the sides were rubbing, but when I took the mic back apart the copper foil on the transformer had been ripped at the back corners. I'll check it's installation and see if it can go down further.


Quote
How does pin 3 connect to the mic body in this build? The xlr tab I was talking about was the tab on the 7p xlr in the mic. That tab connects to the body.


pin 7 and pin 3  are at the same level on the mic pcb andf the pcb ground plane hook to mic body ,

Quote
The xlr tab I was talking about was the tab on the 7p xlr in the mic

it is already grounded via the screw holder

Hope this helps,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on November 16, 2012, 03:55:45 PM
Does anyone know what size screws are needed for connecting the pcb to the mic body with the cathedral pipes body?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on November 16, 2012, 05:00:24 PM
Does anyone know what size screws are needed for connecting the pcb to the mic body with the cathedral pipes body?

IIRC those are 2mm screw but make sure you can take on and measure it to make sure,
Hope this helps,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on November 16, 2012, 05:03:29 PM
Its a 2mm screw... ;D I got mine from the local ACE hardware!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on November 16, 2012, 05:12:54 PM
Cool, thanks guys!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: kpearsall on November 16, 2012, 10:52:36 PM
I should have gone to ACE. Went to Tru Value cuz they were closer, and they "help" there instructed me which screw to use, which didn't fit, and then spent 5 minutes telling me they wouldn't have it and I needed to look elsewhere. Finally got him to go away and found it within 30 seconds.

It's like going into radio shack and asking for a balanced cable. "Uh....Sir, we only have mono and stereo"

Yes. Yes you do. Good boy.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: JessJackson on November 18, 2012, 12:36:23 PM
Is anyone making their ps regulated and filtered?

I also had the idea of adding the potentiometers and Voltmeters to the outside of the case to fine tune the Voltages from location to location as input voltages vary from studio to studio. Taking into consideration the cable loss etc... (could be measured and calibrated)

The thought came from the fact that the heater on my c12 can fluctuate anywhere from 5.2 - 7.5 volts depending on where I use the mic.

Thoughts?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on November 19, 2012, 10:04:40 AM
There are only very few U67 "cloners" who go all the way and, like poctop, do the negative feedback, tertiary winding thing and such.
The Wunder CM67 does make an attempt. There's a thread about that microphone, at the Gearslutz forum. Over there, not everyone posts inside pictures like they would on this here DIY forum. But post #81 does offer us a peek.
Not to hijack; just to add, for those interested.
http://www.gearslutz.com/board/high-end/697529-anyone-heard-wunder-cm67-3.html (http://www.gearslutz.com/board/high-end/697529-anyone-heard-wunder-cm67-3.html)

The body seems to be a Flea 47 with their fitting, 67-ish headbasket.

Dany, if you want me to place this elsewhere, please let me know.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on November 19, 2012, 12:49:22 PM
The transformer in that Wunder mic looks very much like my AMI T67

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: funkymonksf on November 19, 2012, 03:05:33 PM
It's got to be the ami tranny! The use ami in a lot of their mics.. I think Dan has done a finer job compared to pics I've seen..
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on November 19, 2012, 04:30:09 PM
I have a good source that confirmed the tranny to be AMI! But give me a break a chinese capsule!! And that Mic is $3,895. Krripes man! >:( >:( >:(
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: kidvybes on November 19, 2012, 07:03:01 PM
I have a good source that confirmed the tranny to be AMI! But give me a break a chinese capsule!! And that Mic is $3,895. Krripes man! >:( >:( >:(

...red locktight (you know what that means) on the capsule's center terminal screw (looks just like Peluso's P-K67)...hmmm...makes me 'wunder' what the K47 capsule in their CM7-GTS looks like (more 'red' locktight?)...
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on November 19, 2012, 07:50:27 PM
I have a good source that confirmed the tranny to be AMI! But give me a break a chinese capsule!! And that Mic is $3,895. Krripes man! >:( >:( >:(

Quote
And that Mic is $3,895. Krripes man

 :o :o :o :o :o :o,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on November 20, 2012, 03:01:23 PM
I've wonder what a new 67 back in the day went for... Anyone have any ideas?

Cheers,
jb
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on November 20, 2012, 11:42:07 PM
Hello all,
I just wanted to share my thoughts on the DU67 project. I LOVE this mic. It's super sweet and sounds absolutely awesome.
Tskguy's capsules are truly works of art. Here are some tracks I threw together while doing some initial recordings after finishing the mic and installing on of Eric's capsules.
The signal flow is DU67 –> Sound Skulptor MP573 –> ProTools. I'm really digging the way these tracks sound with no eq or comp.
2 acoustic guitars and 2 vox

https://www.dropbox.com/s/43h1rvg0yqdwm7x/DU67-HK67-1073%20GUIT%26VOX.wav

I did this in about 10 min single takes on all the tracks so I'm sorry about my pitchy vox.
This mic is def going to be on all my records from now on and it's already at a colleague's studio doing the duty!

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on November 21, 2012, 06:30:36 AM
Hi all have some problem to find the body for the D67 chuckD stoped he's production so dunno where to look :p any idea about that ?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on November 21, 2012, 06:33:18 AM
http://www.groupdiy.com/index.php?topic=50015.0 (http://www.groupdiy.com/index.php?topic=50015.0)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on November 21, 2012, 12:38:28 PM
Hello all,
I just wanted to share my thoughts on the DU67 project. I LOVE this mic. It's super sweet and sounds absolutely awesome.
Tskguy's capsules are truly works of art. Here are some tracks I threw together while doing some initial recordings after finishing the mic and installing on of Eric's capsules.
The signal flow is DU67 –> Sound Skulptor MP573 –> ProTools. I'm really digging the way these tracks sound with no eq or comp.
2 acoustic guitars and 2 vox

https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993972.wav

I did this in about 10 min single takes on all the tracks so I'm sorry about my pitchy vox.
This mic is def going to be on all my records from now on and it's already at a colleague's studio doing the duty!

Dave

Hey Wave ,  thanks For making my day  this sounds amazing  :o :-\ :D ;) :) ;D ;D ;D
Best,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on November 25, 2012, 06:59:48 PM
Hi All,

i have my U67 clone working, sounds amazing, this is what i have in it:

RK-47 capsule
Sowter 1304f transformer
Nos Tung EF86 valve

and i crammed it all in a SE Z3300A, bit tight but fits in there ok.
Had to run the mic for about a day to burn the valve in and sounds so good now.
the has real depth and loads of gain, smooth on the top end, clear mid range.
Ive got a K-67 capsule coming so gonna try it out, really happy with the sowter transformer as well.

regards

Spence.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on November 26, 2012, 06:49:03 AM
Quote
i have my U67 clone working, sounds amazing, this is what i have in it:

RK-47 capsule
Sowter 1304f transformer
Nos Tung EF86 valve

Isn't it pretty dark with the 47 capsule and the 67 de-emphasis circuit?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on November 26, 2012, 11:02:28 AM
So the adjustment for the Plate voltage is R3 (8.2k) -> 56k -> 50k pot where the 56k is hanging off the pot? Why not just use 68k for R3?
Also I feel like I may be missing a key part of the build info? I've been looking through a ton of pictures, the BOM, and the schematics. But didn't see anything about the 56k until reading through the thread again this morning. Is there another schematic I've missed?
Also, note that the PT for the B+ should be wired parallel primary, series secondary. I made that mistake as well until seeing the sketch on page2 of the thread.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: kidvybes on November 26, 2012, 11:28:19 AM
Isn't it pretty dark with the 47 capsule and the 67 de-emphasis circuit?

...that RK-47 capsule is far from dark on it's own...IMHO, probably the brightest of the aftermarket K47 capsule options...
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on November 26, 2012, 01:08:09 PM
Quote
...that RK-47 capsule is far from dark on it's own...IMHO, probably the brightest of the aftermarket K47 capsule options...

Yes, likely because of its 3 micron thickness.
But still.

Frequency response in this link:
http://microphone-parts.com/rk47-microphone-capsule/ (http://microphone-parts.com/rk47-microphone-capsule/)

And that's without de-emphasis.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on November 27, 2012, 07:01:52 PM
So the adjustment for the Plate voltage is R3 (8.2k) -> 56k -> 50k pot where the 56k is hanging off the pot? Why not just use 68k for R3?
Also I feel like I may be missing a key part of the build info? I've been looking through a ton of pictures, the BOM, and the schematics. But didn't see anything about the 56k until reading through the thread again this morning. Is there another schematic I've missed?
Also, note that the PT for the B+ should be wired parallel primary, series secondary. I made that mistake as well until seeing the sketch on page2 of the thread.

Yes you are correct both is better to have a resitor off board to be able to swap it and adjust the voltage drop for different transformer so once in the ball park you tweak with the pot,
depending on your country 230-115 you need to take in consideration at the primary and the secondary might also depends if you multiple out put.
hope this helps,  :)
dan, 
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993990.jpg)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on December 01, 2012, 09:40:23 AM
Any chance will have to see some completed mic before the end of the world (21 dec-2012),  ;D
just a toughts,   :)
happy building still,  :)
Best, ;D
Dan,
 
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: 3nity on December 01, 2012, 10:30:54 PM
Hey Dan!
I really, really love your D-u67 its the perfect tube mic out there!
Real tube sweetness, detailed and full sound!
I told you i wasnt building one but hey you made me change my mind when i heard yours!

Nice body by chuckD too!

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 02, 2012, 06:10:15 PM
In testing the U67 with RK-47 in it along side a C12 style with a RK-12 in it, yes it did seem a little muffled on the top end, have changed to a R-67 and sounds much better but valve seems to have this wind sound, getting a winged C nos EF86 valve next week, so will hopefully be quiet as a mouse now so i can properly test.
Prelim tests agains C12 on vocals is the C12 wins, but on acoustic guitar the U67 is amazing, really articulate.
did a room mic on drums with the U67 and it sounded great.
Cant wait to get my U47FET version going as putting on kick drum, just need to finish design of U47 style mic body which will have also have 2nd head basket U67 style so i can have a pair of U67's for room mics.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 02, 2012, 06:13:47 PM
And this is hopefully gonna be the U47 style body. I'll post some real pics of the insides and outsides once both types have been made.
Both may also have the option of having a different sleeve with holes in the top for switches.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: mrcase on December 03, 2012, 05:13:52 AM
hey - are you going to offer these mic bodys?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on December 03, 2012, 06:17:30 AM
Quote
In testing the U67 with RK-47 in it along side a C12 style with a RK-12 in it, yes it did seem a little muffled on the top end, have changed to a R-67 and sounds much better

Yeah, that's what I figured. Thanks for the feedback.

Two nice babies for the locker there. Keep us posted, please.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 03, 2012, 08:30:47 AM
Hi,

if enough people were interested in these bodies and the price was right im sure we could do something, gonna take a couple of weeks to go through all the nitty gritty stuff and get it all sorted. I want them to be all interchangeable, so you could have:

1. U47 body + U47 Style head basket with U47 or U47 FET pcbs inside.
2. U47 Body + U47 Style head basket with cutaways for switches with U47, U47FET, U67 or U87 pcbs inside
3. U47 Body + U67 Style head basket with which ever one.

you get the idea, rather than write out every permutation im sure you can decide which would suit you, would be interested in comments and feedback from everyone.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 03, 2012, 08:33:09 AM
Hi Guys,

just thought i'd post a picture of the proposed versions with switches.
These are only really ruff, but you get the idea.

regards

Spence.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 03, 2012, 08:33:51 AM
Rear View.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on December 05, 2012, 12:37:25 AM
Here is a bit to share...After burning in 2 tubes in my stereo pair for a week straight, I found the (previously favored) Tungsol tube to be popping. AND the previously disapproved of Telefunken silver shield tube to be the new champ. So tonight I installed the other ( formally disapproved of) Tele tube from the matched pair that I bought and started to sweep the voltages. I brought the filament V up to 9v and down to 5v, and swept the plate up and down as far as it would go. I noticed a improvement in that tube. (less noise) Now, in three or four days, I hope to see a settling out like the other Telefunken tube. The conclusion...there is a burn in period that can't be ignored. This a delicate circuit that will take some time to get right, but it's totally worth it. This mic, even in it's infancy, rocks.
Also what might be happening here is the PSU needs to be burned in so that the plate voltage remains stable. Turn your monitors down when sweeping the plate. 1 volt will send your speaker into DC land.
Cheers
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on December 05, 2012, 09:46:19 AM
Where did you get your tele's from if you don't mind?
Interesting about the tungsol's and to see whether the tele settles in after a while.

Cheers,
jb
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on December 05, 2012, 02:21:06 PM
Anyone tried a Beezneez K67 Capsule yet, just wandering how they react on this ,
Let me know if anything ,
Best,
 :)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on December 05, 2012, 04:48:22 PM
I just tried a "matched set NOS" from ebay. Most the ebay listings are from Germany. I thought I had two noisy tubes and I was looking for another source. There is a seller in Turkey that will work with you and will take back tubes that prove unacceptable but you have to pay shipping. And they are about $80. I think I got my pair for about 35 dollars but without the return option. Just google telefunken ef86 and he should be close to the top.

Ben has been trying to save his daughter and not sending out any of his online orders. I have an order that is about six weeks old. I keep trying to get updates about her condition but nothing yet. I know he went stateside and I don't know if he's here or in Australia.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Delta Sigma on December 05, 2012, 06:19:47 PM
I bought a Telefunken "Hilumin" EF86 from www.nostubestore.com and picked up a Valvo EF86 for a spare. I did a little searching for info on what the best suited EF86 for mics is and found this: http://prorecordingworkshop.lefora.com/2011/02/06/ef-86-manufacturer-recommendations/

I don't have a capsule yet (ordered the Beesneez) or a body so I haven't tried either tube but Koray @ nostubestore was great to deal with.

@ktfstudio

Ben is sending out his online orders as far as I understand. Both danderloo and winetree confirmed they received their capsules on the Beesneez White Pages thread. Ben had brought a bunch of capsules with him to the states to skin and ship so I'm hoping mine is somewhere in the hands of USPS or Canada Post now.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on December 05, 2012, 07:42:09 PM
That's good news, maybe mine is in route too. Hope this means his daughter pulled through!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 06, 2012, 02:44:54 AM
hi all,

this is very interesting about the valve issue, i got a Tung Sol  and had this wind noise at low level, i first changed the capsule and the wind noise was still there, i then sent it back and got another from karltone on ebay,  it is a winged C EF86, wind noise reduced but still there at low level, i say wind noise but its a combo of wind and bubbling.
You guys mention adjusting voltage, do you mean the other pot in the power supply?
as i was under the impression this was the heater voltage?
just wanted to be clear, i will give this a tweak to see if i can get rid of this noise, rather than plug it all into my monitors i think i'll do it into a small mixer on headphones.
could it be a noisey resistor?
any other help solving this noise issue would be great.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Tommy Radonicus on December 06, 2012, 11:21:57 AM
Hi,

if enough people were interested in these bodies and the price was right im sure we could do something, gonna take a couple of weeks to go through all the nitty gritty stuff and get it all sorted. I want them to be all interchangeable, so you could have:

1. U47 body + U47 Style head basket with U47 or U47 FET pcbs inside.
2. U47 Body + U47 Style head basket with cutaways for switches with U47, U47FET, U67 or U87 pcbs inside
3. U47 Body + U67 Style head basket with which ever one.

you get the idea, rather than write out every permutation im sure you can decide which would suit you, would be interested in comments and feedback from everyone.
Spencer Lee .. Gotta admit I'm Jonesying on those nice looking U47 bodies   :P 

It might be worth starting a separate Feeler thread to gauge how much interest you can get. Have you gauged a price level yet?   

Cheers
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 06, 2012, 11:34:53 AM
No price level on the mic bodies yet, but I am planning for them to be cheaper than anything else out there, if there are enough orders, maybe in orders of 10 or 20 they could work out really reasonable. at a guess im aiming around about $250/£150 for one body, but i'd like to do it as a kit so you can order what head basket you want, what insides you want, and whether you want holes for switches or not.
will try and put another thread up about it when im a bit further to building them.
Everything is in CAD world at the moment!!!

Spence.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 12, 2012, 02:49:53 PM
Hi Guys,

thought i'd post a link to a track i did to test the U67 on acoustic guitar and vocals.

https://soundcloud.com/spencer-lee-horton/snuff-acoustic-version-by

needs a bit more of a mix but i think you get the idea.

regards

Spence.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: tskguy on December 12, 2012, 04:43:07 PM
Sounds very nice!!

Great job,
Eric
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 13, 2012, 04:13:41 AM
Im really pleased with the clarity and detail compared to the C12 style mic i have.
The U67 only has a cheap capsule in there at the moment, but will probably plonk a RK-67 in there as i really like the microphone parts capsules for the price.
The thing i love about it is by using these diy mics i now only use subtracktive eq'ing
which i find simplifies the whole process, and its only normally the bottom end that needs adjusting.
whats everyones thoughts on these capsules
http://www.cathedralpipes.com/zen-cart/index.php?main_page=product_info&cPath=65&products_id=193

seems to cheap to be any good?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Delta Sigma on December 13, 2012, 08:27:15 AM
Spencer,

If you're trying to put a budget capsule in there check out the Chinese capsules that Ben & Veronica brought in to raise funds for their daughter's surgeries. They're $80 AUD and apparently high quality http://www.groupdiy.com/index.php?topic=50260.0 .

If you don't mind spending a little more check out tskguy's WM thread  http://www.groupdiy.com/index.php?topic=49859.0 . The RK-47 is $129 USD and tskguy's 67 capsule is $199 (I think). He's posted samples of his U67 build with his capsule somewhere on this thread.

-Neil
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on December 13, 2012, 07:20:01 PM
Spencer,
The majority of the mic's sound is capsule related. I had a Chinese K67 in mine at first and as soon as I popped in Eric's HK-67 it was night and day. The mic went from "yeah that sounds good" to "OMG that sounds amazing!"
for the price difference between the RK-67 and the HK-67 (tskguy's K67 capsule) there is a huge sound difference. I think Eric is getting the capsule about as close to a real one as possible.
There's nothing wrong with microphone-parts capsules, especially at their price point (I used their RK87 in my first DU87) but for my money the $70 difference for the HK-67 is WAY worth it.

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on December 14, 2012, 05:02:47 AM
Quote
If you're trying to put a budget capsule in there check out the Chinese capsules that Ben & Veronica brought in to raise funds for their daughter's surgeries. They're $80 AUD and apparently high quality http://www.groupdiy.com/index.php?topic=50260.0 .

Or go all the way and get the Beesneez K6 (K67) with authentic bronze alloy. Now on sale for 250 rather than 525 aussie dollars.
http://www.beesneezmicrophones.com.au/store/index.php?_a=viewProd&productId=21 (http://www.beesneezmicrophones.com.au/store/index.php?_a=viewProd&productId=21)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 14, 2012, 07:24:59 AM
All good stuff guys, appreciate all your wisdom.
will probably go for eriks HK-67.

regards

Spence.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on December 14, 2012, 07:44:48 AM
Oh, I forgot to add. Last time I checked (and ordered mine), it had free shipping for GroupDIY members to boot.  :)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 14, 2012, 08:34:46 AM
really free shipping!!! i doubt he'll do that for the UK?

regards

Spence.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on December 14, 2012, 09:44:24 AM
Well, I'm in The Netherlands. Not much difference in this respect.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on December 14, 2012, 09:53:47 AM
So we've got the HK-67's, the RK's, and the K-6... Then there's probably the PK-67....  Choices / choices / choices... I've got a pair of Eric's HK's slated for DU67 #'s 1&2 but then I added a second pair to my build and wanted those to be slightly different just to have more choices...

You know, I've got several xyz-67's laying around in the boneyard from various doners... Think I'll start with those downtown and plan to move uptown a bit later...

Anyone used the K6's? Any comments?

Cheers,
jb
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on December 14, 2012, 10:29:07 AM
OK, I went through the BeesNeez thread in the White Market section and found the quote in reply #37:
Quote
Hi shipping is free on capsules :)
http://www.groupdiy.com/index.php?topic=49869.20 (http://www.groupdiy.com/index.php?topic=49869.20)

Do keep in mind this was right before the Phelicity fundraising Chinese capsules were offered. Those ("cheaper") capsules do come with shipping costs. If only for the good cause.  :)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on December 17, 2012, 10:52:34 AM
the store will be open today only and then back Jan 7th 2013
Thanks all,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on December 17, 2012, 11:11:49 AM
I put in my Beezneez capsule this weekend and tried out the mic.
I do not have good hum suppression. If I move my hand near the mic I hear more hum, and only when I touch the body, the hum is completely gone - very quiet mic.
I have the cable wired as recommended, the shield of the XLRs in the power supply both connected to the case ground, and the ground jumper in the psu connected, as that reduces the hum considerably. I'm sure I am missing a connection somewhere. Any ideas?

Second, the fig8 and cardiod patterns are reversed. I must have a wrong connection up on the switch pcb.

How many people have working mics?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on December 17, 2012, 11:26:30 AM
Whoops - the mic body I got from ChuckD has the pattern labels Omni - Fig8 - Cardiod, as shown on page 1 of this thread.
Schematic shows cardiod in the middle, which is how my mic performs???

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on December 17, 2012, 11:41:23 AM
trough the cable pin 3 ( cableshield ) is the shield either on mic pcb (3) or to psu starground with shield lift jumper , So one of those 2 point will do ,
for the switch all the pins needs to be soldered for proper ground to mic body verify that body switch is short with the mic body , and to psu ,
it really look like something is loooping or not grounded at all and pickup everyRF possible ,


Hope this helps,
Dan ,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on December 17, 2012, 03:47:31 PM
Quote
trough the cable pin 3 ( cableshield ) is the shield either on mic pcb (3) or to psu starground with shield lift jumper , So one of those 2 point will do ,
for the switch all the pins needs to be soldered for proper ground to mic body verify that body switch is short with the mic body , and to psu ,
it really look like something is loooping or not grounded at all and pickup everyRF possible ,

Not sure I understand all this but I'll do some more testing tonight.
The switch pcb grounds through the screws attaching it to the body, yes?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on December 17, 2012, 03:55:12 PM
Quote
trough the cable pin 3 ( cableshield ) is the shield either on mic pcb (3) or to psu starground with shield lift jumper , So one of those 2 point will do ,
for the switch all the pins needs to be soldered for proper ground to mic body verify that body switch is short with the mic body , and to psu ,
it really look like something is loooping or not grounded at all and pickup everyRF possible ,

Not sure I understand all this but I'll do some more testing tonight.
The switch pcb grounds through the screws attaching it to the body, yes?

Yes ,  Keep us posted,  make sure you check continuity trough mic body and psu star ground ,

Dan, you are so near ,
Best,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on December 17, 2012, 04:05:29 PM
And cardiod has to be the middle position, yeah?
ChuckD's bodies were wrong!   :o
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on December 17, 2012, 04:07:28 PM
And cardiod has to be the middle position, yeah?
ChuckD's bodies were wrong!   :o

Yepper,   Chuck's body were protoversion , Newer body are now corrected for this, 
middle = cardiod left is omni and right fig8

Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on December 18, 2012, 05:21:48 PM
Really wish to see some of those mic coming alive before the end of the world  ;D,

Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dissonantstring on December 18, 2012, 09:13:21 PM
that's in 3 days dany...no time until the next year for my DU-67 build :(, so i'll just have to ignore the mayan calendar. ;D
edit: yes, still waiting for my capsule to be shipped too, but doesn't change the fact that I would not be able to finish the project by doomsday.

THANK YOU DANY for being a major contributor in making 2012 " The Year of the Mic"!  Can't wait until 2013!  Happy Holidays!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: kpearsall on December 18, 2012, 09:28:16 PM
yes, I'll be ignoring the mayan calendar too, until my capsules arrive and Max makes new transformers.

I've got the pcb in the mic, and it looks kind of lonely in there without friends.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on December 19, 2012, 04:22:56 AM
Hi,
I need advice on the 220v transformer for the PSU.
I found this in a local shop:
Any chance this will work? There's allways the triad from mouser but if possible id like to avoid the shipping cost.

Features
red leads: 230VAC / 50Hz input
Specifications
voltage: 2 x 12V
current: 1 x 1000mA
rated power: 24VA
weight: 135g
dimensions:
height: 42mm
width: 50mm
depth: 47mm
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 19, 2012, 05:01:09 AM
I got a cheap one off ebay.

http://www.ebay.co.uk/itm/Chassis-Transformer-6VA-20V-20V-/290813757829?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item43b5d9c985

£7.63

works fine in mine.

regards

Spence.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on December 19, 2012, 09:43:10 AM
yes, I'll be ignoring the mayan calendar too, until my capsules arrive and Max makes new transformers.

I've got the pcb in the mic, and it looks kind of lonely in there without friends.

thanks Guys,  i will see you in the new world then .. hopefully this will be a renewal for human conscience  ;D
Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on December 19, 2012, 12:38:18 PM
Really wish to see some of those mic coming alive before the end of the world  ;D,

Best,
Dan,

I'll bring mine with me if I have to. Just need to get a couple more parts together for this road trip. Here's for hoping to find some "real nice" capsules and trafo's on the other side.

Cheers,
jb
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on December 21, 2012, 10:25:02 AM
I figured out my problems with hum. I had the cable wired with the shield connecting to the jacks, not pin3, which must have created a ground loop. Also, the switch pcb that came with ChuckD's bodies does not ground the switches to the chassis. I added some short wires and it's all good now. 
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on December 21, 2012, 10:42:39 AM
I figured out my problems with hum. I had the cable wired with the shield connecting to the jacks, not pin3, which must have created a ground loop. Also, the switch pcb that came with ChuckD's bodies does not ground the switches to the chassis. I added some short wires and it's all good now.

The switch PCB and the switch on the pcb come acrros a gnd plane wich require the 2 hloding pin to be soldered and would make contact with the screw up to the basket portion of the mic , not sure how it can happen but you figured it out  :) ,  So......... How do you find the mic ,
you have a beezneez ca[psule in there ,  I would appreciate any comments you may have and most off all, congratualtions for your new toy , I really hope you ewill like it ,   any pics ;D,

Best, and Happy End of  the world to evryone , ;D ;D

Let me know ,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Delta Sigma on December 21, 2012, 02:21:07 PM
I don't have my mic body yet but I want to get my tubes burned in. I was thinking about wiring a connector on the the board temporarily and firing it up but I don't want to hook up the capsule without the body. I don't have the any of the switches either (they will arrive with the body).

Do you think it should be alright to fire up as is or should I be temporarily shorting the capsule connections?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on December 21, 2012, 02:30:55 PM
I don't have my mic body yet but I want to get my tubes burned in. I was thinking about wiring a connector on the the board temporarily and firing it up but I don't want to hook up the capsule without the body. I don't have the any of the switches either (they will arrive with the body).

Do you think it should be alright to fire up as is or should I be temporarily shorting the capsule connections?

I would rather wait till you have a proper enclosure to safley handle ( b+) this new born , just my 0.02.
Best,
Dan,
 

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Delta Sigma on December 21, 2012, 04:01:51 PM
I'm not too worried about the B+ since it's fairly low voltage. I planned on using my circuit board Pana Vise with a little Plysil 69kV tape to make things safe.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on December 21, 2012, 05:18:21 PM
I wouldn't be worried about burning tubes in.
I'm with poctop, build it right and safely.
You can sub the capsule with a 50-100pf capacitor if you don't have it yet.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Delta Sigma on December 22, 2012, 01:48:59 PM
Well change of plans anyways. Holiday season is brining some unexpected guests so I have been reassigned to cleaning detail. My microphone body should be here before I get back to to working on the mic. Plus the IIHF World Junior tournament is starting. All of a sudden watching TV is more important than building mics!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on December 22, 2012, 02:06:18 PM
Yep got the same Cleaning Duty Here,  >:( :( >:( :) ;D
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on December 30, 2012, 09:46:57 AM
So I swept the frequency response of mine using the calibration port and RMAA. The gain staging was setup as described in the manual; this result is normalized.
I wonder if the spec to be -10 dB at 1500 cps should actually be -10 dB at 15 000 cps?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Delta Sigma on December 30, 2012, 10:46:49 AM
Where do you see a spec of 10db down @ 1.5kHz? That wouldn't be very functional. It looks to me like some of the specs have a 3dB down point of 16kHz but you are 10dB down at that point.

Although that could be your interface or RMAA exaggerating the curves with high frequency attenuation.

I don't see the "gain staging" setup in the manual though. Maybe I'm not on the same wavelength as you. I did find some interesting information of mic stands including a boom attachment!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on December 30, 2012, 11:36:39 AM
From the manual: (The page was posted back in this thread)

Quote
"For purposes of checking the frequency response of the amplifier, a test signal may be fed to the instrument jack marked "calibrating input" at one end of the power supply. Proceed as follows: From the 600 ohm output of a signal generator, feed a 1000 cps tone at a level of -18 dbm to the calibrating input. You may use the model z-58 dummy head or can proceed with the regular head assembly plugged in. The three switches are set for "omni", full sensitivity, and linear frequency response. The following output levels are to be observed at the output of the 150/250 ohm impedance, using a vacuum tube voltmeter:

1000 cps:    -38dB     1dB
40 cps:        -43dB     1dB
1500 cps:   -48dB      1dB

I didn't use a 600 ohm output, just the regular output from my soundcard. The soundcard is flat - the green line is out and in for reference.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: sage on December 31, 2012, 02:33:46 AM
Hi fellow DIYers

I want to finally approach building a great quality mic, actually a couple to use for my drum rooms and to have an alternative to the Sony c800g for vocals that i have in the studio.

So far I have built successfully a few LA2A - LA3A - LA4 - 1176 - SSL G Buss, racapped and modified my MCI board but I would not call myself a tech quite yet...

Which projects do you guys suggest ? 87s ? 67s ?

Which one has the most comprehensive info and parts availability and would be a good one to start with considering for microphone I have only built the Royer Ribbons replicas that are very easy...

Eventually I wanna build the 47 and 87 and the 67 but I am sort of intimidated by the pictures of the 67... though i have recorded with those and I love the sound...

I would appreciate opinions...

sage
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 31, 2012, 04:54:29 AM
Hi Sage,

I am very interested in doing a good valve compressor build (Tube Tech C1 would be nice!), i have a Art Pro Vla which i am gonna mod but thats gonna be down the line a bit.
I would suggest a U67 build and U87, build a pair of them.
I have had awsum results with the U67 on acoustic/electric guitar and vocals, doesnt sound that great in with a drum kit, better mics out there which seem to sound much better.
U47 FET is the one you'll want for kick drum and bass guitar( I have a pair but not built bodies yet for them).
I use the U87s over the kit and they sound fantastic( plenty of donor bodies available for these).
Havnt tried the U87's on the toms yet but some people say this is good.
good luck with it all.

regards

Spence.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: sage on December 31, 2012, 10:06:38 AM
Thank you - sounds like the 87 could be a good start for a pair of Room mics for Drums -
I think it might be a bit easier too as a first mic projects  -

Thank you for the suggestion -

sage
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 02, 2013, 03:29:28 PM
Wave,
The sample you posted sounds GREAT!
You channel the Beatles very well.

I think the sound of my mic is off. It sounds muffled and isn't crisp like I expect.

Quote
The majority of the mic's sound is capsule related.

I have a beezneez capsule in it so that sound be good?

Any test ideas?

- Dan



Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on January 02, 2013, 05:52:04 PM
Dan
Thanks for the kind words. The mic should def not sound muffled. The beezneez capsule should sound great (esp if it's the brass K67 remake). Can you post some pics of the internals so we can take a look?

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 02, 2013, 05:59:32 PM
I'll try to post some pictures.
It is the brass beezneez
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 03, 2013, 10:37:32 AM
Here are some quick pics - without disassembling it is pretty hard to get all the detail.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 03, 2013, 10:38:14 AM
another shot
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 03, 2013, 10:38:46 AM
last one
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on January 03, 2013, 12:55:15 PM
Thanks for the pics.
Could you take one of the HiZ area (under the switchboard from both sides)
Also, what kind of tube are you using? Have you swapped a different one in there or do you just have the one?

Thanks,
Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 03, 2013, 01:01:15 PM
I have other tubes. I can swap it with the one in my G7 to be sure it is good.

I'll have to take it apart to get a better pic of the HiZ area. Probably not until this weekend...

Thanks!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on January 03, 2013, 01:12:59 PM
Try the tube swap as it's easy. Report back

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on January 03, 2013, 02:56:51 PM
Got my bodies (today), Beesnez Brass capsules, BV-12 Transformers,
Mouser BOM parts, and a bag of polys all together.
Getting back to the build so I went through the 12 page post.
What poly goes in C1?
Thanks
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on January 03, 2013, 03:34:06 PM
It looks like a .01µF goes in C1 and I don't think it's a styrene.

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on January 03, 2013, 05:35:12 PM
In the intro post it reads•1X FeedBack Cap (80-160pf) styroflex/630V

--------------------------------------------------------------------------------
What value is used?
In the pictures it looks like it's in C1 a poly (to the right of the 3 red Wimas)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 03, 2013, 06:00:05 PM
Quote
In the intro post it reads•1X FeedBack Cap (80-160pf) styroflex/630V

--------------------------------------------------------------------------------
What value is used?

I think that one is C17. 

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on January 03, 2013, 06:01:22 PM
In the intro post it reads•1X FeedBack Cap (80-160pf) styroflex/630V

--------------------------------------------------------------------------------
What value is used?
In the pictures it looks like it's in C1 a poly (to the right of the 3 red Wimas)

The original BOM implies a 100pf or stick in the middle and you will be fine ,

indeed Feedback cap is C17
D.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on January 03, 2013, 11:52:18 PM
Dany is correct (as usual). Eric and I used 100pF for our mics and they seem to be right to me. You can play with this value to kind of "tune" the mic to your tastes.

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 05, 2013, 10:11:31 AM
So I went over the mic again - comparing to the schematic and everything looks good (except on the original schematic the HPF filter cap is 500pf?)
With a friend tested the mic some more last night. It sounded fantastic! I think I was out of it when I tried it earlier this week.
Whoo hoo!
Very different than my C12, but both are great.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on January 05, 2013, 03:05:44 PM
Ah excellent! Glad it worked out.  I had a similar experience with my MK47, built it up and tested it (worked right off the bat, no trouble shooting) and thought it sounded congested and woofy.  Fresh ears and using it on a few different sources turned me around.  Great mic.  Looking forward to finishing these DU67s up when I release some funds for a mouser order.

Enjoy yours  :)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on January 05, 2013, 03:20:42 PM
So I went over the mic again - comparing to the schematic and everything looks good (except on the original schematic the HPF filter cap is 500pf?)
With a friend tested the mic some more last night. It sounded fantastic! I think I was out of it when I tried it earlier this week.
Whoo hoo!
Very different than my C12, but both are great.

Hi Dan,
Any chance you could post up some sound samples and tell us the signal chain you use to record them?

Thanks,
Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on January 05, 2013, 03:23:11 PM
Important Notice For D-U67 polarity

I have been checking polarity of each 87-47F-67,  and i have found that the initial statement from ktfstudio was right, i did confused Tuchel pin 1 and Switchcraft pin2 ,   as the schematic underlay would point to.   So Since old Tuchel Pin 1 is +   and old Tuchel pin 2 is -  then only the D-U67 mic would have reversed polarity.  this would not be noticeable with the use on the single mic but when used in pair with other microphone this will matter enourmously.

please Let me know if i got this Stament Wrong.
Quote
So Since old Tuchel Pin 1 is +   and old Tuchel pin 2 is -

The Easy FiX :  swap pin 2 and pin 3 on xlr output connector in the power supply. 

Thanks For catching this ktfstudio.  :)

Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 07, 2013, 10:07:56 AM
Quote
Hi Dan,
Any chance you could post up some sound samples and tell us the signal chain you use to record them?
Thanks,
Dave
Sure, I'll try to put something up.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on January 07, 2013, 03:59:06 PM
The Store is back online,

Happy New year All,  :)
Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: ktfstudio on January 07, 2013, 11:27:41 PM
There is a public file on soundcloud that has the DU-67 on drum overheads in a M/S arrangement. I don't know if this is helpful, voice is the king for assessment but there ain't a lot of that going on around here. The search is Pete Hillman and the track is titled "undisciplined".
Happy New Year,
Pete
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 10, 2013, 10:21:23 AM
Here's some quick samples. I had both mics set up at the same time next to each other, and was singing about a foot or so back.
This was just a quick test - not meant to be great in anyway. (But for the great song by the late great W.rr.n Z.v.n!)

U67: Beezneez - Telefunken EF86 - ioaudio bv12
u67 -> DIY Jensen990 (i.e. JH M1) - > echo layla24
http://soundcloud.com/dmpro/u67-sample-16bit (http://soundcloud.com/dmpro/u67-sample-16bit)

C12: T.Campbell C12 - GE 6072 - CM2480
c12 -> DIY Jensen 990 -> echo layla24
http://soundcloud.com/dmpro/c12-sample (http://soundcloud.com/dmpro/c12-sample)

Recorded 44/24, normalized, then exported to 16bit for the upload
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on January 10, 2013, 01:27:07 PM
Thanks!

Same polar pattern on both?

U67> relatively mellow and full. More direct, too.

C12> bright, open, more ambient. But also somewhat harder on the voice.

Here I prefer the U67.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 10, 2013, 01:48:02 PM
Both were set to Cardiod.


Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on January 10, 2013, 06:27:24 PM
Thanks!

Same polar pattern on both?

U67> relatively mellow and full. More direct, too.

C12> bright, open, more ambient. But also somewhat harder on the voice.

Here I prefer the U67.

Nice sample DMP , listen to both sample and i agree 110% with miccadict.  Thanks for taking the time in doing this , i just love my D-U67  8)
Dan,  ;)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 11, 2013, 02:48:32 AM
Hello builders,

I finally started populated the main pcb and I got to C17. The pcb and the files in the build folder say it's polarized...is it? If so, how do I determine the polarity? There's no "+" anywhere on the cap, just "100J 630V" (purchased from justradios.com). Any help is much appreciated, thanks.

-DUDE GUY
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 11, 2013, 03:43:12 AM
Same question as above for C10, the second styroflex. Thanks.

-DUDE GUY
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 11, 2013, 10:11:50 AM
Those caps do not have a + / - 
They can go in either way

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dandeurloo on January 11, 2013, 03:46:05 PM
I fired mine up last night!  Sounds great.  I have a small issue I need to sort out but overall very impressed.  I need to spend more time with the mic but I am excited about this build for sure.  Thanks Dan!

EDIT:  I got my small issue fixed and the mic sounds great!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 12, 2013, 04:00:19 AM
Thanks very much, dmp. I guess the pcb denotes polarity incase someone chooses not to use a styroflex? Anyway, I finished populating the main and socket pcb, building the psu tomorrow. I will post pics.

-DUDE GUY
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on January 12, 2013, 05:33:27 PM
I fired mine up last night!  Sounds great.  I have a small issue I need to sort out but overall very impressed.  I need to spend more time with the mic but I am excited about this build for sure.  Thanks Dan!

EDIT:  I got my small issue fixed and the mic sounds great!

Thanks Dan,
Dan,  :)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 14, 2013, 03:36:15 AM
I noticed that the PSU BOM lists a quantity of 3 Zener diodes, 15V 5W. What's the reason for this? Do I need to select one with a certain characteristic? Thanks.

-Kevin
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on January 14, 2013, 11:15:44 AM
Hi Guys,

just tested 3 different tubes in my U67 build.
results as follows:

EF86 Winged C - full open, good clear top end, full bottom end
EF86 Sovtek Electro Harmix - little bit darker than the winged C, cheaper sounding
EF86 - Tung Sol - muffled, didnt like this one at all, IMHO dont buy this one.

have some sound files which i'll put up later, done on fig 8, mesa boogie dual rectifier, channel 2, into GS3000 Allen & Heath then into Protools HD via 96i, little bit of compression from Art Pro VLA, nothing else.

regards

Spence.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: imo on January 14, 2013, 06:26:41 PM
Got a working mic! Been super busy, so only cursory testing, but sounds amazing. Will try to test it against my partners vintage 67 next week if time permits.
I am noticing a bit of hum when i touch the body, especially when engaging the pad switch. I have not yet tried jumping 2 and 3 in the power supply, so i will give that a go.
I also couldn't hear a difference in the low-cut switch, so may need to revisit that as well..
My Tele EF86 tube is a bit noisy. I'll give it some time to see if it quiets down. I love this mic, probably my fave mic design ever.

One tip that i didn't see in the thread, and this is in regards to the "Chunger bodies": You need to mount the switch/spacer assembly from the bottom. I initially did it from the top. The pattern switch is right in the way of the screw for the headbasket. You need to tighten the headbasket and then tighten the assembly afterwards. It takes some maneuvering to get the screws to sit right, but can be done
Thanks for putting it all together!
Ian
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on January 14, 2013, 06:35:39 PM
Got a working mic! Been super busy, so only cursory testing, but sounds amazing. Will try to test it against my partners vintage 67 next week if time permits.
I am noticing a bit of hum when i touch the body, especially when engaging the pad switch. I have not yet tried jumping 2 and 3 in the power supply, so i will give that a go.
I also couldn't hear a difference in the low-cut switch, so may need to revisit that as well..
My Tele EF86 tube is a bit noisy. I'll give it some time to see if it quiets down. I love this mic, probably my fave mic design ever.

One tip that i didn't see in the thread, and this is in regards to the "Chunger bodies": You need to mount the switch/spacer assembly from the bottom. I initially did it from the top. The pattern switch is right in the way of the screw for the headbasket. You need to tighten the headbasket and then tighten the assembly afterwards. It takes some maneuvering to get the screws to sit right, but can be done
Thanks for putting it all together!

Thanks For the nice word,

1)  I have not yet tried jumping 2 and 3 in the power supply, so i will give that a go.
have you installed the SHLF jumper in the psu this will starground the mic cable shield and body.

Quote
A)   I am noticing a bit of hum when i touch the body, especially when engaging the pad switch.

Make sure the 2 leg of the switch are soldred because only one of the pins goes to the ground plane of the switch pcb you need to use metal screw to fit them there so you would have a perfect short betwen the switch and the body  you need to use the 3 screws to make sure the grounding is good tight them up ,
had the same problem as soon as i was touching a switch and tight it up and then gone

Quote
B) I also couldn't hear a difference in the low-cut switch, so may need to revisit that as well..

make sure you have the 2 wire solder on top of the jumper LC on the main board mic .

C)  You need to tighten the headbasket and then tighten the assembly afterwards. It takes some maneuvering to get the screws to sit right, but can be done
Yes the mic design by itslef implies that you cannot install the headbasket after the switch board but if you remove the screw and loose them just a notch you can acces the headbasket screw.


Quote
D)My Tele EF86 tube is a bit noisy I'll give it some time to see if it quiets down. I love this mic, probably my fave mic design ever.

Many thanks for that and thanks for posting ,  :) :)

Keep us posted   :)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on January 14, 2013, 10:04:57 PM
Wiring Questions I can't see in build guide.
7 pin connector numbers connect to same numbered holes on main P.S.B.
Where do the switch board wires connect?
Where do the wires from the capsule connect?

 
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on January 14, 2013, 10:17:32 PM
Wiring Questions I can't see in build guide.

Quote
7 pin connector numbers connect to same numbered holes on main P.S.B
yes Makes it easier.

Quote
Where do the switch board wires connect?

Did you download and look all the file in the build folder. there is a file called overall connection you need to understand this file 100%
before starting wiring. Attached in this post

https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993a88 (https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993a88)

Quote
Where do the wires from the capsule connect?
see file.

Hope this helps,
dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on January 15, 2013, 12:03:41 AM
Capsule:
Front diaphragm center lead goes to right side turret (if holding the mic straight up and the tube facing you)
Rear diaphragm center lead goes to pattern switch pin 2 (actually soldered to the switch)
backplate lead goes to left turret (mic orientation same as above)

Dave

It is important to try to use Dany's overall connection diagram as well!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on January 15, 2013, 12:31:22 AM
Beesneez Capsule Mounting:
Do I just use the upper black cradle  from the beesneez mount
and screw it to the metal shaft on the white dome mount that came with the body?
not using the beesneez rubber iso shaft?
Don't see how I can mount the whole beesneez mount to the upper plate.
would have to drill 2 holes.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on January 15, 2013, 12:51:32 AM
More than likely yes but I need to see a pic of both mounts to say for sure

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on January 15, 2013, 01:07:49 AM
The white mount has 2 wide spaced mounting holes.
Beesneez has 2 close spaced mounting hole in bottom brass plate.
Trouble is I can't find the right size philips head for the weird saddle screw and it's so tight the metal shaft turns.
Note; I cut the white saddle off and grabed the screw with vise grips and mounted the beesneez saddle
They used loctite on the screw.
The holes on the beesneez saddle are offset. Use one square hole and one round hole to mount capsule.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: imo on January 15, 2013, 01:24:00 AM
i took the actual mount that came with the capsule and put it on the "white" mantle. I don't think the other one lines up with the holes
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 15, 2013, 09:49:32 AM
Quote
Only to find out the holes on the beesneez saddle don't line up with the holes on their capsule. The diameter's not even the same. Nothing's easy. I'm going to e-mail Beesneez.

I had to mess with it a little bit to get it to work. But I did get the screws to fit. I didn't notice a diameter issue but it did seem a little flexible.
I used the black mount that came with the capsule and mounted it on the saddle that came with the mic.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: imo on January 15, 2013, 01:35:32 PM
I used the Beezneez mount, and put the connection to the backplane under the square hole against the capsule. That lines the holes in the capsule pretty well. Seems pretty standard to me
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 16, 2013, 12:09:54 AM
Anyone know why the PSU BOM includes (3) Zener diodes, 15V 5W? Thanks.

-Kevin
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 16, 2013, 10:34:09 AM
Quote
Anyone know why the PSU BOM includes (3) Zener diodes, 15V 5W? Thanks.
I don't know. Maybe because this is DIY and the instructions aren't perfect?   ;)
You only need one for the psu as far as I know.
The way to develop confidence is to analyze the circuit and figure out what the components are doing.
What is the zener diode doing in the circuit?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 16, 2013, 04:06:36 PM
Thanks once again, dmp. I was being paranoid that I might ruin something. I'm somewhat new to building and electronics in general and very new to PSU builds (gonna have my dad, an electrical engineer, help me with the PSU to ensure I don't hurt myself. I know this is serious stuff). From what I can tell, the Zener is used for a voltage regulator? Regulating the voltage across the tube's plate? Maybe? Again, thanks for your help, dmp. Any schooling is much appreciated.

-Kevin
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 16, 2013, 05:06:03 PM
Sure, no problem!
The power supply is creating two voltages for the mic, B+ (210v) and heater (-6.5v).
The U67 is complicated compared to other tube mics in that the heater supply is being set up at less than zero volts. Usually the heater would be +6.3v and 0v, while in the U67 it's -6.3v and 0v.
The zener diode is helping create that voltage below zero for the heater. The upper leg of the zener is at 0v with the lower leg at -15v. (a reverse biased zener diode always holds it's rated voltage and keeps trying to dump current). The key requirement is that the zener can only dump current until it melts down from exceeding it's power rating. In this case, 5w = 15v * max current

So the current through the zener is regulated by R2, which is conducting -15v to appx -20v at the diode bridge from the heater transformer. Current = 5v/22ohm = 227 mA.
With the power formula for the zener diode, that's 3.4 Watts (227mA*15v).
Once the -15v regulated voltage is created by the zener, the next three RC stages regulate it to a clean DC while dropping the voltage to -6.5. Note that the heater current sets the voltage drop (V=IR), so without the mic hooked up, the heater voltage will be -15v.

Be careful with the high voltages! Getting some help is a good idea.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: imo on January 17, 2013, 04:19:50 PM
So i've sorted all of the main issues out(ground was simply a missed solder joint on the pad switch. The low pass is working, though pretty subtle. I had the 2 poles of the switch connected through one of those slip on connectors.
I have a nice Telefunken EF86. Seems like it may be quieting down, but was making that classic EF86 noise that i have come to know far too well.
Curious to hear any updated info on tube preference in the mic. I've seen some impressions through the thread, but have they changed in use?
The 'Chunger' body seems to work really well. Sure sounds like a U67 to me!
Ian
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on January 17, 2013, 05:19:19 PM
TUBE Talk
Went on ebay and found Russian NOS '70-'80's 6j32p tubes. EF86 equivilent.
Tested, matched, etc. Low prices.
Thinking of buying some. Anybody know anything about these tubes?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: alexc on January 17, 2013, 05:57:56 PM
Here are some measured curves and data for the 6J32P

http://www.klausmobile.narod.ru/testerfiles/6j32p.htm (http://www.klausmobile.narod.ru/testerfiles/6j32p.htm)

I like them, but I have found quite a bit of variation in the performance of 'nos' ones.
My experience is in mic preamps, so I guess that is biased for higher current than a mic - haven't looked much at the mic circuit.
Subbing them in gave very different plate and screen currents and hence gain (no feedback connected)

I would say they are similar to ef86, but not the same - the datasheets I have used for the ef86 are fairly approximate also.

Anyway - definately worth trying but I think 1 in 3 or so gives a tube with the best performance.

Also, the microphoncs were pretty good - not much pinging or what not at reasonably high gains.

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on January 17, 2013, 08:55:59 PM
2 builds finished. All I need are the tubes.
What brand EF86 tube did Neumann use in the orginal u67s?
Wouldn't that tube make this mic sound most like the original?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: gevermil on January 17, 2013, 10:45:07 PM
On that note , has anyone tried the E80F / 6084 ?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on January 18, 2013, 01:04:12 AM
2 builds finished. All I need are the tubes.
What brand EF86 tube did Neumann use in the orginal u67s?
Wouldn't that tube make this mic sound most like the original?

Great thread on this subject here (http://prorecordingworkshop.lefora.com/2011/02/06/ef-86-manufacturer-recommendations/).  Oliver's posts are most, ahem, "hiluminating"
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on January 18, 2013, 09:37:41 AM
Quote
The low pass is working, though pretty subtle.

Make sure you have the internal jumper IS installed as this is the default configuration,  make sure you have soldered the wire to LC jumper and not IS jumper they can get confused very easily,  the IS jumper set the curve type for the low cut operation.

Best,
Dan, 

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 21, 2013, 07:16:06 AM
Hello, I have a couple questions

I want to star ground and have the mic shielded, so I should use the jumper in the PSU and connect pin 3 (black wire) in the mic and at the PSU pcb, correct?

Concerning the mic cable, should I simply connect the braided shield to pin 3 on both sides of the cable and not connect the black wire inside the cable?

Any help is appreciated, thanks everyone.

-Kevin
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on January 21, 2013, 10:05:49 AM
Hello, I have a couple questions

Quote
I want to star ground and have the mic shielded, so I should use the jumper in the PSU and connect pin 3 (black wire) in the mic and at the PSU pcb, correct?

if you want to star ground, do not connect pin 3 from the mic xlr to the mic pcb ,  just leave it ,  and use the shlf jumper inside the psu

Quote
Concerning the mic cable, should I simply connect the braided shield to pin 3 on both sides of the cable and not connect the black wire inside the cable?

correct . inside the cable pin 3 becomes the cable shiled.

Any help is appreciated, thanks everyone.

-Kevin
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 21, 2013, 10:06:27 PM
Thanks for clarifying the star ground, Dan.

I've completed my PSU and I'm getting around 214V for the B+ and around -16V at the heater. Going by dmp's great explanation above, I'm in the right ball park, now I just need to calibrate. I tried lowering the B+ voltage using the RTRIMPLATE, but the lowest it will go is 214V. Do I need to increase the value of the pot then?

I also tried raising the voltage for the heater to -15V (mic not connected), but the RTRIM H- doesn't do anything. Maybe my wiring is wrong? Please see the attached picture. Thanks everyone.

-Kevin
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: imo on January 21, 2013, 10:35:22 PM
Kevin,
you need a load for the voltage to come down to what it should be. That all sounds right, though i think my B+ was a bit higher
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: imo on January 21, 2013, 11:08:04 PM
wanted to say that the Telefunken finally quieted down after a number of days. this makes me happy! I am still on the lookout for some other EF86's.
Man, those NOS high end Tele tubes are BIG bucks(hilunum)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 22, 2013, 12:07:48 AM
Thanks imo, that makes perfect sense. Still have to buy my bv.12, hence why no load.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 22, 2013, 06:03:49 AM
Hello, here are some pictures of my PSU for reference. I used the Hammond enclosure included in the BOM, so the real estate was limited, however the overall size of the enclosure is quite nice. The L bracket technique was very useful, thanks to the terrebonne pics in the build folder. I used a terminal strip for the power connections, which made things a bit cleaner. The PSU seems to be working fine, although I don't have a complete mic with which to test. Yes, I put knobs on the trim pots ha. I felt sorry for them, all exposed. Anyway, I welcome any criticisms of my build and techniques, as I'm always looking to learn. Thanks.

-Kevin
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 22, 2013, 06:06:00 AM
Side view
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 22, 2013, 06:07:27 AM
Transformer input, IEC and switch
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 22, 2013, 06:08:47 AM
Transformer output to pcb connections
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 22, 2013, 06:09:55 AM
Terminal strip, velcro'd to transformer
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 22, 2013, 06:11:00 AM
RTRIM PLATE
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 22, 2013, 06:11:48 AM
RTRIM H-
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 22, 2013, 06:12:27 AM
Life
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 22, 2013, 06:29:41 AM
Also, I'm still a bit unclear as to the mic cable connections. On the male end of the mic cable, I have the shield connected to pin 3, but what about the female side? Should it also connect to pin 3? In this case, it wouldn't be connected to anything since I don't have pin 3 connected in the mic. Is this right?

Or should I connect the shield on the female side of the mic cable to pin 3 and on the 7-pin XLR insert, solder a jumper from pin 3 to the ground pin, so it connects to the mic body?

Thanks,

-Kevin
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on January 22, 2013, 07:36:42 AM
Dude guy thx for these pictures ! will be big help.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on January 22, 2013, 09:50:10 AM
Your build is looking really nice dudeguy.

For the ground layout I followed poctops instructions, and once I got it right the mic was silent.

Cable has the shield connect to pin 3 on both sides:
3 - shield - 3
mic:
pin 3 connects to board

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 22, 2013, 07:29:53 PM
Dgoszillai, I'm glad to help. Best of luck on your build.

Dmp, thanks for the kind words and, once again, thanks for clarifying.

I'll post some more pics of my actual mic for reference. Chunger's donor bodies are great, btw.

-Kevin
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on January 22, 2013, 09:44:55 PM
Just finished.
All I need to do is find some tubes.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 22, 2013, 10:05:00 PM
Looks great, winetree! I wish I had two of them! Get some tuuuubes!

-Kevin
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 23, 2013, 01:59:04 AM
Mic cable - showing the braided shield connected to pin 3 on both ends. The black lead was clipped and white heat shrink added just to be clean/safe. This goes along with Dan's GAC-7 cable diagram in the build folder. Hope this helps.

-Kevin
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on January 23, 2013, 03:18:43 PM
Thinking of pushing the button on one $165.00 NOS Telefunken EF 806s tube.
And I need two. I've used the best of everything so far. Do I skimp on the tube?
Any other suggestions?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on January 23, 2013, 10:03:23 PM
Thinking of pushing the button on one $165.00 NOS Telefunken EF 806s tube.
And I need two. I've used the best of everything so far. Do I skimp on the tube?
Any other suggestions?
IMO if you've gone high end with everything else, you might as well go high end with the tube! What kind of capsule are you using?

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on January 23, 2013, 11:33:53 PM
Beesnez group buy orginal metal U-67 Capsule. Haven't heard them yet.
I used their capsules in my MK-47's and think they sound great.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: imo on January 24, 2013, 12:15:16 AM
I have the beezneez 67 capsule and it sounds amazing! Tele EF86, IO audio transformer. I'm using the Chunger bday. Ill bring it to my other studio in the next day or so and give it a run against our vintage 67, but as i said earlier it sounds amazing. Just as i would expect the mic to sound. It has that quality that a SM7 has(but more HIFI) where they just sit in the mix with no eq
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Dylan W on January 24, 2013, 12:32:11 AM
I have the beezneez 67 capsule and it sounds amazing! Tele EF86, IO audio transformer. I'm using the Chunger bday. Ill bring it to my other studio in the next day or so and give it a run against our vintage 67, but as i said earlier it sounds amazing. Just as i would expect the mic to sound. It has that quality that a SM7 has(but more HIFI) where they just sit in the mix with no eq

If you get the chance, a quick shootout against the vintage 67 would be tremendous! Can't wait to finish mine.

Dylan
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on January 24, 2013, 06:59:37 AM
I have the beezneez 67 capsule and it sounds amazing! Tele EF86, IO audio transformer. I'm using the Chunger bday. Ill bring it to my other studio in the next day or so and give it a run against our vintage 67, but as i said earlier it sounds amazing. Just as i would expect the mic to sound. It has that quality that a SM7 has(but more HIFI) where they just sit in the mix with no eq

This is very good news as it's my exact configuration.  Good oh.
What was your source for the tele ef86s?

Also, winetree, if I may, can I ask what your source for the EF806s is?

Peace

Jim
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on January 24, 2013, 01:56:36 PM
I have the beezneez 67 capsule and it sounds amazing! Tele EF86, IO audio transformer. I'm using the Chunger bday. Ill bring it to my other studio in the next day or so and give it a run against our vintage 67, but as i said earlier it sounds amazing. Just as i would expect the mic to sound. It has that quality that a SM7 has(but more HIFI) where they just sit in the mix with no eq

If you get the chance, a quick shootout against the vintage 67 would be tremendous! Can't wait to finish mine.

Dylan

+1 on this ,  well i have to say that i am really glad for you guys  :) :) :) :) :) :)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: imo on January 24, 2013, 05:44:43 PM
Ive had the tele for a while. Tried it in a couple of other builds(i have a lot of mics with EF86s!).
I don't really know a good source, but need to find a reputable tube seller for super low noise. It took a few days to burn this one in. At first I thought i was gonna need another tube, but it has settled in. Could be a little quieter, but as long as it isn't doing that "poppy" thing that the tubes sometimes do, i'm fine. Main thing is that it sounds great.
We are working at my studio today. Typically we don't have time for shootouts(super busy recording) but i will try to do something as soon as i can!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dandeurloo on January 25, 2013, 10:34:29 AM
I've been using my 67  bunch.  It is amazing.  I can't wait to build up my second one.  Even the artist have loved the sound of it.  They comment on how great everything sounds.  From Electric guitar, dobro to vocals.  Pretty great!

Thanks
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Delta Sigma on January 28, 2013, 12:34:34 PM
I don't really know a good source, but need to find a reputable tube seller for super low noise.

I bought a Hulimin Telefunken EF86 and a Valvo EF86 from http://www.nostubestore.com/ both tested for low noise and microphonics.

I haven't tried the Telefunken yet since I've been super busy and fired my mic up with the Valvo just to be safe. The Valvo sounded great on power up and the mic is as quiet as my Beesneez Arabella. I will install the Telefunken soon.

Also, the guy at nostubestore.com was great to deal with. He is selling Hilumin Telefunkens that have other brands stamped on them. This was a very common practice but I've read that sometimes when Telefunken manufactured for other companies (and other companies manufactured for Telefunken) they would use different materials or practices.

Anyways, I could not find any information on the web about Telefunken making Hilumin EF86s for other companies (and the quality of them) so I e-mailed the guy and he said he would make sure that mine would be one labeled Telefunken. There are ways to tell if they are legit anyways but after dealing with this guy I'm confident that they are all fine.

I only recording one song quickly with my Arabella on voice then the DU67 (Valvo), then the DU67 (Valvo) with the low cut. So far it's hard to imagine that by putting in the Telefunken it's going to sound better because even with the Valvo, I've never heard anything this good before.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on January 29, 2013, 07:29:21 PM
Is your Valvo Tube the mesh grill or sold silver?

Has anybody found a wooden mic box that'll fit this mic.
Using SYT-5 body. (Chunger)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dandeurloo on January 29, 2013, 08:27:27 PM
Is your Valvo Tube the mesh grill or sold silver?

Has anybody found a wooden mic box that'll fit this mic.
Using SYT-5 body. (Chunger)

I would love to find a nice wooden box as well for them. 
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Dylan W on January 29, 2013, 08:30:04 PM
Is your Valvo Tube the mesh grill or sold silver?

Has anybody found a wooden mic box that'll fit this mic.
Using SYT-5 body. (Chunger)

I would love to find a nice wooden box as well for them.

I'm going true DIY.

http://www.finewoodworking.com/item/57011/basic-box-making

Dylan
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on January 29, 2013, 09:22:50 PM
That's a lot of woodwork
I'd rather write a check.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Delta Sigma on January 29, 2013, 10:49:50 PM
Is your Valvo Tube the mesh grill or sold silver?

It's the mesh grill, I believe. I will confirm later in the week when I swap it out for the Hilumin Telefunken. I wanted to play with it a little more before swapping it out.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on February 07, 2013, 05:16:01 PM
 
Calibrating PSU -6.3 vdc and the Pot does nothing, Stays at -16.00Vdc
Pot it's 50 ohm. Any suggestions? Using square H- pad and pin7 as Test pionts.
Lowest I can get is 225vdc will that go down with mic hooked-up?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dissonantstring on February 07, 2013, 05:49:47 PM

Calibrating PSU -6.3 vdc and the Pot does nothing, Stays at -16.00Vdc
Pot it's 50 ohm. Any suggestions? Using square H- pad and pin7 as Test pionts.
Lowest I can get is 225vdc will that go down with mic hooked-up?

Are you testing with a load or no load? 
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on February 07, 2013, 05:56:34 PM
No load. Wanted to set levels before I hooked up the mic. They'll go down with a load?
Even though shouldn't the H- pot do something. the 210 vdc does with no load.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: 3nity on February 07, 2013, 06:11:07 PM
Poctop posted about how to test the psu with a dummy load...you ll see!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on February 07, 2013, 06:37:38 PM
Hooked up mic. Adjusted to  -6.3 vdc.
At full could only get 202 vdc. ???
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on February 07, 2013, 09:36:49 PM
Hooked up mic. Adjusted to  -6.3 vdc.
At full could only get 202 vdc. ???

Wich resistance did you put in series with the B+ Pot , in certain instance you may have to tweak the value a little , i used 56K,
Make sure you give it enough time to stabilize and warmup to make sure you are really off a little.
so for less voltage drop try lower value a little ,

Hope this helps,
Dan,


Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Delta Sigma on February 07, 2013, 11:16:00 PM
Hooked up mic. Adjusted to  -6.3 vdc.
At full could only get 202 vdc. ???

How long did you let the mic warm up? It took a few minutes before I was able to get the B+ to 210V.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on February 08, 2013, 12:31:13 AM
Hooked up mic. Adjusted to  -6.3 vdc.
At full could only get 202 vdc. ???

How long did you let the mic warm up? It took a few minutes before I was able to get the B+ to 210V.

I agree with this. I notice that with both of the tube mics I have built (DU67 and MK47) letting the PSU come up to temp yields much better results as far as dialing in the exact B+ and heater voltages. I usually let my mics warm up for about 15 min before I test voltage and apply signal (like singing into it)

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on February 08, 2013, 12:43:43 PM
Let it warm up and got the voltage to +204vdc.
I think I'll try lowering the 56k resistor to raise the voltage a little.
Got the new tubes. Decided to go all the way.
N.O.S. Matched pair. Sound amazing.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Marc Duchesne on February 16, 2013, 10:45:44 PM
IMO wrote:
I have the beezneez 67 capsule and it sounds amazing! Tele EF86, IO audio transformer. I'm using the Chunger bday. Ill bring it to my other studio in the next day or so and give it a run against our vintage 67, but as i said earlier it sounds amazing. Just as i would expect the mic to sound. It has that quality that a SM7 has(but more HIFI) where they just sit in the mix with no eq

--- This is exactly my configuration, but with a NOS Amperex Bugle Boy EF86 tube. Just need to receive my beesneez 67... Can't wait...
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on February 18, 2013, 06:15:41 AM
Quote
Ill bring it to my other studio in the next day or so and give it a run against our vintage 67

IMO, please post samples of that shootout.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on February 19, 2013, 01:50:12 PM
I can't seem to find reference to the second set of jumpers, should I jumper both? I know one is for the internal 200Hz filter, what's the other for?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on February 19, 2013, 02:56:37 PM
I can't seem to find reference to the second set of jumpers, should I jumper both? I know one is for the internal 200Hz filter, what's the other for?

IS is jumpered for default configuration , you will get more bass response and proximity with the jumper off,  the other jumper serves as soldering point for the low cut switching,
Best,
dan,

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993b5d.jpg)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on February 19, 2013, 03:10:15 PM
Thanks Dany  :)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: imo on February 19, 2013, 06:00:58 PM
will  post sound samples as soon as i can. Been working at my studio
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on February 19, 2013, 06:17:43 PM
To avoid possible confusion, 200 Hz is the corner frequency of the switchable high pass on the body of a U67.
The S2 jumper makes for a set 40 Hz (or 30 Hz depending how you measure) high pass or bass roll off. There's no switch for that one on the body.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on February 25, 2013, 01:41:03 PM
Ok pcbs are stuffed, moving onto the PSUs this week and will be buying tubes.

A question, how critical is tube matching for a pair of D-U67s? 
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on February 28, 2013, 12:27:49 PM
seems like a good prospect fun.  i have some but tought l'd let you know,
http://www.ebay.ca/itm/ws/eBayISAPI.dll?ViewItem&item=140920342309&ssPageName=ADME:B:WNA:CA:1123 (http://www.ebay.ca/itm/ws/eBayISAPI.dll?ViewItem&item=140920342309&ssPageName=ADME:B:WNA:CA:1123)
Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on February 28, 2013, 12:51:56 PM
Ok pcbs are stuffed, moving onto the PSUs this week and will be buying tubes.

A question, how critical is tube matching for a pair of D-U67s?

i guess the answer to this would be relative on sligth diff in gain ,emission, response Curve. from the tube at the same  operating conditions (H+ B+ma) , Microphone specifics ( noise, microphonics),
the capsule will also have to be very close in capacitance and tension as well  ;),  those 2 element will interacts.  ;),

just toughts,

Best
DAn.

   
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on March 01, 2013, 01:35:42 AM
Thanks Dany, I bid on those but missed out.  Snagged a matched pair from Germany.

 :)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: MikeFFG on March 02, 2013, 12:44:05 AM
Thanks for clarifying the star ground, Dan.

I've completed my PSU and I'm getting around 214V for the B+ and around -16V at the heater. Going by dmp's great explanation above, I'm in the right ball park, now I just need to calibrate. I tried lowering the B+ voltage using the RTRIMPLATE, but the lowest it will go is 214V. Do I need to increase the value of the pot then?

I also tried raising the voltage for the heater to -15V (mic not connected), but the RTRIM H- doesn't do anything. Maybe my wiring is wrong? Please see the attached picture. Thanks everyone.

-Kevin


Hi someone responded that these seemed alright without a load attached...but I didn't see anyone say that it made sense that the H- not doing anything is correcT? I just want to verify this. I just finished my PSU build and I'm running B+ at 255 with the trim all the way up and H- at -16v...but the H- trim pot doesn't change it at all.  I've read the thread and know that the voltages are fine but just wanted to check on this point before I connect anything else!

I attached a pic of my build. Can't wait to finish the mic and get this tested out!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 02, 2013, 01:09:58 PM
It is perfectly normal for the heater voltage to stay at -16v during pot adjustment with nô load cause the zener is actually eating up the différential

Once the mic with a tube is connected it Will drop down

Best
Dany.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: MikeFFG on March 02, 2013, 11:47:14 PM
Okay thanks...

One more thing...I installed the Low cut and pattern switches backwards, and in the process of desoldering them, broke them. Does anyone have any Mouser part numbers or anything for them?? That'd be great!

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Tedrummerx on March 04, 2013, 06:50:49 PM
Hey guys, I'm having a small issue with one of my u67s, maybe someone can possibly point me in the right direction. In cardioid, both mics seem to be functioning correctly: similar tone and level, both sound great. But on the troublesome mic, when I switch to omni or bi, the level drops significantly and the tone is much darker compared to the other mic. Let it be know, the first mic seems to be functioning just as it should in it's different modes. My first step was comparing the wiring and component placement of the working mic with the non working mic. Seems ok. Can anyone point me in any other direction that may cause my issue? thanks in advance! Capsules are beezneez, ami transformers, telefunken ef86 tubes off ebay.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on March 05, 2013, 03:16:32 AM
Sounds like the rear diaphragm is not connected/not functioning.  Check your patterns switch connections and look for dry joints in this area.  It may be worth reversing your capsule connections to verify that both sides are functioning correctly in cardioid, eliminating this possibility.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Tedrummerx on March 05, 2013, 05:35:25 PM
Thanks Jim50hertz,
Ill try switching the sides and will report back. This has me worried because I noticed a slight issue with the backside of the capsule in the troublesome mic...I won't go into details unless I find this to be the problem and contact the manufacturer first. Thanks again.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Tedrummerx on March 05, 2013, 09:41:19 PM
update: so I swapped the capsule sides and it seems like that's my issue. Now in cardioid mode, there's significant less high end and about 20 db less.  :-\
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on March 06, 2013, 04:15:16 AM
Quote
update: so I swapped the capsule sides and it seems like that's my issue. Now in cardioid mode, there's significant less high end and about 20 db less.  :-\

Let Ben know. He'll do you good.



Henk
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Jar on March 11, 2013, 12:11:08 AM

Sorry this is probably a silly question but im new to all this audio DIY and dont have any experience with electronics but how hard is this to build (im doubting its newbie friendly) and are the PSU's compatible/switchable between the US and UK voltages?

Thanks!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on March 11, 2013, 05:24:23 AM
Welcome!

If you're new to electronics, a tube microphone is not a starting project, I would say. Also, there's lethal voltage (!!!) in the PSU. And the U67 arguably has the most complicated circuit of all tube mics.

On the other hand, the D-U67 is not completely DIY, that is the schematic and layout are already done for you.
If you have a friend who knows what he's doing (!!!) or a good (!) technician in your neighborhood, you may be in luck. Otherwise, I'd do some serious studying and practising first.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on March 11, 2013, 09:10:33 AM
i'm still buying parts for my U67..
for the Styrene 270pf /630V
i assume the Polystyrene Film "Tubular axials" 270pf axial at 630V is fine but i don't understand this :
feedback Capacitor Stryrene 80-160pf/630
does it mean i can buy anything from 80pf to 160pf/630v ?  :-\
sorry i'm not used to this and the justradios is not super explicit :p
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: MikeFFG on March 11, 2013, 11:14:30 AM
Welcome!

If you're new to electronics, a tube microphone is not a starting project, I would say. Also, there's lethal voltage (!!!) in the PSU. And the U67 arguably has the most complicated circuit of all tube mics.

On the other hand, the D-U67 is not completely DIY, that is the schematic and layout are already done for you.
If you have a friend who knows what he's doing (!!!) or a good (!) technician in your neighborhood, you may be in luck. Otherwise, I'd do some serious studying and practising first.

I agree with this...I just finished this project last night and it's working great! With that said, I consider myself 'intermediate' I suppose and don't think there is anyway I could have done this a year or two ago before some of my other builds...not to mention the lethal voltage of course. Plus, although Poctop did a TREMENDOUS job getting this together, there isn't a 'definitive' build guide so you will do lots of referring to the schematic and confusing pictures, which, if you aren't comfortable with the schematic, will be terribly difficult.


On an unrelated note, I just showed the internals of my new U67 to an engineer friend of mine, and his first question was 'won't the tube heat up and melt these wires?' (referring to the wires connecting to the transformer). Is this at all an issue? If it was a concern, I feel like I would've read about it here already. Is there a danger of melting/burning wires or they touch or are too close to the tube? I 'burned in' my tube for about 8 hours last night, and nothing happened, so I assume it's fine, but still interested to know for sure.

Thanks!!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Jar on March 11, 2013, 01:49:06 PM
Thanks for the input chaps!

Ive been looking at a ton of stuff on groupdiy and im trying to think of what would easiest and most useful to start of with, i guess ill have to bug my dad and bro problem is im working out here in NY and there back in the UK  :o

Also just to recap on my other question, do i need anything special in order for these mic psu's to work in both the US and UK or is the voltages switchable on the psu?

Thanks and sorry derailing the thread a bit!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on March 11, 2013, 02:12:32 PM
Quote
do i need anything special in order for these mic psu's to work in both the US and UK or is the voltages switchable on the psu?
you need to use transformers with a dual primary that works with either 120v or 220v.

I would suggest starting with a project that 1) does not have dangerous voltages 2) does not have very expensive components for you to wreck as you learn
A microphone is a poor 1st project for both reasons.
I'd suggest a discrete preamp or compressor. Look at Classic API or Hairball audio to pick something out.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 11, 2013, 03:19:21 PM
i'm still buying parts for my U67..
for the Styrene 270pf /630V
i assume the Polystyrene Film "Tubular axials" 270pf axial at 630V is fine but i don't understand this :
feedback Capacitor Stryrene 80-160pf/630
does it mean i can buy anything from 80pf to 160pf/630v ?  :-\
sorry i'm not used to this and the justradios is not super explicit :p

yes that mean the C17 the feedback capacitor can be from 80-160pf it can be tweaked a notch ,  but usually the stock value from nuemann is 100pf wich is what I supply in the styrokit .

Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: MikeFFG on March 12, 2013, 03:06:17 AM
Finished my build...it's working great!!!!! So excited to record a project with it. I plan on powder coating the body this weekend. Here are some pictures;
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: MikeFFG on March 12, 2013, 03:06:56 AM
2
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: MikeFFG on March 12, 2013, 03:07:22 AM
3
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Delta Sigma on March 15, 2013, 10:50:15 AM
On an unrelated note, I just showed the internals of my new U67 to an engineer friend of mine, and his first question was 'won't the tube heat up and melt these wires?'

Get out your Visa and max it out @ http://www.apexjr.com/ . He sells PTFE (Teflon) wire in various gauges and colours. He's also super nice to deal with.

The PTFE wire won't melt very easily which helps around heat sources and makes soldering in tight spaces easy. His wire is not terribly expensive so I've been stocking up with every build I do. I use it for everything and now have a good colour selection. I won't comment on the necessity of using it in your build since I did not use the AMI transformer but I use this wire everywhere I can now.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 15, 2013, 04:08:39 PM
Quote
On an unrelated note, I just showed the internals of my new U67 to an engineer friend of mine, and his first question was 'won't the tube heat up and melt these wires?'

in all my AMI build the Wire is close but does not touch the tube at all , but the tube will never generate that much heat to melt or even cause a problem i have been myslef using the mic for several several hours and nothing happened here too ,  this has never been an issue here from what i can tell,
just my 2 cents,   ;) ,

if the tube would get hot at this point you would be able to cook an egg on the mic body  ;)

Best,
dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on March 16, 2013, 11:16:54 AM
One of two built, tested and working as it should.  Sounds great too.

Thanks to Dany for making it possible, and Max and Ben for the core components.  8)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: MikeFFG on March 17, 2013, 06:01:02 AM
Quote
On an unrelated note, I just showed the internals of my new U67 to an engineer friend of mine, and his first question was 'won't the tube heat up and melt these wires?'

in all my AMI build the Wire is close but does not touch the tube at all , but the tube will never generate that much heat to melt or even cause a problem i have been myslef using the mic for several several hours and nothing happened here too ,  this has never been an issue here from what i can tell,
just my 2 cents,   ;) ,

if the tube would get hot at this point you would be able to cook an egg on the mic body  ;)

Best,
dan,

Pretty much what I figured, but had to check.

Thanks again for this! I'm powdercoating mine 'black wrinkle' today. Should look pretty cool. And dammit, I'm probably going to have to build another one of these for the stereo pair!

I just did a really quick shootout test in the studio I work at with our U87 (I think it's a 'vintage' one? Definitely not the modern U87 AI) and I could hear a definite difference. Of course I'm biased, but the U67 sounded, I guess...clearer...more 'open' if that makes sense. The best way I could describe it is almost like I was using better converters. The U87 also sounded a bit more 'boxy.'

Edit:

Just so you know, I'm using the capsule from tskguy, the AMI T67 transformer and a NOS Telefunken tube.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on March 17, 2013, 12:01:17 PM
Just so you know, I'm using the capsule from tskguy, the AMI T67 transformer and a NOS Telefunken tube.

That's an awesome combo! I bet it sounds stellar!

Dave
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: kpearsall on March 17, 2013, 10:44:55 PM
Received my capsules friday and finished my first of two 67's yesterday. After initial testing and a really long burn in period, I'm really happy with this mic! I expected an extended debugging period, but it worked first time I plugged it all in, thanks to Dany's great documentation. I'm building a stereo set with Beesneez capsules (matched!) and ioaudio transformers. I'll get started on the next one after some more testing this week. Mine is going up against two original u67's later this week :)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 17, 2013, 10:48:20 PM
Received my capsules friday and finished my first of two 67's yesterday. After initial testing and a really long burn in period, I'm really happy with this mic! I expected an extended debugging period, but it worked first time I plugged it all in, thanks to Dany's great documentation. I'm building a stereo set with Beesneez capsules (matched!) and ioaudio transformers. I'll get started on the next one after some more testing this week. Mine is going up against two original u67's later this week :)

Thanks Ken,
Can't wait to see your feedback on this marvellous testing you are planning to do ,
Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Melodeath00 on March 18, 2013, 11:11:47 AM
Me too! Exciting
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Tedrummerx on March 19, 2013, 04:47:51 PM
Hey guys, wanted to give an update on my capsule. I had it sent out to Ben, it was repaired and shipped back within a week! Sounds great now and performing like the other mic.

I'm still trying to lower some of the noise in my mics. I have that sorta wind/bubbling sound down there. I thought it may be the tubes at first but I replaced them with some low noise tele silver shield hilumins from the nos store, and the noise is still down there. I've been cleaning the circuit with alcohol which seems to be helping. Maybe it's just a matter of getting the circuit really clean? Has anyone else had any successful tricks to lowering noise? Thanks!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 19, 2013, 05:56:43 PM
Hey guys, wanted to give an update on my capsule. I had it sent out to Ben, it was repaired and shipped back within a week! Sounds great now and performing like the other mic.

I'm still trying to lower some of the noise in my mics. I have that sorta wind/bubbling sound down there. I thought it may be the tubes at first but I replaced them with some low noise tele silver shield hilumins from the nos store, and the noise is still down there. I've been cleaning the circuit with alcohol which seems to be helping. Maybe it's just a matter of getting the circuit really clean? Has anyone else had any successful tricks to lowering noise? Thanks!

Make sure the tube Grid node does not touch anything and it is floating , Check the turrent point also , cleanliness is very important in this build, make sure all the floating connection do not touch anything as well , if also can make sure the component on the tube socket board do not touch each other , look for cold solder and flux , are both mics equally noisy  , is it a systematic building error ?  can ou measure the anode point  (a)  on the mic pcb and check it does not vary
Hope this helps,  check your pol voltage , B+ , check the lead from the capsule also ,
Can you post a clip of the noise .
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Tedrummerx on March 19, 2013, 07:05:02 PM
thanks for the reply dan.

Here's mic 1(the noisier of the two): https://soundcloud.com/tedfreeman/u67-1
And mic 2, which i'm pretty happy with as far as the noise: https://soundcloud.com/tedfreeman/u67-2

Through vp26s with maybe 45-50ish db of gain
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 19, 2013, 09:05:26 PM
disconnect the capsule ( is the noise still there ) ?  and then start measuring reference voltage such has B+ , H-, and bias voltage, with the tube in , at the mic PCB and then remove the tube and take the same reading at the tube socket  . double check you wiring and the HZ bridge for short , sounds like a snow storm to me.  if you turn the light off can you actually see the tube glowing in the dark ?  take your time and be carefull  :) the sound i hear is not like an typical HZ contamination tough,  seems like somthing is not wired correctly or cold soldered,
Best,
Dan,
 
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Dylan W on March 19, 2013, 10:42:20 PM
Heads up for anyone who's ordering:

Mouser is out of the 0.01uf polyester film caps, Vishay part number MKT1813310404. I emailed Dany about several alternatives, and he was kind enough to respond with 5 minutes and point out that Newark carries them.

http://www.newark.com/jsp/search/productdetail.jsp?sku=18M2494

Mouser is also out of the 2 watt 18 ohm resistors and 22uf/350V electrolytics, both of which Newark also carries, and the CTS 25K pot, which Digikey carries.

Dylan
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 19, 2013, 10:49:43 PM
you can always check for similar components with mouser ,  the 18 ohm resistor is 5% they might have stock for 1% also ,
the compare tool from mouser is very effective ,
Best,
DAn,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: nolivdacom on March 20, 2013, 04:46:33 AM
same problem for me...
Here are the parts numbers from digikey:
pot 25k 5W: CT2160-ND
resistor 18ohms 2W: 18ZCT-ND
Capacitor 22uF 350V: P5932-ND


I found 0.01uf polyester film caps at mouser's so I don't have any part number from digikey.
Hope it will help.

You also have to know that you have to pay about 18€ for shipping. It was more expensive for me then parts...

best,
Olivier
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on March 20, 2013, 08:20:26 AM
Banzai in the EU stock those 0.01 poly caps.

Conrad stock a 4W 25k pot.  I used this one with no issues.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: nolivdacom on March 20, 2013, 04:35:20 PM
Just a silly question for European people about the PSU:
Do we need to use a transformer to convert 230V to 230V?   :o
Am I wrong if I think that we can go without this tranformer?
Is there any voltage regulation here?
Thanks for any explanation!

 :-\

best,
Olivier
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 21, 2013, 05:23:50 PM
Just a silly question for European people about the PSU:
Do we need to use a transformer to convert 230V to 230V?   :o
Am I wrong if I think that we can go without this tranformer?
Is there any voltage regulation here?
Thanks for any explanation!

 :-\

best,
Olivier

you need it to isolate yourself from everything that happens in the wall-wart, specially Hum
Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: nolivdacom on March 22, 2013, 12:10:41 PM
Quote
you need it to isolate yourself from everything that happens in the wall-wart, specially Hum

Ok thanks!

Another question about fuse for psu:
I read that (for europe) we have to use 0,1A fuse. I tried but it doesn't work. I tried with 0,3A from mouser bom. My psu works well. So, my question is, what is the good value for europe?

best,
Olivier
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 22, 2013, 12:18:39 PM
Quote
you need it to isolate yourself from everything that happens in the wall-wart, specially Hum

Ok thanks!

Another question about fuse for psu:
I read that (for europe) we have to use 0,1A fuse. I tried but it doesn't work. I tried with 0,3A from mouser bom. My psu works well. So, my question is, what is the good value for europe?

best,
Olivier
in therory you should be fine with a 0.1A  but it needs to be a slow-blow type but here i have used 0.3A instead of point 0.2A America and it works fine ,
somtime it is just not enough slow blow type to work if everything reads proper and you have a 0.3A you'll be fine the worst thing that could happen is that you cook the toroid that is why you need a slow blow type fuse,

Best,
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on March 25, 2013, 03:03:30 AM
Received a P.M.
Quote
I saw you had a magic donut on your 67 tube , what is it   and where did you get this ?
Let me know if you have a chance , this is very nice , i'd like to test with a smaller one for th 5840w also ,
intersting material,
Best
Dan,

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Tedrummerx on March 25, 2013, 05:44:53 PM
So I've been playing around with the noisy mic. I've disconnected the capsule, noise is still there. Checked voltages, all seem good. Then I tried swapping the tube from the noisy mic with the quiet mic and sure enough the noise switched to the other mic too. So, maybe my issue is I need to continue my search for low noise tubes?

Also, does it make any sense trying to come up with a test to see if the noise is within the specs of a u67? I'm really just comparing the noise to that of my other mics, like my mk47. Maybe the noise is close to normal for a u67.

With all said, I've been using my 67s and they sound amazing. On sources like drums, the noise isn't even close to an issue, they sound great!

Thanks for your input guys, really appreciate it!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: bkbirge on March 26, 2013, 10:20:25 AM
So I've been playing around with the noisy mic. I've disconnected the capsule, noise is still there. Checked voltages, all seem good. Then I tried swapping the tube from the noisy mic with the quiet mic and sure enough the noise switched to the other mic too. So, maybe my issue is I need to continue my search for low noise tubes?

Also, does it make any sense trying to come up with a test to see if the noise is within the specs of a u67? I'm really just comparing the noise to that of my other mics, like my mk47. Maybe the noise is close to normal for a u67.

With all said, I've been using my 67s and they sound amazing. On sources like drums, the noise isn't even close to an issue, they sound great!

Thanks for your input guys, really appreciate it!


My vintage U67 was quiet as a church mouse. It has probably already been mentioned but the wiring on this build is of utmost importance for noise, take your time and be very meticulous with keeping it clean and short.


Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dmp on March 26, 2013, 10:42:18 AM
Quote
Then I tried swapping the tube from the noisy mic with the quiet mic and sure enough the noise switched to the other mic too.

Seems pretty conclusive that the noise is following the tube. Get some more tubes?
My build was quiet. Never occurred to me to measure the noise floor - it was just not apparent doing room recordings of acoustic music. Using a telefunken tube.
So if you notice the noise, I would say it is too much.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on March 26, 2013, 11:15:31 AM
Telefunken is the quietest (and most expensive) on average, but even those vary.
Cheapest are the Russian EF86s (OK, not counting the Chinese). That means you can buy more and there will be quiet ones among them.
I'm not talking about tone here, mind.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 26, 2013, 06:17:51 PM
just added this for reference,

http://www.levytubes.com/servlet/the-Vacuum-Tube-Dampers-fdsh-Dampeners/Categories

(thanks Winetree)

Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on March 26, 2013, 07:23:32 PM
Are those things really necessary?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Tedrummerx on March 26, 2013, 07:57:22 PM
Thanks for the replies guys.
So far in my search for tubes I purchased two telefunken silver shields off ebay which were not advertised for microphone use, and were a bit noisy, one more than the other. So I then decided to purchase a matched pair of tele silver shield (simens branded), tested for low noise from the nos store. Again lower in noise but one nosier than the other. NOS is actually shipping me a replacement for free which is great. So my search will continue. Anyone having good luck with the 806s?

Quote
My build was quiet. Never occurred to me to measure the noise floor - it was just not apparent doing room recordings of acoustic music. Using a telefunken tube.
So if you notice the noise, I would say it is too much.

And this is the bottom line, is the noise really so apparent that it affects the sound I'm trying to capture. I think maybe i'm being too picky. When really will I be using 50-60+ db of gain with this mic? I feel not often. If i can get my noisy mic around the level of the other quieter mic, I'll be a happy camper.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 29, 2013, 11:41:16 AM
Received my capsules friday and finished my first of two 67's yesterday. After initial testing and a really long burn in period, I'm really happy with this mic! I expected an extended debugging period, but it worked first time I plugged it all in, thanks to Dany's great documentation. I'm building a stereo set with Beesneez capsules (matched!) and ioaudio transformers. I'll get started on the next one after some more testing this week. Mine is going up against two original u67's later this week :)


Thanks Ken,   Any updates this great idea of comparaison with the real thing ,
best,
Dan,


Title: Re: D-U67 Tube Microphone Build Thread.
Post by: kpearsall on March 29, 2013, 10:28:25 PM
Next thursday is the test. The only time we can get together unfortunately. It was postponed due to the u67 owner being out of town.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 30, 2013, 12:09:58 AM
Next thursday is the test. The only time we can get together unfortunately. It was postponed due to the u67 owner being out of town.

Thanks Ken ,  My popcorn will be ready then   :)
Best,
DAn,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on March 30, 2013, 04:37:04 PM
hey guys, I am just about finished with my build here, but I have ran into a little speed bump. I am assuming that the middle lead of the 3 way switch, goes to the front of the capsule, but I can't verify this for sure on the schematic. It shows the middle lead omni, (which is actually labelled figure 8 on my mic), connects to nothing.  I have the ring of the capsule connected to the post on the left side of the tube pcb, which connects to the pad switch. This looks correct to me on the schematic.I'm also assuming that the back plate of the capsule goes to the right post of the tube pcb, which connects to the omni side of the 3 way switch. I am still learning how to correctly read schematics, so I didnt want to continue without verifying these connections.

Another problem I have is, that when I go to mount my Beesneez capsule to either the mount that it came with, or the mount that came with the body, the holes don't line up. I ended up just using one screw. Is this something that anyone else has had an issue with?

Any help is greatly appreciated.


Edit... Now after looking at the schematic and thinking it over a little more, I am thinking the opposite. The back capsule being connected to the 3 way switch in cardiod, turns it off, right?  :-[
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on March 30, 2013, 05:09:17 PM
Quote
It shows the middle lead omni, (which is actually labelled figure 8 on my mic), connects to nothing.

No solution from me, but a possible reason for confusion.
Do you have the earlier SYT-5 body, from ChuckD? If I'm not mistaken, that one indeed has figure eight in the middle.
The ones from chunger have cardioid in the middle position.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 30, 2013, 06:28:21 PM
Quote
It shows the middle lead omni, (which is actually labelled figure 8 on my mic), connects to nothing.

No solution from me, but a possible reason for confusion.
Do you have the earlier SYT-5 body, from ChuckD? If I'm not mistaken, that one indeed has figure eight in the middle.
The ones from chunger have cardioid in the middle position.

If you look at the second part of the m269b build there is a whole pictorial in this section to proper wire the u67 , it is the same except one step wich is clearly noted
Have a look and let me know
Best dan
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on March 30, 2013, 06:47:45 PM
http://www.groupdiy.com/index.php?topic=51350.0 (http://www.groupdiy.com/index.php?topic=51350.0)  :)

But FWIW, aren't there two versions of the SYT-5?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on March 30, 2013, 07:29:35 PM
awesome, got it! now with my psu calibration, I am having an issue measuring the B+. I measure it to any ground right? I easily get 6.3v to the heater. When I measure the "AC in", I get 173v instead of 210v. Thats probably not going to cut it right? I'm so close!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on March 30, 2013, 08:02:05 PM
awesome, got it! now with my psu calibration, I am having an issue measuring the B+. I measure it to any ground right? I easily get 6.3v to the heater. When I measure the "AC in", I get 173v instead of 210v. Thats probably not going to cut it right? I'm so close!

Turns out that the orange and red wires from the xfmr werent tied together, when i thought that they were. I now get 228v at B+. Can someone please tell me if this will be close enough? I have the trim pot completely cranked.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on March 30, 2013, 08:04:08 PM
Quote
It shows the middle lead omni, (which is actually labelled figure 8 on my mic), connects to nothing.

No solution from me, but a possible reason for confusion.
Do you have the earlier SYT-5 body, from ChuckD? If I'm not mistaken, that one indeed has figure eight in the middle.
The ones from chunger have cardioid in the middle position.

Yeah, I have the earlier ones from Chuck. So, I guess it wont be perfect, but close enough for me.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 30, 2013, 08:13:43 PM
awesome, got it! now with my psu calibration, I am having an issue measuring the B+. I measure it to any ground right? I easily get 6.3v to the heater. When I measure the "AC in", I get 173v instead of 210v. Thats probably not going to cut it right? I'm so close!

Turns out that the orange and red wires from the xfmr werent tied together, when i thought that they were. I now get 228v at B+. Can someone please tell me if this will be close enough? I have the trim pot completely cranked.

Have you installed the external series resitor of 56K ish to the B+ trim as in the build picture page 1 of this thread
Let. Me know
Dany
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on March 30, 2013, 08:20:31 PM
Hi Dany, yeah I did. I get 228v unloaded, and about 180v loaded.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on March 30, 2013, 08:35:31 PM
Hi Dany, yeah I did. I get 228v unloaded, and about 180v loaded.

You need 210 loaded can you reach that
Dan
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: janps on March 31, 2013, 12:04:00 PM
YES IT'S DONE. my 2 U67 clones are  now finished and tested, they are sounding amazing and I want to thanks a lot Mr procop for this excellent project as Eric (TSKGUY) that made very nice american capsules, I build mine with AMI transformers ; congratulations to all of you for making this project possible.
All the best.
PS I will try to join something to ear and see (I have the nice PSU cases from Dan , very nice too)
Jean-pierre

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on March 31, 2013, 01:36:25 PM
Quote
they are sounding amazing

Hearing is believing.  ;)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on March 31, 2013, 08:50:24 PM
Hi Dany, yeah I did. I get 228v unloaded, and about 180v loaded.

You need 210 loaded can you reach that
Dan

228v was as low as i could get once it was loaded. Should I add a larger resistor, or do you think that there may be an error in my build?

thanks for the responses
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on April 01, 2013, 09:59:15 AM
Hi Dany, yeah I did. I get 228v unloaded, and about 180v loaded.

You need 210 loaded can you reach that
Dan

228v was as low as i could get once it was loaded. Should I add a larger resistor, or do you think that there may be an error in my build?

thanks for the responses

could you show us a picture of your psu build,  did you check that you wired your the external resistance in series with the pot or in parralle ,  tis may be some high tolerance on the pot doing that along with the resistance ,    if you measure the voltage and then connect the mic is the voltage dropping ? in a sense is your tube drawing B+ plate current if so it shoud drop on power on ,  if everything is wired and installed properly you may fix the problem using a larger resistor ,

if you figures that it is consumming 0.8ma you can then calculate the extra resistive path to put it dow by arround 20V
= around and extra 20K .

Hope this helps,
dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Volume11 on April 02, 2013, 03:50:15 AM
Hi Dany, yeah I did. I get 228v unloaded, and about 180v loaded.

You need 210 loaded can you reach that
Dan

228v was as low as i could get once it was loaded. Should I add a larger resistor, or do you think that there may be an error in my build?

thanks for the responses

could you show us a picture of your psu build,  did you check that you wired your the external resistance in series with the pot or in parralle ,  tis may be some high tolerance on the pot doing that along with the resistance ,    if you measure the voltage and then connect the mic is the voltage dropping ? in a sense is your tube drawing B+ plate current if so it shoud drop on power on ,  if everything is wired and installed properly you may fix the problem using a larger resistor ,

if you figures that it is consumming 0.8ma you can then calculate the extra resistive path to put it dow by arround 20V
= around and extra 20K .

Hope this helps,
dan,
I'm sorry I didn't get back to you on this sooner. I read your last post wrong and was thinking of unloaded instead of loaded, so I was able to get the voltage up to 210v loaded. The mic sounds excellent! I used the beesneez capsule with an ami xfmr. I only had time to test it on speech and a little bit of electric guitar. I'll report back when I get some more time with it.

Thanks for this project!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on April 03, 2013, 01:59:54 PM
Hey Guys, I am building four of these.... Well, I'll be doing two m269's and two 67's. I've got 2x each of Max's and AMI's trafo's and four bodies plus a bunch of parts ready...

I do have 2x of Eric's K67 capsules which I'll build into each a 67 and 269 using the different trafo's.

I'm wondering whether anyone has done either of these with Eric's capsules and/or the BeezKneez K6. Not looking for one to be "better" than the other but am looking for a range of sonic options in the same flavour. I'm sure Ben's K6 will be wonderful but was looking for any observations and any other options for high quality k67 style capsules.

In any case thanks in advance for the input and I'm happy to share my thoughts and results as I put these together.

Ciao,
jb
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: micaddict on April 03, 2013, 03:38:20 PM
Quote
I do have 2x of Eric's K67 capsules which I'll build into each a 67 and 269 using the different trafo's.

For comparison sake, best would be to have four of Eric's capsules, one D-67 with AMI tranny, one with ioaudio tranny, one D-269 with AMI tranny and one with ioaudio tranny. That's four different combos, but with "the same" capsule. Interesting for your fellow GroupDIY members.  ;)

But I have a feeling you prefer to have two pairs that can do stereo.
In that case, get two BeesNeez K6s.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: saint gillis on April 03, 2013, 08:48:33 PM
Hi everybody, thanx for this wonderful thread, I ve just finished my mic with tskguy's capsule & AMI T67 transformer, sounds great!
 Just to say that 11mm 0.01µ caps weren't available on Mouser http://fr.mouser.com/Search/ProductDetail.aspx?R=MKT1813310404virtualkey61310000virtualkey75-MKT1813310404 (http://fr.mouser.com/Search/ProductDetail.aspx?R=MKT1813310404virtualkey61310000virtualkey75-MKT1813310404) but I did it with thoose 16.5mm http://fr.mouser.com/Search/ProductDetail.aspx?R=150103J400BBvirtualkey53900000virtualkey539-150103J400BB (http://fr.mouser.com/Search/ProductDetail.aspx?R=150103J400BBvirtualkey53900000virtualkey539-150103J400BB)
It fits Chunger's body without any problem!
(http://imageshack.us/a/img684/6793/43410008.jpg)
(http://imageshack.us/a/img97/2272/10627409.jpg)
(http://imageshack.us/a/img854/4295/71449556.jpg)
(http://imageshack.us/a/img715/9899/55741158.jpg)
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on April 06, 2013, 02:50:27 PM
Hi everybody, thanx for this wonderful thread, I ve just finished my mic with tskguy's capsule & AMI T67 transformer, sounds great!
 Just to say that 11mm 0.01µ caps weren't available on Mouser http://fr.mouser.com/Search/ProductDetail.aspx?R=MKT1813310404virtualkey61310000virtualkey75-MKT1813310404 (http://fr.mouser.com/Search/ProductDetail.aspx?R=MKT1813310404virtualkey61310000virtualkey75-MKT1813310404) but I did it with thoose 16.5mm http://fr.mouser.com/Search/ProductDetail.aspx?R=150103J400BBvirtualkey53900000virtualkey539-150103J400BB (http://fr.mouser.com/Search/ProductDetail.aspx?R=150103J400BBvirtualkey53900000virtualkey539-150103J400BB)
It fits Chunger's body without any problem!
(http://imageshack.us/a/img684/6793/43410008.jpg)
(http://imageshack.us/a/img97/2272/10627409.jpg)
(http://imageshack.us/a/img854/4295/71449556.jpg)
(http://imageshack.us/a/img715/9899/55741158.jpg)

Glad you made it  :)
Thanks for the tips,  I am glad it works out fine with the 16.5mm  lenght in this build ,  sometimes mouser is out of stock for a while or the minimum quantity is from another planet wich is annoying. but this is a great replacement Thanks to St-Gillis

Quote
but I did it with thoose 16.5mm
http://fr.mouser.com/Search/ProductDetail.aspx?R=150103J400BBvirtualkey53900000virtualkey539-150103J400BB



Best,
D.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on April 08, 2013, 04:00:34 PM
Here is some  alternatives for the 5*11mm caps needed specifically for the M49bc square and round,  also in the U67 and 269c mic,


http://www.alliedelec.com/search/searchresults.aspx?dsNav=Ntk:Primary|MKT1813310405|3|,Ny:True,Ro:0&dsDimensionSearch=D:MKT1813310405,Dxm:All,Dxp:3&SearchType=0 (http://www.alliedelec.com/search/searchresults.aspx?dsNav=Ntk:Primary|MKT1813310405|3|,Ny:True,Ro:0&dsDimensionSearch=D:MKT1813310405,Dxm:All,Dxp:3&SearchType=0)


http://canada.newark.com/vishay-roederstein/mkt1813310405g/capacitor-film-0-01uf-400v-axial/dp/26M1636?Ntt=MKT1813310405

http://canada.newark.com/vishay-roederstein/mkt1813-310404/capacitor-poly-film-0-01uf-400v/dp/18M2494?Ntt=MKT1813310404

http://fr.farnell.com/vishay-roederstein/mkt1813310405g/condensateur-0-01uf-400v/dp/1166851?Ntt=MKT1813310405

Title: Re: D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on April 09, 2013, 06:25:40 PM
Thanks Dan! I ordered 3x TFK EF800's and 4x Valvo EF86's for test/swap/spares in two of these mic's..

Cheers,
jb
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on April 10, 2013, 02:38:36 PM
Hi,

i'm wiring the mic and i would like to know what is the best cables to use inside for switchs capsule and tranny.
i don't have the exact english word but you know you can use cable with one single "connector" ("brin" in french) that is stronger but harder to store inside the mic i guess. and other cables that are with lots of "connectors" ("multibrin" in french) that are easier to bend but maybe not that great (?)

and also maybe with heat one is better than the other ?
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: HellfireStudios on April 10, 2013, 06:09:39 PM
Hi,

i'm wiring the mic and i would like to know what is the best cables to use inside for switchs capsule and tranny.
i don't have the exact english word but you know you can use cable with one single "connector" ("brin" in french) that is stronger but harder to store inside the mic i guess. and other cables that are with lots of "connectors" ("multibrin" in french) that are easier to bend but maybe not that great (?)

and also maybe with heat one is better than the other ?

Solid core refers to one piece of wire. Stranded wire is made with multiple "strands" within the same insulation. Stranded has better flexability. Both wires can do the job well.

As for the heating aspect, PTFE insulated wire won't melt when it is soldered.

-James-
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on April 11, 2013, 08:03:26 AM
hi ;) thx for all the explanation !
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on April 11, 2013, 01:37:17 PM
I have been using stranded cat5 conductors in my builds without issue and in cases where I build my own cable I use conductors from that cable since they are good enough for a 20-30ft run they should be good enough for a couple more inches inside the mic.. CAT5 is small, flexible, multicolored and cheap. I wouldn't recommend using solid core hookup cable since it's somewhat more fragile than stranded but others may have different ideas too.

One of these days i'll get some spools of silver stranded ptfe hookup cable.

Ceers,
j
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Winetree on April 11, 2013, 08:54:12 PM
Quote
One of these days i'll get some spools of silver stranded ptfe hookup cable.

Just ordered over 850 ft. of PTFE Silver plated stranded copper wire from Apexjr Wire (818) 248-0416
Best price I could find
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on April 11, 2013, 08:59:39 PM
Quote
One of these days i'll get some spools of silver stranded ptfe hookup cable.

Just ordered over 850 ft. of PTFE Silver plated stranded copper wire from Apexjr Wire (818) 248-0416
Best price I could find

should I be getting more boards now  ;D,
I bet you will be good for a While :)
Best
Dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on April 12, 2013, 08:03:02 AM
ok stupid question #2
what is the good position to put the AMIt67 on it's "AMII adapt bopad by DanB" i don't see where is the "reading" ont the transformer that inform about the side (or i miss something :p )
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on April 12, 2013, 10:01:26 AM
ok stupid question #2
what is the good position to put the AMIt67 on it's "AMII adapt bopad by DanB" i don't see where is the "reading" ont the transformer that inform about the side (or i miss something :p )

From the build thread page 1   you should be finding some black marking on your transformer somehow.

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993d1c.jpg)


hope this helps,
D
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on April 12, 2013, 10:27:28 AM
Oh yeah thanks i got that picture from page 1 + updates but i didn't see that "black mark" now i  got it !
so i have to put black mark from trans on the "="sign of the PCB.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on April 12, 2013, 10:34:06 AM
Oh yeah thanks i got that picture from page 1 + updates but i didn't see that "black mark" now i  got it !
so i have to put black mark from trans on the "="sign of the PCB.

correct, ;)
dan,
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on April 13, 2013, 03:53:17 PM
For those that will be building the mic project that needs the 0.01uf  capacitor in the package 5*11mm  i have been able to change mouser minds to offer a 10% variation at a minimum qty of 1  ;),

here is a link for it ,
http://ca.mouser.com/ProductDetail/Vishay-Roederstein/MKT1813310405/?qs=N5kmjX/bzE4Fjs7uA0EePA==

i aslo went over my BOM and added in the customer part number cell some nice subsitution for the parts that went back order , should be all good now ,

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Floti on April 25, 2013, 06:43:39 AM
Where are you guys getting bodies to do this build?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: HellfireStudios on April 25, 2013, 09:10:16 AM
Where are you guys getting bodies to do this build?

http://store.studio939.com/product/syt-5-microphone-body-kit

-James-
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Joekkel on April 26, 2013, 02:45:47 AM
hi everybody,

so i finished my build but i'm having some issues. as i plugged the mic to my powersupply, the voltage of B+ dropped to 170V and i had to remove the 56k-resistor in front of the 25k-poti to reach 210V loaded.

H- measures -6.3V, B+ 210V, and a measures 3.3V on the mic-pcb

i don't get any sound from the capsule, only thing i hear are microphonics when touching the mic-body. in the attached pic you can see C9 got touched by the solder-iron. could it be busted?

picture here: http://www.facebook.com/photo.php?fbid=10201190980723419&l=d155cfe515

other strange thing: the H- Pad on the mic-pcb is connected to ground, but only if the tube is in its place. is this normal?

i hear pops, when switching pattern/pad/l-cut. any help would be appreciated, thanks!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 26, 2013, 09:25:21 AM
hi everybody,

so i finished my build but i'm having some issues. as i plugged the mic to my powersupply, the voltage of B+ dropped to 170V and i had to remove the 56k-resistor in front of the 25k-poti to reach 210V loaded.

H- measures -6.3V, B+ 210V, and a measures 3.3V on the mic-pcb

i don't get any sound from the capsule, only thing i hear are microphonics when touching the mic-body. in the attached pic you can see C9 got touched by the solder-iron. could it be busted?

picture here: http://www.facebook.com/photo.php?fbid=10201190980723419&l=d155cfe515

other strange thing: the H- Pad on the mic-pcb is connected to ground, but only if the tube is in its place. is this normal?

i hear pops, when switching pattern/pad/l-cut. any help would be appreciated, thanks!

this looks like a cold solder to me , but may be part of the problem as well.

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993d48.jpg)

Quote
H- measures -6.3V, B+ 210V, and a measures 3.3V on the mic-pcb
 

what does measure 3.3V on the pcb the B+ ? if it is B+ then somthing is not happening up to your mic pcb. check the B+ connection and wiring,

Quote
other strange thing: the H- Pad on the mic-pcb is connected to ground, but only if the tube is in its place. is this normal?

you might be confusing this little resistance for a short it should read something like 10ohm IIRC


it would seems that your tube or something in the circuit is drawing way too much current for your tube ,  what is the plate voltage you get on the (a) pad on your pcb , 

remove the tube and capsule and try to achieve proper bias voltage first , check for short or cold solder,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Floti on April 27, 2013, 10:37:51 AM
Where are you guys getting bodies to do this build?

http://store.studio939.com/product/syt-5-microphone-body-kit

-James-

Yeah, but it's been sold out forever!! I tried contacting Shuaiyin but they won't sell me in small quantity...
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 27, 2013, 10:51:31 AM
Where are you guys getting bodies to do this build?

http://store.studio939.com/product/syt-5-microphone-body-kit

-James-

Yeah, but it's been sold out forever!! I tried contacting Shuaiyin but they won't sell me in small quantity...

Chunger is expecting a load of them pretty Soon I beleive,
Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: nolivdacom on April 29, 2013, 02:10:58 PM
Hello and thanks a lot for this great thread!
I tried to use DU67 on Drum kit, Bass, guitars...
Here is a picture of my last recording. My two DU67 works really well!!!
I'm a really happy guy!  ::)
DU67 vs SM57 vs E906 vs C414 vs Schoeps CMC5!!!  ;D
And the winner is... DU67 and Schoeps CMC5 on distorted rock guitars...

I'll try to post pictures of mics, PSUs and samples as soon as possible.

Good luck to everybody,
Best

Olivier
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: tskguy on April 30, 2013, 08:13:09 AM
Looks like fun!!

I love my 67, its sounds amazing! Good job on the build..

Tskguy
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Joekkel on May 10, 2013, 06:17:32 AM
hi there,

so my measurements with the tube and capsule connected are:

H-: -6.3V
B+: 210V
[a]: 3.22V

what should the [a]-pad measure? all measurements are to ground.

thanks and many regards,

joachim
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 10, 2013, 02:46:14 PM
hi there,

so my measurements with the tube and capsule connected are:

H-: -6.3V
B+: 210V
[a]: 3.22V

what should the [a]-pad measure? all measurements are to ground.

thanks and many regards,

The <a> refers to the anode voltage or plate voltage it should be like 75V ,  so it seems you have no plate current , either a bad tube or something arround the plate resistor Node R14 -C9 ,  check cold solder on the tube socket as a start and arround the tube, 
Best,
Dan,

joachim
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 14, 2013, 09:03:34 AM
Hi,

i'm mounting the capsule right now but i can't figure out how to wire it.  ???
all the pictures i see are not clear enough to understand where the wires go.
+ i see on the tskguy capsule a mark on one side of each capsule is that the "front" ?

on page 13 (http://www.groupdiy.com/index.php?topic=50021.240) there's some info but still lots questions.

1- Front diaphragm center lead goes to right side turret (if holding the mic straight up and the tube facing you)
on POCTOP pictures means : right turret -> GREY CABLE -> front diaphragm
2- Rear diaphragm center lead goes to pattern switch pin 2 (actually soldered to the switch)
on POCTOP pictures means : PAT switch pin2 -> BROWN CABLE -> rear diaphragm
3- backplate lead goes to left turret (mic orientation same as above)
this i don't understand. capsule has 2 wires. do i have to add extra wire with screw on the metal part around the capsule in one of those little holes coveered by transparent plastic there ? any hole should be ok ?
on POCTOP pictures would mean : left turret -> ORANGE CABLE -> capsule "backplate"

any hi rez picture on this part or some diagram i could read ?
thx
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 14, 2013, 02:40:42 PM
(https://dl.dropboxusercontent.com/u/43869772/U67/1-1.jpg)
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993d57.jpg)
Hope this helps,

Refer to M269b build thread for pattern switch and low cut and pad,
Dan,

Yes you need to have the backplate ( metal part of the Capsule connected via a screw eylet) and then wired to middle pin of pattern switch , what i usually do is to have a pre existing lead on the switch board that goes up to the basket ,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: imo on May 16, 2013, 05:22:15 PM
i have a question about plate voltage tolerance. I had a Tele tube that was a bit noisy, so i ordered a couple of Aperex Bugle boys tested for low noise.
The sound floor is definitely better. I am seeing about 85v on the plate, around 1.7v between r10 and r11.
My heater is about 6.1. Right now my B+ is a little high at 213v. I can trim it down, but its still going to be around 80-82 i imagine. Would this be considered in spec? My cathode seems cool, so i am assuming that is much more important
Thanks
Ian
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 16, 2013, 06:19:13 PM
all clear poctop thx for the pirctures !  8)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 17, 2013, 05:19:59 PM
dam   :D .. i was soldering wires close to that large Film Capacitor and i burn it a little :p
do you think it's ok or i have to change it ?
https://lh5.googleusercontent.com/-cG1e2gaw298/UZacvcHxY4I/AAAAAAAABBo/VpjXJmaaS88/s800/IMG_2112.JPG
https://lh4.googleusercontent.com/-wqBQjRvz9Bw/UZactkAzw4I/AAAAAAAABBc/RzOQMXXEJIo/s800/IMG_2111.JPG
https://lh4.googleusercontent.com/-AvkpCCVCTOY/UZacsr0v2UI/AAAAAAAABBY/mUB79cDKGvY/s800/IMG_2110.JPG
https://lh3.googleusercontent.com/-5ae6Njz0hdI/UZacrhiqKjI/AAAAAAAABBQ/4ecUNYcyjwo/s800/IMG_2109.JPG
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: imo on May 17, 2013, 06:09:50 PM
no ideas on the plate voltage, as to whether it is too high? I know that it is kept lower for more clean headroom, but would it being in the low 80's be too high to be in spec?
My cathode resistor seems to be right where it should, so the plate current seems in the ballpark
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: nolivdacom on May 18, 2013, 05:18:19 PM
Hello Everybody,
I'd like to share some pictures of my build...  ;D

best,
Olivier
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: nolivdacom on May 18, 2013, 05:21:05 PM
And the back side...
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: nolivdacom on May 18, 2013, 05:24:59 PM
The inside of my PSU...  ::)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: nolivdacom on May 18, 2013, 05:27:36 PM
And the last one...

good luck!  ;D

best,
olivier
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dandeurloo on May 18, 2013, 10:03:09 PM
I've built 2 of these now and they are fantastic! Love them.  On to the 269 and 47fet.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 21, 2013, 04:03:03 AM
very nice build nolivdacom i'm surprised how you passed the wires from tran pcb to main pcb ! i can not see them  :o



Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: nolivdacom on May 21, 2013, 04:34:06 AM
Thanks!  ::)

Quote
how you passed the wires from tran pcb to main pcb

I passed wires between PCB and Transfo. There is enough space so you don't have to passed it the same way as other wires. It works well and I've got more space around the tube. It's the cleanest way I found to do it, maybe not the best... Hope it's understandable  :D

best,
Olivier
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on May 21, 2013, 06:16:53 AM
Any chance it could be made to fit the longer E80F tube?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Joekkel on May 21, 2013, 07:25:04 AM
good news!! c9 was busted so i replaced it. now the mic works like a charm! i was irritated by the crackling and popping at first, but this disappeard after some burning in of the tube. thanks poctop for helping and making this possible!!

i have the k67 from chunger installed and like it a lot, so... is the capsule from tskguy really so much better?

many regards to all of you! enjoy your new mic as i do ;)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 21, 2013, 08:07:01 AM
a (noob again) question about flux.
in my other projects i didn't clean flux because there's not much and i don't use extra flux.
now this is my "smalest" kit and i wonder if it is super important to clean the board cause i don't exactly know how to do this ?

as i understood from main topic : 0.1A fuse for europe 210v is fine ?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: HellfireStudios on May 21, 2013, 10:29:40 AM
a (noob again) question about flux.
in my other projects i didn't clean flux because there's not much and i don't use extra flux.
now this is my "smalest" kit and i wonder if it is super important to clean the board cause i don't exactly know how to do this ?

as i understood from main topic : 0.1A fuse for europe 210v is fine ?

91% Isopropyl Alcohol and a toothbrush. Be aware that styrene caps don't gt along with alcohol, so you should clean the board just before installing those.

-James-
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Le Roux on May 21, 2013, 03:24:50 PM
Finished my U67.

Iaudio transformer
NOS Telefuken EF86 from Cristian
Ben's capsule

On a comarison with Iaudio MK47, we found the MK47 to have more presence. It was chosen in all preamp-compressor combinations we tried.
The U67 was a little too bassy. (Atleast on my friends vocals)
I have all the jumpers in as factory default.
Should I try removing them or try a different tube?

Thanks for any suggestions.
Neil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 21, 2013, 03:27:23 PM
Finished my U67.

Iaudio transformer
NOS Telefuken EF86 from Cristian
Ben's capsule

On a comarison with Iaudio MK47, we found the MK47 to have more presence. It was chosen in all preamp-compressor combinations we tried.
The U67 was a little too bassy. (Atleast on my friends vocals)
I have all the jumpers in as factory default.
Should I try removing them or try a different tube?

could you let us know what you have as short and open in term of jumpers and fonctionnality.
do you have a shorting jumper on S2 internal Switch ? that will affect the bass response.
S2 should normally be short for Vocal operation.
Best,
Dan,
 


Thanks for any suggestions.
Neil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 21, 2013, 05:03:39 PM
Ok as there's not so many info on the europe version here is a picture of what i did for the ones who could need it.
and because i'm not that great at electronic of course if you find any error please tell me before i power this and blow my house !  8).
(https://lh5.googleusercontent.com/-4dnHSwD8TO0/UZvgmj3k_BI/AAAAAAAABCA/qSov9e9lceA/w965-h749-no/europe-PSU.jpg)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on May 21, 2013, 05:19:49 PM
Finished my U67.

Iaudio transformer
NOS Telefuken EF86 from Cristian
Ben's capsule

On a comarison with Iaudio MK47, we found the MK47 to have more presence. It was chosen in all preamp-compressor combinations we tried.
The U67 was a little too bassy. (Atleast on my friends vocals)
I have all the jumpers in as factory default.
Should I try removing them or try a different tube?

Thanks for any suggestions.
Neil

The U67 was designed to have less bass than its predecessor, the U47, especially in close proximity.

Like Dany said, the S2 short is an important part of that. Most U67s are used like this, but it can be changed.

In other words, if a particular U67 sounds bassier than a particular U47, there's likely something not up to spec in one of the two or in both. Especially if the U67 is in the common vocal mode.

BTW presence is not the exact opposite of bass. They can coincide as they typically do in a good U47.
Some experience the U67 as a dark microphone. I wouldn't necessarily agree, but regardless, dark is not the same as bassy.
Also, presence is sooner a high-mid than a treble thing, I'd say.
FWIW


Henk
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: imo on May 21, 2013, 05:52:42 PM
sorry to keep harping on this, but does anyone have any ideas on spec voltage for a U67. I built Dan's circuit, and in changing the tube have about 83vDC on the plate. I know its right on the edge of the 10% that people spec out for tube circuits, but with this one has anybody dealt with this? My cathode seems to be in spec, at 1.7v
Dan, have you run into this with any of your circuits?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 21, 2013, 11:01:00 PM
sorry to keep harping on this, but does anyone have any ideas on spec voltage for a U67. I built Dan's circuit, and in changing the tube have about 83vDC on the plate. I know its right on the edge of the 10% that people spec out for tube circuits, but with this one has anybody dealt with this? My cathode seems to be in spec, at 1.7v
Dan, have you run into this with any of your circuits?

The Difference in plate current should be arround 0.9 at 75Vplate and 0.833 at 85 plate = 0.066ma difference,  and the tolerance is from 0.8ma to 0.9 ma so you really dont have to worry. each tube from their variation will sit at slighlty different spot in a self bias type circuit ,  if you notice from the schemo the  75V CA is approx !,  you are sitting right in the zone , if the mics sounds great no worry about that,  it will also depends on the heater you feed it as well,
Hope this helps,
Dan,


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 21, 2013, 11:12:43 PM
Ok as there's not so many info on the europe version here is a picture of what i did for the ones who could need it.
and because i'm not that great at electronic of course if you find any error please tell me before i power this and blow my house !  8).
(https://lh5.googleusercontent.com/-4dnHSwD8TO0/UZvgmj3k_BI/AAAAAAAABCA/qSov9e9lceA/w965-h749-no/europe-PSU.jpg)

Everythings look good from here ,  does your iEC have the fuse in there also ,  just wnat to make sure because some dont ,
always a good thing to fuse it before testing , looks great Thanks for the taking the time in doing this ,

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 22, 2013, 06:16:51 AM
great thx :)
yeah i put a 0.1A fuse as i understood from your first post.
EDIT : dam that 0.1A (time lag) just blew of. it blows right away again if i change it. I red somewhere maybe 0.2 would be better ?
i have a little problem. reading this thread i can't understand enough to go through the calibration :p
what i read about "plates" or "unloaded" "B+ and heater" are not clear for both my french and my skills (!)
is there somewhere a 101 procedure that i could follow step by step ?

for what i undertand i should measure this ? :
(https://lh4.googleusercontent.com/-5ZJ0GSdJ5o4/UZy43GZ_BlI/AAAAAAAABC0/859aDC9Yx-s/w800-h533-no/IMG_2120.jpg)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Joekkel on May 22, 2013, 11:01:19 AM
yep, tha'ts right, in europe you need a 0.2A fuse. and the pics right too, 210V on B+ and -6.3V on H-
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 22, 2013, 12:05:29 PM
joekkel thx alot i'll go buy a 0.2 right now to test this :p
means that this info on first page is wrong ?
Quote
fuse will need to be 0.1A instead of a 0.2A for north America

about this B+ and H- they are the same on min mic PCB as in the PSU PCB ?
means i must read 210 @ B+ on that PSU PCB as well as 210 @ B+ on main mic pcb
and same : -6.3 @ H- PSU PCB and -6.3 @ H- mic pcb right ?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Joekkel on May 22, 2013, 01:23:47 PM
Quote
joekkel thx alot i'll go buy a 0.2 right now to test this :p
means that this info on first page is wrong ?

nope, i was wrong, just checked the fuse i installed, it's 0.1A. sorry for that, i just remembered buying both values...

Quote
about this B+ and H- they are the same on min mic PCB as in the PSU PCB ?
means i must read 210 @ B+ on that PSU PCB as well as 210 @ B+ on main mic pcb
and same : -6.3 @ H- PSU PCB and -6.3 @ H- mic pcb right ?

exactly, but B+ on the psu-pcb will only read around 210 when the mic is connected, with no load it will be higher
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 22, 2013, 01:47:16 PM
dam ..
i installed 0.2 and it's going fine now ... so i'm sure 0.1 will blow up again.
without reading your post i checked 220v on B+ and -16 on H- without the mic.
B+ trim works but H- trim doesn't lower this value so i guess something's wrong  :-\
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: tskguy on May 22, 2013, 01:50:45 PM
Hey,

Make sure and check the voltages with the mic connected. The Heater voltage with out a load is high like that. In fact I am sure 16 is as low as I could get it.

Eric
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: imo on May 22, 2013, 01:51:00 PM
Thanks Dan. Heater is around 6.1..Everything else is good, and as before the mic sounds fantastic. I loved the Tele tube i had, but it was too noisy
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 22, 2013, 03:10:45 PM
hi tskguy ;)
thx for support you were right -16v droped and i can trim it very easy. now the problem is B+ that doesn't go high enough.
ok so i read after 20min warmup (still with that 0.2A fuse)
PSU B+ = 202v (max)
MIC B+ = 202v (max)
PSU H- = -6.5v
MIC H- = -6.43v (strange there's a difference ?)

Winetree i red you had same values 202v / 6.3 after warming up 15min
did you change that 56k ? to what value ?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: tskguy on May 22, 2013, 04:31:31 PM
Hey,

202v would most liklley be just fine by the way. If it were me I would just try it.
Over 210 would be more of a concern.
Eric
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 22, 2013, 05:06:07 PM
ok so i pluged it ! (http://www.smileys.lu/repository/Pom_pom/11736.gif)
hell this thing sounds amayzing ! i can't do some major recording tonight because of neigbhoors but wow what a presence on a talking voice ! can't wait to do more audio tests.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Winetree on May 22, 2013, 05:53:54 PM
Don't remember off hand. Try something like 47K.
You can always adjust the value if that doesn't get the adj. pot in range.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: tskguy on May 22, 2013, 07:04:03 PM
So glad your mic sounds good! Please make sure and post some sound samples when you have the chance to do some recording.  And if you want to get the voltage absolutely correct winetree's suggestion would most likely get you there.

Eric
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 22, 2013, 08:43:03 PM
ok so i pluged it ! (http://www.smileys.lu/repository/Pom_pom/11736.gif)
hell this thing sounds amayzing ! i can't do some major recording tonight because of neigbhoors but wow what a presence on a talking voice ! can't wait to do more audio tests.

first time ever i have a animated Gif of hapiness in my thread,
I am glad you made it and enjoy your new toy,
Best,
dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 23, 2013, 05:28:37 AM
haha ;) yeah really was happy and pompom girl is exactly how i felt. i never used a mic with such a sound !
really can't wait to work with this mic. i am still happy this morning but as i am doing five mics i pluged the #2 today on the same psu that worked for the first mic assuming calibration is almost ok. it produced instantly some noisy crack noise in my speakers so i power it of :p i didn't take time to check the voltages. tried #1 mic and all is ok PSU is fine :)
watching the pcb#2 i don't see major problem ..  :o
do you think i should risk to power it up long enough to measure voltages ? this noise is really scary.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: tskguy on May 23, 2013, 08:21:07 AM
Well it could be a number of things, if you already plugged it in and didn't see smoke I'm sure it's fine to check some voltages. Triple check the hi z section as well as the connection to the capsule especially the wire that connects to the mount and backplate.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on May 23, 2013, 01:13:48 PM
Finished my U67.

Iaudio transformer
NOS Telefuken EF86 from Cristian
Ben's capsule

On a comarison with Iaudio MK47, we found the MK47 to have more presence. It was chosen in all preamp-compressor combinations we tried.
The U67 was a little too bassy. (Atleast on my friends vocals)
I have all the jumpers in as factory default.
Should I try removing them or try a different tube?

Thanks for any suggestions.
Neil

I have the same components and this reflects my initial experience.  After a 36 hour burn in I noticed a (subtle) difference.  I do hear this mic as darker than I expected, in the same way as I hear some ribbons as dark.

I'm keen to hear someone's opinion who has or has used a real one on this subject.

What capsule is in your MK47?

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 23, 2013, 01:18:23 PM
Finished my U67.

Iaudio transformer
NOS Telefuken EF86 from Cristian
Ben's capsule

On a comarison with Iaudio MK47, we found the MK47 to have more presence. It was chosen in all preamp-compressor combinations we tried.
The U67 was a little too bassy. (Atleast on my friends vocals)
I have all the jumpers in as factory default.
Should I try removing them or try a different tube?

Thanks for any suggestions.
Neil


I have the same components and this reflects my initial experience.  After a 36 hour burn in I noticed a (subtle) difference.  I do hear this mic as darker than I expected, in the same way as I hear some ribbons as dark.

I'm keen to hear someone's opinion who has or has used a real one on this subject.

What capsule is in your MK47?


I would be really interested into some feedback of the real one for sure,  then i am sure you would enjoy the M269c,
it has an extra edge to it  ;).  the capsule is also important factor , from here i have real vocal sample from mine with D-U67 and Ebay used neumann capsule ? ,
i will post it really soon.

Best,
DAn,


Edit : Here is the sample from D-U67 AMIT67 and Neumann K67,
Recorded Apogee Big Ben Clock 44.1 to FF800 trough Martin's 1073 in Nuendo 32bit float Dithered by Nuendo to 16bit.
Some inexperience into distance gauging tough.

https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993d96.wav

Let me know what you think.

 
Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 23, 2013, 02:44:03 PM
ok i pluged my #2mic using same PSU and cables as the first mic that worked.
but i took it out from the body (last time it was inside)

this time i don't have "crack" but constant 50Hz buzzing loud with no signal but that 50Hz. i tried cardio and bi noLowCut @0db
i get B+ 197v (max) H- -6.5v. looks like my #1 mic except that massive buzz :)
each time i touch the PSU case that buzz drop 3db
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: tskguy on May 23, 2013, 04:20:22 PM
Dogzilla,

All mic's out of the body will for sure hum pretty bad. I would put the body back on and see if you still have the same hum and crackling issue. The voltages seem fine.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 23, 2013, 05:22:43 PM
(http://www.smileys.lu/repository/Sceptiques/2200.gif) dam sorry i'll do this tomorrow.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Le Roux on May 23, 2013, 05:57:12 PM
Finished my U67.

Iaudio transformer
NOS Telefuken EF86 from Cristian
Ben's capsule

On a comarison with Iaudio MK47, we found the MK47 to have more presence. It was chosen in all preamp-compressor combinations we tried.
The U67 was a little too bassy. (Atleast on my friends vocals)
I have all the jumpers in as factory default.
Should I try removing them or try a different tube?

Thanks for any suggestions.
Neil

I have the same components and this reflects my initial experience.  After a 36 hour burn in I noticed a (subtle) difference.  I do hear this mic as darker than I expected, in the same way as I hear some ribbons as dark.

I'm keen to hear someone's opinion who has or has used a real one on this subject.

What capsule is in your MK47?

I have a Thiersch Blue line PVC if I remember correctly.

I've been playing around with recording my Gibson Hummingbird using the U67 and noticed a huge difference in sound with the LC switch. Didn't find much difference on my friends vocals though.
I'm going to do more vocal recordings this weekend with him.

I must admit, I do love the all the options on the U67. And i am no way saying its a bad sound.
Just not sure what I was to expect.
One more thing I did notice is it picks up alot of the room, whereas my MK47 and Audio Technica 4060 cancels out that noise.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 23, 2013, 06:09:46 PM
Quote
I have a Thiersch Blue line PVC if I remember correctly.

I've been playing around with recording my Gibson Hummingbird using the U67 and noticed a huge difference in sound with the LC switch. Didn't find much difference on my friends vocals though.
I'm going to do more vocal recordings this weekend with him.

I must admit, I do love the all the options on the U67. And i am no way saying its a bad sound.
Just not sure what I was to expect.
One more thing I did notice is it picks up alot of the room, whereas my MK47 and Audio Technica 4060 cancels out that noise.


Let us know ,  and on a side note the original SYT-5 body from chuckD had the label wrong for the pattern on the mic , just want to make sure you really have it in cardiod there , the best is to try the position to make sure ,

Best,
DAn,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on May 25, 2013, 07:38:50 AM
Quote
I've been playing around with recording my Gibson Hummingbird using the U67 and noticed a huge difference in sound with the LC switch. Didn't find much difference on my friends vocals though.

The singer will probably be closer. But more importantly, the low cut or roll off starts at 200 Hz. The low E on the Hummingbird is about 82.5 Hz (and the big woof from the main body resonance will roughly be around 100 Hz). A bass singer can hit this note (low E) too, but most of his notes will be higher. Even more so for tenors, of course. Also, many singers use a twangy technique (often without knowing it) and pretty much eliminate the fundamentals of the notes anyway.

BTW, S2 is inside the body (no switch) and offers a choice between a 40 Hz cut or flat down to 20.


Quote
One more thing I did notice is it picks up alot of the room

Sounds like the back of the capsule is "active". Like poctop said, in cardioid this should not be the case.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 25, 2013, 07:14:26 PM
great news !
my #2 mic is fine !
as i put it back in it's body i noticed a very tiny piece of cable that was not covered by thermo (dam don't know the word for that plastic thing you heat) any way i changed that and it's fine now no buzz no crak only pure hapiness of sound !
let's go test #3 now.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on May 26, 2013, 06:25:44 PM
by the way.
i found this site (http://vintagemicrophone.com/JShop/product.php?xProd=13&xSec=5&jssCart=1f21b63cd43c335bd2a67eda611d077d) to get some wooden box for the D67. do you have any other propositions for that ?
and i'm searching for a nice suitcase with foam to store mic / psu / suspension / cable again if you have any idea.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on May 27, 2013, 03:39:31 AM
Nice box, but if it's an exact fit for the U67 then the D67 (SYT-5 body) will not fit.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: ben_studio on May 27, 2013, 04:14:56 AM
Dear All,
I'm just building a D67 with my collegue DGODZILLAI, and my mic works fine except with the PAD SWITCH "On".
The signal is still there but there's an added noise on it.
Do you have any idea where I should focus my research to sort that issue out ?

Thanks ! and besides this, it sounds great !

Ben
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 27, 2013, 04:08:43 PM
Dear All,
I'm just building a D67 with my collegue DGODZILLAI, and my mic works fine except with the PAD SWITCH "On".
The signal is still there but there's an added noise on it.
Do you have any idea where I should focus my research to sort that issue out ?

Thanks ! and besides this, it sounds great !

Ben

Is the functionnality of the switch work,  Have you solder the 2 legs for the switch support , what kind of noise is it  ?

does the casing of the switch is 0 Ohm in regards to the mic body or railing or PCB gnd,  Do you have the original Schematic handy.

Can you make sure you have it wired corectly there is a nice tutorial on this on the M269B thread !
Let us know,

Hope this helps,



Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: nolivdacom on May 29, 2013, 06:41:05 AM
Quote
EDIT : dam that 0.1A (time lag) just blew of. it blows right away again if i change it. I red somewhere maybe 0.2 would be better ?

Same problem for me with 0,1A. I use 160mA Slow Blow Fuse. All is right for me. I had problems with my psu because I choose to not solder power switch and 20VA transfo. My psu break down twice during recording session. I decided to solder all parts in my psu!

Quote
i'm searching for a nice suitcase with foam to store mic / psu / suspension / cable again if you have any ide

http://www.thomann.de/fr/thon_flexcut_universal_mischpult_2.htm (http://www.thomann.de/fr/thon_flexcut_universal_mischpult_2.htm)
not sure about size but it seems to be a good solution...

best
Olivier
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 29, 2013, 11:16:02 AM
Quote
EDIT : dam that 0.1A (time lag) just blew of. it blows right away again if i change it. I red somewhere maybe 0.2 would be better ?

Same problem for me with 0,1A. I use 160mA Slow Blow Fuse. All is right for me. I had problems with my psu because I choose to not solder power switch and 20VA transfo. My psu break down twice during recording session. I decided to solder all parts in my psu!

Quote
i'm searching for a nice suitcase with foam to store mic / psu / suspension / cable again if you have any ide

http://www.thomann.de/fr/thon_flexcut_universal_mischpult_2.htm (http://www.thomann.de/fr/thon_flexcut_universal_mischpult_2.htm)
not sure about size but it seems to be a good solution...

best
Olivier

Yep For sure soldering Stuff is always better IMHO,  as Per the Fuse the original PsU is spec'd 0.1A for Voltage from 220V to 240V and 0.2A for 117V to 127V,
those Fuse needs to be A very good quality Slow Blow Fuse to not be disrupted by initial inrush current ,  I had this problem on all My 1176 (4) i did where the Fuse was the exact amperage required but it would intermittlently blow the fuse on startup, i just increased a bit the amperage and they never failed again :)

Hope this helps,
dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: nolivdacom on May 29, 2013, 12:25:58 PM
Quote
Yep For sure soldering Stuff is always better IMHO,
;D
About that, I didn't solder wires to or from main board on my PSU... I used connectors to do it...
Is it important?

best,
Olivier
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 29, 2013, 04:32:37 PM
Quote
Yep For sure soldering Stuff is always better IMHO,
;D
About that, I didn't solder wires to or from main board on my PSU... I used connectors to do it...
Is it important?

best,
Olivier

the use of screw in connector is fine if they are used properly i guess a matter of personal taste i guess but i would have to mention that i never use connector for the PCB gND to chassis i always solder it to the pcb pad for perfect connection that will last forever

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on June 06, 2013, 10:21:15 AM
pelicase 1500 works fine looks sexy and can resist a tank :)

(https://lh4.googleusercontent.com/-0Ob9QAsyCoY/UbCQxoslRnI/AAAAAAAABIw/PJNXEu-L7Rc/s1024/IMG_2173.jpg)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: nolivdacom on June 07, 2013, 04:46:31 AM
Where did you get that pelicase?  ::)

best,
Olivier
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Veronica Sneesby on June 07, 2013, 04:05:57 PM
Where did you get that pelicase?  ::)

best,
Olivier

If you need help getting a case, let me know, i will be able to help.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: nolivdacom on June 08, 2013, 08:53:17 AM
Quote
If you need help getting a case, let me know, i will be able to help.

Yes, for sure, I'm interested in getting two cases for both mic, psu, shock mount and cable!

Thanks.

best

Olivier
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on June 10, 2013, 04:30:53 AM
Hi,
I ordered them at thomann (http://www.thomann.de/fr/peli_1500000110.htm?sid=6b6ffa1e9d5702c3c362589e56db9358). You should not take something smaller because this size is ok for mic/psu/mount/ but the 2 cables have to put on top of these. There's no romm in the foam for the cables. But bigger case is to much in size for me.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jackymurda on June 10, 2013, 06:20:28 PM
tabarnac!!

just recording some vocals with one of my new DU67's . sounds pretty darn good. dead quiet. sounds way better than my TLM67. the DU67 sounds more hype in the top, with something nice goin on in the lows that the TLM just doesnt come close too.. we used new K67 capsules from neumann berlin, the AMI T67 transformers from kansas, ShuaiYin SYT-5 bodies n shocks from chunger, power supply cases from danderloo.. got some electro harmonix tubes in at the moment, gonna switch out one with the hilumin silver shield telefunken EF86 and see how they compare..

merci dany!!! :D 
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: G-Sun on June 13, 2013, 02:43:23 AM
Hi Guys,

thought i'd post a link to a track i did to test the U67 on acoustic guitar and vocals.

https://soundcloud.com/spencer-lee-horton/snuff-acoustic-version-by

needs a bit more of a mix but i think you get the idea.

regards

Spence.
Thanks!
Sound very good. Especially on guitar.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on June 24, 2013, 05:35:26 AM
ok here is finally a comparaison between classic U67 and my D67 at mythic studio gang paris
i did a little article (english) on my blog with the audio files there and building pictures (in french)
hope to do more but that's it for now :)
massive thx to poctop this is a great kit !
http://www.sylvainmoreau.com/sylvain_moreau/?p=940 (http://www.sylvainmoreau.com/sylvain_moreau/?p=940)
(say hello in comments ;) )
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on June 24, 2013, 08:28:05 AM
ok here is finally a comparaison between classic U67 and my D67 at mythic studio gang paris
i did a little article (english) on my blog with the audio files there and building pictures (in french)
hope to do more but that's it for now :)
massive thx to poctop this is a great kit !
http://www.sylvainmoreau.com/sylvain_moreau/?p=940 (http://www.sylvainmoreau.com/sylvain_moreau/?p=940)
(say hello in comments ;) )

Thanks for the nice article sylvain ,  Remember that there is an errata on the polarity for the D-67 all you have to do to fix it is reverse pin 2 and pin 3 up in the power supply xlr connector and you will be ready to rock,


What is your impression overall, Let me know,

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on June 24, 2013, 10:45:00 AM
here is my feeling about the sound. compared to the classic one i found the D67 with more little subtle high end + better presence there too. I found the U67 a bit bassy to me. And the more i listen to it what ever the voice or the loudness (depending on mouth position maybe) i always thought that the D67 would be my choice for that tiny difference (can you belive this :s) and not to mention the price ..
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: tskguy on June 24, 2013, 04:33:36 PM
Dgoszillai!,

Thats so cool you prefer the D67! I am so glad ;D ;D. Did you have a chance to compare the 5 capsules with each other?? I am oping they are as matches as I intended.

Please let us know!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dgoszillai on June 24, 2013, 07:55:46 PM
about the caspules the only test i did was to put 2 D67 side by side. i didn't swap capsules on the same mic so not sure the difference i heard is not due to electronic or mic position. and i still can't belive that the final result is sweeter to the U67 to my ears  :o
i still have 2 mics at home i will do some recording tomorrow to se how they sound.
the problem is i have one good tube and 3 bad ! so for that test i'll have to use one bad tube.
i'm a bit desapointed about the tubes and hope the seller will consider some replacement for the one he gave me because on the 6 i ordered  3 are good 2 are totally wasted (!) 1 is .. not that great. they all do a noise that sound like a low vinyl hum and cracks. some very loud and continuously and one low and sometime.

anyway we're so happy about this project we're almost ready to start some U47fet (about 5 or 6)

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: G-Sun on June 27, 2013, 04:17:51 AM
ok here is finally a comparaison between classic U67 and my D67 at mythic studio gang paris
i did a little article (english) on my blog with the audio files there and building pictures (in french)
hope to do more but that's it for now :)
massive thx to poctop this is a great kit !
http://www.sylvainmoreau.com/sylvain_moreau/?p=940 (http://www.sylvainmoreau.com/sylvain_moreau/?p=940)
(say hello in comments ;) )
Thanks!
I always appreciate being able to listen to the gear :)
Do you believe the Neve preamp adds to the bass for both mics?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on June 27, 2013, 10:46:41 AM
ok here is finally a comparaison between classic U67 and my D67 at mythic studio gang paris
i did a little article (english) on my blog with the audio files there and building pictures (in french)
hope to do more but that's it for now :)
massive thx to poctop this is a great kit !
http://www.sylvainmoreau.com/sylvain_moreau/?p=940 (http://www.sylvainmoreau.com/sylvain_moreau/?p=940)
(say hello in comments ;) )

Hello.  :)
Or should I say bonjour?

Anyway, the two samples sound pretty close indeed. That figures because one is a clone/copy of the other, right? Well, actually the U67 has proven to be one of the most difficult mics to copy. Plus most of the parts on/in the new one are not exactly the same (different manufacturers, different age etc.). So that makes this achievement extra special.

Don't I hear any differences? Yes, I do.

The U67 sounds a little thinner at first, but I believe that is because it comes after the D67, and in the second half of the samples you seem a litlle closer (more proximity). So if you play the U67 first, you get the same feeling when the D67 starts, if that makes sense.
BTW, although my French isn't much to speak of, I think I hear something like "je suis à dix centimetres; c'est pas beaucoup" which would mean something like "I am at ten centimeters (four inches); that ain't much (distance). On a typical U67 you can (!) actually get significantly closer, especially if the 40 Hz high pass is in the circuit.

Interestingly, the original pops more, despite it having one more layer of mesh. The D67 "wins" in this department. Were you right in the middle of the two mics?

When it comes to esses it is extremely hard to beat a U67 and I do hear the esses as being smoother in the original. But even that hurdle will be taken as this project matures, I'm sure. What K67 capsule did you use?

Short version: congrats !!!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Melodeath00 on June 27, 2013, 10:58:23 AM
ok here is finally a comparaison between classic U67 and my D67 at mythic studio gang paris
i did a little article (english) on my blog with the audio files there and building pictures (in french)
hope to do more but that's it for now :)
massive thx to poctop this is a great kit !
http://www.sylvainmoreau.com/sylvain_moreau/?p=940 (http://www.sylvainmoreau.com/sylvain_moreau/?p=940)
(say hello in comments ;) )

Hello.  :)
Or should I say bonjour?

Anyway, the two samples sound pretty close indeed. That figures because one is a clone/copy of the other, right? Well, actually the U67 has proven to be one of the most difficult mics to copy. Plus most of the parts on/in the new one are not exactly the same (different manufacturers, different age etc.). So that makes this achievement extra special.

Don't I hear any differences? Yes, I do.

The U67 sounds a little thinner at first, but I believe that is because it comes after the D67, and in the second half of the samples you seem a litlle closer (more proximity). So if you play the U67 first, you get the same feeling when the D67 starts, if that makes sense.
BTW, although my French isn't much to speak of, I think I hear something like "je suis à dix centimetres; c'est pas beaucoup" which would mean something like "I am at ten centimeters (four inches); that ain't much (distance). On a typical U67 you can (!) actually get significantly closer, especially if the 40 Hz high pass is in the circuit.

Interestingly, the original pops more, despite it having one more layer of mesh. The D67 "wins" in this department. Were you right in the middle of the two mics?

When it comes to esses it is extremely hard to beat a U67 and I do hear the esses as being smoother in the original. But even that hurdle will be taken as this project matures, I'm sure. What K67 capsule did you use?

Short version: congrats !!!
I agree that there is more sibilance in the D67 than the U67. They do sound pretty close, but personally, I have a much easier time detecting differences on instruments, not voice.

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on June 27, 2013, 11:27:51 AM
Dogzillai used Tskguy Capsule , and I agree sometimes to get a real picture you need to record instruments such as AC guit and such,  i did post some female vocal with mine with a Genuine vintage Neumann K67 earlier in this thread for your reference if needed.

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kpearsall on July 05, 2013, 03:56:54 AM
HELP!!!! I took my first finished mic out today to use, and there was small marks all over it like it's corroding! on the bottom connector, there's small areas of what looks like green mold! On the inside, the plate that the capsule mount attaches to is brown with a light rust!! I've kept both mics side by side in their original pouches. The second one looks just fine! so I don't think it's the wisconsin heat and humidity. Can anyone tell me what this is? what's happening? How to clean it up and protect it??
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: HellfireStudios on July 05, 2013, 08:55:41 AM
HELP!!!! I took my first finished mic out today to use, and there was small marks all over it like it's corroding! on the bottom connector, there's small areas of what looks like green mold! On the inside, the plate that the capsule mount attaches to is brown with a light rust!! I've kept both mics side by side in their original pouches. The second one looks just fine! so I don't think it's the wisconsin heat and humidity. Can anyone tell me what this is? what's happening? How to clean it up and protect it??

Which donor body are you using?

-James-
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kpearsall on July 05, 2013, 09:05:15 AM
Oh sorry. Im using the first run chuck D body.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on July 05, 2013, 09:11:49 AM
HELP!!!! I took my first finished mic out today to use, and there was small marks all over it like it's corroding! on the bottom connector, there's small areas of what looks like green mold! On the inside, the plate that the capsule mount attaches to is brown with a light rust!! I've kept both mics side by side in their original pouches. The second one looks just fine! so I don't think it's the wisconsin heat and humidity. Can anyone tell me what this is? what's happening? How to clean it up and protect it??

That is indeed very strange, unless they were contact with oxydising agent at the factory and it has not been totally removed inside the mic body parts and it continued to slowly attacked the metal parts, and you are certain that it has not been exposed to humidity , were there a mini pouch of sillica gel in each of the case in this instance ?
D
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kpearsall on July 05, 2013, 10:29:33 AM
I do not believe either of them came with silica gel. If they did, it's long gone. I just don't know why one started doing it and the other didn't. Weather is humid here, but they've been side by side the whole time.

What I really need to know is, is there anything I can do to repair it? or clean it? I managed to remove the green stuff, but it pitted the nickel plating.

is there a chemical I can use to treat it to prevent further damage?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on July 05, 2013, 11:11:37 AM
Strange - another potential problem with chuckD's bodies.
Green usually means copper oxidation.
Clean them thoroughly obviously. There are anti rust chemicals at autobody stores but I don't know if that would be a good idea.
Clear coat?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on July 10, 2013, 04:04:20 AM
HI All,

Just thought i should put a comment in about a comparison between Erics 67 Capsule with the Sowter 1304 vs Neumann 67 Capsule with the AMI T67 from Jack Murda (as built by Proctop).

The first major difference visually is that the Sowter 1304 is a bit smaller, this may account for differences in the low end, as when we compared my DU67 to Jacks DU67 there was improved bottom end on Jacks, more focused defined.

The other difference which Jack very kindly demonstrated was the sibilance on Erics Capsule, a slight lift about 1khz Jack thought.
Jack described this as smearing, when compared with the Neumann capsules, no smearing was present.

I have to say to my ear it was close, but very different, all the things that Jack demonstrated were clearly audible and has made me get back in touch with Brian Sowter to revisit the 1304 and hopefully build a version which is much better on the bottom end.
I am also looking into trying another capsule for my DU67 to see if i can get rid of the smearing, i will contact Eric to hear his thoughts on this.

Hope this finds everyone well and none of this is ment to offend anyones hard work that has gone into all this, these are just my thoughts and some comments that i have used from what other people has said.

regards

Spence.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Melodeath00 on July 10, 2013, 09:13:30 AM
Spencer,

Did you indeed mean the T49 transformer, or T67?

I'd love to hear people chime in on the BeesNees K6 capsule.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on July 10, 2013, 09:36:50 AM
sorry corrected it!! butter fingers!!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on August 11, 2013, 03:10:33 PM

Side Note: For those having a polarity that is reversed for a known or unknow reason , remember that you can swap the wire inside the psu at the xlr output connector swapping wire pin 2 and wire pin 3 will reverse the polarity of the ouput.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Gilgamesh on August 14, 2013, 03:42:17 AM
Has anyone used or considered AMI's BV12 transformer? I want to have a look at how the wiring might work but I can't find a data sheet for it.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on August 26, 2013, 04:31:39 PM
Hi, perhaps a silly question, but in the mouser BOM it says R10 is a 10K resistor (in the comments), but on the schematic and also silkscreened on my PCB it says R10 is 15K. Does the mouser BOM have a typo?

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on August 26, 2013, 08:02:51 PM
Hi, perhaps a silly question, but in the mouser BOM it says R10 is a 10K resistor (in the comments), but on the schematic and also silkscreened on my PCB it says R10 is 15K. Does the mouser BOM have a typo?

Mike

Disregard the Mouser Bom (Customer part number) if this is waht you mean,  as they come back once you set them for other project wich is not very good , I use this tough in My BOM to include substituion art number usually ,


in the U67 R10 is definetely 15K,

Best,
Dan,




Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on August 26, 2013, 11:55:11 PM
Thanks Dan! Loving this project! I've been piece-mealing the parts together since last year; finally bit the bullet and bought the mouser BOM with some modifications and upgraded the internal mic resistors to Shinkoh's...cost a bit...not sure if it was worth it but I do tend to be an audiophool. Next up is getting the Beez capsule...

Thanks, you'll hear more from me as I get my build under way. I greatly appreciate you, this project, all the guys/gals on this forum.

Blessings,

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on August 27, 2013, 04:12:48 AM
Quote
I greatly appreciate you, this project, all the guys/gals on this forum.

+1

But where are those gals? How many do we actually have on board?
Hmmmm, I'd better take that question elsewhere.
Carry on.  :)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on August 27, 2013, 05:03:06 AM
Well actually...lol...I originally had written "guys" but then I thought, hey now! Ya never know!  ;)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on August 27, 2013, 05:15:53 AM
Only one I can think of right now is Veronica Sneesby. She actually sent me the capsule for this here project.

And I think I noticed another woman here recently, but they surely are few and far between.

Again, I don't want to hijack this superb thread. I might take this to another thread and section.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on August 30, 2013, 04:50:25 AM
I thought I was all set to build the PSU when I realized to my horror my case, a lovely danderloo, was set for binders. I have them but was going to use them on another project. Since I'm going to sacrifice the other project binders for the PSU for this project, I thought it only made sense to go higher end for the mic connection rather than the 7-pin xlr. So, even though it might be funny to mix a binder on the PSU case and an Amphenol on the mic end, at least it will be quality.

I found the mic amphenol connector that wave posted in another thread here (thx wave!):

http://www.mouser.com/Search/ProductDetail.aspx?R=T_3477_000virtualkey52360000virtualkey523-T3477-000

And searching on mouser found this cable connector:

http://www.mouser.com/Search/ProductDetail.aspx?R=T_3476_001virtualkey52360000virtualkey523-T3476-001

Do I have those parts mated correctly for going into the microphone from Chunger?

Also what is involved in the boring on the bottom of the mic exactly? I don't have a lot of equipment but what is it going to take?

Thanks for responses,

Mike

EDIT: for clarity and doing my own homework for this post
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 04, 2013, 05:41:58 AM
I can't seem to find reference to the second set of jumpers, should I jumper both? I know one is for the internal 200Hz filter, what's the other for?

IS is jumpered for default configuration , you will get more bass response and proximity with the jumper off,  the other jumper serves as soldering point for the low cut switching,
Best,
dan,

(https://dl.dropbox.com/u/43869772/bb.jpg)

Hi poctop, any reason you have to install the second rightmost jumper at all, if it's used just to solder the wires to the low cut switch? Wouldn't it just be easier to solder the low cut switch wires right to the PCB?

Thanks,

Mike
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on September 04, 2013, 08:00:53 AM
I can't seem to find reference to the second set of jumpers, should I jumper both? I know one is for the internal 200Hz filter, what's the other for?

IS is jumpered for default configuration , you will get more bass response and proximity with the jumper off,  the other jumper serves as soldering point for the low cut switching,
Best,
dan,

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993ea3.jpg)

Hi poctop, any reason you have to install the second rightmost jumper at all, if it's used just to solder the wires to the low cut switch? Wouldn't it just be easier to solder the low cut switch wires right to the PCB?

Thanks,

Mike


The wire could also be wired directly on the pcb but i found that it was easier Job doing it it that way , but nothing is preventing you to do that , I guess i had in mind at all case to install a jumper there in the eventuallity that you have to troubleshoot stuff ,,,,makes it easier in all case  :) .
Best,
DAn,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 04, 2013, 08:34:53 AM
Ok as there's not so many info on the europe version here is a picture of what i did for the ones who could need it.
and because i'm not that great at electronic of course if you find any error please tell me before i power this and blow my house !  8).
(https://lh5.googleusercontent.com/-4dnHSwD8TO0/UZvgmj3k_BI/AAAAAAAABCA/qSov9e9lceA/w965-h749-no/europe-PSU.jpg)

One comment I noticed folks are only interrupting the IEC hot line, and not both hot and neutral, in their PSU switch. While this is "correct" and "OK" from my understanding if there's a miswiring in the wall then that puts the hot line in constant contact internally in the PSU, dangerous. The solution I found is to use a DPDT switch for the PSU and wire BOTH hot and neutral to it, so both are interrupted.

Just my humble thoughts on making DIY safer and making you all less dead-er. Or burned-er. Or...you get the idea.

PS awesome diagram dgoszillai!
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 04, 2013, 08:52:43 AM
I can't seem to find reference to the second set of jumpers, should I jumper both? I know one is for the internal 200Hz filter, what's the other for?

IS is jumpered for default configuration , you will get more bass response and proximity with the jumper off,  the other jumper serves as soldering point for the low cut switching,
Best,
dan,

(https://dl.dropbox.com/u/43869772/bb.jpg)

Hi poctop, any reason you have to install the second rightmost jumper at all, if it's used just to solder the wires to the low cut switch? Wouldn't it just be easier to solder the low cut switch wires right to the PCB?

Thanks,

Mike


The wire could also be wired directly on the pcb but i found that it was easier Job doing it it that way , but nothing is preventing you to do that , I guess i had in mind at all case to install a jumper there in the eventuallity that you have to troubleshoot stuff ,,,,makes it easier in all case  :) .
Best,
DAn,

Thanks Dan!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: potstweaker on September 05, 2013, 02:17:10 AM
Sorry for the noob question but it was very hard to tell by the pics how to connect the capsule and where to solder,any one have pics that could better show me?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 05, 2013, 07:43:54 AM
Sorry for the noob question but it was very hard to tell by the pics how to connect the capsule and where to solder,any one have pics that could better show me?

please Refer to this thread here as the capsule connection is the same as the M269c or 269b

http://www.groupdiy.com/index.php?topic=51350.0  ( section in the bottom )

there is nice picture that shows how to and where to connect the capsule ,

but basically here it is,

Backplate = second turret point ,
Front diaphragme = first turret point ( Grid of the tube where the tube pin is floating or any connection that lead to the tube floating grid  )
back diaphragme will connect to pattern pin 2 ( the wire that i push into the basket , )

Let me know if this helps,
Best,
Dan,

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 05, 2013, 02:18:49 PM
I thought I was all set to build the PSU when I realized to my horror my case, a lovely danderloo, was set for binders. I have them but was going to use them on another project. Since I'm going to sacrifice the other project binders for the PSU for this project, I thought it only made sense to go higher end for the mic connection rather than the 7-pin xlr. So, even though it might be funny to mix a binder on the PSU case and an Amphenol on the mic end, at least it will be quality.

I found the mic amphenol connector that wave posted in another thread here (thx wave!):

http://www.mouser.com/Search/ProductDetail.aspx?R=T_3477_000virtualkey52360000virtualkey523-T3477-000

And searching on mouser found this cable connector:

http://www.mouser.com/Search/ProductDetail.aspx?R=T_3476_001virtualkey52360000virtualkey523-T3476-001

Do I have those parts mated correctly for going into the microphone from Chunger?

Also what is involved in the boring on the bottom of the mic exactly? I don't have a lot of equipment but what is it going to take?

Thanks for responses,

Mike

EDIT: for clarity and doing my own homework for this post

bump?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 09, 2013, 04:15:01 AM
OK, PSU complete! Wow, whoever said DIY was cheaper or easier than buying is nuts! It's a sick addiction!!!

I'll post three photos, three posts. Anyone know how to do multiple photos per post?

I'm getting -16.45v for H-, and 246v for B+, unloaded. As others have reported, The B+ trimmer works fine but the H- does not, until loaded. I can't test that yet since I still have to put the mic together!  :o
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 09, 2013, 04:15:23 AM
Second pic.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 09, 2013, 04:15:57 AM
And the all-important "action shot." Look mom, the LIGHT works!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on September 09, 2013, 05:26:44 AM
Quote
Wow, whoever said DIY was cheaper or easier than buying is nuts!

http://www.ebay.com/itm/1965-NEUMANN-U67-ORIGINAL-VINTAGE-TUBE-CONDENSER-MIC-/300961737208 (http://www.ebay.com/itm/1965-NEUMANN-U67-ORIGINAL-VINTAGE-TUBE-CONDENSER-MIC-/300961737208)



Quote
It's a sick addiction!!!

 ;D
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 09, 2013, 07:48:15 AM
OK, PSU complete! Wow, whoever said DIY was cheaper or easier than buying is nuts! It's a sick addiction!!!

I'll post three photos, three posts. Anyone know how to do multiple photos per post?

I'm getting -16.45v for H-, and 246v for B+, unloaded. As others have reported, The B+ trimmer works fine but the H- does not, until loaded. I can't test that yet since I still have to put the mic together!  :o

Thanks for the picture, Very Neat Build,  if you want to post several picture on a post you can use the image tag and post a link from a dropbox site public link or such ,

you are correct saying that the voltage cannot be adjusted with no load , the heater voltage at -16.45V is perfectly in line and the B+ also ,
if you wish you could calculate a load for the heater and also for the B+ and stick a resistor at the xlr psu connector and Pre adjust it before connecting the mic , 

i had made the demonstration on how to do it and calculate it a little earlier in this thread for your reference ,


Best,
Dan,


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 09, 2013, 10:43:55 AM
Thank-you, sir creator, sir PocTop Dan!!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 09, 2013, 01:10:12 PM
Quote
Wow, whoever said DIY was cheaper or easier than buying is nuts!

http://www.ebay.com/itm/1965-NEUMANN-U67-ORIGINAL-VINTAGE-TUBE-CONDENSER-MIC-/300961737208 (http://www.ebay.com/itm/1965-NEUMANN-U67-ORIGINAL-VINTAGE-TUBE-CONDENSER-MIC-/300961737208)



Quote
It's a sick addiction!!!

 ;D

Touche! But then again, doubt I could sell this baby for 6.5K even though it's a great design!  :P
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 10, 2013, 02:06:48 AM
I thought I was all set to build the PSU when I realized to my horror my case, a lovely danderloo, was set for binders. I have them but was going to use them on another project. Since I'm going to sacrifice the other project binders for the PSU for this project, I thought it only made sense to go higher end for the mic connection rather than the 7-pin xlr. So, even though it might be funny to mix a binder on the PSU case and an Amphenol on the mic end, at least it will be quality.

I found the mic amphenol connector that wave posted in another thread here (thx wave!):

http://www.mouser.com/Search/ProductDetail.aspx?R=T_3477_000virtualkey52360000virtualkey523-T3477-000

And searching on mouser found this cable connector:

http://www.mouser.com/Search/ProductDetail.aspx?R=T_3476_001virtualkey52360000virtualkey523-T3476-001

Do I have those parts mated correctly for going into the microphone from Chunger?

Also what is involved in the boring on the bottom of the mic exactly? I don't have a lot of equipment but what is it going to take?

Thanks for responses,

Mike

EDIT: for clarity and doing my own homework for this post

bump?

No thoughts, anyone? I wonder if wave Dave ever visits now that he's done his U67's...:)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: potstweaker on September 15, 2013, 04:16:02 AM
im getting a hum out of the mic,and not really picking up anything. any ideas?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 15, 2013, 08:39:37 AM
im getting a hum out of the mic,and not really picking up anything. any ideas?

are your switch pins all soldered in the swicth board and the shell of the switch short to ground and mic chassis ,
do you have the jumper installed on Shlf in the psu , how is your cabling arrange , ground scheme ,  did you try swapping tube to see if it improves or not ,
 Hope this helps,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Dylan W on September 15, 2013, 10:22:57 AM
I thought I was all set to build the PSU when I realized to my horror my case, a lovely danderloo, was set for binders. I have them but was going to use them on another project. Since I'm going to sacrifice the other project binders for the PSU for this project, I thought it only made sense to go higher end for the mic connection rather than the 7-pin xlr. So, even though it might be funny to mix a binder on the PSU case and an Amphenol on the mic end, at least it will be quality.

I found the mic amphenol connector that wave posted in another thread here (thx wave!):

http://www.mouser.com/Search/ProductDetail.aspx?R=T_3477_000virtualkey52360000virtualkey523-T3477-000

And searching on mouser found this cable connector:

http://www.mouser.com/Search/ProductDetail.aspx?R=T_3476_001virtualkey52360000virtualkey523-T3476-001

Do I have those parts mated correctly for going into the microphone from Chunger?

Also what is involved in the boring on the bottom of the mic exactly? I don't have a lot of equipment but what is it going to take?

Thanks for responses,

Mike

EDIT: for clarity and doing my own homework for this post

bump?

Yes, those parts are correct. To bore the mic end cap, I used a drill press at low RPMs and an Irwin step bit. I seem to remember that I needed to go partway in with the largest diameter step (7/8" on a #4 bit). The tab on the connector required making a notch with a needle file. Installed it with some JB Weld (make sure to solder leads to it first).

The stepbit was kind of a kludge... there's probably a better straight bit to use. I would be wary of trying this without a drillpress.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 15, 2013, 10:27:08 AM
I thought I was all set to build the PSU when I realized to my horror my case, a lovely danderloo, was set for binders. I have them but was going to use them on another project. Since I'm going to sacrifice the other project binders for the PSU for this project, I thought it only made sense to go higher end for the mic connection rather than the 7-pin xlr. So, even though it might be funny to mix a binder on the PSU case and an Amphenol on the mic end, at least it will be quality.

I found the mic amphenol connector that wave posted in another thread here (thx wave!):

http://www.mouser.com/Search/ProductDetail.aspx?R=T_3477_000virtualkey52360000virtualkey523-T3477-000

And searching on mouser found this cable connector:

http://www.mouser.com/Search/ProductDetail.aspx?R=T_3476_001virtualkey52360000virtualkey523-T3476-001

Do I have those parts mated correctly for going into the microphone from Chunger?

Also what is involved in the boring on the bottom of the mic exactly? I don't have a lot of equipment but what is it going to take?

Thanks for responses,

Mike

EDIT: for clarity and doing my own homework for this post

bump?

Yes, those parts are correct. To bore the mic end cap, I used a drill press at low RPMs and an Irwin step bit. I seem to remember that I needed to go partway in with the largest diameter step (7/8" on a #4 bit). The tab on the connector required making a notch with a needle file. Installed it with some JB Weld (make sure to solder leads to it first).

The stepbit was kind of a kludge... there's probably a better straight bit to use. I would be wary of trying this without a drillpress.

I did the mod on one of mine , IIRC i used a 11/16 or 13/16 ? metal bell on a press drill and taped a side hole wth a 4/40 thread and mounted with a set screw  the unibit is also a great tool for this , a must have DIY tool in all case ,
Best,
DAN,

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 15, 2013, 03:32:19 PM
Dylan and Dan, thanks much!

Right now I don't have access to a garage or have a drill press, so I'm thinking I may just take it over to a local machine shop and see if they can do it for me. I know that's not DIY but sometimes you gotta get outside help for things you aren't currently equipped to do.

I bored the hole for the PSU light; had to get a 5/16" bit with reduced shank (bit cost $21.99!! yikes!). I didn't have a drill press, and all I can say is thank the Gods for the bevel around the light or that PSU would look like $.it. The PSU kept jumping around and the hole was definitely *not* round.

Thanks both of you; this confirms I'll go the machine shop route and I'll let you guys know how it came out. I much prefer the beefier Tuchel/Amphenol connectors, although the 7=pin XLR is OK.

By the way Dan was your threaded hole there for ground connection or was that just how you mounted the endcap to the mic after boring?

Thanks,

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 16, 2013, 05:13:30 AM
Little confused building the high-Z section.

One doc has C5 C4 C7 the other has C5 C7 C4...not sure why the caps are interchanged. Are the connections still right? Or is one right and the other has an error?

How do I handle this?

Thanks,

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 16, 2013, 07:46:08 AM
Little confused building the high-Z section.

One doc has C5 C4 C7 the other has C5 C7 C4...not sure why the caps are interchanged. Are the connections still right? Or is one right and the other has an error?

How do I handle this?

Thanks,

Mike

Thanks For catchinig this Mike,  i remember at one time i corrected that for the production pcb , so the pcb is entirely correct, Even checked it this morning and it is all correct, 
I made a note on correcting the wiring diagram document at some point and it fell in the cracks, it was that the component label was misplaced on the drawing ,

Can you Let me know the exact source of those 2 document your are pointing out, As I will correct it to avoid further confusion ,

also note that the M269b thread is a nice complement for the U67 build as it has a switch board pictorial and also for the capsule.

Let me know,
Best,
DAN,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 16, 2013, 09:41:40 PM
HI Dan, no problem. One is the OverallConnections.pdf, and the other is the Main Board Identification.pdf. Both are in the build folder.

My predicment now is I don't remember which is the right one and I already installed the caps! Can anyone remind me, which is the correct order so I don't screw up the high-z section I'm trying to figure out?

Is it what shows in the Main Board Identification file, C5 C7 C4, or is it as shown in the Overall Connections file, C5, C4 C7?

Thanks,

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 16, 2013, 09:44:00 PM
Nevermind; I was able to carefully lift the caps and the correct order, as shown on the PCB anyway is: C5 C7 C4

Since Dan said the PCB is entirely correct, this would match the main board identification file, and not the Overall Connections file.

So now the question is, what is right on the Overall Connections file? Are the caps as labelled wired correctly to the other connections? I'm not sure if I can follow the Overall Connections file now...

Dan?

Thanks,

Mike  :)

Edit for clarity.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 17, 2013, 08:43:00 AM
Nevermind; I was able to carefully lift the caps and the correct order, as shown on the PCB anyway is: C5 C7 C4

Since Dan said the PCB is entirely correct, this would match the main board identification file, and not the Overall Connections file.

So now the question is, what is right on the Overall Connections file? Are the caps as labelled wired correctly to the other connections? I'm not sure if I can follow the Overall Connections file now...

Dan?

Thanks,

Mike  :)

Edit for clarity.

Quote
So now the question is, what is right on the Overall Connections file? Are the caps as labelled wired correctly to the other connections? I'm not sure if I can follow the Overall Connections file now...

everything is right on the overall connection document except that the cap number are inverted, pcb and main identification are correct.  if you make abstraction of the cap number and since they are the same value 0.01u nothing will change but i will be correcting the overall connection document to avoid confusion , thanks for catching this,
Best,
Dan,


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 17, 2013, 03:36:18 PM
Nevermind; I was able to carefully lift the caps and the correct order, as shown on the PCB anyway is: C5 C7 C4

Since Dan said the PCB is entirely correct, this would match the main board identification file, and not the Overall Connections file.

So now the question is, what is right on the Overall Connections file? Are the caps as labelled wired correctly to the other connections? I'm not sure if I can follow the Overall Connections file now...

Dan?

Thanks,

Mike  :)

Edit for clarity.

Quote
So now the question is, what is right on the Overall Connections file? Are the caps as labelled wired correctly to the other connections? I'm not sure if I can follow the Overall Connections file now...

everything is right on the overall connection document except that the cap number are inverted, pcb and main identification are correct.  if you make abstraction of the cap number and since they are the same value 0.01u nothing will change but i will be correcting the overall connection document to avoid confusion , thanks for catching this,
Best,
Dan,

Thanks Dan, I think I get it. I can be a bit dyslexic about such things, but I'll post if I can't figure it. I think it's clear.

I'm going to contact a couple of machine shops this week for boring the base of the mic for the Amphenol connectors; hope I can find someone local who can do it. Doesn't look like a big job.

Thanks again,

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 18, 2013, 08:00:48 PM
I'm excited! Just got the mic to a local machine shop and they are going to bore the base for the Amphenol connector...gonna be a little bit trick, if it turns out right, because I'm having them bury the Amphenol into the base a lot like the XLR connector is. It's gonna be a little pricey, but should have it back in a week. I'll post photos if it comes out great! And then it might be something to consider as an option for Chunger's bodies; to have this kind of base mod for the Amphenol.

Mike

Edit: include pic
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 21, 2013, 03:23:32 AM
Ok couple questions. First, this is dumb, but I have to ask - my studio is in another city and I haven't been there in a while.

The bottom of the mic has a screw base. Does this fit into mic shockmounts that have a screw base? Or is the screw base at the bottom of the mic just to screw on the bell? I'm asking because I had spec'ed the machine shop to remove about 1/4" thinking I didn't want it to stick out, but maybe if it serves a useful purpose like fitting into a neumann shock mount with screw on, I'll have them not cut off the last 1/4" of the screw base. I need to let them know asap, so if anyone has a quick answer I would be most grateful.

Second, I have a question about the wiring of the switches. I went through the d269 tutorial, and it all made sense except there are a couple of images referencing bridging of C1-C10, which I believe we have already done in the DU67 up to that point. Is there some other bridging here that I'm not catching due to my eyesight/misreading of the pic/schematic?

I'm including one of 2 of those pix here; Dan - is this an additional bridging necessary for the DU67?

Thanks a lot folks!

Mike


PS I had a run-in with some conformal coating the other night. I thought after making the high-z section it would make sense to use some brush-on conformal coating. Well, it was thick. WAAY too thick in the bottle and I ended up making a big mess of my high-z....ended up having to scrape it all off...lesson learned: use conformal coating thinner!

Is anyone else using conformal coating on their high-z section? I had picked up some Q-Dope but now I'm not sure if I'm gonna buy the thinner and reapply it...traumatized... :o
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 21, 2013, 10:04:38 AM
Ok couple questions. First, this is dumb, but I have to ask - my studio is in another city and I haven't been there in a while.

The bottom of the mic has a screw base. Does this fit into mic shockmounts that have a screw base? Or is the screw base at the bottom of the mic just to screw on the bell? I'm asking because I had spec'ed the machine shop to remove about 1/4" thinking I didn't want it to stick out, but maybe if it serves a useful purpose like fitting into a neumann shock mount with screw on, I'll have them not cut off the last 1/4" of the screw base. I need to let them know asap, so if anyone has a quick answer I would be most grateful.

Second, I have a question about the wiring of the switches. I went through the d269 tutorial, and it all made sense except there are a couple of images referencing bridging of C1-C10, which I believe we have already done in the DU67 up to that point. Is there some other bridging here that I'm not catching due to my eyesight/misreading of the pic/schematic?

I'm including one of 2 of those pix here; Dan - is this an additional bridging necessary for the DU67?

Thanks a lot folks!

Mike


PS I had a run-in with some conformal coating the other night. I thought after making the high-z section it would make sense to use some brush-on conformal coating. Well, it was thick. WAAY too thick in the bottle and I ended up making a big mess of my high-z....ended up having to scrape it all off...lesson learned: use conformal coating thinner!

Is anyone else using conformal coating on their high-z section? I had picked up some Q-Dope but now I'm not sure if I'm gonna buy the thinner and reapply it...traumatized... :o


Not sure why you used conformal coating on the H-Z section but this is DIY after all,  I understand that they use to at certain time , but i did not and had no issue with noise.

as per the bridging they are many ways to do it but the principle will stay the same in the 269 thread i have done it a bit diefferenly but the connection overall is the same wich is  that the top of C1, C10 and R8 need to floating connect to the grid of the tube as well as the front diaphragme and the switch pin 1 of te pattern switch. and this is for the D-U67 only there is some subtility in the 269C mic
you can use the turret point as a bridging aid or you could float all the connection straight to it , using the turret wil allow to connect the front diaphragme easier i always leve a little bit of the lead of the resistor when i do that to allow a solder point for the other wire that will come in

see the picture atached, and see the yelow line are the actual phsical connection that need to be made , the gray line is just the same thing
hope this helps,
Best,
DAn,

PS I also notice that the reference in the text on the picture is referering the wrong resistor it is R8 not R6 i corrected the picture in the pictorial  of the 269B thread where you took the picture from , 
the PCB is correct.

(https://dl.dropboxusercontent.com/u/43869772/U67/bridge.jpg)

So basically at the end it will look like this , notice the extra lenght of lead that i leave to solder the front Diaphragme and pattern switch pin 1

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993ef1.jpg)

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 21, 2013, 02:28:55 PM
Thanks Dan. I will study this; I appreciate your explanation and updated photos.

Regarding the conformal coating, my understanding is, it's not so much about noise as long-term stability issues. Any moisture, dust, fingerprints, etc in the long-term can cause issues since it's such a high resistance and subject to minute contaminants. It was recommended to me by a neumann mic tech, Andreas Grosser, for a U47 build I am doing. I may leave it out in the end, but that was the thinking.

Any thoughts on the screw thread at the bottom of the mic...is this only for the bottom bell to connect to, or does this actually fit mic shock mounts with a screw thread?

Thanks all,

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 21, 2013, 02:34:22 PM
Thanks Dan. I will study this; I appreciate your explanation and updated photos.

Regarding the conformal coating, my understanding is, it's not so much about noise as long-term stability issues. Any moisture, dust, fingerprints, etc in the long-term can cause issues since it's such a high resistance and subject to minute contaminants. It was recommended to me by a neumann mic tech, Andreas Grosser, for a U47 build I am doing. I may leave it out in the end, but that was the thinking.

Any thoughts on the screw thread at the bottom of the mic...is this only for the bottom bell to connect to, or does this actually fit mic shock mounts with a screw thread?

Thanks all,

Mike

the standard shockmount that is supplied with the Syt-5 body is a press fit one ,
no screwing on this one , not sure if this helps,
Best,
DAn,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 21, 2013, 02:51:21 PM
Hi Dan, thanks. Yes I have the press-fit shock mount that came with it. I was wondering if the screw base happened to fit standard neumann screw-fit shock mounts. Thx.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 21, 2013, 02:59:33 PM
OK, I understand your explanation about the bridge. Where I'm unclear is in the actual black photo you posted. It seems there are connections going to points next to the turret point, but not the actual turret point - I'm confused. There are a couple of holes on the PCB marked with an * but as far as I can tell they are unused in your build photos but it seems there are connections going there in the black photo that are really supposed to go to the turret point.

There are not actually any wires supposed to go to the holes in the PCB marked *, right? This was just a best-effort way of showing the 3D connections of the bridge using a 2D photo...right?

See my attached photo. Thanks so much Dan...project is incredible!

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 23, 2013, 07:53:04 AM
OK, I understand your explanation about the bridge. Where I'm unclear is in the actual black photo you posted. It seems there are connections going to points next to the turret point, but not the actual turret point - I'm confused. There are a couple of holes on the PCB marked with an * but as far as I can tell they are unused in your build photos but it seems there are connections going there in the black photo that are really supposed to go to the turret point.

There are not actually any wires supposed to go to the holes in the PCB marked *, right? This was just a best-effort way of showing the 3D connections of the bridge using a 2D photo...right?

See my attached photo. Thanks so much Dan...project is incredible!

where you show the picture with the 2 pad hole that are not used it is correct because the top end of those component will float direclty to the tube grid- Turret point(R8)
you are not in a obligation to use the turret point if you send the top of R8 direclty to the grid as well but it will be usefull to connect later capsuile connection and pattern pin 1 connection as depicted in the overall connection document, 


Quote
Unused Right
Correct.

PS: the connection on the black picture is a representation of how the CAD software make the connection but it cannot interepret any floating connection.
The astrerisk on the pcb denote a floating connection up to the tube grid pin.  :)

Let me know if this makes sense, dont hesitate to question me if it isnt.  :)



Best,
Dan,


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 23, 2013, 03:33:29 PM
Hi Dan, beautiful answer - thanks! Yes your pictures are very clear!!! I thought I was going to have a terrible time with this project, but between your pix and the schemos, it was fairly easy!

I just lost my nerve a little when I was trying to interpret the CAD version - my mind is very literal sometimes so I was thinking that perhaps I had made a mistake.

But I'm happy to report I got the whole floating bridge and temporary capsule setup! I'm waiting on a capsule from BeesKneez, and some machining, and then I can get the party really started!

Thanks again for a super project!! I used premium components so I think this going to come out great!

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 23, 2013, 03:39:52 PM
Hi Dan, beautiful answer - thanks! Yes your pictures are very clear!!! I thought I was going to have a terrible time with this project, but between your pix and the schemos, it was fairly easy!

I just lost my nerve a little when I was trying to interpret the CAD version - my mind is very literal sometimes so I was thinking that perhaps I had made a mistake.

But I'm happy to report I got the whole floating bridge and temporary capsule setup! I'm waiting on a capsule from BeesKneez, and some machining, and then I can get the party really started!

Thanks again for a super project!! I used premium components so I think this going to come out great!

Mike

Thanks For Nice word,  I too am like that, when i get something to accomplish i make sure i understand it all and all the details that comes with it,
Keep me posted,

Best,
dAn ,


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on September 23, 2013, 08:34:55 PM
Hi guys.
I'm just about to finish the first of my four u67. I have an issue with the psu. I blew a couple of fuses trying to power it up. The 250v pilot just flashes and then it's gone. After disconnecting the 210v transformer from the pcb the fuse won't brake. Getting 20v from the other transformer.
There's 0,9ohm resistance between one of the 210v inputs on the psu and 0v. Is that right? It's the same on all of my four psu pcbs. I've double checked all the components and the wiring/soldering.
Triad 210v tranny in series, bridging violet/gray on primary and red/orange on secondary. 250v/2w pilot light.
I'm in Europe (230v) and I'm using the spec 0,1a fuse. Microphone not connected.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 23, 2013, 10:15:46 PM
Hi guys.
I'm just about to finish the first of my four u67. I have an issue with the psu. I blew a couple of fuses trying to power it up. The 250v pilot just flashes and then it's gone. After disconnecting the 210v transformer from the pcb the fuse won't brake. Getting 20v from the other transformer.
There's 0,9ohm resistance between one of the 210v inputs on the psu and 0v. Is that right? It's the same on all of my four psu pcbs. I've double checked all the components and the wiring/soldering.
Triad 210v tranny in series, bridging violet/gray on primary and red/orange on secondary. 250v/2w pilot light.
I'm in Europe (230v) and I'm using the spec 0,1a fuse. Microphone not connected.
/
Emil

yes this is correct if you look at the PSU schemo on page 1 one leg of the secondary 230VAC is tied to ground, and the other one at the half phase rect diode,  did you try another fuse like 0.2A or 0.3A , sometime the fuse is not slow blow enough or not slow blow at all,   and there a smal inrush current at startup, is you pilot direclty wired to AC or the current involved in the pilot lamp is counted in ,

Hope this helps,
Best,
DAn,


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on September 24, 2013, 05:53:03 AM
Hi guys.
I'm just about to finish the first of my four u67. I have an issue with the psu. I blew a couple of fuses trying to power it up. The 250v pilot just flashes and then it's gone. After disconnecting the 210v transformer from the pcb the fuse won't brake. Getting 20v from the other transformer.
There's 0,9ohm resistance between one of the 210v inputs on the psu and 0v. Is that right? It's the same on all of my four psu pcbs. I've double checked all the components and the wiring/soldering.
Triad 210v tranny in series, bridging violet/gray on primary and red/orange on secondary. 250v/2w pilot light.
I'm in Europe (230v) and I'm using the spec 0,1a fuse. Microphone not connected.
/
Emil

yes this is correct if you look at the PSU schemo on page 1 one leg of the secondary 230VAC is tied to ground, and the other one at the half phase rect diode,  did you try another fuse like 0.2A or 0.3A , sometime the fuse is not slow blow enough or not slow blow at all,   and there a smal inrush current at startup, is you pilot direclty wired to AC or the current involved in the pilot lamp is counted in ,

Hope this helps,
Best,
DAn,

Hi dan and thansk for replying!
I have not tried a larger fuse yet but i will this evening. Tje pilot is drawing from the fuse yes. Its inside the IEC.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on September 24, 2013, 11:22:09 AM
I'm excited! Just got the mic to a local machine shop and they are going to bore the base for the Amphenol connector...gonna be a little bit trick, if it turns out right, because I'm having them bury the Amphenol into the base a lot like the XLR connector is. It's gonna be a little pricey, but should have it back in a week. I'll post photos if it comes out great! And then it might be something to consider as an option for Chunger's bodies; to have this kind of base mod for the Amphenol.

Mike

Edit: include pic
I have done the exact same thing on mine. Had a friend of mine do it at work. I'm very happy with the looks and feel of it.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 24, 2013, 11:50:09 AM
Cool Emil!

Maybe post a pic?  8)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on September 24, 2013, 05:26:04 PM
Cool Emil!

Maybe post a pic?  8)

Hi!
Here's a pic of the mic with the binder mounted. I did like you and drilled a hole and fixed a stop screw to guide the connector. It's a bit tricky to get the microphone side connector to sit tight. I drilled another hole throught the mic and inserted another screw to hold it in place, high enough so it's not visibe with the body mounted.

I have a problem you guys can probably help me with: I cant get 210v to the mic. It stays at ca 196v.
I cant get 210v to the mic. A lower value resistor in series with the pot?
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on September 24, 2013, 05:28:17 PM
Cool Emil!

Maybe post a pic?  8)

Here's another pic.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 24, 2013, 07:34:28 PM
Emil yours is even cooler than mine will be! I have a binder at the PSU, but went for the Amphenol for the mic itself. It's small... :( But I think it will be better than the xlr...

Thx for sharing!

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on September 24, 2013, 08:09:04 PM
Hi guys.
I'm just about to finish the first of my four u67. I have an issue with the psu. I blew a couple of fuses trying to power it up. The 250v pilot just flashes and then it's gone. After disconnecting the 210v transformer from the pcb the fuse won't brake. Getting 20v from the other transformer.
There's 0,9ohm resistance between one of the 210v inputs on the psu and 0v. Is that right? It's the same on all of my four psu pcbs. I've double checked all the components and the wiring/soldering.
Triad 210v tranny in series, bridging violet/gray on primary and red/orange on secondary. 250v/2w pilot light.
I'm in Europe (230v) and I'm using the spec 0,1a fuse. Microphone not connected.
/
Emil

yes this is correct if you look at the PSU schemo on page 1 one leg of the secondary 230VAC is tied to ground, and the other one at the half phase rect diode,  did you try another fuse like 0.2A or 0.3A , sometime the fuse is not slow blow enough or not slow blow at all,   and there a smal inrush current at startup, is you pilot direclty wired to AC or the current involved in the pilot lamp is counted in ,

Hope this helps,
Best,
DAn,

First 67 up and running. Everything seems to work and no noise. Will get it going in the studio ASAP for feedback.
I ended up paralleling the 56k resistor in series with the 210v adjust pot with another 56k, = 28k. Seems to work better here.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 25, 2013, 08:15:11 AM
Hi guys.
I'm just about to finish the first of my four u67. I have an issue with the psu. I blew a couple of fuses trying to power it up. The 250v pilot just flashes and then it's gone. After disconnecting the 210v transformer from the pcb the fuse won't brake. Getting 20v from the other transformer.
There's 0,9ohm resistance between one of the 210v inputs on the psu and 0v. Is that right? It's the same on all of my four psu pcbs. I've double checked all the components and the wiring/soldering.
Triad 210v tranny in series, bridging violet/gray on primary and red/orange on secondary. 250v/2w pilot light.
I'm in Europe (230v) and I'm using the spec 0,1a fuse. Microphone not connected.
/
Emil

yes this is correct if you look at the PSU schemo on page 1 one leg of the secondary 230VAC is tied to ground, and the other one at the half phase rect diode,  did you try another fuse like 0.2A or 0.3A , sometime the fuse is not slow blow enough or not slow blow at all,   and there a smal inrush current at startup, is you pilot direclty wired to AC or the current involved in the pilot lamp is counted in ,

Hope this helps,
Best,
DAn,

First 67 up and running. Everything seems to work and no noise. Will get it going in the studio ASAP for feedback.
I ended up paralleling the 56k resistor in series with the 210v adjust pot with another 56k, = 28k. Seems to work better here.

Great News,

Let me know how the story ends up  :),
Best,
DAn
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on September 26, 2013, 01:48:58 PM
Everything seems to be working super with my mic. Sounds unbelievable!
My final question is about the 40Hz filter. Is that on with or without the jumper?
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 26, 2013, 02:13:48 PM
Everything seems to be working super with my mic. Sounds unbelievable!
My final question is about the 40Hz filter. Is that on with or without the jumper?
/
Emil

With the Jumper on S2 internal is default if you want to have a bit more Proxy and Move the lc further remove the Jumper on S2.

I am very Glad that you like it ,  it is one of those mics.. ;)  Wich Trio do you have Tube, cap and Tran

Thanks for your post ,. appreciate it .
Best,

edit :   :) :) :)
<dAn
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on September 26, 2013, 02:24:56 PM
Everything seems to be working super with my mic. Sounds unbelievable!
My final question is about the 40Hz filter. Is that on with or without the jumper?
/
Emil

With the Jumper on S2 internal is default if you want to have a bit more Proxy and Move the lc further remove the Jumper on S2.

I am very Glad that you like it ,  it is one of those mics.. ;)  Wich Trio do you have Tube, cap and Tran

Thanks for your post ,. appreciate it .
Best,

edit :   :) :) :)
<dAn

Thanks!
I'm using beesneez capsule, vintage telefunken ef86 and ioaudio transformer. I'm building a pair of these and then a second pair with the same specs but ami transformer.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on September 27, 2013, 05:01:27 PM
whats everyone building these inside now… since the sty-5 is not available?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 28, 2013, 02:32:22 AM
Hi gang, just got my chunger body back from the machinist...I wanted to install an Amphenol connector instead of the 7-pin XLR. I don't have tools for boring the base myself, or I'd DIY it.  Came out great! Here's some photos prior to me installing the wiring. Excited!

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on September 29, 2013, 11:22:29 PM
whats everyone building these inside now… since the sty-5 is not available?

anyone?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 30, 2013, 02:36:03 AM
She's breathing! Just plugged in my completed D67...a pulse! She passes audio! Wow! First try!!

A little concerned about voltages...H- is -6.29 at the lowest possible setting - can only turn pot up from there, and B+ only goes as high as +201 (measured inside the mic of course!). Unloaded at the psu I get 245v and -16v. I also noted that testing ground from the mic frame to the psu (through the cable) yielded about 12.1R, which kind of surprised me. Can anyone else test their ground resistance through the mic to the psu and report back? I had a sneaking suspicion I should have used that black wire along with the blue one for the ground but...I didn't...

Oh if anyone thinks it matters I used 22awg in the mic for both H- and B+...the thicker cable was a huge hassle and I ended up just using my teflon stuff...I know it's a little smaller guage but it's only a 2 inch run so I figured that shouldn't matter.

Anyone have any thoughts? Tube has not burned in at all - just plugged in and waited a couple minutes, maiden voyage so to speak...making that cable took a lot out of me lol!

Tried posting an mp3 but I see we cannot...dang would have loved to have shared how good it sounds but I'm not up for figuring out external storage right now.

What I can't get over is just how GOOD the thing sounds! I mean, WOW! It just oozes quality. Very, very clean, high-end, pro sounding and very complimentary to the voice! And it didn't cost me a house!

And by the way this is with a Max (ioaudio) BV12, a Phillips Mullard tube, Shinkoh resistors, stock capacitors from build,  and a super cheap Chinese capsule; I have a beeskneez coming....it will only get better from here!

Thanks to Dan and everyone else on this forum for making it so incredibly fun and, well, worthwhile!!

Thanks all!!

 Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 30, 2013, 02:47:41 AM
I just want to go on the record and say, those gearsnobs who spout things like "there's NOTHING like an original xyz" have never had the thrill of creating something so incredible, and so good sounding! I could give a rat's --- if this mic isn't a "real U67" by golly it's an amazing mic! And my singers in my studio will agree what an incredible tool this is going to be...all hand made in the US of A!

Poctop, Dan, we all owe you big for your generosity of spirit in helping everyone, your genius in coming up with these DIY-able designs, your great support, and awesome attitude!

Not to mention, you've cloned every great mic in existence by now haven't you? Wow!!!!

This one's for you Dan!  :) ;) :D ;D 8)

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 30, 2013, 08:08:52 AM
I just want to go on the record and say, those gearsnobs who spout things like "there's NOTHING like an original xyz" have never had the thrill of creating something so incredible, and so good sounding! I could give a rat's --- if this mic isn't a "real U67" by golly it's an amazing mic! And my singers in my studio will agree what an incredible tool this is going to be...all hand made in the US of A!

Poctop, Dan, we all owe you big for your generosity of spirit in helping everyone, your genius in coming up with these DIY-able designs, your great support, and awesome attitude!

Not to mention, you've cloned every great mic in existence by now haven't you? Wow!!!!

This one's for you Dan!  :) ;) :D ;D 8)

Mike

Thanks For the kind word it is appreciated,   

Quote
H- is -6.29 at the lowest possible setting - can only turn pot up from there, and B+ only goes as high as +201 (measured inside the mic of course!). Unloaded at the psu I get 245v and -16v. I also noted that testing ground from the mic frame to the psu (through the cable) yielded about 12.1R, which kind of surprised me. Can anyone else test their ground resistance through the mic to the psu and report back? I had a sneaking suspicion I should have used that black wire along with the blue one for the ground but...I didn't...

sometimes different tubes will put up slighlty different plate and heater current ,  to bring back the 210VDC loaded you will need to adjust the external resistor on the B+ Pot you should have currently 56K over there as this is what works for me , in your case you should go ahead and replace the 56K resistor with a lower value like 33K 1/4 watt is ok and you will get the upper range back ,   -6.3VDC on the heater is what the spec is but if you need to go lower just Add a external resistor on the pot Leg as per the B+ something like 22 ohm in 1 or 2 watt format, this will bring the range down a bit as the standard pot is 50 ohm ,

as per the continuity make sure you mic pcb ground and mic chassis is zero ohm, make sure you installed the jumper in the psu SHLF as this is a sheild lift for pin 3 to bring back star ground on the psu,   keep me posted,  unpower everyting and check your ground scheme and ground continuity untill you find the culprit,

you may have taken the filament resistance pad to check your continuity as this might have gven you a reading of approx 12 ohm depending on the tube ,

hope this helps,
Dan,

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 30, 2013, 03:32:17 PM
Thanks For the kind word it is appreciated,   
Deserved!!
Quote
sometimes different tubes will put up slighlty different plate and heater current ,  to bring back the 210VDC loaded you will need to adjust the external resistor on the B+ Pot you should have currently 56K over there as this is what works for me , in your case you should go ahead and replace the 56K resistor with a lower value like 33K 1/4 watt is ok and you will get the upper range back
Understood...I just hated having to desolder in the PSU just to match a tube, so maybe I'll try my second tube. Sounds gorgeous by the way, even at just 200v...! I mean full and silky and warm even with the Chinese capsule!
Quote
-6.3VDC on the heater is what the spec is but if you need to go lower just Add a external resistor on the pot Leg as per the B+ something like 22 ohm in 1 or 2 watt format, this will bring the range down a bit as the standard pot is 50 ohm
Didn't know if I should try to underheat the tube...I could leave this as-is; any recommendations? Will the tube last longer if I put it at -5.8v, or will this cause buildup of unwanted chemicals in the tube over time if underheated? What are people doing, just using spec'ed -6.3v? Thx.
Quote
as per the continuity make sure you mic pcb ground and mic chassis is zero ohm, make sure you installed the jumper in the psu SHLF as this is a sheild lift for pin 3 to bring back star ground on the psu,   keep me posted,  unpower everyting and check your ground scheme and ground continuity untill you find the culprit,
Yes I do have the jumper installed in the PSU. Within the PSU internally, and within the mic internally, grounding is .2R or .1R; my Fluke always has a tiny little bit of resistance showing maybe the probe leads. But it's when I check through the mic cable that I get the 12R. I'm wondering if the mic cable needs redoing; it was a bugger getting it soldered up right. I'll look into it more carefully tonight...I was just so jazzed it worked at all (not that I doubted you Dan...just something about making something yourself and breathing life into it....Frankenstein lol!).
Quote
you may have taken the filament resistance pad to check your continuity as this might have gven you a reading of approx 12 ohm depending on the tube
Actually I used the mic rails for the mic ground point and the PSU case for the PSU ground point...Are there different points I should use for ground resistance check? Would what I used account for the 12R? Bothered me since I was so careful with this build!

Quote
hope this helps,
Dan,
Yes it's all helpful Dan; you're awesome! Thank-you!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 30, 2013, 03:41:07 PM
Thanks For the kind word it is appreciated,   
Deserved!!
Quote
sometimes different tubes will put up slighlty different plate and heater current ,  to bring back the 210VDC loaded you will need to adjust the external resistor on the B+ Pot you should have currently 56K over there as this is what works for me , in your case you should go ahead and replace the 56K resistor with a lower value like 33K 1/4 watt is ok and you will get the upper range back
Understood...I just hated having to desolder in the PSU just to match a tube, so maybe I'll try my second tube. Sounds gorgeous by the way, even at just 200v...! I mean full and silky and warm even with the Chinese capsule!
Quote
-6.3VDC on the heater is what the spec is but if you need to go lower just Add a external resistor on the pot Leg as per the B+ something like 22 ohm in 1 or 2 watt format, this will bring the range down a bit as the standard pot is 50 ohm
Didn't know if I should try to underheat the tube...I could leave this as-is; any recommendations? Will the tube last longer if I put it at -5.8v, or will this cause buildup of unwanted chemicals in the tube over time if underheated? What are people doing, just using spec'ed -6.3v? Thx.
Quote
as per the continuity make sure you mic pcb ground and mic chassis is zero ohm, make sure you installed the jumper in the psu SHLF as this is a sheild lift for pin 3 to bring back star ground on the psu,   keep me posted,  unpower everyting and check your ground scheme and ground continuity untill you find the culprit,
Within the mic internally, and within the PSU internally, grounding is .2R or .1R; my Fluke always has a tiny little bit of resistance showing maybe the probe leads. But it's when I check through the mic cable. I'm wondering if the mic cable needs redoing; it was a bugger getting it soldered up right.
Quote
you may have taken the filament resistance pad to check your continuity as this might have gven you a reading of approx 12 ohm depending on the tube
Actually I used the mic rails for the mic ground point and the PSU case for the PSU ground point...Are there different points I should use for ground resistance check? Would what I used account for the 12R? Bothered me since I was so careful with this build!

Quote
hope this helps,
Dan,
Yes it's all helpful Dan; you're awesome! Thank-you!

Thanks ,

Quote
Understood...I just hated having to desolder in the PSU just to match a tube, so maybe I'll try my second tube. Sounds gorgeous by the way, even at just 200v...! I mean full and silky and warm even with the Chinese capsule!

you dont have to desolder anything on the pcb since you will change or add an external resistance to the external Pot in the psu
For sure you could install a 200ohm pot 5W for the heater if you wish it will cover all need sometimes it is quicker just to add a resistor on the leg of the pot and choose your own range  ;)

I havent notice any major difference in underheating a tube well not yet ,  but you should not underheat under 10% IIRC,


Might the cable has a cold solder or an issue but it should read 0 ohm or ver very close from the mic rail to the psu
you could take a wire from the psu pin 3 and pinch it on the mic rail and you will have your answer about the cable , remember the SHLF jumper must be installed.

Best,
Dan,.





Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 30, 2013, 08:45:09 PM
Thanks Dan for the encouragement and awesome support!

I disconnected power and systematically checked 1-7 connections. Here's what I got:

Pin   R
1   0.9
2   0.9
3   0
4   0.2
5   0.9
6   0.9
7   0.1

interesting the thinner 22awg cables all got .9R and the fatter heater and ground (3,7) were at .1 and .2R. The gigantic cable shield pin 3 was dead 0R. I'm using a Fluke 87 and compensated for the meter probe resistance. My last mic cable I wired up was also Gotham GAC-7 and as I recall I was getting about 1R for the thinner wires and .4R for the thicker ones, so this is in the ballpark. I think that says the cable must be OK, right?

Also measuring from the mic rail to ground on the PSU, or from mic rail to the chassis on PSU, I got 0.1R, which is inline with what you said Dan.

When I was doing the measuring last night I did have the unit on and powered; I turned it on just now and tried just measuring the PSU chassis to the mic rail and again got a high reading - 16.5R - but that's with the unit ON. Off, the resistance is what I shared above. Why would that be? Just curious; I think the cable/grounding is fine but to me it's odd I would get resistance when the unit is powered vs when it is unplugged from the wall.

What value resistor would you recommend adding to the H- to bring the pot more into useable range? I will try another tube and find out if it needs different voltages.

Thank-you Dan and everyone for everything; great forum!

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on September 30, 2013, 09:00:42 PM
Just swapped the tube out; now I get a tiny bit more range in the H-, still gets to -6.3v, and B+ goes to 209 at the top end. I think I will change out the resistor in the B+ to get a little more range.

Thanks all,

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on October 02, 2013, 04:49:01 AM
Quick question about the B- resistor Dan,

You had said earlier:

"-6.3VDC on the heater is what the spec is but if you need to go lower just Add a external resistor on the pot Leg as per the B+ something like 22 ohm in 1 or 2 watt format, this will bring the range down a bit as the standard pot is 50 ohm , "

I'm not the genius you are please bear with me...

Currently the B- pot range with tube installed is 6v ~ 9v. So roughly a 3v span.

If I wanted the range to drop to say, 4v ~7v, a 2v drop in overall range, and we know the B- eats about roughly.2A per schematic, wouldn't a good value be calculated:

v=ir
2v=.2A x r
r = 10 Ohms

Or is the current different or am I not understanding something?

Thanks a million man.

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on October 04, 2013, 04:33:31 AM
Heres a Question,

Do you think this could be built inside a u87ai body?

Reason I ask is that I'm building mine with neumann capsule which is roughly $800, u87ai's can be gotten for 1,500 or less which wouldn't be much for a great body, grill and capsule.

J
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on October 04, 2013, 09:18:12 AM
Quick question about the B- resistor Dan,

You had said earlier:

"-6.3VDC on the heater is what the spec is but if you need to go lower just Add a external resistor on the pot Leg as per the B+ something like 22 ohm in 1 or 2 watt format, this will bring the range down a bit as the standard pot is 50 ohm , "

I'm not the genius you are please bear with me...

Currently the B- pot range with tube installed is 6v ~ 9v. So roughly a 3v span.

If I wanted the range to drop to say, 4v ~7v, a 2v drop in overall range, and we know the B- eats about roughly.2A per schematic, wouldn't a good value be calculated:

v=ir
2v=.2A x r
r = 10 Ohms

Or is the current different or am I not understanding something?

Thanks a million man.


that is correct,  now you have to calculate the dissipated power as per P=VI
so P = 2V*0.2A  = 0.4W or P= R*I(square that you will give the same results)
Best,
DAn,

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on October 04, 2013, 09:20:24 AM
Heres a Question,

Do you think this could be built inside a u87ai body?

Reason I ask is that I'm building mine with neumann capsule which is roughly $800, u87ai's can be gotten for 1,500 or less which wouldn't be much for a great body, grill and capsule.

J

I could not tell you because i never been able to attempt it, but someone here on the forum is atempting to build the 269c inside a U87 body he will  let us know if it can be done look at the white Thread for more info or the 269c thread , but in the meantime i have a feeling that Chunger SyT-5 mic body should be returning pretty soon,

Best,
dAn,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on October 04, 2013, 10:00:28 AM
Quick question about the B- resistor Dan,

You had said earlier:

"-6.3VDC on the heater is what the spec is but if you need to go lower just Add a external resistor on the pot Leg as per the B+ something like 22 ohm in 1 or 2 watt format, this will bring the range down a bit as the standard pot is 50 ohm , "

I'm not the genius you are please bear with me...

Currently the B- pot range with tube installed is 6v ~ 9v. So roughly a 3v span.

If I wanted the range to drop to say, 4v ~7v, a 2v drop in overall range, and we know the B- eats about roughly.2A per schematic, wouldn't a good value be calculated:

v=ir
2v=.2A x r
r = 10 Ohms

Or is the current different or am I not understanding something?

Thanks a million man.


that is correct,  now you have to calculate the dissipated power as per P=VI
so P = 2V*0.2A  = 0.4W or P= R*I(square that you will give the same results)
Best,
DAn,

Mike

Thanks Dan. Good to know my brain is still functioning. Thx for the advice on the wattage; makes sense. Again, how do you have time to not only produce all these amazing pcb's and designs, but help all the newbies through their growing pains??? Amazing! Thank-you!!!!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on October 04, 2013, 05:22:20 PM
Quick question about the B- resistor Dan,

You had said earlier:

"-6.3VDC on the heater is what the spec is but if you need to go lower just Add a external resistor on the pot Leg as per the B+ something like 22 ohm in 1 or 2 watt format, this will bring the range down a bit as the standard pot is 50 ohm , "

I'm not the genius you are please bear with me...

Currently the B- pot range with tube installed is 6v ~ 9v. So roughly a 3v span.

If I wanted the range to drop to say, 4v ~7v, a 2v drop in overall range, and we know the B- eats about roughly.2A per schematic, wouldn't a good value be calculated:

v=ir
2v=.2A x r
r = 10 Ohms

Or is the current different or am I not understanding something?

Thanks a million man.


that is correct,  now you have to calculate the dissipated power as per P=VI
so P = 2V*0.2A  = 0.4W or P= R*I(square that you will give the same results)
Best,
DAn,

Mike

Thanks Dan. Good to know my brain is still functioning. Thx for the advice on the wattage; makes sense. Again, how do you have time to not only produce all these amazing pcb's and designs, but help all the newbies through their growing pains??? Amazing! Thank-you!!!!

I am really trying to do my best , thanks for the nice words,
Best,
dAn,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on October 04, 2013, 07:06:49 PM
Question on the P.S

I wanted to bypass the PCB for modulation.

Is this correct to link all together:

[[ XLR pin 3 > Chassis > Pin 7 > Pin 3 > PCB Gnd ]]

Reason I ask is because of switch on pin 3 to pin 7, default on schematic shows open position yet still goes to chassis regardless.

Cheers

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on October 05, 2013, 09:25:43 AM
Question on the P.S

I wanted to bypass the PCB for modulation.

Is this correct to link all together:

[[ XLR pin 3 > Chassis > Pin 7 > Pin 3 > PCB Gnd ]]

Reason I ask is because of switch on pin 3 to pin 7, default on schematic shows open position yet still goes to chassis regardless.

Cheers

could you explain the modulation thing ?


if you tie the cable shield from the cable to the mic body then pin 3 Sheild and pin 7 0V are at the same level , the SHLF jumper wich is open by default allows to lift the shield or not if your shield jumper is on or not , hence you can have a floating shield or not,  just permits 2 ways of doing things as somtimes it can help on RF wierd situation,  if you actually dont tie the pin 3 to pin 7 on the mic pcb or mic body you can have both functionnality operated with the jumper

but basically if it is now tied up to the mic body then ou are good to go ,

hope this helps,
Let me know .
Best,
DAn,

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on October 05, 2013, 05:00:39 PM
Great thanks dan,

I'm just anal over certain things, Like all the vintage power supplies, I just wanted to prevent modulation (audio + and -) from unnecessarily going through the PCB in an attempt to retain pure common mode rejection with a twisted pair direct to the XLR.

I have one more question, Inside the Gac-7 cable, do I attach the braided sleeve to pin 3 along with the (8th pin - housing shell) on both ends? My first time building a 7pin tube mic cable.

Cheers

J
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on October 05, 2013, 06:19:34 PM
Great thanks dan,

I'm just anal over certain things, Like all the vintage power supplies, I just wanted to prevent modulation (audio + and -) from unnecessarily going through the PCB in an attempt to retain pure common mode rejection with a twisted pair direct to the XLR.

There is no problem with that as the pad on the pcb are just a convienent option anywhay,

I have one more question, Inside the Gac-7 cable, do I attach the braided sleeve to pin 3 along with the (8th pin - housing shell) on both ends? My first time building a 7pin tube mic cable.

connect the cable sheild from pin 3 to psu and then run in to the cable, once inside the mic you can connect it to the pad for it on the mic pcb #3

then you connector should already be at ground level with the mic body even easier than on the connector as both will be at 0V


Best,
Dan,

Cheers

J
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on October 17, 2013, 05:30:25 PM
I'm at the end of my build, which one would you rock first?? hmm the choices… although that big 1841 won't fit

(http://www.JessJackson.com/images/capchoice.jpg)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on October 17, 2013, 07:24:32 PM
And heres a question…

When utilizing a dual backplate design such as erics capsules in a pure cardioid only circuit with rear capsule floating. Do you still tie both backplates together or do you use only the front backplate?

cheers

J
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on October 18, 2013, 01:16:06 AM
And heres a question…

When utilizing a dual backplate design such as erics capsules in a pure cardioid only circuit with rear capsule floating. Do you still tie both backplates together or do you use only the front backplate?

cheers

J

if you are in cardiod only then use only the front backplate connection,
Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on October 18, 2013, 06:51:59 AM
And heres a question…

When utilizing a dual backplate design such as erics capsules in a pure cardioid only circuit with rear capsule floating. Do you still tie both backplates together or do you use only the front backplate?

cheers

J

if you are in cardiod only then use only the front backplate connection,
Best,
Dan,

That makes sense to me in the u87 build but in designs which use a shared backplate such as the c12 unlike the elam, the backplates are tied together.

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: pasarski on October 18, 2013, 11:53:35 AM
And heres a question…

When utilizing a dual backplate design such as erics capsules in a pure cardioid only circuit with rear capsule floating. Do you still tie both backplates together or do you use only the front backplate?

cheers

J

if you are in cardiod only then use only the front backplate connection,
Best,
Dan,

That makes sense to me in the u87 build but in designs which use a shared backplate such as the c12 unlike the elam, the backplates are tied together.

For omni and fig8 yes. In cardioid mode the membrane "doesn't know" there's an other backplate, it only "sees" the one next to it :)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on October 18, 2013, 05:41:50 PM
I'm at the end of my build, which one would you rock first?? hmm the choices… although that big 1841 won't fit

(http://www.JessJackson.com/images/capchoice.jpg)

Miam miam , personnaly i would go for the ero the package is nice and it looks cool too,  ;)
Best,
dAn,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: MikeFFG on October 23, 2013, 02:43:44 PM
Hey guys -

I built this about 6 motnhs ago and got it fully working and sounding amazing! I've used it dozens or more times probably and was loving it. But all of a sudden it's been making some weird sounds and I'm very unhappy and sad   :-\

I haven't gotten in there with a scope or to see what's wrong just yet...I'm scared! Haha, but seriously, if anyone hears this and is like "oh that's definitely a the diaphragm, or the tube, or a capacitor" or whatever...That would be a HUGE help...

You can listen here: http://prettyuglyproductions.net/wp-content/uploads/2013/10/badu67.wav (http://prettyuglyproductions.net/wp-content/uploads/2013/10/badu67.wav)

Thanks fellas!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on October 23, 2013, 03:25:15 PM
Link doesn't work here, but the first thing I'd check would be the EF86.
Whimsical tube that (but so musical). Make sure you have a couple spares around.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on October 24, 2013, 12:06:37 AM
so i finished my build, sounds great and just shot it out against vintage unmodified u67 here at paramount studios

Im using:

T67
Eric's 87 capsule with backplates tied together in cardioid
ero 1uf cap as seen above.
I'm at 208v b+ at full turn and 6.3 heater

Going back and forth on female singer my mic instantly is 5db hotter than the vintage u67
The top end is slightly more harsh/brittle and the bottom end is massive, too much lower mids in comparison to the u67 but was thinking it could be using the 1uf instead of a 0.5 over saturating the transformer possibly.

Other than that its very similar but I probably wouldn't use it until I can tune it to sound right without additional eq

I may throw a neumann k67 in there as i suspect thats the culprit for the slightly harsher tops.

cheers.

J
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on October 24, 2013, 08:30:06 AM
so i finished my build, sounds great and just shot it out against vintage unmodified u67 here at paramount studios

Im using:

T67
Eric's 87 capsule with backplates tied together in cardioid
ero 1uf cap as seen above.
I'm at 208v b+ at full turn and 6.3 heater

Going back and forth on female singer my mic instantly is 5db hotter than the vintage u67
The top end is slightly more harsh/brittle and the bottom end is massive, too much lower mids in comparison to the u67 but was thinking it could be using the 1uf instead of a 0.5 over saturating the transformer possibly.

Other than that its very similar but I probably wouldn't use it until I can tune it to sound right without additional eq

I may throw a neumann k67 in there as i suspect thats the culprit for the slightly harsher tops.

cheers.

J

did you jump the S2 internal switch this will affect the low end response  , what tube are you using for this one,  the end value of the bypass cap will also play a role into this i would stick to the original value to start with and go from there .  for sure trying it out with a real K67 would be nice to hear  your feedback from,  8)

Thanks for the post,
Keep us posted on how it goes,
Best,
dAN,


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on October 24, 2013, 08:34:26 AM
Hey guys -

I built this about 6 motnhs ago and got it fully working and sounding amazing! I've used it dozens or more times probably and was loving it. But all of a sudden it's been making some weird sounds and I'm very unhappy and sad   :-\

I haven't gotten in there with a scope or to see what's wrong just yet...I'm scared! Haha, but seriously, if anyone hears this and is like "oh that's definitely a the diaphragm, or the tube, or a capacitor" or whatever...That would be a HUGE help...

You can listen here: http://prettyuglyproductions.net/wp-content/uploads/2013/10/badu67.wav (http://prettyuglyproductions.net/wp-content/uploads/2013/10/badu67.wav)

Thanks fellas!

currently out of town but once i am back i will give it a listen and see if i can hear something that i feel i already heard before.
did you try another tube as a start and check all the reference voltage including ,bias, b+ ,and heater and if the plate voltage is swinging for no reason ,.
is the mic passing the breath test or not , checking cold solder or weak wire in the HZ section.
hope this helps,
DAn,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on October 24, 2013, 09:01:29 AM
so i finished my build, sounds great and just shot it out against vintage unmodified u67 here at paramount studios

Im using:

T67
Eric's 87 capsule with backplates tied together in cardioid
ero 1uf cap as seen above.
I'm at 208v b+ at full turn and 6.3 heater

Going back and forth on female singer my mic instantly is 5db hotter than the vintage u67
The top end is slightly more harsh/brittle and the bottom end is massive, too much lower mids in comparison to the u67 but was thinking it could be using the 1uf instead of a 0.5 over saturating the transformer possibly.

Other than that its very similar but I probably wouldn't use it until I can tune it to sound right without additional eq

I may throw a neumann k67 in there as i suspect thats the culprit for the slightly harsher tops.

cheers.

J

did you jump the S2 internal switch this will affect the low end response  , what tube are you using for this one,  the end value of the bypass cap will also play a role into this i would stick to the original value to start with and go from there .  for sure trying it out with a real K67 would be nice to hear  your feedback from,  8)

Thanks for the post,
Keep us posted on how it goes,
Best,
dAN,

Whats up Dan, hope your well mate.

Yeah i have a jumper across S2 and I'm using a phillips mini watt tube. I just ordered two ero 0.47uf caps mkt1813 to keep it stock values for the moment.

cheers J
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on October 24, 2013, 09:15:53 AM
so i finished my build, sounds great and just shot it out against vintage unmodified u67 here at paramount studios

Im using:

T67
Eric's 87 capsule with backplates tied together in cardioid
ero 1uf cap as seen above.
I'm at 208v b+ at full turn and 6.3 heater

Going back and forth on female singer my mic instantly is 5db hotter than the vintage u67
The top end is slightly more harsh/brittle and the bottom end is massive, too much lower mids in comparison to the u67 but was thinking it could be using the 1uf instead of a 0.5 over saturating the transformer possibly.

Other than that its very similar but I probably wouldn't use it until I can tune it to sound right without additional eq

I may throw a neumann k67 in there as i suspect thats the culprit for the slightly harsher tops.

cheers.

J

did you jump the S2 internal switch this will affect the low end response  , what tube are you using for this one,  the end value of the bypass cap will also play a role into this i would stick to the original value to start with and go from there .  for sure trying it out with a real K67 would be nice to hear  your feedback from,  8)

Thanks for the post,
Keep us posted on how it goes,
Best,
dAN,

Whats up Dan, hope your well mate.

Yeah i have a jumper across S2 and I'm using a phillips mini watt tube. I just ordered two ero 0.47uf caps mkt1813 to keep it stock values for the moment.

cheers J

thanks Jesse,
Do you still plan on sticking a Neumann K67 in there to try out ?
Best,
daN,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Melodeath00 on October 24, 2013, 10:59:22 AM
I'm looking forward to hear your new opinions with the stock values and k67. This project is definitely on my list of builds.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on October 24, 2013, 06:09:58 PM
so i finished my build, sounds great and just shot it out against vintage unmodified u67 here at paramount studios

Im using:

T67
Eric's 87 capsule with backplates tied together in cardioid
ero 1uf cap as seen above.
I'm at 208v b+ at full turn and 6.3 heater

Going back and forth on female singer my mic instantly is 5db hotter than the vintage u67
The top end is slightly more harsh/brittle and the bottom end is massive, too much lower mids in comparison to the u67 but was thinking it could be using the 1uf instead of a 0.5 over saturating the transformer possibly.

Other than that its very similar but I probably wouldn't use it until I can tune it to sound right without additional eq

I may throw a neumann k67 in there as i suspect thats the culprit for the slightly harsher tops.

cheers.

J

did you jump the S2 internal switch this will affect the low end response  , what tube are you using for this one,  the end value of the bypass cap will also play a role into this i would stick to the original value to start with and go from there .  for sure trying it out with a real K67 would be nice to hear  your feedback from,  8)

Thanks for the post,
Keep us posted on how it goes,
Best,
dAN,

Whats up Dan, hope your well mate.

Yeah i have a jumper across S2 and I'm using a phillips mini watt tube. I just ordered two ero 0.47uf caps mkt1813 to keep it stock values for the moment.

cheers J

thanks Jesse,
Do you still plan on sticking a Neumann K67 in there to try out ?
Best,
daN,

yeah why not…

I'm gonna use the one from my u87ai and try it up against paramounts u67.

The sound is VERY close, its just an eq thing now at this point. It has to match for me, for times when songs that are half cut at one location and continued elsewhere.

I was actually close to just buying a u67 a few months ago and held off to see how this build would sound, its so close that i may as well get it perfect.

What was the original coupling cap used? anyone have one spare for me to try?

cheers
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: MikeFFG on October 25, 2013, 04:03:41 PM
Hey guys -

I built this about 6 motnhs ago and got it fully working and sounding amazing! I've used it dozens or more times probably and was loving it. But all of a sudden it's been making some weird sounds and I'm very unhappy and sad   :-\

I haven't gotten in there with a scope or to see what's wrong just yet...I'm scared! Haha, but seriously, if anyone hears this and is like "oh that's definitely a the diaphragm, or the tube, or a capacitor" or whatever...That would be a HUGE help...

You can listen here: http://prettyuglyproductions.net/wp-content/uploads/2013/10/badu67.wav (http://prettyuglyproductions.net/wp-content/uploads/2013/10/badu67.wav)

Thanks fellas!

currently out of town but once i am back i will give it a listen and see if i can hear something that i feel i already heard before.
did you try another tube as a start and check all the reference voltage including ,bias, b+ ,and heater and if the plate voltage is swinging for no reason ,.
is the mic passing the breath test or not , checking cold solder or weak wire in the HZ section.
hope this helps,
DAn,

Thanks for the ideas. I checked b+ and heater and they are fine...I think it passed the breath test, at least as far sa I understand it. It didn't do anything crazy at least.  I'm still figuring out how to check bias and the plate voltage...I'm searching through the thread. Part of the problem being that once I finished the build 6 months ago I kind of forgot half of what I learned while doing it!

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: MikeFFG on October 25, 2013, 04:10:14 PM
Hey guys -

I built this about 6 motnhs ago and got it fully working and sounding amazing! I've used it dozens or more times probably and was loving it. But all of a sudden it's been making some weird sounds and I'm very unhappy and sad   :-\

I haven't gotten in there with a scope or to see what's wrong just yet...I'm scared! Haha, but seriously, if anyone hears this and is like "oh that's definitely a the diaphragm, or the tube, or a capacitor" or whatever...That would be a HUGE help...

You can listen here: http://prettyuglyproductions.net/wp-content/uploads/2013/10/badu67.wav (http://prettyuglyproductions.net/wp-content/uploads/2013/10/badu67.wav)

Thanks fellas!

currently out of town but once i am back i will give it a listen and see if i can hear something that i feel i already heard before.
did you try another tube as a start and check all the reference voltage including ,bias, b+ ,and heater and if the plate voltage is swinging for no reason ,.
is the mic passing the breath test or not , checking cold solder or weak wire in the HZ section.
hope this helps,
DAn,

Thanks for the ideas. I checked b+ and heater and they are fine...I think it passed the breath test, at least as far sa I understand it. It didn't do anything crazy at least.  I'm still figuring out how to check bias and the plate voltage...I'm searching through the thread. Part of the problem being that once I finished the build 6 months ago I kind of forgot half of what I learned while doing it!

Mike

So this is weird, but I just tested it again after putting it back together (I took it apart for the troubleshooting and breath test, etc.) and now it sounds fine again!! I wonder if some wire or something was out of place or hitting the side or something? But anyways, it sounds fine for the moment...

Still a killer mike!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on October 25, 2013, 04:20:31 PM
Quote
So this is weird, but I just tested it again after putting it back together (I took it apart for the troubleshooting and breath test, etc.) and now it sounds fine again!! I wonder if some wire or something was out of place or hitting the side or something? But anyways, it sounds fine for the moment...

Still a killer mike!

Make sure it is not just a wire touching the tube grid point connection , that might could be it ,
easiest solution the better,

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mistasanshou on October 31, 2013, 11:57:10 PM
so i finished my build, sounds great and just shot it out against vintage unmodified u67 here at paramount studios

Im using:

T67
Eric's 87 capsule with backplates tied together in cardioid
ero 1uf cap as seen above.
I'm at 208v b+ at full turn and 6.3 heater

Going back and forth on female singer my mic instantly is 5db hotter than the vintage u67
The top end is slightly more harsh/brittle and the bottom end is massive, too much lower mids in comparison to the u67 but was thinking it could be using the 1uf instead of a 0.5 over saturating the transformer possibly.

Other than that its very similar but I probably wouldn't use it until I can tune it to sound right without additional eq

I may throw a neumann k67 in there as i suspect thats the culprit for the slightly harsher tops.

cheers.

J
Did u get a chance to put that k67 in? If so how does it compsre to the vintage u67 now?  Im thinking of going all out with the neumann k67. 

Dan, thanks for this awesome project, ive wanted a u67 ever since the day I heard one and now its within reach.  How do the ami t67 and the ioaudio bv12 compare and which one do you recommend? Thanks again
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on November 01, 2013, 07:05:09 AM
so i finished my build, sounds great and just shot it out against vintage unmodified u67 here at paramount studios

Im using:

T67
Eric's 87 capsule with backplates tied together in cardioid
ero 1uf cap as seen above.
I'm at 208v b+ at full turn and 6.3 heater

Going back and forth on female singer my mic instantly is 5db hotter than the vintage u67
The top end is slightly more harsh/brittle and the bottom end is massive, too much lower mids in comparison to the u67 but was thinking it could be using the 1uf instead of a 0.5 over saturating the transformer possibly.

Other than that its very similar but I probably wouldn't use it until I can tune it to sound right without additional eq

I may throw a neumann k67 in there as i suspect thats the culprit for the slightly harsher tops.

cheers.

J
Did u get a chance to put that k67 in? If so how does it compsre to the vintage u67 now?  Im thinking of going all out with the neumann k67. 

Dan, thanks for this awesome project, ive wanted a u67 ever since the day I heard one and now its within reach.  How do the ami t67 and the ioaudio bv12 compare and which one do you recommend? Thanks again

Nah I haven't had the chance yet… been too busy in the studio.. i'll do it this week. I did powder coat one side of the basket black though, lol

I would rock the k67 if I was you, there doesn't seem to be anyone able to match it and according to the greats, neumann senheiser still manufacture them to the highest quality.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Melodeath00 on November 07, 2013, 02:53:40 PM
Has anyone posted any clips of their build with the BeesNeez K6?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mistasanshou on November 21, 2013, 11:54:38 PM
so i finished my build, sounds great and just shot it out against vintage unmodified u67 here at paramount studios

Im using:

T67
Eric's 87 capsule with backplates tied together in cardioid
ero 1uf cap as seen above.
I'm at 208v b+ at full turn and 6.3 heater

Going back and forth on female singer my mic instantly is 5db hotter than the vintage u67
The top end is slightly more harsh/brittle and the bottom end is massive, too much lower mids in comparison to the u67 but was thinking it could be using the 1uf instead of a 0.5 over saturating the transformer possibly.

Other than that its very similar but I probably wouldn't use it until I can tune it to sound right without additional eq

I may throw a neumann k67 in there as i suspect thats the culprit for the slightly harsher tops.

cheers.

J
Did u get a chance to put that k67 in? If so how does it compsre to the vintage u67 now?  Im thinking of going all out with the neumann k67. 

Dan, thanks for this awesome project, ive wanted a u67 ever since the day I heard one and now its within reach.  How do the ami t67 and the ioaudio bv12 compare and which one do you recommend? Thanks again

Nah I haven't had the chance yet… been too busy in the studio.. i'll do it this week. I did powder coat one side of the basket black though, lol

I would rock the k67 if I was you, there doesn't seem to be anyone able to match it and according to the greats, neumann senheiser still manufacture them to the highest quality.
hey man, any time for an update yet?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on November 22, 2013, 12:09:29 AM
I'm excited because I finally got my beesknees K6 capsule back...Now to replace the cheapie Chinese capsule with it! I'll let you guys know how it ends up sounding etc, I'm excited!!

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on November 22, 2013, 05:59:19 AM
Me, too!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Melodeath00 on November 22, 2013, 11:19:58 AM
Me as well! Update us ASAP. Did you like the mic before even with the cheap capsule?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on November 22, 2013, 12:48:58 PM
Me, too!

+1
D :)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on November 22, 2013, 02:33:18 PM
Me as well! Update us ASAP. Did you like the mic before even with the cheap capsule?
Yes! As you know psychoacoustics can play a huge role in our experience/perception of auditory phenomena; ie if I think it's a crappy capsule I'll hear a crappy sound, but it had a nice full smooth and beefy sound with a hint of that special magic we look for in great mics. I'll post back after installing the new capsule, although it might be a little while since I may have to rework PSU voltages for the new capsule (I probably need to swap some resistors).

Thanks,

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on November 22, 2013, 03:30:38 PM
Me as well! Update us ASAP. Did you like the mic before even with the cheap capsule?
Yes! As you know psychoacoustics can play a huge role in our experience/perception of auditory phenomena; ie if I think it's a crappy capsule I'll hear a crappy sound, but it had a nice full smooth and beefy sound with a hint of that special magic we look for in great mics. I'll post back after installing the new capsule, although it might be a little while since I may have to rework PSU voltages for the new capsule (I probably need to swap some resistors).

Thanks,

Mike

thats great news , but you would not have to change any voltage for a diefferent capsule , could you explain a bit ,
Best,
daN,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on November 23, 2013, 12:04:23 AM
I was being vague sorry - of course not changing voltage for the capsule. What I meant was, I want to install the new capsule, and then check to see where voltages are since at the moment I'm getting barely in-range voltages for B+ and H. I likely need to change resistor values as per our previous discussion, which is likely due to the particular tube I have or other unknown factors to why my voltages are not in the center of the pot range. I didn't know if the new capsule would have any effect on the existing voltages - my ignorance but I thought I would change the capsule first and then check the voltages.

I'll post back, and thanks Dan.

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on December 06, 2013, 01:13:58 AM
OK, got the new capsule installed! As usual, there was a lot more to it than "drag and drop"! I had to do a lot of drilling/prepping the new capsule holder arrangement since the K6 capsule has its own stand and I wanted to use it. Sigh. As expected, anything custom takes more time!

So I'm posting links to clips, one using a Chinese capsule I got from a Chunger build, and the second the BeesKneez K6 capsule. It's yours truly singing, so please don't kill the messenger!

I was holding the mic (iknow!) about 4-6" from my mouth. Different days - actually weeks apart. Some of the difference is simply my voice was different between the two takes! This is not scientific at all! Only processing whatsoever was to use the "normalize" effect on each to within 0.5db of 0.

Thoughts?

Mike

Chinese Capsule: http://pctrainingexperts.com/portals/0/audio/chinese.mp3 (http://pctrainingexperts.com/portals/0/audio/chinese.mp3)
Beeskneez K6: http://pctrainingexperts.com/portals/0/audio/k67-2.mp3 (http://pctrainingexperts.com/portals/0/audio/k67-2.mp3)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on December 06, 2013, 05:11:04 AM
Thanks for the samples, Mike. We need more brave guys like you!

The different takes do make it a bit tricky. I hear somewhat smoother esses on the second as well as more body down below, but e.g. that could also be caused by just a hair closer proximity.

Now that the K6 is in there, could you do some samples with you closer on the mic? The U67 was designed to be well suited for close miking (pun intended), that is, in case of less forte singing of course (or talking for that matter). But you may need a popfilter for that (if you don't use one already).


Henk
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on December 06, 2013, 05:37:57 AM
Thanks for the feedback Henk. In both cases I had the mic "about" the same distance - I was holding it in my hand since at my house I don't have a studio stand. I was probably about 4-6" from the mic; almost eating it, so although I could get even closer, this was a lot of proximity. While I obviously will not be able to post future clips of the mic with the Chinese capsule, I'll see what I can do about getting some samples from my studio proper.

I feel the new capsule is much clearer and yet also retains warmth, which sometimes is mutually exclusive! Being anal, funny how the word anal is part of anal-ysis, I concur that better matching of the clips and proper setup would have been much preferred. I was just delighted to note that I even had saved the original takes, so thought to just post something quick.

Hope this is a little helpful anyhow, and thanks guys for the terrific community and camaraderie. As pathetic as it may sound, you guys are like my buddies and I enjoy interacting with you all and building cool stuff.

Warm regards,

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on December 16, 2013, 07:33:39 PM
http://store.studio939.com/product/35mm-k67-style-capsule

Sorry if I have missed but has anyone tried these K67 cheap capsules ..... nice price.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on December 17, 2013, 01:33:30 AM
http://store.studio939.com/product/35mm-k67-style-capsule

Sorry if I have missed but has anyone tried these K67 cheap capsules ..... nice price.
Yes I tried this capsule; it was what I had installed before I got the Sneesby capsule.

I thought overall it was a fairly nice capsule; maybe a little "softer" sounding but still useable. With the world-class circuit of the D67 behind it, I think it helps. I'm glad to have the higher end one, however, as it seems fuller, to have more "presence."

hth,

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on December 17, 2013, 08:18:38 PM
Thanks Mike thats good news any thoughts on the mic n mod K67 anyone....thanks
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on December 24, 2013, 08:59:10 PM
I just knocked up an experimental version of U67 circuit .... I dont have correct transformer & capsule at moment so i used maxes BV08 & a k47 capsules... I left out C3 C17 R18 r19 & R20 for Im getting audio but fairly low level lower than U87 circuit ...... does that sound right....... for now Im using two power supplies one for B+ & one for heater but reversed 6.3Volt is that ok way to power it.....just wanting to learn about the circuit for now..... the sound I get from the mic is pretty good little bit white noise mush tho ...... I was just experimenting with the much simpler circuit  of the Oliver Archut UM75/92/92.1 with same transformer & capsule good sound more level less noise...... not expecting too much as Im using wrong transformer but Im wondering where the noise is coming from.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on December 24, 2013, 09:04:15 PM
Quick update to my last post...... if I turn off the 6.3 heater voltage the white noise goes completly mis still passes audio for a few seconds as heater cools down .....the heater PSU doest cause any noise with mic I made that are powered the usual way..... I need to understand more about the way the U67 is powered ...... interesting .....

Merry christmas
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on December 30, 2013, 05:23:55 PM
Hello,

I finished my U67 recently. It sounds great, works fine, but seems slightly dull to me. Is this normal?

RK67 capsule
BV12 transformer

Having no experience with a real U67, I'm wondering if this is the way it should sound or if I'm way off. I didn't do any kind of calibration, is there a calibration process other than the frequency response test described in the manual?

Any help is appreciated. Thanks.

-Kevin
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: wave on January 03, 2014, 10:54:17 AM
The real 67s that we have used and shot out with were def not dull. You got any sound samples?

Dave
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on January 03, 2014, 03:32:55 PM
The D-U67 is the most sparkling mic I have, it sounds like like a U87 on steroid with that tube sounds in bonus ,  to answer your question I guess it would be best to let chime in the folks that actually have built one and could comment on it. there is many sound sample trough the thread also

here is one of many, Thanks to Sylvain.

Quote
ok here is finally a comparaison between classic U67 and my D67 at mythic studio gang paris
i did a little article (english) on my blog with the audio files there and building pictures (in french)
hope to do more but that's it for now :)
massive thx to poctop this is a great kit !

http://www.sylvainmoreau.com/sylvain_moreau/?p=940 (http://www.sylvainmoreau.com/sylvain_moreau/?p=940) (http://www.sylvainmoreau.com/sylvain_moreau/?p=940 (http://www.sylvainmoreau.com/sylvain_moreau/?p=940))
(say hello in comments ;) )

thanks to Dave,

Quote
Hello all,
I just wanted to share my thoughts on the DU67 project. I LOVE this mic. It's super sweet and sounds absolutely awesome.
Tskguy's capsules are truly works of art. Here are some tracks I threw together while doing some initial recordings after finishing the mic and installing on of Eric's capsules.
The signal flow is DU67 –> Sound Skulptor MP573 –> ProTools. I'm really digging the way these tracks sound with no eq or comp.
2 acoustic guitars and 2 vox

https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993f40.wav

I did this in about 10 min single takes on all the tracks so I'm sorry about my pitchy vox.
This mic is def going to be on all my records from now on and it's already at a colleague's studio doing the duty!

Dave

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: ben_studio on January 04, 2014, 01:27:56 PM
Dear all,
I've finished last june the D67, works great, but I've been concerned the last couple of weeks by the sound of it and I Guess it's probably coming from the tube, which is a TELEFUNKEN EF86. When a singer sings into the mic without a PopKiller, sometimes the mic' starts doing a heavy unwanted sound, crackles a little bit, and then calm down again after 5/10sec. It's similar as the noise we can hear when we start using the mic the first seconds, while the tube is warming up.
Anyone is aware of this kind of trouble or is this my tube which is non working fine ?

I've also noticed, that at equivalent recording levels, my D67 does have a floor noise higher than a TLM103 for e.g. Is this also normal that the D67 is not "as quiet" a Neumann TLM ? (which has no tube inside)

Let me know your thoughts about this,

Thanks

Ben
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on January 04, 2014, 01:53:29 PM
Hi Ben, these symptoms sound like you may have a microscopic or larger hole in the diaphragm. Or the diaphragm has become overly contaminated with debris or other foreign material.

You can do the breath test (easy to do anytime. Just search it of you are not familiar) as well as investigating with a magnifying glass.

If one side is damaged and you usually use cardioid you may be able to turn the capsule around and retire so your not using the damaged side.

Cheers,
Jonathan
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on January 04, 2014, 02:14:19 PM
Hi Ben, these symptoms sound like you may have a microscopic or larger hole in the diaphragm. Or the diaphragm has become overly contaminated with debris or other foreign material.

You can do the breath test (easy to do anytime. Just search it of you are not familiar) as well as investigating with a magnifying glass.

If one side is damaged and you usually use cardioid you may be able to turn the capsule around and retire so your not using the damaged side.

Cheers,
Jonathan

Thanks JB, this is exactely what i had in mind , and to answer your noise question the noise is directly dependant on the tube used,  in "general" tube mic are a tad noisier than tranformer-less - microphone without tube but it depends also if it is hum or hiss (with noise) and at wich level it becomes abnormal
Best,
dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: ben_studio on January 04, 2014, 02:27:13 PM
Thanks to both of you for your answers.

I've been doing the same tests with Sylvain Moreau this afternoon on his mic, and regarding the sound produced after a "p" sound for example (that would be also really close to it, like 2cm) he noticed exactly the same problem.
I would really go into a tube issue as this sound of "vynil hum" I can hear it when the mic is warming up (and before singing into it)

I don't think (well I hope) our two capsules are not down or presenting a small problem, but in case, I'll probably try to reverse the side as suggested.

Regarding the noise, it's not a hiss noise, it's really like there's more 'white noise' in the tube Mic than in the FET, but as you said it's probably a characteristic of tube Mic.

I'll try to make 2 recordings to make you hear the differences, and in the same time, will soon post a few vocals and cellos I've been doing for future builders !

Thanks again

Ben
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on January 04, 2014, 02:32:15 PM
Quote
I've been doing the same tests with Sylvain Moreau this afternoon on his mic, and regarding the sound produced after a "p" sound for example (that would be also really close to it, like 2cm) he noticed exactly the same problem.

could you ellaborate on this what is the issue with the p sound does it pop the diaphrgame out , just curious are you using a pop filter and also is your S2 internal switch  jumpered for "bass proximity"
also wich capsule are you using?
 
Let me know,
Best,
dAN, '
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: wave on January 04, 2014, 02:54:40 PM
Dany,
That is def the best way to show how the mics should sound! I had forgotten about that lil test track I did.
I still think it sounds amazing.

Kevin,
Do you have any sound samples you can share with us? I'm interested to hear what your mic sounds like. I had an RK-67 in my D-U67 initially and it was def not as good sounding as my HK-67 (Heiserman Audio).
I am def a proponent of 80% of the mic's sound is in the capsule

just my 2¢
Dave
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on January 04, 2014, 03:13:49 PM
Hey Ben, the breath test is easy to do by exhaling slowly close to the head basket directly into the capsule (not popping it). So that the capsule gets a slow-and-humid breath all over it. It shouldn't cut out or make wind noises in that case unless the humidity is causing small shorts between the backplate and sputtering or if there is a hole and the humidity is condensing in between the backplate and membrane/hole. It dries itself within a couple seconds with this test.

Popping it can do the same thing but you want to listen when exposed to slow-breath-high-humidity.

Cheers,
Jonathan
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: ben_studio on January 05, 2014, 09:12:20 AM
Hey Ben, the breath test is easy to do by exhaling slowly close to the head basket directly into the capsule (not popping it). So that the capsule gets a slow-and-humid breath all over it. It shouldn't cut out or make wind noises in that case unless the humidity is causing small shorts between the backplate and sputtering or if there is a hole and the humidity is condensing in between the backplate and membrane/hole. It dries itself within a couple seconds with this test.

Popping it can do the same thing but you want to listen when exposed to slow-breath-high-humidity.

Cheers,
Jonathan

Dear Jonathan,
It seems in fact that with the breath test, it produces a noise growing up as described before, and I found out the other side of the capsule (in bidirectional mode for testing) seems to work better and the sound is even louder.
I can't physically turn around the capsule, so do you think I can disconnect and switch the wires on the capsule to use the other side when I'll be in Cardiod position ?
I mean, take the wire fixed on the damaged side, unscrew it, and screw it back to the other side ?

thanks

Ben
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on January 05, 2014, 10:17:38 AM
Ben, don't unscrew the wires from the capsule. It is not recommended in any case unless you don't particularly want to use it anymore.

Instead you should desolder the front/back wires from down in the hi-z section and reverse them.

Be very careful to cover the capsule with a loose plastic Baggie or something to protect it while soldering. A tiny hot blob of vaporized flux will melt a tiny hole in the diaphragm pretty easily.

I would also take the opportunity to visually inspect the capsule for damage or other foreign material contamination to confirm our suspicions of what the breath-test appears to have suggested.

Cheers,
Jonathan
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: ben_studio on January 05, 2014, 12:58:36 PM
Ben, don't unscrew the wires from the capsule. It is not recommended in any case unless you don't particularly want to use it anymore.

Instead you should desolder the front/back wires from down in the hi-z section and reverse them.

Be very careful to cover the capsule with a loose plastic Baggie or something to protect it while soldering. A tiny hot blob of vaporized flux will melt a tiny hole in the diaphragm pretty easily.

I would also take the opportunity to visually inspect the capsule for damage or other foreign material contamination to confirm our suspicions of what the breath-test appears to have suggested.

Cheers,
Jonathan

Dear again,
Here is the sound before I Fixed the problem :
http://benoitlaur.com/soundonline/
Click on file 'd67 exhaling'

I did the changes of the wires from back to front, (with extreme care on the capsule well protected of course)
The sound is better, and when I do the exhaling test again on the new good side, it does not produce any more 'huming' or anything you could hear on the file I recorded before.
So I guess one side of the capsule might have been damaged, I'll join photos, but I'm not sure you can actually notice especial on it.

Thanks again, this was as you said not a "tube problem"

Ben
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: ben_studio on January 05, 2014, 01:06:15 PM
Ben, don't unscrew the wires from the capsule. It is not recommended in any case unless you don't particularly want to use it anymore.

Instead you should desolder the front/back wires from down in the hi-z section and reverse them.

Be very careful to cover the capsule with a loose plastic Baggie or something to protect it while soldering. A tiny hot blob of vaporized flux will melt a tiny hole in the diaphragm pretty easily.

I would also take the opportunity to visually inspect the capsule for damage or other foreign material contamination to confirm our suspicions of what the breath-test appears to have suggested.

Cheers,
Jonathan

And here is the link with the 2 pictures of both sides :
http://benoitlaur.com/pictureonline/

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on January 06, 2014, 04:46:30 AM
Hi what is the 270P for thats not in the BOM thanks ...
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on January 06, 2014, 08:09:46 AM
Hi what is the 270P for thats not in the BOM thanks ...

it is for the low cut/pad section operation in the D-269c and the D-67

the 270 pf/630V  polystyrene is difficult to find that is why i supply complimentary kit trough the webstore for the mic projects,
this is also true for all the mic project i host on groupdiy,

what we generally found as polystyrene is 50V and it is not enough to survive long in the mics,

hope this helps,
Best,
dAN,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on January 06, 2014, 09:20:22 AM
Thanks for info so its C10 ? its not on your schematic on original schematic its 500pf does smaller value pad down less, thanks again...
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on January 06, 2014, 09:47:05 AM
Thanks for info so its C10 ? its not on your schematic on original schematic its 500pf does smaller value pad down less, thanks again...

there were tiny difference over the year , here is 2 schematic showing the use of the 500pf and the 270pf and also 400M over 500M and 60M over 68M,  might also be the availability of the parts also,
I beleive that the mic was too hot when it came out early 60s for the US gear and then the pad cap value was modified over the years also the 500M and the 400M were used interchangeably, this value will affect the pad efficiency and broadcasting quality related to how the low end behaves. it can be swapped and tryed out for sure.

hope this helps,
Dan,

(https://dl.dropboxusercontent.com/u/43869772/U67/Schemo%20after%20343.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281993f4f.jpg)


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on January 06, 2014, 09:58:23 AM
How interesting thanks  :) , I see 1uf C9 too, I came across a schematics showing no C17 too

great info big thanks
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Melodeath00 on January 06, 2014, 10:08:28 AM
Any guesses why they changed C9 in terms of both value, and voltage rating? First one is 250V and the next is 450V. Also not seeing a date/year on those schematics
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on January 06, 2014, 10:20:51 AM
Any guesses why they changed C9 in terms of both value, and voltage rating? First one is 250V and the next is 450V. Also not seeing a date/year on those schematics

the first schematis shown dates from 1960  serial after 343 the second one serial after 10,000 ,  that gives you an idea ,
the bypass cap has been tweaked a bit probably to alter the overall sound might 1uf instead of 0.5 will give slighlty different low end behavior,
for the rating 250V is sufficient as the voltage seen there is about 75V, might 450V is what they had handy a this time ,
just some toughts,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on January 06, 2014, 10:21:11 AM
Wasnt 1uf earlier and the to keep bass down swapped to .5uf also swapped 500M down to 400M & 68M down to 60M

question does the 60/68M positioned resistors add bass the higher the value as would R8 ? Im assuming they would....
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on January 06, 2014, 10:27:23 AM
sorry cross posted....

My schematic with no C17 is also 1960

I have just kinda breadboarded the U67 circuit to learn Im interested in the reversed polarty of the heater..... can anyone explain ? my breadboard 67 is working but was a little white noisy & cant get my plate below 62V BUT if I swap polartity of my heater back to the more common way my plate is then 73V & white noise mush much lower ?

Thanks
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on January 06, 2014, 10:34:25 AM
sorry cross posted....

My schematic with no C17 is also 1960

I have just kinda breadboarded the U67 circuit to learn Im interested in the reversed polarty of the heater..... can anyone explain ? my breadboard 67 is working but was a little white noisy & cant get my plate below 62V BUT if I swap polartity of my heater back to the more common way my plate is then 73V & white noise mush much lower ?

Thanks

Like it was mentionned before in this thread,  the negative grid bias is derived from the heater negative supply , a unique way of doing it
this tough should not prevent you from having he the proper plate voltage at setup since it is self bias,  the feedback capactitor coupled with this even more special transformer is (very very) sensitive to RF and surrounding and even crap from space. so if your breadboarding is not shielded and enclosed this wil have the you know effect on it , if you swap the polarity you will be changing your overall bias and affect the gain structure of the mic hence the white mush .

Just my 2 cents,
D
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on January 06, 2014, 11:39:28 AM
sorry cross posted....

My schematic with no C17 is also 1960

I have just kinda breadboarded the U67 circuit to learn Im interested in the reversed polarty of the heater..... can anyone explain ? my breadboard 67 is working but was a little white noisy & cant get my plate below 62V BUT if I swap polartity of my heater back to the more common way my plate is then 73V & white noise mush much lower ?

Thanks

Like it was mentionned before in this thread,  the negative grid bias is derived from the heater negative supply , a unique way of doing it
this tough should not prevent you from having he the proper plate voltage at setup since it is self bias,  the feedback capactitor coupled with this even more special transformer is (very very) sensitive to RF and surrounding and even crap from space. so if your breadboarding is not shielded and enclosed this wil have the you know effect on it , if you swap the polarity you will be changing your overall bias and affect the gain structure of the mic hence the white mush .

Just my 2 cents,
D

Thanks Dany the odd thing Im finding is that when I wire the special heater bais scheme the correct way as per schematic I get wrong plate voltage of between 51V & 62V & 1.9 to 2V at r 9 10 11 12 depending of my EF86 AND as a crap bonus white mush.......But if I reverse heater polarity mush goes away  well nearly plate between 71v 78V & 1.65V R9 10 11 12..... when I say breadboard I just mean made for testing not proper build but mic is enclosed , I have no humm or other issues the mic sounds very good not using bv12 using BV08 for test with no feedback circuit tim cambel capsule for now

Thanks for info
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on January 07, 2014, 09:49:43 PM
Aha ! realize my mistake I had reversed the heater connections in the first place  :-[ silly me so now all voltages are spot on mush noise is quieter except when S2 open.....

I think the mush is just the tube dont think Ive ever come across a quiet EF86, I need to find some more EF86s

Something interesting in my 1960 U67 schematic the heater polarity IS indeed reversed, ie 6.3+ connected to R10...... R4 R7 also different values ..... having by accident been running my U67 this way as I reported could get the voltages right ( the voltages on my starnge 1960 schematic are same as other schematics ive seen so far)  so I wonder how the voltages could ever be right, I did lower the plate resistor value to get correct plate voltage, wondering if R4 R7 values have any affect on the voltages so I will try the different values, Im wondering if they just effect the low frequecies ...... either way will be fun to eexperiment.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on January 07, 2014, 10:28:21 PM
If the heater was reversed so it gets +6V3 wouldn't the grid then get a positive bias?

That would certainly not sound "good" if so.

Cheers,
jb

EDIT:
Reversed as in the 0V line gets -6.3V and the -6.3V line gets 0V?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on January 08, 2014, 08:34:16 AM
Aha ! realize my mistake I had reversed the heater connections in the first place  :-[ silly me so now all voltages are spot on mush noise is quieter except when S2 open.....

I think the mush is just the tube dont think Ive ever come across a quiet EF86, I need to find some more EF86s

Something interesting in my 1960 U67 schematic the heater polarity IS indeed reversed, ie 6.3+ connected to R10...... R4 R7 also different values ..... having by accident been running my U67 this way as I reported could get the voltages right ( the voltages on my starnge 1960 schematic are same as other schematics ive seen so far)  so I wonder how the voltages could ever be right, I did lower the plate resistor value to get correct plate voltage, wondering if R4 R7 values have any affect on the voltages so I will try the different values, Im wondering if they just effect the low frequecies ...... either way will be fun to eexperiment.

can you post this schematic where the heater is reversed ?  both the schematic i posted yesterday were -6.3V,
DAn,

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on January 08, 2014, 09:18:16 PM
http://repforums.prosoundweb.com/index.php?topic=36297.0

schematic is in this disscussion.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on January 09, 2014, 08:24:18 AM
http://repforums.prosoundweb.com/index.php?topic=36297.0

schematic is in this disscussion.

I looked at it and if you look at the voltage shown on the schematic at R10 node the voltage reading is negative , so it must be a typo or just an omission,
Best,
DAN,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 18, 2014, 03:59:33 AM
Kevin,
Do you have any sound samples you can share with us? I'm interested to hear what your mic sounds like. I had an RK-67 in my D-U67 initially and it was def not as good sounding as my HK-67 (Heiserman Audio).
I am def a proponent of 80% of the mic's sound is in the capsule

just my 2¢
Dave

Hey Dave,

Yes I definitely agree, the capsule is 80% of the sound, no question. In my case, I feel like something has to be off. It's awfully dull. That being said, it's still is a nice sound overall, if you're going for that. Anyway, I recorded some acoustic guitar (Seagull S6 Spruce), if you wouldn't mind giving it a listen here:

https://soundcloud.com/kevinwinrich/u67-acoustic-guitar (https://soundcloud.com/kevinwinrich/u67-acoustic-guitar)

Signal Chain: U67 into Digi 003 preamp (no EQ, compression, or effects)

Mic placement: 5 inches from the 10th fret, slightly of axis towards the nut

Mic Info: RK67, BV12, JJ EF806-S

Picture of the guts attached..

Any help is greatly appreciated.

-Kevin
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on January 18, 2014, 06:06:09 AM
OK, got the new capsule installed! As usual, there was a lot more to it than "drag and drop"! I had to do a lot of drilling/prepping the new capsule holder arrangement since the K6 capsule has its own stand and I wanted to use it. Sigh. As expected, anything custom takes more time!

So I'm posting links to clips, one using a Chinese capsule I got from a Chunger build, and the second the BeesKneez K6 capsule. It's yours truly singing, so please don't kill the messenger!

I was holding the mic (iknow!) about 4-6" from my mouth. Different days - actually weeks apart. Some of the difference is simply my voice was different between the two takes! This is not scientific at all! Only processing whatsoever was to use the "normalize" effect on each to within 0.5db of 0.

Thoughts?

Wondering if anymore samples from these capsules, dont know if its my ears but I dont hear a lot of difference between the capsules was kinda expecting night & day difference .....my ears are not great due to many years as a singer...... what do other ears think....

Mike

Chinese Capsule: http://pctrainingexperts.com/portals/0/audio/chinese.mp3 (http://pctrainingexperts.com/portals/0/audio/chinese.mp3)
Beeskneez K6: http://pctrainingexperts.com/portals/0/audio/k67-2.mp3 (http://pctrainingexperts.com/portals/0/audio/k67-2.mp3)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on January 18, 2014, 12:55:32 PM
Kevin,
Do you have any sound samples you can share with us? I'm interested to hear what your mic sounds like. I had an RK-67 in my D-U67 initially and it was def not as good sounding as my HK-67 (Heiserman Audio).
I am def a proponent of 80% of the mic's sound is in the capsule

just my 2¢
Dave

Hey Dave,

Yes I definitely agree, the capsule is 80% of the sound, no question. In my case, I feel like something has to be off. It's awfully dull. That being said, it's still is a nice sound overall, if you're going for that. Anyway, I recorded some acoustic guitar (Seagull S6 Spruce), if you wouldn't mind giving it a listen here:

https://soundcloud.com/kevinwinrich/u67-acoustic-guitar (https://soundcloud.com/kevinwinrich/u67-acoustic-guitar)

Signal Chain: U67 into Digi 003 preamp (no EQ, compression, or effects)

Mic placement: 5 inches from the 10th fret, slightly of axis towards the nut

Mic Info: RK67, BV12, JJ EF806-S

Picture of the guts attached..

Any help is greatly appreciated.

-Kevin

i would start  by looking at the basic voltage ( Bias ), (Plate) , (Polarisation Voltage),  (Heater), (B+) and specially the Hz bridge and capsule connection ,
the HZ bridge is definitely the first place to look after checking all of this,
Keep us posted,
D
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mistasanshou on January 21, 2014, 02:30:21 AM
Did u get a chance to put the neumann capsule in yet?
so i finished my build, sounds great and just shot it out against vintage unmodified u67 here at paramount studios

Im using:

T67
Eric's 87 capsule with backplates tied together in cardioid
ero 1uf cap as seen above.
I'm at 208v b+ at full turn and 6.3 heater

Going back and forth on female singer my mic instantly is 5db hotter than the vintage u67
The top end is slightly more harsh/brittle and the bottom end is massive, too much lower mids in comparison to the u67 but was thinking it could be using the 1uf instead of a 0.5 over saturating the transformer possibly.

Other than that its very similar but I probably wouldn't use it until I can tune it to sound right without additional eq

I may throw a neumann k67 in there as i suspect thats the culprit for the slightly harsher tops.

cheers.

J
Did u get a chance to put that k67 in? If so how does it compsre to the vintage u67 now?  Im thinking of going all out with the neumann k67. 

Dan, thanks for this awesome project, ive wanted a u67 ever since the day I heard one and now its within reach.  How do the ami t67 and the ioaudio bv12 compare and which one do you recommend? Thanks again

Nah I haven't had the chance yet… been too busy in the studio.. i'll do it this week. I did powder coat one side of the basket black though, lol

I would rock the k67 if I was you, there doesn't seem to be anyone able to match it and according to the greats, neumann senheiser still manufacture them to the highest quality.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 21, 2014, 05:07:30 AM
i would start  by looking at the basic voltage ( Bias ), (Plate) , (Polarisation Voltage),  (Heater), (B+) and specially the Hz bridge and capsule connection ,
the HZ bridge is definitely the first place to look after checking all of this,
Keep us posted,
D

Hey Dan, thanks for the help.

Heater: -6.50V
B+: +210V

Where are good test points for Bias, Plate, and Polarization Voltage? I've searched the forum and the build folder, but couldn't find anything. Also, what voltage should i see for each of these? Thanks again.

-Kevin
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 27, 2014, 01:41:57 AM
Sorry to bump, but does anyone know where to test Bias, Plate, and Polarization Voltages on the PSU and/or the main PCB? Any help is appreciated, thanks.

-Kevin
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 28, 2014, 04:54:02 AM
Ok now I'm being a little less stupid :o. I realized I could take one step further and post my measurements across each XLR pin and ground. I also measured voltages at the capsule connections.

Please let me know if these voltages look right:

PIN1: XLR OUT PIN 3 (8.7 mVAC, noise floor? I'm guessing this is negligible)
PIN2: XLR OUT PIN 2 (1.6 mVAC, noise floor? Again, negligible)
PIN3: -36 mV (marked "CGND" on schematic)
PIN4: -6.4 V (H-)
PIN5: 210.5 (B+)
PIN6: -36 mV (marked "CAL" on schematic, calibration input?)
PIN7: -36 mV (marked "0V" on schematic)


Capsule Voltages (tested at their connection points to the tube PCB (FD and BCK) and the switch PCB (BD):

FD: -.87 V
BD: Omni= -.87 V, Cardioid= -35 mV, Figure 8= Starts at 4V, then steadily drops
BCK: 8.5 V

I've identified the Heater and B+ voltages, but I'm unsure as to which are the Bias, Plate, and Polarization voltages. Also, where can I test the Hz bridge?

Please help, I'm pretty lost. Thanks.

-Kevin

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on January 28, 2014, 05:42:38 AM
Hi Kevin dont know if I can help you help yourself I dont have the boards so its hard for me to help but I have been experimenting with this circuit....firstly you prob wont be able to measure the capsule voltages from the high impedances capsule connections with a usual meter but should be able to from by looking at original schematics measure from junction of R12 R13 should be 59V also I think from R13 R15....  again looking at the original schematic ( not sure if Danys schematic using same number cant see it on this PC but prob is) juction of 9 10 11 & 12 should be 1.6 or 1.8V for the bias ......for the plate its pin 6 of the tube junction of C9 output cap & R14 should be about 75V ...... need to find these junctions on your PCB & tube to measure I hope Im not leading you astray if anyone else wants to jump in as I say dont have the boards to look at your B+ & low tension look good, good luck
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 28, 2014, 03:24:20 PM
Thanks so much, Gary!! I'll definitely test voltages at the points you suggested, hopefully I can find them.

I'll post my results.

-Kevin
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: MikeFFG on January 28, 2014, 06:04:54 PM
Hi -

So a couple months ago I posted with my U67 having some noise issues, and it resolved itself. But a new noise is kind of back. It's totally intermittent (ie not all the time or every 3 seconds...just sporadic...but happens quite regularly). I've recorded it and uploaded it. Can anyone tell if that's a problem they've heard like a bad tube or a bad cap or something obvious? The mic did seem to pass the breath test so I don't think it's the diaphragm. And the recordings still sound good, they just have this intermittent low level popping throughout them. It's fairly low level (I have cranked it in the example) but enough that it would ruin a good take.

You can listen here: http://prettyuglyproductions.net/wp-content/uploads/2014/01/Noise.wav (http://prettyuglyproductions.net/wp-content/uploads/2014/01/Noise.wav)

In the recording, there's obviously background noise and hum and stuff, that's obviously not the part I'm talking about though!

Thanks!

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on January 28, 2014, 06:56:52 PM
Hi Mike could be many things maybe dry solder joint dodgy capacitor dirt on high impedance parts I guess first thing give it a good clean are tube pins clean.....
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on January 28, 2014, 11:27:35 PM
Yeah. I had all those Gary mentions cause that sound. Bad cap was specifically a back-to-front styro which was probably heat stressed but also on different mic's. Cleaning the hi-z connections on others, and "even a tube" on another. Once had a cathode bypass cap cause that sound or similar and the heater dropping resistor on a 47 style on another. Same sound though (or very similar) in all of those cases but probably "louder" from a snr standpoint.

Cheers,
Jonathan
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: DUDE GUY on January 29, 2014, 04:57:07 AM
...measure from junction of R12 R13 should be 59V also I think from R13 R15....  again looking at the original schematic ( not sure if Danys schematic using same number cant see it on this PC but prob is) juction of 9 10 11 & 12 should be 1.6 or 1.8V for the bias ......for the plate its pin 6 of the tube junction of C9 output cap & R14 should be about 75V...

OK, here are my results:

(B+): 210V

(H-): -6.4V (as low as I can get it)

Junction R12 and R13 (Polarization): 50V

Junction R13 and R15: Starts at around 110V and slowly drops down to 98.6V

Junction of C9 and R14 (Plate): 80V

Junction of R9 - R12 (Bias): -1.8V

So it looks like my polarization voltage is low and my plate is too high. Any ideas?

Thanks,

-Kevin
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on January 29, 2014, 05:40:45 AM
Hi Kevin Im not enough of an expert but I would say your plate is ok as schematic says about 75V yours not much higher less than 10% & your cathode bias is about right at 1,8V..... if you have another tube you could pop that in and measure voltages again it prob would be different but hopefully there abouts too but this tube seems ok to me.

Regarding the capsule polar voltages Im not convinced your meter is telling the truth..... I dont totally understand this myself something like connecting our not really expensive super meter to that part of the circuit adds load & buggers up the readings ( please help me out clever chaps to explain this & learn myself)...... I usually check all resistor values and B+ voltage as you have and trust that capsule voltage should be correct & as long as mic works correct I leave it..... when I made my version of this circuit   I didnt add the omni & fig 8 patterns by the way...my R12 R13 junction measured 50V too, I did experiment & swapped the 3.3M R15 for a 2.2M & in brought voltage up to 60V on my meter mic sounded the same so I swapped resistor back incase voltage was really higher trying to measure capsule voltage with my cheap meter in other mics I have made also was strange in most cases.

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gyraf on January 29, 2014, 05:49:23 AM
Regarding the capsule polar voltages Im not convinced your meter is telling the truth..... I dont totally understand this myself something like connecting our not really expensive super meter to that part of the circuit adds load & buggers up the readings ( please help me out clever chaps to explain this & learn myself)...... I usually check all resistor values and B+ voltage as you have and trust that capsule voltage should be correct & as long as mic works correct I leave it.....

Remember that your voltmeter has a finite input resistance - most often 1M Ohm or 10M Ohm - specified in it's manual.

Then recalculate expected voltages at the point in question by adding in this value across the measuring point.

If you have e.g. a 10M input voltmeter, and measure a point with a 10M source resistance, you'll get a readout of half the actual voltage

Jakob E.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gary o on January 29, 2014, 06:12:42 AM
Thankyou Jakob that make sense the way you put that..... so its like adding 10M resistor between ground & test point .....so in our U67 circuit here how do we work out our source resistance as we are in a chain of resistors do we add up some resistor values ?

thanks
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: MikeFFG on January 29, 2014, 07:36:44 AM
Alright thanks Gary and Jonathan! That was my fear...

Was hoping it was like "hey that's TOTALLY a bad tube" lol.

Will have to really get in there and check it out.

Thanks guys.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Barton on February 05, 2014, 10:09:20 AM
I haven't been able to find a clear wiring diagram for the D-U67 PSU, and just wanted to make sure that I have it correct.  If someone could take a look at the attached diagram and provide feedback I'd appreciate it.  I plan on using 2 lamps, as the collective cases PSU case already has holes pre-drilled for both.
(http://)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Winetree on February 05, 2014, 12:49:30 PM
The extra hole is for the fuse holder. Where's the fuse in your diagram?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on February 06, 2014, 03:20:11 PM
I haven't been able to find a clear wiring diagram for the D-U67 PSU, and just wanted to make sure that I have it correct.  If someone could take a look at the attached diagram and provide feedback I'd appreciate it.  I plan on using 2 lamps, as the collective cases PSU case already has holes pre-drilled for both.
(http://)

if you are based on 120V this is correct,  the thing is to understand why we wire in parralle and in series but clearly you understand that as per your diagram
there is also one posted in the thread the TSKGUy have done for it 120V and also another one for 230V europe ,

Best,
dAN,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on February 06, 2014, 03:22:08 PM
...measure from junction of R12 R13 should be 59V also I think from R13 R15....  again looking at the original schematic ( not sure if Danys schematic using same number cant see it on this PC but prob is) juction of 9 10 11 & 12 should be 1.6 or 1.8V for the bias ......for the plate its pin 6 of the tube junction of C9 output cap & R14 should be about 75V...

OK, here are my results:

(B+): 210V

(H-): -6.4V (as low as I can get it)

Junction R12 and R13 (Polarization): 50V

Junction R13 and R15: Starts at around 110V and slowly drops down to 98.6V

Junction of C9 and R14 (Plate): 80V

Junction of R9 - R12 (Bias): -1.8V

So it looks like my polarization voltage is low and my plate is too high. Any ideas?

Thanks,

-Kevin

this looks in the range  to drop your heater voltage even more increase the value of the series resistor attached to the Heater trimmer pot it will increase your dropping range ,
BEst.,
dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kpearsall on February 24, 2014, 10:09:43 PM
If anyone is still looking for cases, I recently got a Pelican 1550 which fits everything nicely, you just need to sit the microphone in it's bag on top of the cables.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on March 08, 2014, 06:01:35 PM
I was about to shootout the u67 against an all original vintage u67 yesterday but mine needed 1 click on the neve 1081 and a little trim resulting in +6db of extra gain to match the vintage u67

This contradicts the last time i tested the mic, http://groupdiy.com/index.php?topic=50021.msg689359#msg689359

All my voltages are good (210+, 6.3v H, 84v plate)

I'm running an eric capsule with the two backplates tied together ami t67 trans.

what could be causing this much lower output level?

J
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: ben_studio on March 15, 2014, 06:55:10 AM
I've recently done some tests with original U67.
If you want to have a listen to them, here is the link :

http://benoitlaur.com/a-b-original-neumann-u67-vs-clone-u67/

Hope this will encourage people to go into the project,

Ben
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on March 15, 2014, 11:48:15 AM
Great samples, Ben. Thanks.

They both sound like 67s to me, but I actually like the D67 better. Wow, what a sound! Big, lush and hifi at the same time.
To my ears the U67 is a little more middy (mid-mid, hi-mid) or the D67 a bit more extended on both ends.
Because of stronger high mids and less bass (and low mids even), the U67 may seem brighter, but I hear more true air in the D67.
This is noticeable in the sound of the fast moving slide bar (vibrato) on the wound strings, for instance. And in the breathing sounds.
The U67 has a little more "cut", though.

The U67 will probably be about half a century old. Makes you wonder if aging caps and all would cause some loss of bass and such. In other words, could it be the D67 sounds like the U67 did when it was brandnew?

But other factors could play a part. E.g. the tubes. What exactly is in the U67 and what in the D67?
And did you jumper S2 (40 Hz high pass) in the new build?
Oh, and what about the capsule and tranny?


Henk
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 15, 2014, 01:30:09 PM
I've recently done some tests with original U67.
If you want to have a listen to them, here is the link :

http://benoitlaur.com/a-b-original-neumann-u67-vs-clone-u67/

Hope this will encourage people to go into the project,

Ben
Thanks For Taking The time for doing this , in the End i wish you are happy with your new toy :)
Best,
Dany,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jpertusi on March 17, 2014, 06:56:46 PM
I hope this is the correct method of posting questions...

This is a USA 115v build.

I have 3 quick ones, please see attached image.


1. - Is the 56k resister in the upper left labeled "RTRIMPLATE" the same one some folks are hanging off one leg of the trim pot?  Are they just doing that because its easier to swap out?

2. - R9 (upper right) was 560r and not 536r as the PCB is labeled.  Is this intentional?

3. - The location labeled "lin 50R-2W" had nothing to populate it with in my kit, is this OK?



Thanks everyone,

-JP
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 17, 2014, 08:09:39 PM
I hope this is the correct method of posting questions...

This is a USA 115v build.

I have 3 quick ones, please see attached image.


1. - Is the 56k resister in the upper left labeled "RTRIMPLATE" the same one some folks are hanging off one leg of the trim pot?  Are they just doing that because its easier to swap out?

No this is not the same resistor the 56K is a custom trimming resistor that is not on the pcb this location mentioned on your picture is the spot to install a Fixed resistor in case you dont install the Pot and need to have this replaced as a fixed resistance

2. - R9 (upper right) was 560r and not 536r as the PCB is labeled.  Is this intentional?
yes 560R is for this resistance as 536r is not available and not really important to have this one at that precision

3. - The location labeled "lin 50R-2W" had nothing to populate it with in my kit, is this OK?

this location on your picture is the spot to install a Fixed resistor in case you dont install the Pot and need to have this replaced as a fixed resistance for the Heater

Thanks everyone,

-JP

Hope this helps,
Best,
DAn,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jpertusi on March 17, 2014, 08:32:17 PM
Thanks for your quick reply Dan, perfectly clear.

So... is the 56k resistor on the leg of the trim pot always necessary?  Or only if you can't get the voltage right with the pot alone?

-JP
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 17, 2014, 08:47:47 PM
Thanks for your quick reply Dan, perfectly clear.

So... is the 56k resistor on the leg of the trim pot always necessary?  Or only if you can't get the voltage right with the pot alone?

-JP

Yes you need it to adjust your range , from 33K -56K ?  To have the Sweet-Zone on the Pot as you wish.

Best,
DAN

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on March 18, 2014, 01:33:44 PM
I used the pads on the pcb mentioned for the "fixed-resistor" and cut some traces/made some jumper connections so I could have the trimmer resistor mounted directly on the PCB instead of flying. I thought it a little more robust that way as the B+ is going through there and it makes me feel a little more comfortable if other people are going to ever be "trimming".

Same with H-. I used the fixed resistor pcb position (cut traces and routed jumpers) for a series-resistor to get more "Useful Play" out of the trimmer with the desired H- value ending up near "the middle".

Cheers!
-jb
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jpertusi on March 19, 2014, 05:39:50 PM
Next question...

Anyone know if ioaudio's bv12 transformers are still available?  I sent an email but have not heard back.

Thanks,

JP
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on March 22, 2014, 01:07:32 AM
Next question...

Anyone know if ioaudio's bv12 transformers are still available?  I sent an email but have not heard back.

Thanks,

JP

Yeah i never heard back from him either.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: ioaudio on March 22, 2014, 08:13:48 AM
I have been in contact with JP.

Jess, not sure if i missed your emeil, pls try again at [email protected]
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on March 23, 2014, 05:43:04 AM
Cheers I'll shoot one over max.

I'm still 5db down from original u67. Ive replaced Capsule, Coupling Cap and Tube with no difference in level.

My voltages are as follows:

B+ (+210v)
H (-6.3v)
Plate (+84v)
R12 - R13 (+49.7v)
R10 - R11 (-1.83v)

It seems capsule voltage is 10v low and bias is off slightly?... Any suggestions?

I haven't checked transformer for ratio's but that would be my last resort.

J
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 24, 2014, 08:27:27 AM
is your R12-R13 Polarisation Divider well matched ,
you should be getting 55V at least for the backplate , it has to be measured before the capsule Charging resistor tough,
but this would not explain a 4db difference
keep us posted,

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jpertusi on March 24, 2014, 11:31:24 AM
OK so, I've got the power supplies built.

No funny blue smoke on power up (good sign)!!!

I'm wondering if anyone has testing/calibration instructions.  I don't have the mics built yet so I know the voltages will be off but I want to make sure I'm in the ballpark.

The trouble is, I'm a good follower of instructions, built a fair number of kits, but I'm not SUPER experienced with this kind of thing and I don't want to electrocute myself or worse yet, fry my multimeter ;-)

I'd like to know what kind of voltages to expect expect with the PS unloaded, and I quite literally where to place my multimeter probes...

Any help is appreciated.

Also, thanks to Max at audio for getting back to me quickly and shipping out the bv12's.  Can't wait to get going o the mics!!!





Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 24, 2014, 11:42:56 AM
OK so, I've got the power supplies built.

No funny blue smoke on power up (good sign)!!!

I'm wondering if anyone has testing/calibration instructions.  I don't have the mics built yet so I know the voltages will be off but I want to make sure I'm in the ballpark.

The trouble is, I'm a good follower of instructions, built a fair number of kits, but I'm not SUPER experienced with this kind of thing and I don't want to electrocute myself or worse yet, fry my multimeter ;-)

I'd like to know what kind of voltages to expect expect with the PS unloaded, and I quite literally where to place my multimeter probes...

Any help is appreciated.

Also, thanks to Max at audio for getting back to me quickly and shipping out the bv12's.  Can't wait to get going o the mics!!!

There is Test point on the PSU PCB and also on the Mic PCB take some time to locate them ,
basically reading of the psu with no mic connected will look like this , if you dont feel comfortable doing the reading ask someone who has experience to show you and help you with this. Safety is everything , one thing to always remember is that when you switch off the PSU there will still be Voltage for a little while slowly dischragin from the caps ,  it is always recommended to monitor those voltage B+ and H- before sticking your in hand in there , and the good thing is that this is valid with any working electronics you will work on.

Heater = -16VDC
B+ 275VDC

with mic connected,
Heater H- = -6.3VDC when adjusted
B+ 210 VDC when adjusted.

There is also a little test point on the mic pcb label a wich you should be able to read the Plate voltage 75-85VDC

hope this helps,
Dan,


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jpertusi on March 24, 2014, 11:55:39 AM
Thanks Dan,

I see the B+ and H- test points on the PCB.  I assume the hot lead of my multimeter goes to one of them and the ground lead goes to one of the points labeled CAL (either"siggnd" or "sig"?)

Thanks as always for your help.

-JP
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 24, 2014, 11:58:51 AM
Thanks Dan,

I see the B+ and H- test points on the PCB.  I assume the hot lead of my multimeter goes to one of them
yes

 and the ground lead goes to one of the points labeled CAL (either"siggnd" or "sig"?)
No, the ground Lead will go to 0V near the Ac supply you will have a label call 0V

CAL is for audio measurement

Thanks as always for your help.

-JP

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jpertusi on March 24, 2014, 12:01:36 PM
Got it.  I suspected as much but when I saw the CAL points I wanted to be extra sure.

I'm going in... one hand behind my back ;-)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jpertusi on March 24, 2014, 12:11:58 PM
OK, so here are the results:

H- is at -16.7vdc (the trim pot seems to have no effect on this... maybe that is normal with no load?)

B+ varies from 236vdc to 260vdc (at the extremes of the B+ trim pot settings)

It could be I need to let it warm up a little longer? I took those readings right away.

My multimeter is fine and I am still very much alive.

-JP
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 24, 2014, 12:29:09 PM
OK, so here are the results:

H- is at -16.7vdtc (the trim pot seems to have no effect on this... maybe that is normal with no load?)
yes no effect normal
B+ varies from 236vdc to 260vdc (at the extremes of the B+ trim pot settings)
yes this is correct with no mic,
It could be I need to let it warm up a little longer? I took those readings right away.
yes it will take a little moment until the capacitor Charges
My multimeter is fine and I am still very much alive.
-JP

Then The story is that you are doing Great ,
keep on the good work,
D
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jpertusi on March 24, 2014, 12:35:39 PM
Brilliant!!!  I thought I was looking for exactly 275vdc.

Thanks for all your help Dan (I'm sure I'll have more questions once I dive in to the mics).  Much appreciated!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jpertusi on March 26, 2014, 04:55:19 PM
OK, last PS question...  ;)

Do the numbered locations on the PCB (1, 2, 3 on the XLR out and 1 thru 7 on the MIC out) correspond to the pin numbers I should be connecting them to?

Thanks as always,

-JP
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 26, 2014, 10:03:04 PM
Hi guys!
I built 4 u67's. 2 each of the AMI and IOaudio transformers. All have Beesneez K6 and vintage telefunken EF86.

The IOaudio transformers seem to be very dull sounding as compared to the AMI. To get close match of the two using ears and spectrogram the ones using IOaudio transformers need +6,5db shelving from ca 1,5kHz. Quite a difference... They work as amb for drums but that's about it unless your looking for a dull-/lofi-ish sound. Anybody else have the same experience? Could i have gotten transformers form a bad batch or is that just what they sound like?

Also when troubleshooting one of the AMI versions i noticed the output measures 50ohm. Shouldn't that read 200Ohm for modern use?
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Melodeath00 on March 27, 2014, 09:47:40 AM
Hi guys!
I built 4 u67's. 2 each of the AMI and IOaudio transformers. All have Beesneez K6 and vintage telefunken EF86.

The IOaudio transformers seem to be very dull sounding as compared to the AMI. To get close match of the two using ears and spectrogram the ones using IOaudio transformers need +6,5db shelving from ca 1,5kHz. Quite a difference... They work as amb for drums but that's about it unless your looking for a dull-/lofi-ish sound. Anybody else have the same experience? Could i have gotten transformers form a bad batch or is that just what they sound like?

Also when troubleshooting one of the AMI versions i noticed the output measures 50ohm. Shouldn't that read 200Ohm for modern use?
/
Emil

Unfortunately I can't answer you, but are we talking about the AMI T67 or the BV12?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 27, 2014, 09:55:36 AM
Quote
Hi guys!
I built 4 u67's. 2 each of the AMI and IOaudio transformers. All have Beesneez K6 and vintage telefunken EF86.
The IOaudio transformers seem to be very dull sounding as compared to the AMI. To get close match of the two using ears and spectrogram the ones using IOaudio transformers need +6,5db shelving from ca 1,5kHz. Quite a difference... They work as amb for drums but that's about it unless your looking for a dull-/lofi-ish sound. Anybody else have the same experience? Could i have gotten transformers form a bad batch or is that just what they sound like?
Also when troubleshooting one of the AMI versions i noticed the output measures 50ohm. Shouldn't that read 200Ohm for modern use?
Emil

Interesting observation. I built one with ioaudios bv12 (with Beesneez K6 and vintage telefunken EF86) but don't have an AMI to compare.
Can you post sound clips showing the comparison?
Mine is a great mic, but it does not sound bright. It does work great as a front mic for a drum kit, or on a guitar amp. A lot of people I work with love it.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 27, 2014, 12:49:21 PM
Quote
Hi guys!
I built 4 u67's. 2 each of the AMI and IOaudio transformers. All have Beesneez K6 and vintage telefunken EF86.
The IOaudio transformers seem to be very dull sounding as compared to the AMI. To get close match of the two using ears and spectrogram the ones using IOaudio transformers need +6,5db shelving from ca 1,5kHz. Quite a difference... They work as amb for drums but that's about it unless your looking for a dull-/lofi-ish sound. Anybody else have the same experience? Could i have gotten transformers form a bad batch or is that just what they sound like?
Also when troubleshooting one of the AMI versions i noticed the output measures 50ohm. Shouldn't that read 200Ohm for modern use?
Emil

Interesting observation. I built one with ioaudios bv12 (with Beesneez K6 and vintage telefunken EF86) but don't have an AMI to compare.
Can you post sound clips showing the comparison?
Mine is a great mic, but it does not sound bright. It does work great as a front mic for a drum kit, or on a guitar amp. A lot of people I work with love it.

Im using the T67 not the BV12. I'll try to get some clips
Here's files to compare.
https://dl.dropboxusercontent.com/u/42125780/AMI%20T67.wav
https://dl.dropboxusercontent.com/u/42125780/IOaudio.wav
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 27, 2014, 01:01:28 PM
Could it be a combination of two extremes? A bright AMI transformer and a duller IOaudio.
I would not call the AMI version bright as compared to other microphones even though it sounds veri bright in comparison here.
It might be an error in my stuffing the boards but i made all four in parallell. Both of my IOAduio ones sound identical. As do the AMI ones though i have a weaker output in one of them which im currently investigating.

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 27, 2014, 01:54:07 PM
Thanks for posting the clips.
Curious if you could do the calibration sweep of them and compare the amplifier response. See my post back on page 11 showing the response with the bv12
Wondering if the feedback winding on the T67 vs BV12 differ.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 27, 2014, 02:32:26 PM
Thanks for posting the clips.
Curious if you could do the calibration sweep of them and compare the amplifier response. See my post back on page 11 showing the response with the bv12
Wondering if the feedback winding on the T67 vs BV12 differ.

You're right. I'll try to do that. Couldn't you modify the feedback to work best with a certain transformer. The cap in the schematics is specified 80-160 so maybe trying different values there can "tune" the circuit to the transformer?
Anybody?

Also I would like to confirm that the output is wired for 200ohm or not. I few posts back someone said the clone didn't have the same output as an original u67. Different output impedance could be the answer to that question.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: tskguy on March 27, 2014, 02:37:28 PM
Have you ruled out the capsule??? I would be more inclined to think it was the capsule more than the TX...
  Wave and I built 67's at the same time his has a AMI tx and my tx is an IoAudio  and they could be a matched pair, If it were me I would swap capsules and see if it fallows the capsule.

Eric
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 27, 2014, 03:15:47 PM
Have you ruled out the capsule??? I would be more inclined to think it was the capsule more than the TX...
  Wave and I built 67's at the same time his has a AMI tx and my tx is an IoAudio  and they could be a matched pair, If it were me I would swap capsules and see if it fallows the capsule.

Eric

Well I guess it might, but given my two pairs sound identical and try only parts that differ is the transformer I just figured that's the issue. All capsules bought at the same time from beesneez. I'll try to perform more tests on them and try to figure out what's wrong.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 27, 2014, 04:23:02 PM
With comparing two identical pairs, it seems unlikely that is capsule variations.
I wonder if the feedback loop of the t67 is wrong. If they aren't correctly rolling off the high end, it would definitely sound brighter.
Sweeping the amplifier response will answer this.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 27, 2014, 04:28:27 PM
With comparing two identical pairs, it seems unlikely that is capsule variations.
I wonder if the feedback loop of the t67 is wrong. If they aren't correctly rolling off the high end, it would definitely sound brighter.
Sweeping the amplifier response will answer this.

So you think that the IOaudio is the most authentic sounding? I havent worked with a real one so im kind of guessing which one is closest. My immediate impression is that the IOaudio is dull but it might just as well be the other way around. I sure find the brighter AMI ones more usefull int the studio.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 27, 2014, 04:35:18 PM
I don't know, but I don't think subtle differences in the transformer winding wouldn't cause such a big difference. I think there is something out of spec in one of the mics.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 27, 2014, 04:46:34 PM
I don't know, but I don't think subtle differences in the transformer winding wouldn't cause such a big difference. I think there is something out of spec in one of the mics.

You're probably right I'll try to crosscheck them and see if i might done something wrong on them. Still anybody who's heard both versions, and maybe the an original, please share your experience. Would be very gratefull!

/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 27, 2014, 04:53:55 PM
Thanks for posting the clips.
Curious if you could do the calibration sweep of them and compare the amplifier response. See my post back on page 11 showing the response with the bv12
Wondering if the feedback winding on the T67 vs BV12 differ.

So you just ran a 1k signal through the test input and recorded the output from the microphone? Capsule mounted or a cap instead?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 27, 2014, 05:03:05 PM
Either way, manual excerpt below.  The 1500 cps is a misprint I believe and should be 15000 cps.
Basically set it to omni, feed the calibrating input and measure the mic output level for the 1kHz signal. Then change to 15kHz and the level should be 10 dB lower.


Quote
"For purposes of checking the frequency response of the amplifier, a test signal may be fed to the instrument jack marked "calibrating input" at one end of the power supply. Proceed as follows: From the 600 ohm output of a signal generator, feed a 1000 cps tone at a level of -18 dbm to the calibrating input. You may use the model z-58 dummy head or can proceed with the regular head assembly plugged in. The three switches are set for "omni", full sensitivity, and linear frequency response. The following output levels are to be observed at the output of the 150/250 ohm impedance, using a vacuum tube voltmeter:

1000 cps:    -38dB     1dB
40 cps:        -43dB     1dB
1500 cps:   -48dB      1dB
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 27, 2014, 07:08:55 PM
Thanks for posting the clips.
Curious if you could do the calibration sweep of them and compare the amplifier response. See my post back on page 11 showing the response with the bv12
Wondering if the feedback winding on the T67 vs BV12 differ.

You're right. I'll try to do that. Couldn't you modify the feedback to work best with a certain transformer. The cap in the schematics is specified 80-160 so maybe trying different values there can "tune" the circuit to the transformer?
Anybody?

Also I would like to confirm that the output is wired for 200ohm or not. I few posts back someone said the clone didn't have the same output as an original u67. Different output impedance could be the answer to that question.
/
Emil

I can confirm that the output from the 2 audio coil are connected in series and connected trough the adapter board for the AMI and the main pcb for Max transformer  ;) , meaning 200ohm output impedance  not to be confused with DCR of the coil it self.
Best,
dAn,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 27, 2014, 07:26:46 PM
Posted this a While Ago , with the 2 Iron ,   this is what you should expect as comparaison ,

See here,

http://www.groupdiy.com/index.php?topic=49675.msg629064#msg629064

http://db.tt/OrBatA9S First clip is the BV.12

https://io.groupdiy.com/file/gdiy-2017/u/39511/58d028199409f First clip is the AMI
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 27, 2014, 07:28:38 PM
Thanks for posting the clips.
Curious if you could do the calibration sweep of them and compare the amplifier response. See my post back on page 11 showing the response with the bv12
Wondering if the feedback winding on the T67 vs BV12 differ.

You're right. I'll try to do that. Couldn't you modify the feedback to work best with a certain transformer. The cap in the schematics is specified 80-160 so maybe trying different values there can "tune" the circuit to the transformer?
Anybody?

Also I would like to confirm that the output is wired for 200ohm or not. I few posts back someone said the clone didn't have the same output as an original u67. Different output impedance could be the answer to that question.
/
Emil

I can confirm that the output from the 2 audio coil are connected in series and connected trough the adapter board for the AMI and the main pcb for Max transformer  ;) , meaning 200ohm output impedance  not to be confused with DCR of the coil it self.
Best,
dAn,

Alright. Thanks for clearing that up for me Dan!!
Can you chime in on the hi end difference between my Max/Ami transformers? I know you did a voice test early on which confirmed the max version having less hi end/more saturated. What's your first impression listening to the clips a few posts back? Transformer alone or something I've done wrong putting them together? How would changing value of C17 alter the sound?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 27, 2014, 07:36:35 PM
Thanks for posting the clips.
Curious if you could do the calibration sweep of them and compare the amplifier response. See my post back on page 11 showing the response with the bv12
Wondering if the feedback winding on the T67 vs BV12 differ.

You're right. I'll try to do that. Couldn't you modify the feedback to work best with a certain transformer. The cap in the schematics is specified 80-160 so maybe trying different values there can "tune" the circuit to the transformer?
Anybody?

Also I would like to confirm that the output is wired for 200ohm or not. I few posts back someone said the clone didn't have the same output as an original u67. Different output impedance could be the answer to that question.
/
Emil

I can confirm that the output from the 2 audio coil are connected in series and connected trough the adapter board for the AMI and the main pcb for Max transformer  ;) , meaning 200ohm output impedance  not to be confused with DCR of the coil it self.
Best,
dAn,

Alright. Thanks for clearing that up for me Dan!!
Can you chime in on the hi end difference between my Max/Ami transformers? I know you did a voice test early on which confirmed the max version having less hi end/more saturated. What's your first impression listening to the clips a few posts back? Transformer alone or something I've done wrong putting them together? How would changing value of C17 alter the sound?

I did not heard your sample yet , but  I will shorlty ,   and report back ,
I do like the "gritty" harmonics from IOaudio Transformer it really reminds me of the neumanish sounds,
as far a C17 goes it dictates the linearity of the High end the slope in other terms  , so it might have to be adjusted for your transfomer,
i would suggest you put up the lowest values and then the highest value to suit and listen out,
Best,
DAN,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 27, 2014, 07:45:31 PM
Thanks for posting the clips.
Curious if you could do the calibration sweep of them and compare the amplifier response. See my post back on page 11 showing the response with the bv12
Wondering if the feedback winding on the T67 vs BV12 differ.

You're right. I'll try to do that. Couldn't you modify the feedback to work best with a certain transformer. The cap in the schematics is specified 80-160 so maybe trying different values there can "tune" the circuit to the transformer?
Anybody?

Also I would like to confirm that the output is wired for 200ohm or not. I few posts back someone said the clone didn't have the same output as an original u67. Different output impedance could be the answer to that question.
/
Emil

I can confirm that the output from the 2 audio coil are connected in series and connected trough the adapter board for the AMI and the main pcb for Max transformer  ;) , meaning 200ohm output impedance  not to be confused with DCR of the coil it self.
Best,
dAn,

Alright. Thanks for clearing that up for me Dan!!
Can you chime in on the hi end difference between my Max/Ami transformers? I know you did a voice test early on which confirmed the max version having less hi end/more saturated. What's your first impression listening to the clips a few posts back? Transformer alone or something I've done wrong putting them together? How would changing value of C17 alter the sound?

I did not heard your sample yet , but  I will shorlty ,   and report back ,
I do like the "gritty" harmonics from IOaudio Transformer it really reminds me of the neumanish sounds,
as far a C17 goes it dictates the linearity of the High end the slope in other terms  , so it might have to be adjusted for your transfomer,
i would suggest you put up the lowest values and then the highest value to suit and listen out,
Best,
DAN,
Thanks Dan!
I could tell instantly that max's trafos were darker from your first speech tests and I liked it. That's why I got two ami and two max kits. To have two flavors at hand. But in use the difference is quite brutal.. I will try to mod C17 to get what I want. I like them dark sounding, I'm not looking for a hifi thing here, only to get some more hi frequencies.
I will also test the amplifiers and try to measure the transformers for faults. Do you know what the correct measurements of the BV12 would be? Can I tear this with a ohm-meter?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 27, 2014, 10:33:11 PM
I recommend you contact Max for the DCR measurement of each windings,

best,
dAn,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 29, 2014, 06:27:04 PM
A question about C17. The ones I got from the guy on the first page on this thread are labels 100j. Isn't that 10pf? 101 is 100. 102 is 1000. 100 is from what I've gathered 10.
That could sure explain strange hi end behavior.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jpertusi on March 29, 2014, 06:42:11 PM
...anyone...  Bueller?

"Do the numbered locations on the PCB (1, 2, 3 on the XLR out and 1 thru 7 on the MIC out) correspond to the pin numbers I should be connecting them to on the connectors?"

Is there a pinout for this section of the PCB?  I just want to be extra careful here...

Also... just got my bv12's!!!  Thanks Max!!!

Thanks as always gang.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Bassniac on March 30, 2014, 04:36:51 AM
Hey there.
What switch and lamp is everybody using for their PSU? (230Vs)

Cheers
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: tskguy on March 30, 2014, 08:30:55 AM
It really truly dumbfounds me how you guys are spinning all this comparison with different capsules!!
Please at least use the same capsule while doing these comparisons!! Or none at all! Remember 90 percent of the sound of a mic is the capsule. GEESH!!!

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 30, 2014, 10:10:25 AM
It really truly dumbfounds me how you guys are spinning all this comparison with different capsules!!
Please at least use the same capsule while doing these comparisons!! Or none at all! Remember 90 percent of the sound of a mic is the capsule. GEESH!!!

I totally agree.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 30, 2014, 10:11:45 AM
...anyone...  Bueller?

"Do the numbered locations on the PCB (1, 2, 3 on the XLR out and 1 thru 7 on the MIC out) correspond to the pin numbers I should be connecting them to on the connectors?"

Is there a pinout for this section of the PCB?  I just want to be extra careful here...

Also... just got my bv12's!!!  Thanks Max!!!

Thanks as always gang.

the first Link on page 1 in the thread contains Precious information for this build including this file here ,
do not hesitate to consult and download the Build Folder from this link, 
Best,
dAN,


(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d02819940c1.gif)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on March 30, 2014, 01:53:59 PM
I could tell instantly that max's trafos were darker from your first speech tests and I liked it. That's why I got two ami and two max kits. To have two flavors at hand. But in use the difference is quite brutal.. I will try to mod C17 to get what I want. I like them dark sounding, I'm not looking for a hifi thing here, only to get some more hi frequencies.

I've also noticed that my DU67 mics with Max's trafos are very dark sounding, requiring Hi EQ lifts depending on the sound source.  I'll be following your explorations as regards C17 with keen interest.  Thanks for this.

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 30, 2014, 02:05:41 PM
I could tell instantly that max's trafos were darker from your first speech tests and I liked it. That's why I got two ami and two max kits. To have two flavors at hand. But in use the difference is quite brutal.. I will try to mod C17 to get what I want. I like them dark sounding, I'm not looking for a hifi thing here, only to get some more hi frequencies.

I've also noticed that my DU67 mics with Max's trafos are very dark sounding, requiring Hi EQ lifts depending on the sound source.  I'll be following your explorations as regards C17 with keen interest.  Thanks for this.

Ill kerp i posted. Both transformers measure pretty much identical so i guess the difference must be the actuall winding, material etc. Im experimenting on this in breaks in between sessions so it might take a while.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on March 30, 2014, 02:10:48 PM
Ill kerp i posted. Both transformers measure pretty much identical so i guess the difference must be the actuall winding, material etc. Im experimenting on this in breaks in between sessions so it might take a while.

I appreciate it and am in no rush.  I've subscribed to the thread and will watch with interest.
Peace
Jim
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on March 30, 2014, 03:11:41 PM
Studio Mollan,

I'm trying to track down a low output (5db) and have pretty much ruled out everything other than the transformer. I purchased two t67's and had A few questions for you:

I was going to play devils advocate and say "maybe the bv12 is normal and the t67 is hyped" but I have shot my mic out against two original untouched u67's and despite being 5db down, I'm getting the exact EQ as found in the original.

Do you get the same output levels from all four mics? If so, have you shot them up against an original?

Do your resistance tests across all transformer show the same ratio's?

Do you use the same coupling capacitor across all four mics and what material / values are they?

Cheers.

J
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 30, 2014, 03:53:50 PM
Studio Mollan,

I'm trying to track down a low output (5db) and have pretty much ruled out everything other than the transformer. I purchased two t67's and had A few questions for you:

I was going to play devils advocate and say "maybe the bv12 is normal and the t67 is hyped" but I have shot my mic out against two original untouched u67's and despite being 5db down, I'm getting the exact EQ as found in the original.

Do you get the same output levels from all four mics? If so, have you shot them up against an original?

Do your resistance tests across all transformer show the same ratio's?

Do you use the same coupling capacitor across all four mics and what material / values are they?

Cheers.

J

Hi!
The levels are within ca 1db across the four microphones but I have not had a chance to compare with an original. My gut feeling is that the t67 is more like the original but not having tested it's no more than a gut feeling. The transformers measure pretty much identical across the windings which is a bit strange as they sound so different. I'll try to do more measurements next week and will post here. As the shelving point from where the two versions differ I'm feeling confident it can be calibrated with C17. As I said earlier a hi shelf plus 6db from ca 1500Hz made the two almost identical. That seems to correspond with a sweep of the amplifier seen earlier in this thread.
I'm using the cap from the BOM but actually just today I looked through my shelves and found some alternatives. All vintage. Films/PIOs. Looking forward to hear what the will do to this microphone. From my experience with other builds the difference will be subtle changing caps though. The brand or type of cap can not be causing the amount of dullness I'm experiencing with the IOaudio transformer.

Just to clarify. I am absolute positive that the IOaudio transformer is not poorly made or bad sounding. I'm pretty sure the circuit needs alterations to suit it though.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on March 30, 2014, 06:59:32 PM
is your R12-R13 Polarisation Divider well matched ,
you should be getting 55V at least for the backplate , it has to be measured before the capsule Charging resistor tough,
but this would not explain a 4db difference
keep us posted,

Best,
Dan,

Hi Dan,

Cheers for answering this, i never saw it.

I don't know what you mean if they are well matched? I used the resistors from mouser in the BOM.

It would seem that i am 10 volts (20%) down at the divider though, I'm measuring using a 30meg capable Fluke 115.

You don't think 20% is a big enough difference to create 5db down on output?

Cheers

Jess
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 31, 2014, 07:50:21 AM
is your R12-R13 Polarisation Divider well matched ,
you should be getting 55V at least for the backplate , it has to be measured before the capsule Charging resistor tough,
but this would not explain a 4db difference
keep us posted,

Best,
Dan,

Hi Dan,

Cheers for answering this, i never saw it.

I don't know what you mean if they are well matched? I used the resistors from mouser in the BOM.

It would seem that i am 10 volts (20%) down at the divider though, I'm measuring using a 30meg capable Fluke 115.

You don't think 20% is a big enough difference to create 5db down on output?

Cheers

Jess

I had a Diode Current Regulator in one of my original 87 that burnt out and i was getting about 30V polarisation and the output did not change that much but this is from far away in my memory
but at this point it is hard to tell,  i might be affecting the sensitivity but at wich point is hard to predict is the 2 resistor are well match wich they should from the BOM you should have pretty much something like 56-58V easilly you might want to recheck values and make sure you can actually compare those as i never had one below 56V,
how much voltage do you get from the noe R15-R13-R16 , I will try to check on the mic here and confrim with you over next weekend,
BEst,
DAN,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 31, 2014, 10:32:37 AM
Studio Mollan,

I'm trying to track down a low output (5db) and have pretty much ruled out everything other than the transformer. I purchased two t67's and had A few questions for you:

I was going to play devils advocate and say "maybe the bv12 is normal and the t67 is hyped" but I have shot my mic out against two original untouched u67's and despite being 5db down, I'm getting the exact EQ as found in the original.

Do you get the same output levels from all four mics? If so, have you shot them up against an original?

Do your resistance tests across all transformer show the same ratio's?

Do you use the same coupling capacitor across all four mics and what material / values are they?

Cheers.

J

Ok so i ran some tests. Replaced the Output cap with vintage PIO (Erofoil) on the IOaudio builds and Bosch PIO on the T67's. Both a lot smoother and less agressiv en the upper mids and air bands. Can really recommend you guys to experiment with this!

As for the transformers:
I meassured both and contrary to my earlier post they do differ. Possibly enough to cause the HF issues I've been writing about.
AMI:
Winding_
1 655r
2 26r
3 35r
4 35r
5 26r
6 635r

I/O-Audio
Winding.
1 1035r
2 42r
3 18r
4 1035r
5 42r
6 18r

They are not pin compatible. I don't know which windings do what but the 18r on the I/O audio is pretty off. If they are to share their relations between the windings i guess the 18r should be somewhat higher, as go for the 42r.

Im starting to think that changing the C17 cap wont change the amount of HF in the feedback loop only the point from where it starts subtracting. could adding resistance in series with C17 lift the high end maybee? If so what values should i start experimenting with. More resistance = less voltage to the Feedvack = less HF deduction. Am i right? (i could be way off here and will not be offended if you correct me. Please be gentle though..)  :)

/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 31, 2014, 11:00:54 AM
I Do Have a Hand drawn schematic of the AMI T67 that Oliver provided a While Ago , i looking for the picture of it, i will post it here so you can refer this one per your winding scheme ,  as far as the IOaudio transformer it is very well documented on his WM,

stay tuned,
Best,
dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 31, 2014, 11:04:17 AM
Emil,

Why are you swapping caps path before measuring the frequency response of the two amplifiers w/ the stock circuit and the different transformers???
If you made that simple measurement it would give you some solid footing to move forward from, as well as contribute some info to all the other people here interested.

All you need is to run a signal through the mic and measure the level coming out. Or download RMAA and make a nice sweep.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 31, 2014, 11:13:28 AM
Quote
I meassured both and contrary to my earlier post they do differ. Possibly enough to cause the HF issues I've been writing about.

You're measuring DCR - which isn't the key thing for a transformer (an ideal transformer would have zero DCR). The DCR will be higher of a winding if the wire gauge is different or the total number of turns. But the ratios and inductance are much more important. The pinouts are different for the two transformers and the winding method, but each transformer has three windings. primary, secondary, and feedback. The primary will typically be much higher DCR than secondary since it has more turns. Both transformers look reasonable i think.
The EQ of the circuit is created by the amount of signal returned by the transformer through the feedback winding (hence primary/feedback turns ratio sets this level).
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 31, 2014, 11:26:30 AM
Quote
I was going to play devils advocate and say "maybe the bv12 is normal and the t67 is hyped" but I have shot my mic out against two original untouched u67's and despite being 5db down, I'm getting the exact EQ as found in the original.

What capsule are you using? This is going to dominate the perceived EQ.

5 dB down is almost half volume. The windings would have to be wrong by 50% amount. A wiring or measuring mistake is more likely.
Can you sweep the amplifier response of an original 67? That would be IMMENSELY valuable to this thread. Back a few pages I posted the sweep for a build w/ recommended components and bv12.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 31, 2014, 11:28:54 AM
Quote
I was going to play devils advocate and say "maybe the bv12 is normal and the t67 is hyped" but I have shot my mic out against two original untouched u67's and despite being 5db down, I'm getting the exact EQ as found in the original.

What capsule are you using? This is going to dominate the perceived EQ.

5 dB down is almost half volume. The windings would have to be wrong by 50% amount. A wiring or measuring mistake is more likely.
Can you sweep the amplifier response of an original 67? That would be IMMENSELY valuable to this thread. Back a few pages I posted the sweep for a build w/ recommended components and bv12.

wich page again ,
Best,
dAN,
I might repost it here,
Thanks,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 31, 2014, 11:41:59 AM
dAN,
No problem - here is the plot again.
This is built with recommended components and bv12. I used RMAA to make this freq sweep.
I am using a beezneez capsule - I do feel my mic is dark (but not in a bad way).
Hoping we'll get to the bottom of this! Not only bv12 vs. ami, but how close are we to an original. (and remember, the mic sound is usually 95% the capsule...)
Dan
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 31, 2014, 11:51:42 AM
dAN,
No problem - here is the plot again.
This is built with recommended components and bv12. I used RMAA to make this freq sweep.
I am using a beezneez capsule - I do feel my mic is dark (but not in a bad way).
Hoping we'll get to the bottom of this! Not only bv12 vs. ami, but how close are we to an original. (and remember, the mic sound is usually 95% the capsule...)
Dan

Quote
I was going to play devils advocate and say "maybe the bv12 is normal and the t67 is hyped" but I have shot my mic out against two original untouched u67's and despite being 5db down, I'm getting the exact EQ as found in the original.


I remember the one I sold that had a neumann capsule in it with the Max Bv12 and it was beautifully shinny or was it the aMI T67 version Jeez My memory plays me tricks,

AnyBody with a AMI T67 would like to comment regarding the IOaudio Bv12 ,
Or someone else that has both,

I really would like to see a sweep with the AMI T67

here a reference

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d02819940d4.gif)

Let me know,
Best,
dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 31, 2014, 12:08:13 PM
Quote
here a reference

Remember - those frequency plots are for the full mic with capsule in a anechroic (sp?) chamber. Not many DIYer's have the means to measure that.
The u67 had a capsule designed to boost high frequencies with an amplifier designed to roll off those same frequencies (see my plot), such that the overall freq response was flat. This design was intended to reduce noise. 
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 31, 2014, 12:37:33 PM
Quote
here a reference

Remember - those frequency plots are for the full mic with capsule in a anechroic (sp?) chamber. Not many DIYer's have the means to measure that.
The u67 had a capsule designed to boost high frequencies with an amplifier designed to roll off those same frequencies (see my plot), such that the overall freq response was flat. This design was intended to reduce noise.

Got it , this is the amplifier only sweep,  wich include the de-emphasis portion in the circuit to tame this particular section of the high end not to be confused with the sweeps with the capsule K67 with the high lift included,

Best,
Dan,
 
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 31, 2014, 01:13:49 PM
Quote
I meassured both and contrary to my earlier post they do differ. Possibly enough to cause the HF issues I've been writing about.

You're measuring DCR - which isn't the key thing for a transformer (an ideal transformer would have zero DCR). The DCR will be higher of a winding if the wire gauge is different or the total number of turns. But the ratios and inductance are much more important. The pinouts are different for the two transformers and the winding method, but each transformer has three windings. primary, secondary, and feedback. The primary will typically be much higher DCR than secondary since it has more turns. Both transformers look reasonable i think.
The EQ of the circuit is created by the amount of signal returned by the transformer through the feedback winding (hence primary/feedback turns ratio sets this level).
Hi, Im well aware I'm meassuring DCR. Dan actually taught me this only a few days ago. However the recistance over the windings translate to the turns ratio of the transformer if im not mistaken? Im positive this is the cause for the difference in the two transformers. But then again I'm also aware that I've been dead wrong on lots of DIY stuff in the past so me being the cause is not ruled out. =)
I did the meassurements cos a forum member asked about them and also the output cap tests. When i got an hour off ill try to do the sweeps.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 31, 2014, 01:59:07 PM
DCR will correlate in that the longer the piece of wire, the higher the DCR. The more turns, the more wire. But the ratio of DCR does not equal the turns ratio.
The primary to secondary should be 7:1, and the primary to tertiary should be 22:1, if I recall correctly. Simple way to measure this - you put a AC signal on one winding and take the ratio of the voltage amplitudes. I have a bv12 at home for my m269 build, I can measure the ratios later this week.
That being said, if the ratios ARE the same, the transformers could still lend different sonic signatures to the circuit due to the difference in DCR.
Thanks for helping with these discoveries. We're all interested to learn about the differences.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 31, 2014, 04:02:45 PM
DCR will correlate in that the longer the piece of wire, the higher the DCR. The more turns, the more wire. But the ratio of DCR does not equal the turns ratio.
The primary to secondary should be 7:1, and the primary to tertiary should be 22:1, if I recall correctly. Simple way to measure this - you put a AC signal on one winding and take the ratio of the voltage amplitudes. I have a bv12 at home for my m269 build, I can measure the ratios later this week.
That being said, if the ratios ARE the same, the transformers could still lend different sonic signatures to the circuit due to the difference in DCR.
Thanks for helping with these discoveries. We're all interested to learn about the differences.

Thank you! This would be 100% impossible without this forum and its members contributions!
Well, breaking news. I did the amplifier test on both versions. Max'x trafo is DEAD ON!! Contrary to my presumtions thats aparently what they are supposed to sound like, given that theres nothing wrong in the cirquit. 15kHz is -10dB from 1kHz. 40Hz was actually louder but as i had my capsule on im assuming thats disturbance from my room.
The T67 did maintaind its level all across the spectrum so i guess theres something wrong in the feedback cirquit. Ill recheck that and return here when im done. Pretty strange that both of my t67 equiped builds both behave the same?

I need to compare my builds to a real Neumann 67. I still like the brighter ones though so im actually leaning on leaving them as they are.


DMP. Please remind me. What transformer did you use with the sweep you posted?

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 31, 2014, 04:12:09 PM
Interesting! I used the BV12 in my build & for my sweep.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 31, 2014, 04:39:04 PM
I'm wondering if the Beesneez K6 is a darker sounding capsule than a Neumann capsule. Harder to measure the capsule response. We'll just have to hope someone with a real 67 speaks up
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 31, 2014, 04:56:50 PM
I'm wondering if the Beesneez K6 is a darker sounding capsule than a Neumann capsule. Harder to measure the capsule response. We'll just have to hope someone with a real 67 speaks up

Indeed!! From what ive heard so far from this thread the clone is supposedly a bit brighter than the original..

Well i replaced C17 and still no HF roll of in the amplifier test. Very strange! I'm loocking at the schematics and its either C17 or the transformer itself thats bad. The transformer meassures correctly and the cap is brand new = I'm going crazy.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 31, 2014, 05:01:01 PM
Seems like there must be a disconnection from the winding on the AMI. Have you double checked all the transformer connections? Maybe post some pics. Poctop can ID inconsistencies like lightning.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jpertusi on March 31, 2014, 05:20:57 PM
Thanks, Not sure how I missed that.  it even looks familiar so I mast have seen it when researching.  My poor brain.

Anyway, I got Mogami cable and the colors are different as follows:

Twisted pair (I assume this is audio signal):
White
Orange

Heavy gauge (I assume this is B+):
Blue
Green

Non twisted lighter gauge (I assume this is the heater):
Red
Purple

Braided shield


I'm going to look for a pinout for the PCB.

Thanks again.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on March 31, 2014, 05:22:49 PM
Heavy gauge is heater.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jpertusi on March 31, 2014, 05:37:14 PM
Understood.

So I guess my problem is that I don't know what is on each of the outputs 1 through 7 on the PCB.


-JP
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jpertusi on March 31, 2014, 06:15:18 PM
OK, I never saw the build folder... I'm on board now, thanks.

I still am not quite sure what I should use the second heavier gauge cable for (I assume 0V?)

This is what I've got from all that info (just to be sure):

1 and 2 are the audio out from the mic

3 is the cable shield

4 is the heater (heavy cable)

5 is B+

6 is the calibration

7 is 0V (the other heavy cable)


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on March 31, 2014, 06:54:34 PM
Seems like there must be a disconnection from the winding on the AMI. Have you double checked all the transformer connections? Maybe post some pics. Poctop can ID inconsistencies like lightning.
I have continuity all the way to C17 out from the feedback. and the transformer measures correct. I also doublechecked all the resistors. again.. I haven't gone throgh the caps cus actually i dont know how my dmm do not meassure capacitance and i dont know any other convenient methods. Dont know whu the caps should fail though.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 31, 2014, 07:23:21 PM
I have checked consitency again and again and again...... and again during the developpment of the mic wich was the hardest challenge for me till the mic pcb project ,
but I have done it again with the board file and the schematic and i have compared the hand drawn drawing from Oliver today just for the cause  ;),
audio output is set for 200 ohm impedance (output coil in series) , checked the adaptor pcb again and the main board again and everything is as expected still,
feedback winding output winding primary winding connection to pcb and hopefully i cannot find deadly squat of an error.  :) :) :) :) :)

here is the documentation i refered to and compared it to original drwaing from oliver and everything is inline ,
I am really curious if this could not be a systematic miswiring issues or the adaptor pcb or transfomer is installed the wrong way ,
well keep up the good work, i too want to see the end of this , Let me know if you find anything

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d02819940e6.jpg)

Hope this helps,
Best,
Dan,
 
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 31, 2014, 07:46:26 PM
Seems like there must be a disconnection from the winding on the AMI. Have you double checked all the transformer connections? Maybe post some pics. Poctop can ID inconsistencies like lightning.
I have continuity all the way to C17 out from the feedback. and the transformer measures correct. I also doublechecked all the resistors. again.. I haven't gone throgh the caps cus actually i dont know how my dmm do not meassure capacitance and i dont know any other convenient methods. Dont know whu the caps should fail though.

Do you mean that you measure a short continuity  form bypass cap C9 + side trough the leg of the feedback winding ?
Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 01, 2014, 05:57:20 PM
I have a spare t67 and cash for the difference here if someone wants to trade me their bv12.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 01, 2014, 06:11:59 PM
I have checked consitency again and again and again...... and again during the developpment of the mic wich was the hardest challenge for me till the mic pcb project ,
but I have done it again with the board file and the schematic and i have compared the hand drawn drawing from Oliver today just for the cause  ;),
audio output is set for 200 ohm impedance (output coil in series) , checked the adaptor pcb again and the main board again and everything is as expected still,
feedback winding output winding primary winding connection to pcb and hopefully i cannot find deadly squat of an error.  :) :) :) :) :)

here is the documentation i refered to and compared it to original drwaing from oliver and everything is inline ,
I am really curious if this could not be a systematic miswiring issues or the adaptor pcb or transfomer is installed the wrong way ,
well keep up the good work, i too want to see the end of this , Let me know if you find anything

(https://dl.dropboxusercontent.com/u/43869772/U67/AMI%20T67%20Documentation.jpg)

Hope this helps,
Best,
Dan,

I actually thought about this the very minute you posted. Maybe the transformer is mounted backwards? Would that explain the feedback not working?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Winetree on April 01, 2014, 07:36:27 PM
I think I remember POCTOP saying that on one of the Microphone
Transformer boards the lettering was on the wrong side. Therefore possibly
making the mounting of the transformer backwards. Was it this project?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on April 02, 2014, 02:31:28 AM
I think that was on a run of T14s (C12 build), but I'd have to check that, too.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 02, 2014, 07:50:19 AM
I have checked consitency again and again and again...... and again during the developpment of the mic wich was the hardest challenge for me till the mic pcb project ,
but I have done it again with the board file and the schematic and i have compared the hand drawn drawing from Oliver today just for the cause  ;),
audio output is set for 200 ohm impedance (output coil in series) , checked the adaptor pcb again and the main board again and everything is as expected still,
feedback winding output winding primary winding connection to pcb and hopefully i cannot find deadly squat of an error.  :) :) :) :) :)

here is the documentation i refered to and compared it to original drwaing from oliver and everything is inline ,
I am really curious if this could not be a systematic miswiring issues or the adaptor pcb or transfomer is installed the wrong way ,
well keep up the good work, i too want to see the end of this , Let me know if you find anything

(https://dl.dropboxusercontent.com/u/43869772/U67/AMI%20T67%20Documentation.jpg)

Hope this helps,
Best,
Dan,

I actually thought about this the very minute you posted. Maybe the transformer is mounted backwards? Would that explain the feedback not working?

This would make a lot of sense, my u67 sounds like it has no de emphasis at all, the top end sounds wide open like c12 and mids sound scooped. also could have something to do with my 5db down.

Im gonna remove the transformer and test the ratio's to figure out where primary secondary and feedbacks are on mine. but isn't it symmetrical and wouldn't the transformer be the same regardless of which side gets bridged?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: adeptusmajor on April 02, 2014, 08:11:53 AM
Regarding the AMI -

It might be worth noting that when I built my du-87's, the AMI t13s I used (which were from his first run) had the primary and secondary wires reversed compared to what the color code and the data sheet said. So I had a very low output pair of mics at first until I figured it out. Might be the same thing going on with your T67. I plan on using the AMI for my pair of 67's, so I'm very interested to hear if this is the case.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 02, 2014, 08:29:10 AM
I think I remember POCTOP saying that on one of the Microphone
Transformer boards the lettering was on the wrong side. Therefore possibly
making the mounting of the transformer backwards. Was it this project?


this was on the T47-49 PcB adaptor initial batch for the Fet 47 it has been corrected a while ago , and people who have bought it solo were warned about this at the time ,
the U67 pcb adaptor board was correct from the beginning ,  the actual PCB adaptor for the T67 has all the link on the same side so reversing would just linked the coil to the other side.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 02, 2014, 08:32:42 AM
Quote
Im gonna remove the transformer and test the ratio's to figure out where primary secondary and feedbacks are on mine. but isn't it symmetrical and wouldn't the transformer be the same regardless of which side gets bridged?

i beleive the symmetry is actually the key here as well if it would not have any effect but the polarity if we assume the windings are correct on Oliver drawing and his webiste info ,
the good thing if if this is the case it could be corrected just correcting to the proper wiring to the main mic pcb , so there would be no change to the PCB adaptor itself.

If I compare what Olivers sent me as a hand drawing and the info on the website they 100% match togheter.

Looking forward to have a confirmation on this as well, 

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 02, 2014, 08:50:36 AM
I have checked consitency again and again and again...... and again during the developpment of the mic wich was the hardest challenge for me till the mic pcb project ,
but I have done it again with the board file and the schematic and i have compared the hand drawn drawing from Oliver today just for the cause  ;),
audio output is set for 200 ohm impedance (output coil in series) , checked the adaptor pcb again and the main board again and everything is as expected still,
feedback winding output winding primary winding connection to pcb and hopefully i cannot find deadly squat of an error.  :) :) :) :) :)

here is the documentation i refered to and compared it to original drwaing from oliver and everything is inline ,
I am really curious if this could not be a systematic miswiring issues or the adaptor pcb or transfomer is installed the wrong way ,
well keep up the good work, i too want to see the end of this , Let me know if you find anything

(https://dl.dropboxusercontent.com/u/43869772/U67/AMI%20T67%20Documentation.jpg)

Hope this helps,
Best,
Dan,

I actually thought about this the very minute you posted. Maybe the transformer is mounted backwards? Would that explain the feedback not working?

This would make a lot of sense, my u67 sounds like it has no de emphasis at all, the top end sounds wide open like c12 and mids sound scooped. also could have something to do with my 5db down.

Im gonna remove the transformer and test the ratio's to figure out where primary secondary and feedbacks are on mine. but isn't it symmetrical and wouldn't the transformer be the same regardless of which side gets bridged?

It sure looks symmetrical. I also thought about that. I can't see how reversing it on the pcb would change anything. I still haven't had the time to follow up on it but will try to work with them next week.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 02, 2014, 09:01:40 AM
we really need to contact oliver and get the wiring diagram of whats going on inside this transformer because on the original you have 6 connections on one side and 8 on the other,

and by the looks of things 1 of which goes to chassis and one is left undetermined. leaving the 12 colored on the schematic.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 02, 2014, 09:36:26 AM
we really need to contact oliver and get the wiring diagram of whats going on inside this transformer because on the original you have 6 connections on one side and 8 on the other,

and by the looks of things 1 of which goes to chassis and one is left undetermined. leaving the 12 colored on the schematic.

hmm.. thats interesting. Can you try to contact him? I've been trying to get a hold of him for months about servicing a V78 and i get dead silence back.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 02, 2014, 09:40:48 AM
we really need to contact oliver and get the wiring diagram of whats going on inside this transformer because on the original you have 6 connections on one side and 8 on the other,

and by the looks of things 1 of which goes to chassis and one is left undetermined. leaving the 12 colored on the schematic.

There should be 6 point of connection to the  mic schematics, 2 Feedback , 2 for audio and 2 for primary ,
the internal link ( series primary and series audio output and series feedback are actually on the adaptor board)
there is no core ground on oliver Traffo but max has them, )
Let me know,
Best,
Dan,


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 02, 2014, 10:11:25 AM
we really need to contact oliver and get the wiring diagram of whats going on inside this transformer because on the original you have 6 connections on one side and 8 on the other,

and by the looks of things 1 of which goes to chassis and one is left undetermined. leaving the 12 colored on the schematic.

There should be 6 point of connection to the  mic schematics, 2 Feedback , 2 for audio and 2 for primary ,
the internal link ( series primary and series audio output and series feedback are actually on the adaptor board)
there is no core ground on oliver Traffo but max has them, )
Let me know,
Best,
Dan,

yeah I'm with you, all the additional wiring is internal or unnecessary due to single impedance.

1 pair to primary (c9 +ground)
1 pair to feedback (r18)
1 pair secondary (xlr 1-2 / c13 c12)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 02, 2014, 10:43:14 AM
we really need to contact oliver and get the wiring diagram of whats going on inside this transformer because on the original you have 6 connections on one side and 8 on the other,

and by the looks of things 1 of which goes to chassis and one is left undetermined. leaving the 12 colored on the schematic.

There should be 6 point of connection to the  mic schematics, 2 Feedback , 2 for audio and 2 for primary ,
the internal link ( series primary and series audio output and series feedback are actually on the adaptor board)
there is no core ground on oliver Traffo but max has them, )
Let me know,
Best,
Dan,

yeah I'm with you, all the additional wiring is internal or unnecessary due to single impedance.

1 pair to primary (c9 +ground)
1 pair to feedback (r18)
1 pair secondary (xlr 1-2 / c13 c12)

So do you think it's necessary trying to reverse the transformer then? I would do it in a snap but i'd rather not desolder a PCB transformer if its not necessary. Really easy to break a wire even with a desoldering station.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 02, 2014, 10:49:19 AM
Flipping the transformer around won't make any difference, based on the wiring diagram.
Someone with a scope should test the windings. Since everyone is getting sound out  of there mics, the primary and secondary seem correct. But the feedback seems to be whacked. It could be that one of the feedback windings is connected backwards or not at all.
If you feed a 1v signal into the primary, the signal on the feedback should be 1/22.
If I had a t67 I could test it on my scope, but I don't have a transformer.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 02, 2014, 10:52:56 AM
Flipping the transformer around won't make any difference, based on the wiring diagram.
Someone with a scope should test the windings. Since everyone is getting sound out  of there mics, the primary and secondary seem correct. But the feedback seems to be whacked. It could be that one of the feedback windings is connected backwards or not at all.
If you feed a 1v signal into the primary, the signal on the feedback should be 1/22.
If I had a t67 I could test it on my scope, but I don't have a transformer.

Thanks for confirming that!
Well iäve meassured the fedback windings for DCR and they show upp identical. ca32r both and they make connection to the R18.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 02, 2014, 10:59:02 AM
If the two feedback windings were connected out of phase it wouldn't work right.


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 02, 2014, 11:01:26 AM
Flipping the transformer around won't make any difference, based on the wiring diagram.
Someone with a scope should test the windings. Since everyone is getting sound out  of there mics, the primary and secondary seem correct. But the feedback seems to be whacked. It could be that one of the feedback windings is connected backwards or not at all.
If you feed a 1v signal into the primary, the signal on the feedback should be 1/22.
If I had a t67 I could test it on my scope, but I don't have a transformer.

Can i do that with a wavegenerator? Just send 1kHz 1v to the input and then meassure the Feedback? You need an AC generator right? not sure if mine is that.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 02, 2014, 11:08:31 AM
Yeah, send a 1kHz 1V sine wave to the input and monitor the feedback. If you pull C17 and R18 and monitor the voltage at the 'ws' points on the image I just posted, you should see a step down of 1:22. 
1 kHz implies it is a AC generator. DC doesn't have a freq.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Melodeath00 on April 02, 2014, 11:36:02 AM
This would make a lot of sense, my u67 sounds like it has no de emphasis at all, the top end sounds wide open like c12 and mids sound scooped. also could have something to do with my 5db down.

Wait, I thought you said it was "right there" with a real U67, just 5dB down.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 02, 2014, 11:59:27 AM
If the two feedback windings were connected out of phase it wouldn't work right.

Just had a quick chat with Oliver ,  he confirmed that if the feedback winding is reversed it would affect the de-emphasis portion as well as dmp says (Thanks for the pointer dmp  :))
so this might be the issue ,  Oliver suggested to reversed the wire from the feedback winding and test it again with the amplifier sweep
i will be rechecking that as well from the mic pcb to make ultra sure the polarity is right , and Oliver said he would check out the drawing he made for me a the time to make sure it has not been inverted as well, hope this well get resolved.

Best,
Dan,
 
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 02, 2014, 01:32:36 PM
If the two feedback windings were connected out of phase it wouldn't work right.

Just had a quick chat with Oliver ,  he confirmed that if the feedback winding is reversed it would affect the de-emphasis portion as well as dmp says (Thanks for the pointer dmp  :))
so this might be the issue ,  Oliver suggested to reversed the wire from the feedback winding and test it again with the amplifier sweep
i will be rechecking that as well from the mic pcb to make ultra sure the polarity is right , and Oliver said he would check out the drawing he made for me a the time to make sure it has not been inverted as well, hope this well get resolved.

Best,
Dan,

Thanks for checking!
Ok i just meassured the turns ratio of the feedback. I sent in 1V (actually 0,096) to the primaries and got back 0,043V from the feedback. That translates to roughly 1:22 ratio. Transformer works just fine.
I'll try to reverse polarity of the feedback.

It's a hard thing to miss since the microphone actually sounds really good this way. Nothing like the original i assume but none the less a very good sounding microphone.

/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on April 02, 2014, 01:44:56 PM
Presumably if the feedback audio is reversed polarity it would "Add" instead of "Subtract".... Making the de-emphasis inverse...

Glad someone caught this! You guys rock!

Cheers,
jb
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 02, 2014, 01:54:42 PM
Quote
Ok i just meassured the turns ratio of the feedback. I sent in 1V (actually 0,096) to the primaries and got back 0,043V from the feedback. That translates to roughly 1:22 ratio. Transformer works just fine.
I'll try to reverse polarity of the feedback.

great - good test.  Both feedback windings look good on there own, from your test.   I was thinking one of the two feedback primaries might be reversed phase with respect to the other, which would cause the two to fight and cancel out.
Can you do the basically the same thing with the signal running through both primaries in series, and measuring both feedbacks in series? So you would jumper the pins on the opposite side as in the pic above
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 02, 2014, 03:27:55 PM
This would make a lot of sense, my u67 sounds like it has no de emphasis at all, the top end sounds wide open like c12 and mids sound scooped. also could have something to do with my 5db down.

Wait, I thought you said it was "right there" with a real U67, just 5dB down.

So did I, until i got it home and cut some unusable female vocals with it yesterday. on my voice just talking and using ns-10s i couldn't tell the difference much but after cutting a female driven song at home studio i realized the vocals weren't in keeping with the other u67 vocals on the rest of the album.

could also be that the head grill is more open, capacitor is not electrolytic, 0.01s are not wimp tfm's. could be so many factors

but I'm about to build another custom u67 inside u87ai so i really want to get to the bottom of this.

J
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 02, 2014, 03:34:25 PM
Quote
Ok i just meassured the turns ratio of the feedback. I sent in 1V (actually 0,096) to the primaries and got back 0,043V from the feedback. That translates to roughly 1:22 ratio. Transformer works just fine.
I'll try to reverse polarity of the feedback.

great - good test.  Both feedback windings look good on there own, from your test.   I was thinking one of the two feedback primaries might be reversed phase with respect to the other, which would cause the two to fight and cancel out.
Can you do the basically the same thing with the signal running through both primaries in series, and measuring both feedbacks in series? So you would jumper the pins on the opposite side as in the pic above

This confused me a little... can you draw that and post it quickly please
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 02, 2014, 04:06:29 PM
Quote
Ok i just meassured the turns ratio of the feedback. I sent in 1V (actually 0,096) to the primaries and got back 0,043V from the feedback. That translates to roughly 1:22 ratio. Transformer works just fine.
I'll try to reverse polarity of the feedback.

great - good test.  Both feedback windings look good on there own, from your test.   I was thinking one of the two feedback primaries might be reversed phase with respect to the other, which would cause the two to fight and cancel out.
Can you do the basically the same thing with the signal running through both primaries in series, and measuring both feedbacks in series? So you would jumper the pins on the opposite side as in the pic above

I reversed polarity and on the feedback and now I', pretty sure the hf attenuation is working correctly. I'm not 100% cos i was unable to test them properly. Just speech and singing through headphones.

I also noticed this while speaking in very close proximity to the capsule. Lips almost touching the head basket.
https://dl.dropboxusercontent.com/u/42125780/Exhale%20U67%203.wav
I exhaled very softly on to the capsule and the following noise came up. It's only Omni and figure of 8.Tare in the rear membrane?
 

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 02, 2014, 04:08:44 PM
Quote
This confused me a little... can you draw that and post it quickly please

In the schematic pic I posted, the feedback winding actually has two windings connected in series (top and bottom on the right side of the transformer). Each winding has a dot indicating where the winding starts. If one of the windings was 'flipped' and they were connected out of phase, they would fight each other. Someone just needs to scope out this transformer and see if anything's funky.
There isn't going to be voodoo with this for cap types or whatnot --  a -10db rolloff filter at 15khz is a HUGE difference from no rolloff.

Does anyone with the AMI transformer have the right amplifier response?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 02, 2014, 04:09:54 PM
Quote
I exhaled very softly on to the capsule and the following noise came up. It's only Omni and figure of 8.Tare in the rear membrane?

Humidity is a no-no. Use a pop filter.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 02, 2014, 04:46:14 PM
Quote
I exhaled very softly on to the capsule and the following noise came up. It's only Omni and figure of 8.Tare in the rear membrane?

Humidity is a no-no. Use a pop filter.

But I actually read somewhere on this forum that breathing on it and listening for artifacts is a test for checking torn membranes. I'm very into fixing these microphones right now. Think I'm loosing my mind a bit... We'll I'll try to run actual studio tests in the following days.
/
E
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on April 02, 2014, 05:03:33 PM
Quote
I exhaled very softly on to the capsule and the following noise came up. It's only Omni and figure of 8.Tare in the rear membrane?

Humidity is a no-no. Use a pop filter.

But I actually read somewhere on this forum that breathing on it and listening for artifacts is a test for checking torn membranes. I'm very into fixing these microphones right now. Think I'm loosing my mind a bit... We'll I'll try to run actual studio tests in the following days.
/
E

I didn't listen to the sound but you are correct. Performing the "Breath Test" should not cause snats/pops/wind/frying-bacon sounds.... And if it happens only in bi/omni then it may well be the back capsule like you mentioned.

It could be dirty or otherwise "contaminated" too. For instance with a hair or other foreign material bridging between backplate and the sputtering that causes these sounds when "humid". It doesn't necessarily mean there is a hole. The hole can be pretty microscopic too and still cause issues.

Cheers,
jb
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 02, 2014, 05:30:47 PM
Quote
Ok i just meassured the turns ratio of the feedback. I sent in 1V (actually 0,096) to the primaries and got back 0,043V from the feedback. That translates to roughly 1:22 ratio. Transformer works just fine.
I'll try to reverse polarity of the feedback.

great - good test.  Both feedback windings look good on there own, from your test.   I was thinking one of the two feedback primaries might be reversed phase with respect to the other, which would cause the two to fight and cancel out.
Can you do the basically the same thing with the signal running through both primaries in series, and measuring both feedbacks in series? So you would jumper the pins on the opposite side as in the pic above



I reversed polarity and on the feedback and now I', pretty sure the hf attenuation is working correctly. I'm not 100% cos i was unable to test them properly. Just speech and singing through headphones.

I also noticed this while speaking in very close proximity to the capsule. Lips almost touching the head basket.
https://dl.dropboxusercontent.com/u/42125780/Exhale%20U67%203.wav
I exhaled very softly on to the capsule and the following noise came up. It's only Omni and figure of 8.Tare in the rear membrane?
 

This gives me a little hope... did you literally just swap pin 5 and 12 on the ami pcb? I might try this quickly

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 02, 2014, 05:37:34 PM
Very interesting. I don't have a scope here unfortunately.

I'm in LA if anyone wants to use my mic to test this.. i also have spare t67 sitting here.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 02, 2014, 05:39:11 PM
Quote
Ok i just meassured the turns ratio of the feedback. I sent in 1V (actually 0,096) to the primaries and got back 0,043V from the feedback. That translates to roughly 1:22 ratio. Transformer works just fine.
I'll try to reverse polarity of the feedback.

great - good test.  Both feedback windings look good on there own, from your test.   I was thinking one of the two feedback primaries might be reversed phase with respect to the other, which would cause the two to fight and cancel out.
Can you do the basically the same thing with the signal running through both primaries in series, and measuring both feedbacks in series? So you would jumper the pins on the opposite side as in the pic above



I reversed polarity and on the feedback and now I', pretty sure the hf attenuation is working correctly. I'm not 100% cos i was unable to test them properly. Just speech and singing through headphones.

I also noticed this while speaking in very close proximity to the capsule. Lips almost touching the head basket.
https://dl.dropboxusercontent.com/u/42125780/Exhale%20U67%203.wav
I exhaled very softly on to the capsule and the following noise came up. It's only Omni and figure of 8.Tare in the rear membrane?
 

This gives me a little hope... did you literally just swap pin 5 and 12 on the ami pcb? I might try this quickly

Yes.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 03, 2014, 04:41:26 PM
any further results?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 03, 2014, 05:10:08 PM
any further results?
No sorry. Busy working. I'll try to check them tomorrow.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 04, 2014, 08:51:46 AM
Confirmed. Reversing the wires out from the feedback winding on the T67 fixes the problem. Its now rolling off perfectly as stated in the manual.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 04, 2014, 09:15:12 AM
Quote
I exhaled very softly on to the capsule and the following noise came up. It's only Omni and figure of 8.Tare in the rear membrane?

Humidity is a no-no. Use a pop filter.

But I actually read somewhere on this forum that breathing on it and listening for artifacts is a test for checking torn membranes. I'm very into fixing these microphones right now. Think I'm loosing my mind a bit... We'll I'll try to run actual studio tests in the following days.
/
E

I didn't listen to the sound but you are correct. Performing the "Breath Test" should not cause snats/pops/wind/frying-bacon sounds.... And if it happens only in bi/omni then it may well be the back capsule like you mentioned.

It could be dirty or otherwise "contaminated" too. For instance with a hair or other foreign material bridging between backplate and the sputtering that causes these sounds when "humid". It doesn't necessarily mean there is a hole. The hole can be pretty microscopic too and still cause issues.

Cheers,
jb
Hi and thansk for answering!
I actually get this on 3 out of 4 U67 builds... Im thinking that it might be a dirty soldering on the Switch PCB? Any idéas?
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on April 04, 2014, 10:07:07 AM
You could confirm that by replacing the capsule with a couple 60pf caps to keep it electrically the same but no acoustic/audio.... Then breath-test into that area....

Flux or material contamination in those hi-z areas can cause the sounds too.

Cheers,
jonathan

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 04, 2014, 12:04:59 PM
You could confirm that by replacing the capsule with a couple 60pf caps to keep it electrically the same but no acoustic/audio.... Then breath-test into that area....

Flux or material contamination in those hi-z areas can cause the sounds too.

Cheers,
jonathan
Thanks for the tip!
I went through all the connetcions, tightened all the screws, cleaned all the terminals and solder joints. Now totaly gone. Success!!

I'll try to do a comparative test with the U67:s some day next week.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 04, 2014, 12:16:34 PM
Quote
Thanks for the tip!
I went through all the connetcions, tightened all the screws, cleaned all the terminals and solder joints. Now totaly gone. Success!!

Awesome - glad you didn't follow my advice to just use a pop filter 
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 04, 2014, 05:03:18 PM
Confirmed. Reversing the wires out from the feedback winding on the T67 fixes the problem. Its now rolling off perfectly as stated in the manual.
/
Emil

ok gonna try that now. lets see what happens!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 04, 2014, 05:15:19 PM
Confirmed. Reversing the wires out from the feedback winding on the T67 fixes the problem. Its now rolling off perfectly as stated in the manual.
/
Emil

ok gonna try that now. lets see what happens!

To all you out there this is really easy. Just take tip and ring from a jack out of your interface. Load it with a sine wave generator. Use alligator clips from the connector and hold them against the test poles in the psu. Record the output from the microphone output. Compare the levels from 1k and 15k or just do a sweep. Everything you need is in your DAW. 
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: sedit1 on April 08, 2014, 02:52:20 PM
If the two feedback windings were connected out of phase it wouldn't work right.

Just had a quick chat with Oliver ,  he confirmed that if the feedback winding is reversed it would affect the de-emphasis portion as well as dmp says (Thanks for the pointer dmp  :))
so this might be the issue ,  Oliver suggested to reversed the wire from the feedback winding and test it again with the amplifier sweep
i will be rechecking that as well from the mic pcb to make ultra sure the polarity is right , and Oliver said he would check out the drawing he made for me a the time to make sure it has not been inverted as well, hope this well get resolved.

Is there any new news regarding this?  Just thinking was Emils xfmr somekind of exception.

In many samples the D-U67 mic have been sounding littlebit bright for what I have used to hear from U67, always tought that It was tube or capsule choise but this could explain it.
Cant wait to finish my own, just few finishing touches :)

Thanks!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 08, 2014, 03:16:05 PM
If the two feedback windings were connected out of phase it wouldn't work right.

Just had a quick chat with Oliver ,  he confirmed that if the feedback winding is reversed it would affect the de-emphasis portion as well as dmp says (Thanks for the pointer dmp  :))
so this might be the issue ,  Oliver suggested to reversed the wire from the feedback winding and test it again with the amplifier sweep
i will be rechecking that as well from the mic pcb to make ultra sure the polarity is right , and Oliver said he would check out the drawing he made for me a the time to make sure it has not been inverted as well, hope this well get resolved.

Is there any new news regarding this?  Just thinking was Emils xfmr somekind of exception.

In many samples the D-U67 mic have been sounding littlebit bright for what I have used to hear from U67, always tought that It was tube or capsule choise but this could explain it.
Cant wait to finish my own, just few finishing touches :)

Thanks!

I think Dan has contacted Oliver. From what I gather I guess either the AMI T67 transformers feedback winding is not inverted, the circuit board is wrong (probably not from my comparisons to the schematic) or I've done something wrong with my build. Already a few members seem to experience the same thing with the AMI builds so most likely it's in the transformer.
Having gotten the first batch of mislabeled t13:s I'm starting to question AMI to be honest. Never answers emails either.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 08, 2014, 04:02:01 PM
Important Notice

Hi All, 

I just got of the phone with Oliver and after all analysis done with the hand drawing I received and the schematic , the conclusion is that nothing is wrong with the AMI T67.  The connection from the adaptor PCB to the main microphone pcb has been inadvertly mirrored as my brain was about to blow up ( this meant not to be an excuse) i tought at first that inverting the polarity everywhere was nulling it out for audio and feedback but as dmp pointed out ( Thanks dmp) the fact that the feedback winding was inverted would not activate the de-emphasis at all since the assymetry from C17,  I am glad this can be fixed easy as the transformer connection are actually wired in and not fixed on the pcb for the AMI T67,  from data reported by Studio Mollan ( Thanks Emil) the feedback winding fixes the issue and the de-emphasis is working correctly after the the inversion of wire 5 and 12 on the mic pcb and the amplifier sweep test is inline with the Original U67 documentation.
I am still trying to confirm that swaping both audio transfomer tap is necessary and it will probably be in the best interest to make sure everything is 100% polarity Correct,   ( Polarity Happens "Albert Einstein")

So the complete Fixe will probably be to swap the both audio taps and the feedback winding for the AMI T67 build. "so we will take no prisonners"

I have prepared a huge mailing list to warn about this errata on this particular transformer configuration for everyone to be reached

I would like to thank Studio Mollan and dmp and all other fellow member of this group for catching this wiring mistakes.

As far as Max BV12 mic pcb is concerned the great and clear documentation from Max resulted in all the correct connections from the very beginning , ( Thanks Max)

 thanks For your understanding and patience on this matter to be finally resolved ,

this is the real power of this community as no one is exempt from doing a mistake.

Best regards,

Dany,

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on April 08, 2014, 04:04:44 PM
Maybe we just need a "Bright" switch?

Cheers,
jb

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 08, 2014, 04:09:30 PM
Maybe we just need a "Bright" switch?

Cheers,
jb
I seriously consider making the inverting switchable. Or at least an internal jumper. As stated before I really don't have a problem with the 67 without the feedback circuit. A good soundig microphone either way.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 10, 2014, 06:55:52 AM
So dan are you saying the complete fix would be swapping:

5 with 12
7 with 10
1 with 4

?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 10, 2014, 08:24:12 AM
So dan are you saying the complete fix would be swapping:

5 with 12
7 with 10
1 with 4

?

from the top of my head yes

So audio Primary, Secondary , and then the feedback winding as well , so 3 swaps and everything will be on track.

 , but i have prepared a huge mailing list with all the explanation and pad number swapping procedure that I should be able to send out once i am back home as i am travelling this week,  every customer from the very beginning will be adressed.

thanks for you wrap-up Jesse and thanks to all user for you understanding and cooperation.
Best,
Dan,



Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 10, 2014, 08:42:40 AM
So dan are you saying the complete fix would be swapping:

5 with 12
7 with 10
1 with 4

?

from the top of my head yes

So audio Primary, Secondary , and then the feedback winding as well , so 3 swaps and everything will be on track.

 , but i have prepared a huge mailing list with all the explanation and pad number swapping procedure that I should be able to send out once i am back home as i am travelling this week,  every customer from the very beginning will be adressed.

thanks for you wrap-up Jesse and thanks to all user for you understanding and cooperation.
Best,
Dan,
I just switched 5-12. You're saying that th secondary and primary needs to be reversed as well? Wouldn't that just undo the whole feedback polarity change?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 10, 2014, 08:51:26 AM
So dan are you saying the complete fix would be swapping:

5 with 12
7 with 10
1 with 4

?

from the top of my head yes

So audio Primary, Secondary , and then the feedback winding as well , so 3 swaps and everything will be on track.

 , but i have prepared a huge mailing list with all the explanation and pad number swapping procedure that I should be able to send out once i am back home as i am travelling this week,  every customer from the very beginning will be adressed.

thanks for you wrap-up Jesse and thanks to all user for you understanding and cooperation.
Best,
Dan,
I just switched 5-12. You're saying that th secondary and primary needs to be reversed as well? Wouldn't that just undo the whole feedback polarity change?

Since I did not have a definitive answer on this one as I asked Oliver as well  but it maybe that some interaction with the feedback winding have an interaction with the the phase of both audio winding and prevent any phase shifting issue as well if any , it may very well be that just swapping 5-12 on the mic pcb clear the de-emphasis issue , but reversing the audio in and out as well will ensure that everything will work as intented,

so the complete 100% fix is to swap the feedback , audio primary and audio secondary , you would then be the best candidate at this time to tell us that swapping the audio tap as well makes a difference or not .

Best,
DAn,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on April 10, 2014, 09:52:59 AM
So what does this mean for this comparison, for instance?
http://benoitlaur.com/a-b-original-neumann-u67-vs-clone-u67/ (http://benoitlaur.com/a-b-original-neumann-u67-vs-clone-u67/)
Ben did use the AMI tranny.



Henk
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 10, 2014, 09:58:39 AM
So what does this mean for this comparison, for instance?
http://benoitlaur.com/a-b-original-neumann-u67-vs-clone-u67/ (http://benoitlaur.com/a-b-original-neumann-u67-vs-clone-u67/)
Ben did use the AMI tranny.



Henk

I had tons of very nice comments on the mic even tough it had and feedback winding errata

just means that it will probably even sounds much better with the fix.

means also that some comparaison will remain relative for the moment beeing.

and i am very sorry for the mistake but it can be fixed very easy.

I will not miss anyone on the annoucment Promised

 :)

Ps: i am just in touch with a fellow member that has a D-U67 with a genuine K67 neumann in it and the feeback errata , i am working with him to take sample before and after the fix and have some picture done while fixing it .  eventough the first impression from this user was awesome.  i guess we might see this as an optional de-emphasis if needed or not ,  ;)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 10, 2014, 10:08:56 AM
Quote
so the complete 100% fix is to swap the feedback , audio primary and audio secondary

Swapping all three windings will give you the exact same setup as not swapping any.
Swapping the feedback only, with respect to the primary, is the solution that makes sense.
Only swap the secondary (with respect to the primary) if the mic output is out of phase with the sound source - i.e. compare to a known good mic.

Quote
So what does this mean for this comparison, for instance?

If you boost +10dB @ 15kHZ on a correct u67, it would probably still sound good. It would just sound brighter.
I think this shows DIY is a learning experience!
And the jury is still out on the AMI transformer. It could be that not all the transformers are wound the same way. Some may work as original.
Best to scope out your transformer to verify how it is built.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 10, 2014, 10:23:59 AM
So dan are you saying the complete fix would be swapping:

5 with 12
7 with 10
1 with 4

?

from the top of my head yes

So audio Primary, Secondary , and then the feedback winding as well , so 3 swaps and everything will be on track.

 , but i have prepared a huge mailing list with all the explanation and pad number swapping procedure that I should be able to send out once i am back home as i am travelling this week,  every customer from the very beginning will be adressed.

thanks for you wrap-up Jesse and thanks to all user for you understanding and cooperation.
Best,
Dan,
I just switched 5-12. You're saying that th secondary and primary needs to be reversed as well? Wouldn't that just undo the whole feedback polarity change?

Since I did not have a definitive answer on this one as I asked Oliver as well  but it maybe that some interaction with the feedback winding have an interaction with the the phase of both audio winding and prevent any phase shifting issue as well if any , it may very well be that just swapping 5-12 on the mic pcb clear the de-emphasis issue , but reversing the audio in and out as well will ensure that everything will work as intented,

so the complete 100% fix is to swap the feedback , audio primary and audio secondary , you would then be the best candidate at this time to tell us that swapping the audio tap as well makes a difference or not .

Best,
DAn,

Ok. That sold me. I will do all the tests, as comparative as possible, but I'm under a pretty heavy work load at the moment and the studio is busy pretty much 24/7. I'll try to do it this weekend. I'd love to give something back to the forum.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on April 10, 2014, 10:24:57 AM
I ask because I really liked the D67 in Ben's shootout. In this particular case I liked it better than the original U67.
I did notice some extra air in the D67, which I reported in my reply to Ben's post. But it didn't sound as +10dB @ 15kHz or as other examples I've heard of K67 capsules without any de-emphasis. Hey, I don't even like overly bright microphones.
::)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 10, 2014, 10:42:31 AM
I ask because I really liked the D67 in Ben's shootout. In this particular case I liked it better than the original U67.
I did notice some extra air in the D67, which I reported in my reply to Ben's post. But it didn't sound as +10dB @ 15kHz or as other examples I've heard of K67 capsules without any de-emphasis. Hey, I don't even like overly bright microphones.
::)
I'm also not sure if I like the t67 with the feedback filter but I will try it out. The comparison I did earlier was between the ami without feedback and correctly set up IOaudio transformer. They the dif was ca 6,5db from 1500Hz. What the difference will e with a correctly wired t67 is yet to be discovered. I'll do some shoot outs ASAP but listening to speech in headphones gave me the feeling that the ami is still brighter than IOaudio. Correctly wired the t67 was duller but heavily saturated in the HF. Very present.  Still not confirmed but clips will be posted soon. Speech alone is not a good microphone test in my words. Acoustic guitar and drums are better to get the whole bandwidth and saturation/distortion. 
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 10, 2014, 10:44:11 AM
Quote
Swapping all three windings will give you the exact same setup as not swapping any.
Swapping the feedback only, with respect to the primary, is the solution that makes sense.
Only swap the secondary (with respect to the primary) if the mic output is out of phase with the sound source - i.e. compare to a known good mic.

i definitively agree with you on this but i am not 100% sure this configuration would not introduce phase shift or other diminishing effect on the demphasis functionnality that i could not confirmed yet.
beeing at swapping the wire, swapping the 3 pair will make sure it will work as intended since the feeback winding is not symetrical. but the final judge is your ear , as stated by micaddict he preffered the non-deempahsis version of it over the real U67  :),  this can still be seen as an extra functionnality or not ,
I will leave this to your discretion but not beeing able to confirm for sure that they can be issue with this only swap i can only recommend to everyone to swap the 3 pair
and if they prefered the currently configured version over the one with the extra demphasis one. then the bright switch can come into play or not.

Quote
And the jury is still out on the AMI transformer. It could be that not all the transformers are wound the same way. Some may work as original.
Best to scope out your transformer to verify how it is built.
I am 100% convinced that all the AMI T67 are made the same way. ;)

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 10, 2014, 10:48:03 AM
Quote
I'll do some shoot outs ASAP but listening to speech in headphones gave me the feeling that the ami is still brighter than IOaudio. Correctly wired the t67 was duller but heavily saturated in the HF. Very present.  Still not confirmed but clips will be posted soon. Speech alone is not a good microphone test in my words. Acoustic guitar and drums are better to get the whole bandwidth and saturation/distortion. 

Absolutely  :) :) :)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 13, 2014, 12:35:23 PM
I have tried to Reach out as many member as possible with the mailing list but some of the contact are expired but here it is again ,

Hi All,

This is a message for all member of the vintage microphone group mailing list , to warn about an errata regarding the connection of the AMI T67 transformer feedback winding through the main mic PCB. It has been identified that the feedback winding is not working properly since an error in the connection to the microphone PCB. The result of this winding being connected backward will affect the de-emphasis portion of the circuit that permits to tame down some high frequency in the response of the microphone.
Don’t worry as this is a simple fix to perform.  As per the builder that have used the IOaudio transformer the connection is correct. This only applies to the use of the AMI T67 transformer in the D-U67 Build.

I would like to ask you  to consult this thread here from page 37 to 41 for the explanation of the quick fix.

I would like to Thank specially member dmp and all other member that helped for pointing this out.

http://groupdiy.com/index.php?topic=50021.720
(Page 37 to 41)

I am really Sorry for the inconvenience and I thank you all  in advance for your cooperation on this matter.

Please let me know if you have any questions regarding this matter.

Best Regards,
Dany ,
http://www.vintagemicrophonepcbkit.com
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 13, 2014, 09:33:29 PM
Important AMI T67 Errata

applies to D-M269c and D-U67 with AMI T67 transformer only

Hi All, with the help of  fellow member I have been able to have some testing done about the proper correction for the de-emphasis to work correctly,

it has been found that swapping only 5-12 from the mic pcb make a very sublte difference hence to permits the de-emphasis to work 100% correct,

it is imperative that you swap pad 5-12,  pad 7-10 and pad 1-4 from the mic pcb as the connection have been mistakenly mirrrored.


so the complete 100% fix is
swap 5-12 , 7-10 1-4 pad on the mic PcB,  this will correct for all winding polarity including feedback winding error and correct for a Full de-emphasis.
they all are adjacent pad so it should be pretty easy to correct.



For any Future Build or for the summary of the correction here is the wiring guide for the transformer to the mic pcb ,
this wiring guide ensure all the polarity and connection are as intended at the first place.

From transformer board to mic PCB

Pad 5 ----->  mic pcb pad T1212
Pad 12 -------> mic pcb pad T55
Pad 1 --------> mic pcb pad T44
Pad 4 --------> mic pcb pad T11
Pad 7 --------> mic pcb pad T1010
Pad 10 ------> mic pcb Pad T77



here is some sample before and after the complete fix. Thanks To Dan for the samples.


with wiring error
https://dl.dropboxusercontent.com/u/43869772/U67/Feedback%20winding%20Correction/Orginal.wav

With wiring correction  WoW :)
https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281994117.wav




Quote
Remember that there is an errata on the polarity for the D-67 all you have to do to fix it is reverse pin 2 and pin 3 up in the power supply xlr connector and you will be ready to rock,


PS: for those of you who had the mic output polarity error this will fix this at the same time so i you have reversed xlr pin 2-3 to previously correct for this in the psu please account for that as well as this errata will correct both at the same time.
 
Thanks For you patience and cooperation and all member helping out resolving this isssues
Best,
Dan.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 15, 2014, 01:49:16 PM
Thanks Dani,

Makes complete sense as i was getting reversed phase also. Going to try this out now and put the mic back up today with senheiser / Neumann authentic capsule out of my u87ai.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 15, 2014, 02:13:12 PM
Thanks Dani,

Makes complete sense as i was getting reversed phase also. Going to try this out now and put the mic back up today with senheiser / Neumann authentic capsule out of my u87ai.

Awesome , Cant wait for your verdict,
Best,
DAN,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: [email protected] on April 20, 2014, 05:00:26 PM
Just done the rewire for AMI transformer and it's made all the difference.. The mic sounded ok before... But now it has the weight I was expecting from a u67. Top end now sounds perfect!
Thx. [email protected]
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on April 21, 2014, 08:59:30 AM
Now that this is settled, it would be nice to have some new A/Bs between the AMI and ioaudio tranny in the D67. For sound that is.
Any chance this could happen? E.g. two members getting together somehow. Both mics should have the "same" capsule at least.
Or Dany, will you be building two anywhere in the near future?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: saint gillis on April 22, 2014, 04:56:34 PM
Just done the rewire for AMI transformer and it's made all the difference.. The mic sounded ok before... But now it has the weight I was expecting from a u67. Top end now sounds perfect!
Thx. [email protected]

  Totally agree, seems far better!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 22, 2014, 05:15:33 PM
Now that this is settled, it would be nice to have some new A/Bs between the AMI and ioaudio tranny in the D67. For sound that is.
Any chance this could happen? E.g. two members getting together somehow. Both mics should have the "same" capsule at least.
Or Dany, will you be building two anywhere in the near future?

Hi.
I'll try to run some test Thursday/Friday.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 22, 2014, 05:46:15 PM
I'm gonna do this mod today, I have original modern k67
Neumann Capsule and have original vintage u67 here I can do test up against. I'm in la if someone wants to join in on the test
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on April 23, 2014, 04:04:53 AM
Now that this is settled, it would be nice to have some new A/Bs between the AMI and ioaudio tranny in the D67. For sound that is.
Any chance this could happen? E.g. two members getting together somehow. Both mics should have the "same" capsule at least.
Or Dany, will you be building two anywhere in the near future?

Hi.
I'll try to run some test Thursday/Friday.

 :)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 24, 2014, 08:18:47 AM
Ok, ive run a new test. IOaudio version as they are and AMI T67 version converted as instructed by Dan.

Converted AMI
https://dl.dropboxusercontent.com/u/42125780/U67%20T67%20Take%201%20Reversed%20as%20instructed.wav

IOaudio
https://dl.dropboxusercontent.com/u/42125780/U67%20IOaudio%20Take%201%20reference.wav

Please listen and share your thoughts. 
/
Emil


EDIT:
When only reversing 5-12 the pad starts to behave strange. With pad engaged it seems to roll of a lot of high end, and actually makes it sound a lot like the IOaudio transformer. Am i on to something here? Take a lsiten below.

AMI T67 only reversed 5-12 with -10db pad in.
https://dl.dropboxusercontent.com/u/42125780/U67%20T67%20reversed%205-12%20only%20with%20pad%20take%203.wav

IOaudio
https://dl.dropboxusercontent.com/u/42125780/U67%20IOaudio%20reference%20take%203.wav


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 24, 2014, 01:02:27 PM
Quote
When only reversing 5-12 the pad starts to behave strange. With pad engaged it seems to roll of a lot of high end, and actually makes it sound a lot like the IOaudio transformer. Am i on to something here? Take a lsiten below.

The answer is yes cause the pad is tied to the feedbackloop in the filter network below it , Since only swapping 5-12 create phase inversion and phase shift it will affect the whole feedback function,  if you swap the 3 pair as previously suggested your correct all the phase and feedback issue so the pad should not affect the response
except for the output.

I would defo suggest that you experiment with the feedback cap value for the IOaudio transformer to see if a lowest or highest possible value to see how it impact it,

hope this helps,
Best,
Dan,


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 24, 2014, 04:18:35 PM
Quote
When only reversing 5-12 the pad starts to behave strange. With pad engaged it seems to roll of a lot of high end, and actually makes it sound a lot like the IOaudio transformer. Am i on to something here? Take a lsiten below.

The answer is yes cause the pad is tied to the feedbackloop in the filter network below it , Since only swapping 5-12 create phase inversion and phase shift it will affect the whole feedback function,  if you swap the 3 pair as previously suggested your correct all the phase and feedback issue so the pad should not affect the response
except for the output.

I would defo suggest that you experiment with the feedback cap value for the IOaudio transformer to see if a lowest or highest possible value to see how it impact it,

hope this helps,
Best,
Dan,

Thanks fr clarifying that Dan!
I'll try out some other values for C17 on the IOaudio builds. After listening to the now correct AMI T67 I'm still not convinced that my IOaudio versions are correctly wired. I going to have to go through my wiring again.
I find my last comparison in the above post a bit intriguing. When I only reverse 5-12 on the AMI with -10dB pad engaged it sounds pretty much exactly as the IOaudio. Is it possible I could have reversed or misplaced some components/switches etc? The air is simply not there in my IOaudios. The difference in sound between the two is still I think to large just to be caused by different brands of transformers.
Any help here would be very appreciated. Any way to measure polarity in the IOaudio transformer? Maybe accidental polarity change?
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on April 24, 2014, 04:43:05 PM
One way is to disconnect the trafo and tone out all the pins/coils while also notating DCR values.
Make a sketch of all the coils and the termination ends/pin-numbers.
You'll need a scope and a tone generator so you can determine polarity from I to O (or pri-to-sec).... Notate which pins are + and which are - with respect to the source signal and associated pins.

Once you know and have notated which coils are which and which pins are +/- for each coil then review the documentation for that trafo as well as the wiring/linking diagrams, u67 schematic, and tone out the PCB traces to confirm that all the +'s and -'s are connected as specified in the schematic.

If you'e got a tone gen and scope hooked up you may also want to compare saturation levels and phase response WRT frequency between similar style transformers or various suppliers transformers.

You can also measure the AC Signal voltage (from the tone gen) at pri/sec to determine/confirm the ratio.

Once that's all good to go it should be connected up in-circuit (terminated to a pre) while using the CAL input to send signal in, sweep, and scope at the various ckt-nodes to confirm multiples of the same build are "within spec" of each-other.

Cheers,
jb
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 25, 2014, 05:08:50 AM
One way is to disconnect the trafo and tone out all the pins/coils while also notating DCR values.
Make a sketch of all the coils and the termination ends/pin-numbers.
You'll need a scope and a tone generator so you can determine polarity from I to O (or pri-to-sec).... Notate which pins are + and which are - with respect to the source signal and associated pins.

Once you know and have notated which coils are which and which pins are +/- for each coil then review the documentation for that trafo as well as the wiring/linking diagrams, u67 schematic, and tone out the PCB traces to confirm that all the +'s and -'s are connected as specified in the schematic.

If you'e got a tone gen and scope hooked up you may also want to compare saturation levels and phase response WRT frequency between similar style transformers or various suppliers transformers.

You can also measure the AC Signal voltage (from the tone gen) at pri/sec to determine/confirm the ratio.

Once that's all good to go it should be connected up in-circuit (terminated to a pre) while using the CAL input to send signal in, sweep, and scope at the various ckt-nodes to confirm multiples of the same build are "within spec" of each-other.

Cheers,
jb
Wow thanks! Ill try to get my scope running and try that out. Think ill start of by going through my wiring one more time.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 25, 2014, 10:31:20 AM
Quote
When only reversing 5-12 the pad starts to behave strange. With pad engaged it seems to roll of a lot of high end, and actually makes it sound a lot like the IOaudio transformer. Am i on to something here? Take a lsiten below.

The answer is yes cause the pad is tied to the feedbackloop in the filter network below it , Since only swapping 5-12 create phase inversion and phase shift it will affect the whole feedback function,  if you swap the 3 pair as previously suggested your correct all the phase and feedback issue so the pad should not affect the response
except for the output.

I would defo suggest that you experiment with the feedback cap value for the IOaudio transformer to see if a lowest or highest possible value to see how it impact it,

hope this helps,
Best,
Dan,

Thanks fr clarifying that Dan!
I'll try out some other values for C17 on the IOaudio builds. After listening to the now correct AMI T67 I'm still not convinced that my IOaudio versions are correctly wired. I going to have to go through my wiring again.
I find my last comparison in the above post a bit intriguing. When I only reverse 5-12 on the AMI with -10dB pad engaged it sounds pretty much exactly as the IOaudio. Is it possible I could have reversed or misplaced some components/switches etc? The air is simply not there in my IOaudios. The difference in sound between the two is still I think to large just to be caused by different brands of transformers.
Any help here would be very appreciated. Any way to measure polarity in the IOaudio transformer? Maybe accidental polarity change?
/
Emil

Hi Emil,  I went in and rechecked again... and triple checked again all connection on the Mic PCB for Max Transformer and everyting is Inine with Max documentation I have identified on this picture what could be the ony thing that might be a little confusing but in all in makes senses and i iam 100% everything is correct with IOaudio transformer ( Polarity of feedback and Phase )unless there is an error on Max traffo document wich i doubt very very much , you coud still consut him if you have any questions on his transfo

I am gad you made those point as i am always willing to re-re validate my work, cause no ones is perfect,
those are the connection point i used in regards to Max Specifications, even if I had made a mistake wich is not the case here the mic should sound brighter wich would point to having the feedback not functionning or inverted wich is not the case here wich is seems to sound darker, i am starting to think you might actualy switch the capsule as no assumption can be made for a critical part ike this ,

Hoping I can hep on this matter,
Best,
DAN,


nomenclature from Max Spec sheets,
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d028199417b.jpg)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 25, 2014, 10:45:59 AM
It may not be a problem the feedback with Max's transformer... the size of C9 has an effect on the sound of a microphone as it interacts with the inductance of the transformer primary.  But this (in my testing experience) is most apparent in the transformer low end.

Quote
if you swap the 3 pair as previously suggested your correct
I don't understand how swapping all three windings makes any change at all to the circuit! This is basic transformer 101, right? The ends of the windings don't have any absolute polarity.
I'm really scratching my head as to how this is making a difference. 
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 25, 2014, 10:52:42 AM
It may not be a problem the feedback with Max's transformer... the size of C9 has an effect on the sound of a microphone as it interacts with the inductance of the transformer primary.  But this (in my testing experience) is most apparent in the transformer low end.

Quote
if you swap the 3 pair as previously suggested your correct
I don't understand how swapping all three windings makes any change at all to the circuit! This is basic transformer 101, right? The ends of the windings don't have any absolute polarity.
I'm really scratching my head as to how this is making a difference.

+1 this is exately what i wanted to post as well 2 seconds late,  since the same core pcb as been used for the T67 and the MAX BV12,
i would like to remind that the swap fix only applies to AMI T67 not to confuse furthermore , i have toroughy check Max config on the pcb and everything is correct ,  when i made the mistake initialy with AMI T67 i have on purpose made all the connection mirrored but as you pointed out the feedback winding is assymetric then the relation with the primary needs to folow that is why , you can hear the difference from the sample Dan have made in the previous page and it is day and night it sounds so much sweeter on the top end with the correction. as far as of now i am thinking that C17 woud need to be experimented with for Max transformer,  as pointed out earlier the amplifier test with max traffo is in specification hence it seems to point out on the capsule,

hope this helps,
Best,
dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 25, 2014, 01:36:51 PM
It may not be a problem the feedback with Max's transformer... the size of C9 has an effect on the sound of a microphone as it interacts with the inductance of the transformer primary.  But this (in my testing experience) is most apparent in the transformer low end.

Quote
if you swap the 3 pair as previously suggested your correct
I don't understand how swapping all three windings makes any change at all to the circuit! This is basic transformer 101, right? The ends of the windings don't have any absolute polarity.
I'm really scratching my head as to how this is making a difference.

+1 this is exately what i wanted to post as well 2 seconds late,  since the same core pcb as been used for the T67 and the MAX BV12,
i would like to remind that the swap fix only applies to AMI T67 not to confuse furthermore , i have toroughy check Max config on the pcb and everything is correct ,  when i made the mistake initialy with AMI T67 i have on purpose made all the connection mirrored but as you pointed out the feedback winding is assymetric then the relation with the primary needs to folow that is why , you can hear the difference from the sample Dan have made in the previous page and it is day and night it sounds so much sweeter on the top end with the correction. as far as of now i am thinking that C17 woud need to be experimented with for Max transformer,  as pointed out earlier the amplifier test with max traffo is in specification hence it seems to point out on the capsule,

hope this helps,
Best,
dan,


Thanks for all this valuable info guys!!
I'll run some more tests as soon as I can. A fellow forum member who's also helping out.
I'll switch capsules between the two versions to rule out capsule issues.
Then maybe removing c17 on both to see how the two different transformers behave without the feedback circuit. That might shed some light on the issue.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 25, 2014, 01:45:15 PM
Quote
Thanks for all this valuable info guys!!
I'll run some more tests as soon as I can. A fellow forum member who's also helping out.
I'll switch capsules between the two versions to rule out capsule issues.
Then maybe removing c17 on both to see how the two different transformers behave without the feedback circuit. That might shed some light on the issue.
/
Emil

++++++++1

dD
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on April 26, 2014, 02:33:15 PM
I've been experimenting with C17.  I apologise for the omission of frequency sweeps and the general lack of a scientific approach in the following.  These were kind of quick and dirty tests to see what difference (if any) swapping out values for C17 would make to the top end in this mic. 

I went above and below the range of values suggested in the schematic at Dany's suggestion.

The mics in the sound samples are two DU67s with Max's BV12s, Beesneez K6s and NOS Silver Shield Telefunken EF86s.  I left one stock (100pf) and changed values of C17 in the other.

Here are some sound samples with speech, singing and tambourine.  The mics were side by side for the bulk of the recordings. 

180pf v Stock

Stock Speech then Singing (https://www.dropbox.com/sh/w13eqfb14aa3bt7/--TmF5qG71/Stock%20Speech%20then%20Singing.wav)
180pf Speech then Singing (https://www.dropbox.com/sh/w13eqfb14aa3bt7/51wVSkrRZg/180pf%20Speech%20then%20Singing.wav)
Stock Tambourine (https://www.dropbox.com/sh/w13eqfb14aa3bt7/VtwoBykvV2/Stock%20Tambourine.wav)
180pf Tambourine (https://www.dropbox.com/sh/w13eqfb14aa3bt7/rrTp-j7kwh/180pf%20Tambourine.wav)

68pf v Stock

Stock Speech (https://www.dropbox.com/sh/w13eqfb14aa3bt7/gTqbYhU492/Stock%20Speech%202.wav)
68pf Speech (https://www.dropbox.com/sh/w13eqfb14aa3bt7/ZTkJPHtvbV/68pf%20Speech.wav)
Stock singing (https://www.dropbox.com/sh/w13eqfb14aa3bt7/orPvSaZwsa/Stock%20Singing.wav)
68pf Singing (https://www.dropbox.com/sh/w13eqfb14aa3bt7/p9Q_MYwgnz/68pf%20Singing.wav)
Stock Tambourine (https://www.dropbox.com/sh/w13eqfb14aa3bt7/kG4NfAoprF/StockTambourine2.wav)
68pf Tambourine (https://www.dropbox.com/sh/w13eqfb14aa3bt7/YC3jlA55hD/68pf%20Tambourine.wav)


For these last two I sang directly into each mic.  Different takes obviously.


Stock singing direct (https://www.dropbox.com/sh/w13eqfb14aa3bt7/p4rWo7dY_V/Stock%20Singing%20direct.wav)
68pf Singing direct (https://www.dropbox.com/sh/w13eqfb14aa3bt7/yarm7Gc-2Z/68pf%20Singing%20direct.wav)

Any feedback (Hur Hur  :P) very welcome.  Please forgive the inconsistencies of my warble and the varying timbres and keys  :o

Peace

Jim
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 26, 2014, 02:49:33 PM
I've been experimenting with C17.  I apologise for the omission of frequency sweeps and the general lack of a scientific approach in the following.  These were kind of quick and dirty tests to see what difference (if any) swapping out values for C17 would make to the top end in this mic. 

I went above and below the range of values suggested in the schematic at Dany's suggestion.

The mics in the sound samples are two DU67s with Max's BV12s, Beesneez K6s and NOS Silver Shield Telefunken EF86s.  I left one stock (100pf) and changed values of C17 in the other.

Here are some sound samples with speech, singing and tambourine.  The mics were side by side for the bulk of the recordings. 

180pf v Stock

Stock Speech then Singing (https://dl-web.dropbox.com/get/DU67%20C17%20Experiments/Stock%20Speech%20then%20Singing.wav?_subject_uid=37163803&w=AAAR7LjQdhOLFdAsMaPFqzw_eMrAzNuE6kqM_434avHSEw)
180pf Speech then Singing (https://dl-web.dropbox.com/get/DU67%20C17%20Experiments/180pf%20Speech%20then%20Singing.wav?_subject_uid=37163803&w=AAAZf_LRej-6q9_V4r5_QQei1s5qltS0pKyDJqjA4PcRfA)
Stock Tambourine (https://dl-web.dropbox.com/get/DU67%20C17%20Experiments/Stock%20Tambourine.wav?_subject_uid=37163803&w=AAAUOD316kRLgny-douGExx5mkE6fZCPLOEWvl08jtJpdw)
180pf Tambourine (https://dl-web.dropbox.com/get/DU67%20C17%20Experiments/180pf%20Tambourine.wav?_subject_uid=37163803&w=AADPM2vYxRK_SvIVe8hILAjOrETLi1hBhUsxcO1xwa1PVQ)

68pf v Stock

Stock Speech (https://dl-web.dropbox.com/get/DU67%20C17%20Experiments/Stock%20Speech%202.wav?_subject_uid=37163803&w=AAAP9gN9U3ZpUtTiMvfzIFhni2U_ys_T-mC_NdAaMwUpTQ)
68pf Speech (https://dl-web.dropbox.com/get/DU67%20C17%20Experiments/68pf%20Speech.wav?_subject_uid=37163803&w=AAB20v_xfNiFGZc769Pgc7kq45rTR05jKzO-qt6w62EjQg)
Stock singing (https://dl-web.dropbox.com/get/DU67%20C17%20Experiments/Stock%20Singing.wav?_subject_uid=37163803&w=AABtaKM-b6yIyB8cAxCYN3AFyft90ze-3PMAUVk0j7iDBw)
68pf Singing (https://dl-web.dropbox.com/get/DU67%20C17%20Experiments/68pf%20Singing.wav?_subject_uid=37163803&w=AADZxqC6wol5tgPxnnSc7Fp7gTRuFkZB-z80IP0Hggk3Cg)
Stock Tambourine (https://dl-web.dropbox.com/get/DU67%20C17%20Experiments/StockTambourine2.wav?_subject_uid=37163803&w=AACYMhfJrDin0YDcVt8D36fYX-rN7NA02SFfNBiODHZGKQ)
68pf Tambourine (https://dl-web.dropbox.com/get/DU67%20C17%20Experiments/68pf%20Tambourine.wav?_subject_uid=37163803&w=AAB-lPBp9HNdbbFz_YlfDpkEPyBMze1nGzSsCqrR1emJgA)


For these last two I sang directly into each mic.  Different takes obviously.


Stock singing direct (https://dl-web.dropbox.com/get/DU67%20C17%20Experiments/Stock%20Singing%20direct.wav?_subject_uid=37163803&w=AADklvyCe6iUAPy8QbvkiLJPC9D6JfuPQbcCMH-S-LlSOA)
68pf Singing direct (https://dl-web.dropbox.com/get/DU67%20C17%20Experiments/68pf%20Singing%20direct.wav?_subject_uid=37163803&w=AADuYBSPfITLiPuG7zKO1IJW4OwmtLftv1d9xc2_Wzpb6g)

Any feedback (Hur Hur  :P) very welcome.  Please forgive the inconsistencies of my warble and the varying timbres and keys  :o

Peace

Jim

Great! I can't seem to get to the files though.
/
Emil
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on April 26, 2014, 03:07:03 PM
Links fixed  8)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Studio Mollan on April 26, 2014, 04:10:38 PM
Links fixed  8)

There's difference, really subtle. I dont think swaping C17 will solve this dullness that we are experiencing.
Great test Jim!


I looked at the schematic and found another filter. C12+C13. A long shot maybe but if the transformers have different DCR on the secondary could that affect the cut of of that filter? I dont know how to calculate the cutof. This is a radio interference filter?   
/
Emil

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kaguenpituak on April 27, 2014, 04:24:26 AM
I have do the complete mod. (5-12,1-4,7-10) and no sound change...I have compared with another no mod. Tomorrow I will try only 5-12
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on April 27, 2014, 06:32:51 AM
This is the stock mics on piano.

Stock mics piano (https://www.dropbox.com/sh/w13eqfb14aa3bt7/YGzhYcnOhW/Stock%20Mics%20Piano.wav)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 27, 2014, 02:17:08 PM
I have do the complete mod. (5-12,1-4,7-10) and no sound change...I have compared with another no mod. Tomorrow I will try only 5-12

Now thats weird, this would suggest that the feedback circuit IS symmetrical!!... We shouldn't have to be here testing and guessing polarities and windings of Oliver's transformers. I think he needs to explain exactly the windings on his T67.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 27, 2014, 02:37:07 PM
I have do the complete mod. (5-12,1-4,7-10) and no sound change...I have compared with another no mod. Tomorrow I will try only 5-12

Now thats weird, this would suggest that the feedback circuit IS symmetrical!!... We shouldn't have to be here testing and guessing polarities and windings of Oliver's transformers. I think he needs to explain exactly the windings on his T67.

according with the hand drawing I have from him with polarity , with the correction applied everthing is correct now ,  it has been tested by DMP and Dandeurloo, and another member and proof on sample. Maybe Oliver could chime in on this ,


Best,
dan,

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 27, 2014, 02:43:11 PM
I've been so busy writing and producing I haven't had a moment to do the mod myself but I think today will be the day.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 27, 2014, 02:45:11 PM
I've been so busy writing and producing I haven't had a moment to do the mod myself but I think today will be the day.

that would be awesome to have your confirmation as well,
Thanks Jess,
I guess we need that day,  i am trying so hard to make sure i do my part ,
Best,
dAN,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 28, 2014, 11:08:30 AM
Quote
according with the hand drawing I have from him with polarity , with the correction applied everthing is correct now ,  it has been tested by DMP and Dandeurloo


I have NOT tested this out. I only have Max's transformers, I haven't had a AMI to try. As I've posted a few times, I would expect reversing all three windings to make no difference in the circuit. Transformer windings do not have absolute polarity, only with respect to each other. (to flip phase / to not flip phase)

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 28, 2014, 11:12:16 AM
Quote
according with the hand drawing I have from him with polarity , with the correction applied everthing is correct now ,  it has been tested by DMP and Dandeurloo


I have NOT tested this out. I only have Max's transformers, I haven't had a AMI to try. As I've posted a few times, I would expect reversing all three windings to make no difference in the circuit. Transformer windings do not have absolute polarity, only with respect to each other. (to flip phase / to not flip phase)

Sorry i must Have made a typo,  but here it is again ,

here is some sample before and after the complete fix. Thanks To Dan for the samples.

Errata Feedback winding polarity  http://groupdiy.com/index.php?topic=50021.800 reply # 814

AMI T67 Corrected Wiring to main microphone pcb

From transformer board to mic PCB

Pad 5 ----->  mic pcb pad T1212
Pad 12 -------> mic pcb pad T55
Pad 1 --------> mic pcb pad T44
Pad 4 --------> mic pcb pad T11
Pad 7 --------> mic pcb pad T1010
Pad 10 ------> mic pcb Pad T77

with wiring error
https://dl.dropboxusercontent.com/u/43869772/U67/Feedback%20winding%20Correction/Orginal.wav

With wiring correction  WoW :)
https://io.groupdiy.com/file/gdiy-2017/u/39511/58d02819941ac.wav
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 28, 2014, 11:17:32 AM
Quote
here is some sample before and after the complete fix. Thanks To Dan for the samples.

Definitely a difference in these before-and-after...
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 28, 2014, 11:29:42 AM
Quote
here is some sample before and after the complete fix. Thanks To Dan for the samples.

Definitely a difference in these before-and-after...

indeed , :)
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: wave on April 28, 2014, 11:58:55 AM
Hey fellow builders,
I've been following the AMI errata since Dany sent me the email and I'm wanting to chime in. I have an AMI in my DU67 and I have A/B'd it against Tskguy's Du67 with ioaudio's trafo. We both have the same other components including HK-67 capsules. Our 2 mics are so close they could be a matched pair. We have both thought this since they were built in 2012.

That being said, I home etched my T67 adapter pcb as Dany's was not yet available at the time (this was very early on in development) I feel like when I look at photos of the fabricated pcb it's slightly different from my layout.

Any thoughts on this?

Dave
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 28, 2014, 01:01:21 PM
Hey fellow builders,
I've been following the AMI errata since Dany sent me the email and I'm wanting to chime in. I have an AMI in my DU67 and I have A/B'd it against Tskguy's Du67 with ioaudio's trafo. We both have the same other components including HK-67 capsules. Our 2 mics are so close they could be a matched pair. We have both thought this since they were built in 2012.

That being said, I home etched my T67 adapter pcb as Dany's was not yet available at the time (this was very early on in development) I feel like when I look at photos of the fabricated pcb it's slightly different from my layout.

Any thoughts on this?





Dave

The PCB kit for Max transformer has never changed since its apparition and it has been checked over and over for transfomer connection and it is 100% correct,
however the AMI adaptor board has been designed with all the connection mirrored as i tought this would null out but the feedback winding interaction with the rest of the transformer needs all the polarity to be corrected in order to have the feedback properly working as Dan sample show the true difference between the 2 in the previous post this way everything works as it should this is only valid for the AMI T67 the adaptor board deisgn is always been the same. could you explain the slight differences ?  That would not explain why the D-67 with Max traffo in your case is closer or airier than the D-67 with the AMI traffo.
DAn,

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: wave on April 28, 2014, 01:13:49 PM
Dany,
I was referring to my AMI Du67. Eric has the ioaudio version.
If you remember, I etched my own transformer adapter pcb and I'm wondering if because of how I made the file..if mine is right.
BTW mine does look kinda like a mirror of your fabricated pcbs.

Make sense?

Dave
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 28, 2014, 01:18:17 PM
Hi Wave,
I remember the samples you posted of your mic were fantastic - really great sounding.
Did you and tskguy every check the amplifier response for the proper rolloff?
Maybe there are capsule differences between the HK-67 and Beezneez.
Dan


Quote
Hey fellow builders,
I've been following the AMI errata since Dany sent me the email and I'm wanting to chime in. I have an AMI in my DU67 and I have A/B'd it against Tskguy's Du67 with ioaudio's trafo. We both have the same other components including HK-67 capsules. Our 2 mics are so close they could be a matched pair. We have both thought this since they were built in 2012.

That being said, I home etched my T67 adapter pcb as Dany's was not yet available at the time (this was very early on in development) I feel like when I look at photos of the fabricated pcb it's slightly different from my layout.

Any thoughts on this?

Dave
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kaguenpituak on April 28, 2014, 02:36:19 PM
Hi, I have inverted 5-12, sound very good like neumann, but not HF whit the -10pad..  :-[
I have try again the complete fix and no changes..
It is posible to modify for reduce HF??
Thanks!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 28, 2014, 02:40:10 PM
Hi, I have inverted 5-12, sound very good like neumann, but not HF whit the -10pad..  :-[
I have try again the complete fix and no changes..
It is posible to modify for reduce HF??
Thanks!

I have a hard time following here,
could you explain with a little more details what is your issue ,
Note that the correction is only for the AMI T67 wich i presume you have ,
the microphone shall be corrected in only one way wich is the 3 pair swap according to this ,

From transformer board to mic PCB

Pad 5 ----->  mic pcb pad T1212
Pad 12 -------> mic pcb pad T55
Pad 1 --------> mic pcb pad T44
Pad 4 --------> mic pcb pad T11
Pad 7 --------> mic pcb pad T1010
Pad 10 ------> mic pcb Pad T77
 
what is the issue you have with the pad,
Let me know, i will see if i can assist
Best,
DAN,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kaguenpituak on April 28, 2014, 03:20:04 PM
Yes I have the AMI t67. I have inverted the 3 pair and it is the same sound.. I have inverted only 5-12 and it sound very good, but if I put the -10 pad it sound very dark (no higth frecuencis..)
I consider (with the 3 pair swap) it is too bright..
What can I do to make it less bright?
 ;D
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 28, 2014, 05:19:43 PM
yeah somethings not right with this build.

What if we were to reverse all connections to the transformer but left the feedback connections like original the first revision.

I could be wrong but in my head the phase would be corrected and the feedback would work properly?

Has anyone thought about doing this?

Jesse
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: wave on April 28, 2014, 05:26:16 PM
Hi Wave,
I remember the samples you posted of your mic were fantastic - really great sounding.
Did you and tskguy every check the amplifier response for the proper rolloff?
Maybe there are capsule differences between the HK-67 and Beezneez.
Dan


Quote
Hey fellow builders,
I've been following the AMI errata since Dany sent me the email and I'm wanting to chime in. I have an AMI in my DU67 and I have A/B'd it against Tskguy's Du67 with ioaudio's trafo. We both have the same other components including HK-67 capsules. Our 2 mics are so close they could be a matched pair. We have both thought this since they were built in 2012.

That being said, I home etched my T67 adapter pcb as Dany's was not yet available at the time (this was very early on in development) I feel like when I look at photos of the fabricated pcb it's slightly different from my layout.

Any thoughts on this?

Dave
Dan,
Do you mean the amplifier part of the mic circuit? No we didnt get that deep. We are both using the HK-67 capsules tho. Basically everything is the same between our two mics except the trafo. I etched my own AMI adapter PCB that I think may have been mirrored. I'm def not gonna change anything cuz that mic does sound amazing...I was just wondering.

Dave
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 28, 2014, 05:29:16 PM
Hi Wave,
I remember the samples you posted of your mic were fantastic - really great sounding.
Did you and tskguy every check the amplifier response for the proper rolloff?
Maybe there are capsule differences between the HK-67 and Beezneez.
Dan


Quote
Hey fellow builders,
I've been following the AMI errata since Dany sent me the email and I'm wanting to chime in. I have an AMI in my DU67 and I have A/B'd it against Tskguy's Du67 with ioaudio's trafo. We both have the same other components including HK-67 capsules. Our 2 mics are so close they could be a matched pair. We have both thought this since they were built in 2012.

That being said, I home etched my T67 adapter pcb as Dany's was not yet available at the time (this was very early on in development) I feel like when I look at photos of the fabricated pcb it's slightly different from my layout.

Any thoughts on this?

Dave
Dan,
Do you mean the amplifier part of the mic circuit? No we didnt get that deep. We are both using the HK-67 capsules tho. Basically everything is the same between our two mics except the trafo. I etched my own AMI adapter PCB that I think may have been mirrored. I'm def not gonna change anything cuz that mic does sound amazing...I was just wondering.

Dave

did you bridge the pins on the opposite side of the transformer as to what dany bridged?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 28, 2014, 05:29:52 PM
Quote
Dan,
Do you mean the amplifier part of the mic circuit? No we didnt get that deep. We are both using the HK-67 capsules tho. Basically everything is the same between our two mics except the trafo. I etched my own AMI adapter PCB that I think may have been mirrored. I'm def not gonna change anything cuz that mic does sound amazing...I was just wondering.
Dave

Yes, I was wondering if you checked if the response followed the spec (-10 dB at 15kHz).
Good to know that the mics sounded very similar with the two different transformers though.

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 28, 2014, 05:31:36 PM
Even if the transformer was mirrored, it is symmetrical. It shouldn't make a difference.

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 28, 2014, 05:33:17 PM
If someone has a function generator and a scope, the windings could be confirmed
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: wave on April 28, 2014, 05:36:18 PM
Congrats to Wave for is really nice build 8) , Dave was involved at the very first stage of the developpment of the D-U67 microphone as you can see that he has etched his own adaptor board,  I was allowed to post picture of his new toy,  Keep us posted,  I do like the AMI transformer look  8)

(http://dl.dropbox.com/u/43869772/U67/AMIA.JPG)
(http://dl.dropbox.com/u/43869772/U67/AMIB.JPG)
Best,
Dan,
This is a photo of my etched pcb. It looks to me that mine is installed in what would be from the backside and 180 degrees rotated than Dany's production PCB...basically the black lines on the transformer are underneath the etched line markings not facing...
or maybe I'm crazy

Dave
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 28, 2014, 05:43:48 PM
Even if the transformer was mirrored, it is symmetrical. It shouldn't make a difference.

Im not sure if this is entirely the case though. it all depends on what the windings are doing inside the transformer.

I have a spare t67 here unmounted. tell me the test to do and ill do it.
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 28, 2014, 05:50:25 PM
Congrats to Wave for is really nice build 8) , Dave was involved at the very first stage of the developpment of the D-U67 microphone as you can see that he has etched his own adaptor board,  I was allowed to post picture of his new toy,  Keep us posted,  I do like the AMI transformer look  8)

(http://dl.dropbox.com/u/43869772/U67/AMIA.JPG)
(http://dl.dropbox.com/u/43869772/U67/AMIB.JPG)
Best,
Dan,
This is a photo of my etched pcb. It looks to me that mine is installed in what would be from the backside and 180 degrees rotated than Dany's production PCB...basically the black lines on the transformer are underneath the etched line markings not facing...
or maybe I'm crazy

Dave

cheers dave,

ok this is interesting.

my black markings on the transformer are under the numbers side of Dany's mount. (The same orientation as yours / top side in your lower picture). Therefore you have bridged the opposite sides of the transformer than I have.

Can you list where the cable colors end up on your main pcb please?

cheers, jesse
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on April 28, 2014, 05:56:33 PM
I would hook a 1 kHz sine wave up to the primary and then compare each of the other windings to it by looking at them on the scope. On the scope you can see if they are in phase or out of phase with respect to the primary and what the voltage levels are.
You should be able to hook it up and measure the correct voltage ratios  - primary to secondary should be 7:1 and the primary to feedback should be 22:1.

If you try this and things seemed really baked, i.e. you aren't seen clean sine waves on the seconday & feedback, then look into whether the two individual windings of the primary / secondary / feedback are out of phase with each other.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: wave on April 28, 2014, 06:02:28 PM
EDIT...I'm just gonna open it up and look. Screw the pics
Dave
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 28, 2014, 07:04:44 PM
If Oliver's transformers are symmetrical then why has he added a black mark on one side? :o
Title: Re: D-U67 Tube Microphone Build Thread.
Post by: poctop on April 28, 2014, 07:12:18 PM
Congrats to Wave for is really nice build 8) , Dave was involved at the very first stage of the developpment of the D-U67 microphone as you can see that he has etched his own adaptor board,  I was allowed to post picture of his new toy,  Keep us posted,  I do like the AMI transformer look  8)

(http://dl.dropbox.com/u/43869772/U67/AMIA.JPG)
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d02819941bb.jpg)
Best,
Dan,
This is a photo of my etched pcb. It looks to me that mine is installed in what would be from the backside and 180 degrees rotated than Dany's production PCB...basically the black lines on the transformer are underneath the etched line markings not facing...
or maybe I'm crazy

Dave

Thanks Dave yes your are not crazy,  as i did a good job (mistake) mirroring it , you install the transformer adaptor backwards or should i say the right way now, ;)
it is so fortunate that this particular model with the AMI can be rewired any way you like it  best,  ;)
but the initial intention was to connect it to this adaptor board the right wa no less,  :o
Best,
Dan,
 
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 28, 2014, 07:14:14 PM
If Oliver's transformers are symmetrical then why has he added a black mark on one side? :o

the black mark on the transfo and Pcb is to denote the polarity of the windings,
but this particular transformer cannot have the polarity all screwed up as far as i remember my last discussion with oliver cause the feedback wont work ,
 ;)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 29, 2014, 08:44:54 AM
Feedback

Since i have been looking on feedback on this wiring correction matter i did ask to some fellow member to report the status of their AMI T67 mics after the wiring corrections has been done ,

After several have confirmed the same thing i am glad to say that this case is closed,  at least for future build with the AMI T67 please follow the wiring guide in the first notice page.

here is one i received this morning ,

Quote
Hi Dan.
No the tone/frequency range sounds the same with pad on. Followed your full instructions and the mic just sounded better so much so its over taken the mk47 to be my 'go to' mic.
thanks,

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 29, 2014, 01:01:45 PM
Hi dan, don't you think we have to take into consideration the fact that not everyone might have mounted their t67 to your board the same polarity. Since it's a symmetrical pin layout, some may have mounted the black mark on the other side which would reverse the feedback ?

J
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 29, 2014, 01:13:24 PM
Hi dan, don't you think we have to take into consideration the fact that not everyone might have mounted their t67 to your board the same polarity. Since it's a symmetrical pin layout, some may have mounted the black mark on the other side which would reverse the feedback ?

J

this is a very good point , however i did include a very special note about this in the very first page of the build thread that has been there ever since I offered this PCB,
I really have to assume that folks that have built it with the AMI transformer have properly followed the instruction given for this particular matter,
here is the instruction in question from the pictorial on the first page.
Best,
Dan,


(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d02819941ce.jpg)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kaguenpituak on April 29, 2014, 04:30:59 PM
Is there any way to reduce some brightness U67? Thanks ;D
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on April 29, 2014, 08:45:11 PM
Hi dan, don't you think we have to take into consideration the fact that not everyone might have mounted their t67 to your board the same polarity. Since it's a symmetrical pin layout, some may have mounted the black mark on the other side which would reverse the feedback ?

J

this is a very good point , however i did include a very special note about this in the very first page of the build thread that has been there ever since I offered this PCB,
I really have to assume that folks that have built it with the AMI transformer have properly followed the instruction given for this particular matter,
here is the instruction in question from the pictorial on the first page.
Best,
Dan,


(http://dl.dropbox.com/u/43869772/U67/Picture%20Tron/amitrans.jpg)

I mounted it that way but Dave's is actually mounted the other way. You ask your quoted reference which way they mounted theirs

J
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: [email protected] on April 30, 2014, 01:23:40 PM
Quote
I mounted it that way but Dave's is actually mounted the other way. You ask your quoted reference which way they mounted theirs

Jess i followed all of Dans instructions from start to finish including mounting the transformer correctly. I then did the recent rewire correction he posted and my mic and switches are working as they should. Once I did the rewire i preferred the over all sound of the mic.
Hope this helps.
[email protected]
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on May 01, 2014, 03:50:20 PM
I removed the k67 from my u87ai and installed it. Cardioid only for the moment. Removed the switches. F those switches!

Couldn't get the rubber capsule mount to separate from the u87ai plastic plate... think its secured with glue on the screw. Had to use sh*tty white mount which rotates capsule slightly but I actually think its the proper orientation and the way neumann mount it is off center it seems.

I reversed all pins to the transformer as per Dany's document (which made my build now look messy as I had to extend some wires). Going to use it tonight. have a great quiet NOS Telefunken tube.

On u67 does the output cap size 0.5 - 1uf effect the feedback circuit rolloff? some schematics show 0.5 some show 1uf.

(http://www.jessjackson.com/images/u67/u67k671.jpg)

(http://www.jessjackson.com/images/u67/u67k672.jpg)

(http://www.jessjackson.com/images/u67/u67k673.jpg)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: wave on May 01, 2014, 04:04:09 PM
That is sick Jess!

Dave
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Dylan W on May 01, 2014, 06:56:59 PM
I removed the k67 from my u87ai and installed it. Cardioid only for the moment. Removed the switches. F those switches!

Jess, wondering how you got the black coloration on the back of the grille. Spraypaint? Powerdercoat? And how did you mask it?  It looks great.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 01, 2014, 07:13:34 PM
That is sick Jess!

Dave

(That is sick Jess!)*2
:)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on May 02, 2014, 01:40:20 AM
I removed the k67 from my u87ai and installed it. Cardioid only for the moment. Removed the switches. F those switches!

Jess, wondering how you got the black coloration on the back of the grille. Spraypaint? Powerdercoat? And how did you mask it?  It looks great.

Thanks, I just purchased a cheap powder coat gun off eBay and some black satin powder. I masked it with painters masking tape then shot it in cardboard box. I removed the tape carefully and used my fingernail to clear any additional powder that leaked and baked it for 30 mins in a small toaster oven I got off craigslist for $10. It Looks as good as any high end grill up close.

J
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: G-Sun on May 03, 2014, 04:35:44 AM
The D-U67 is not he easiest mic-project to jump on right?
And rather expensive as well?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on May 03, 2014, 05:54:50 AM
Not compared to a real one  ;D

Figure on around €800-1200 or so per mic, depending on capsule/transformer/tube/PSU enclosure/cable choices.

Worth it?

Yes 8)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on May 03, 2014, 06:17:20 AM
Best ever LDC mic design.
Does that count? ::)

 :P
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: G-Sun on May 03, 2014, 10:27:21 AM
Not compared to a real one  ;D
Yes, indeed
Quote

Figure on around €800-1200 or so per mic, depending on capsule/transformer/tube/PSU enclosure/cable choices.

Worth it?

Yes 8)
Good, yet still costly compared to a D-U87 or something right?

Best ever LDC mic design.
Does that count? ::)
Absolutely :)

How about difficulty and number of vendors needed?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on May 06, 2014, 04:07:24 PM
Tested, sounds great with this wiring and capsule... much much better, no de-essing needed. still bright and open and smooth, probably helped by the coupling cap type.

Still 5-6db down from vintage u67 here. smh. Not the end of the world for now though. All voltages seem good. except from r10-r11 and r12-r13 very odd.

B+ (210v)
H (-6.3v)
R12 - R13 (+49.7v)
R10 - R11 (-1.83v)
Plate (+84v)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on May 06, 2014, 04:10:17 PM
R12/13 @ 49V. Is that the backplate node? Lower voltage there would decrease sensitivity wouldn't it?

Thx,
jb
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on May 06, 2014, 04:14:59 PM
R12/13 @ 49V. Is that the backplate node? Lower voltage there would decrease sensitivity wouldn't it?

Thx,
jb

yeah exactly. It should be 59v which should continue on to remain 59v at the capsule. I'm pretty sure this is my reason for decreased output / sensitivity but my b+ is 210v exactly measured at the mic.

Can someone else measure the same point on your mics please? my bias seem ok at the top end -1.8v

Cheers

Jesse
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 06, 2014, 04:28:27 PM
R12/13 @ 49V. Is that the backplate node? Lower voltage there would decrease sensitivity wouldn't it?

Thx,
jb

yeah exactly. It should be 59v which should continue on to remain 59v at the capsule. I'm pretty sure this is my reason for decreased output / sensitivity but my b+ is 210v exactly measured at the mic.

Can someone else measure the same point on your mics please? my bias seem ok at the top end -1.8v

Cheers

Jesse

great news Jess ,  did you check your polarisation divider to see if they match ,
Let me know,
Dany,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on May 06, 2014, 05:11:34 PM
Quote
Tested, sounds great with this wiring and capsule... much much better, no de-essing needed. still bright and open and smooth, probably helped by the coupling cap type.

Good news!

Quote
Still 5-6db down from vintage u67 here.

IME the tube alone could account for that.
They vary a lot.


Henk
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on May 06, 2014, 05:57:46 PM
Quote
R12 - R13 (+49.7v)

The impedance of your multimeter can cause the voltage at this point to drop noticeably, if the meter impedance is on the order of 1-10 Mohm.


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on May 06, 2014, 06:07:45 PM
So a quick calc, neglecting the -1.8v at the end of the divider

v ~=210*(2.2M)/(2.2M+2.2M+3.3M) = 60

When you measure this, the impedance of the meter is in parallel with R12 to ground

v ~=210*(Rm||2.2M)/(Rm||2.2M+2.2M+3.3M)

I did this in a spreadsheet and if the meter impedance is 7M, the voltage drops to 49v

If you use a lower impedance meter the voltage would drop even more.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on May 06, 2014, 08:24:08 PM
So a quick calc, neglecting the -1.8v at the end of the divider

v ~=210*(2.2M)/(2.2M+2.2M+3.3M) = 60

When you measure this, the impedance of the meter is in parallel with R12 to ground

v ~=210*(Rm||2.2M)/(Rm||2.2M+2.2M+3.3M)

I did this in a spreadsheet and if the meter impedance is 7M, the voltage drops to 49v

If you use a lower impedance meter the voltage would drop even more.

Thanks brother! Really appreciate these calculations although I am actually using a fluke 115 multimeter which states a rated max impedance of 30meg but I've tested 40meg resistors on it no problem.

So where does this leave me?

Cheers.

Jesse
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on May 06, 2014, 09:02:59 PM
With 30 Mohm, the voltage will only drop a couple volts. Not sure why the voltage is low. Could a resistor be wrong?
You might have to start pulling components to figure out the problem.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: baadc0de on May 07, 2014, 12:05:03 AM
Quick question from the side.. has anyone tested both ioaudio and Oliver's transformer offerings and could weigh in if there is a significant difference between the two?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on May 07, 2014, 12:53:26 AM
With 30 Mohm, the voltage will only drop a couple volts. Not sure why the voltage is low. Could a resistor be wrong?
You might have to start pulling components to figure out the problem.

Thanks bro, I'm going to run some more voltage tests in a moment when i get a minute to open it up ;)

Jesse
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: wave on May 07, 2014, 12:22:18 PM
Quick question from the side.. has anyone tested both ioaudio and Oliver's transformer offerings and could weigh in if there is a significant difference between the two?
Tskguy and I have done this and we both thought they were very similar. That being said IMO ioaudio's trafo is slightly less saturated in the bottom.


Dave
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kaguenpituak on May 11, 2014, 03:31:36 PM
It is posible to modify  to have a little less brightness? Only a little.. Thanks ;)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kaguenpituak on May 12, 2014, 04:50:30 PM
I have a problem :(, I have a lot of interferences around 6-8k .. with the u87 and u47 (diy) not have. How I can remove? thanks ;)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 16, 2014, 11:11:38 AM
I have a problem :(, I have a lot of interferences around 6-8k .. with the u87 and u47 (diy) not have. How I can remove? thanks ;)

what kind of capsule did you put in,  interference ? if using AMI T67 hoping you have made the proper wiring correction,
as recommended ,
best,
dAn,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kaguenpituak on May 16, 2014, 04:29:32 PM
I have 2 units, one with peluso k67 and another with mparts 67. The interference is caused by a lift (elevator).. in my u47 diy is less listenable, and not listenable in my u87.. I have conected the t67 correctly ;) Thanks
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 16, 2014, 05:02:48 PM
I have 2 units, one with peluso k67 and another with mparts 67. The interference is caused by a lift (elevator).. in my u47 diy is less listenable, and not listenable in my u87.. I have conected the t67 correctly ;) Thanks

wich one is problematic ?

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kaguenpituak on May 16, 2014, 05:07:59 PM
Both...
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on May 16, 2014, 06:00:02 PM
Quote
I have a problem :(, I have a lot of interferences around 6-8k .. with the u87 and u47 (diy) not have. How I can remove? thanks ;)

Sounds like poor grounding / shielding
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kaguenpituak on May 17, 2014, 01:46:50 AM
Quote
I have a problem :(, I have a lot of interferences around 6-8k .. with the u87 and u47 (diy) not have. How I can remove? thanks ;)

Sounds like poor grounding / shielding

Yes, I've already checked grounding. I have also tried wrapping in foil microphone and psu. I tried to put ferrite filters. Can it be more sensitive to interference circuit? I have found that the interference creates a lift (elevator). The beep lasts between 3 seconds and 20 seconds,it is between 6khz and 8 kHz and it is intermittent. Thanks ;D
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: stitch-o on May 18, 2014, 03:43:20 PM
Hello all!

I have completed a D67 build - Beezknees capsule, Max's IO transformer and NOS Valvo EF86.
Recently had the mic into a studio to test against a pair of immaculate and very-well conditioned
original U67s. The U67s sounded almost matched in their sound.
First the good - the mic sounds really good in general. Very low noise floor and big sounding.

The D67 had 3 differences -
1) roughly 6dB more of gain - I have emailed studio owner to confirm that the originals are
wired for 30/50 Ohm output as opposed to IO's 250. This would account for the gain discrepancy.
2) Very bassy with a pronounced proximity effect - I am using the Chinese S body suggested.
It definitely rings. I will felt the internal vertical bars and possibly silicone the bottom piece.
Would adding felt to the bottom of the headbasket also possibly help this issue?

3) Biggest thing - Noticeably dull in comparison with the originals. Both originals had the characteristic
"air" and highend articulation U67s are well known for. The D67 seemed veiled and dull, as said.

I have been studying this build thread for possible tweaks but it doesn't seem like anyone has
resolved this dullness issue....or am I missing something....

Cheers and thanks for everyone (especially Dany, what a great catalog of work!!) and their time!

-s
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Dylan W on May 18, 2014, 09:07:50 PM
Did you confirm that the U 67s have the filter intact and have not had the capsules modded (Stephen Paul mod, etc)?

Did you try swapping tubes between the DU-67 and U 67? In my testing, different models of EF86 seem to make a subtle, though noticable, difference in the "tonal balance" of the mic, especially up top.

Hello all!

I have completed a D67 build - Beezknees capsule, Max's IO transformer and NOS Valvo EF86.
Recently had the mic into a studio to test against a pair of immaculate and very-well conditioned
original U67s. The U67s sounded almost matched in their sound.
First the good - the mic sounds really good in general. Very low noise floor and big sounding.

The D67 had 3 differences -
1) roughly 6dB more of gain - I have emailed studio owner to confirm that the originals are
wired for 30/50 Ohm output as opposed to IO's 250. This would account for the gain discrepancy.
2) Very bassy with a pronounced proximity effect - I am using the Chinese S body suggested.
It definitely rings. I will felt the internal vertical bars and possibly silicone the bottom piece.
Would adding felt to the bottom of the headbasket also possibly help this issue?

3) Biggest thing - Noticeably dull in comparison with the originals. Both originals had the characteristic
"air" and highend articulation U67s are well known for. The D67 seemed veiled and dull, as said.

I have been studying this build thread for possible tweaks but it doesn't seem like anyone has
resolved this dullness issue....or am I missing something....

Cheers and thanks for everyone (especially Dany, what a great catalog of work!!) and their time!

-s
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: stitch-o on May 18, 2014, 09:12:43 PM
Hi Dylan
Thanks for the reply.
The Capsule is a new BeezKneez U67 repro capsule unmolested.
I am looking at getting a few more EF86s when I can afford it.
Of course the ones Im looking at (GEC, Telefunken) are pricey...
FWIW: From my research, the valvo are the original models in the early U67s.
Dont think my friend would take kindly to me pulling apart his U67s... :o

The dullness of topend seems like it might be a combination of tweaking C17 value and tube?
But other here have expressed the same results.

Did you confirm that the U 67s have the filter intact and have not had the capsules modded (Stephen Paul mod, etc)?

Did you try swapping tubes between the DU-67 and U 67? In my testing, different models of EF86 seem to make a subtle, though noticable, difference in the "tonal balance" of the mic, especially up top.

Hello all!

I have completed a D67 build - Beezknees capsule, Max's IO transformer and NOS Valvo EF86.
Recently had the mic into a studio to test against a pair of immaculate and very-well conditioned
original U67s. The U67s sounded almost matched in their sound.
First the good - the mic sounds really good in general. Very low noise floor and big sounding.

The D67 had 3 differences -
1) roughly 6dB more of gain - I have emailed studio owner to confirm that the originals are
wired for 30/50 Ohm output as opposed to IO's 250. This would account for the gain discrepancy.
2) Very bassy with a pronounced proximity effect - I am using the Chinese S body suggested.
It definitely rings. I will felt the internal vertical bars and possibly silicone the bottom piece.
Would adding felt to the bottom of the headbasket also possibly help this issue?

3) Biggest thing - Noticeably dull in comparison with the originals. Both originals had the characteristic
"air" and highend articulation U67s are well known for. The D67 seemed veiled and dull, as said.

I have been studying this build thread for possible tweaks but it doesn't seem like anyone has
resolved this dullness issue....or am I missing something....

Cheers and thanks for everyone (especially Dany, what a great catalog of work!!) and their time!

-s
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Dylan W on May 18, 2014, 10:19:28 PM
I was thinking more about the capsules in your friend's U 67s. There are a lot of modded mics out there... some U 67s have had capsules rediaphragmed with thinner material, which significantly affects the top end response. Some have had the filters disabled or modified. Not that this is necessarily the case with your friend's mic, but I don't think you can make an accurate comparison until you know you're working 1:1.

You should also swap the same tubes back and forth if you can, or at least find out what's in your friend's mics.

Hi Dylan
Thanks for the reply.
The Capsule is a new BeezKneez U67 repro capsule unmolested.
I am looking at getting a few more EF86s when I can afford it.
Of course the ones Im looking at (GEC, Telefunken) are pricey...
FWIW: From my research, the valvo are the original models in the early U67s.
Dont think my friend would take kindly to me pulling apart his U67s... :o

The dullness of topend seems like it might be a combination of tweaking C17 value and tube?
But other here have expressed the same results.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on May 19, 2014, 04:26:04 AM
Quote
Both originals had the characteristic
"air" and highend articulation U67s are well known for.

It's sooner the opposite, actually. U67s are "known" for being dark sounding microphones, especially by modern standards. Although I personally wouldn't call them dark, airy they are not. (They do take EQ exceptionally well.)
Many (!) U67s have been altered (filters removed), though, to make them sound brighter or more "modern". Pairs included.

As for the added bass in the D67, check if S6 is jumpered. This is a key feature of the U67. Most originals have the 40 Hz roll off activated. It makes the mic less prone to proximity, popping and booming.
This is not the roll off switch (200 Hz) on the body.


Henk
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: stitch-o on May 19, 2014, 10:20:16 AM
Hi guys, thanks for the replies,
-Yes the mics are unmolested and in original condition.

-This Jumper?
(http://s30.postimg.org/5vmthcwkh/photo.jpg)


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mickdundee63 on May 20, 2014, 05:35:46 AM
The capsule will of course make the most significant difference. I wouldn't think that a beesneez capsule would sound "dull" in comparison to the original but it will not sound exactly the same as a neumann.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: 0dbfs on May 20, 2014, 09:22:08 AM
You could use the CAL input and run plots on all of the mic's to determine whether the head-amp or the capsule is suspect.

Cheers,
jb
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 20, 2014, 09:29:18 AM
Important Info

Hi All,  I had a lot of "feedback" regarding the IOaudio transformer configuration for this build and all reported that they had a rather dark microphone ,
this weekend i reskinned some vintage original neumann capsule and finished wrapping up the a D-U67 i have also at home with tele ef86 and IOaudio transformer
and it sounded pretty dark as well,  all reported the same thing with this transformer and i can assure that the De-emphasis is working 100% on this one , in comparaison with what i had handy IE a D-M269c with AMI T67 corrected wiring and a vintage neumann capsule that i reskinned , and it was night and day, i will post sample here soon when i have some time , but it was just awesomely airy and sweet in comparaison with the IOaudio config,  So at this point in time I stronlgy beleive that the resulting sound of the D-67 with IOaudio transformer will sound pretty dark in comparaison with the AMI transformer Since IOaudio transfomer is also pretty lowd end ish it contributes to a more present proximity effect,.  all thing beeing equals i have gathered this feedback for a long time now and there is nothing wrong with those mic , .... it is the way this transformer (IOaudio) sounds afterall in this mic, and there is nothing negative about that dont get me wrong,  those who prefer the darker sound just need to install an IOaudio trannie and those who would like to have the airy thing of the original U67 goes with AMI,
i have heard of no one complaining about a dark mic with the AMI and with the wiring correction for the feedback to work properly the air is just right where it supposed to be,  tweaking the C17 wont affect much the sound of the IOaudio transformer its just the way it sounds.

i would invite anyone here to comment on this topics .

Best To All,
Dany,



 
 

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on May 20, 2014, 09:54:40 AM
Isn't the M269 an inherently brighter microphone than a U67?

Thanks for your work on this Dany.

Peace

Jim
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: stitch-o on May 20, 2014, 10:00:46 AM
Hi Dan,
Thanks for the astounding amount of dedication to this project!
And to be fair: YES, the mic as is sounds VERY good.
My bar is just a bit more finicky as this mic was being built for a client who want
an exact (as possible) reproduction of a U67 and has used and had access to the best conditioned ones. The IO transformer obviously doesn't quite deliver that sound.

So two questions: is this a matter of tuning of parts around the IO transformer to
tweak the response or should I look to replace the transformer with an AMI brand?
Second - if I do go with the AMI transformer, but already have PCBs for the IO,
is there any way to make the AMI transformer work in this configuration?

CHEERS and many many thanks!!

-s
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 20, 2014, 10:03:00 AM
Isn't the M269 an inherently brighter microphone than a U67?

Thanks for your work on this Dany.

Peace

Jim

yes indeed it is but from my experience with both D-67 at some time conclusion is the same + plus i never had a comment on AMI transformer setup that sounded dark
only a tad too bright before with the help of this community we figured out that the  transformer was wired wrong. after that it was perfect
, in this case with the M269c the evidence is just multiplied by a factor 2.
Best,
DAn,

Dan,
 

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 20, 2014, 10:05:25 AM
Hi Dan,
Thanks for the astounding amount of dedication to this project!
And to be fair: YES, the mic as is sounds VERY good.
My bar is just a bit more finicky as this mic was being built for a client who want
an exact (as possible) reproduction of a U67 and has used and had access to the best conditioned ones. The IO transformer obviously doesn't quite deliver that sound.

So two questions: is this a matter of tuning of parts around the IO transformer to
tweak the response or should I look to replace the transformer with an AMI brand?
Second - if I do go with the AMI transformer, but already have PCBs for the IO,
is there any way to make the AMI transformer work in this configuration?

CHEERS and many many thanks!!

-s

IMHO you will need an AMI PCB and then you will be able to reach what you were hoping and  need,
Best,
Dan,

Thanks To dandeurloo a  sound sample with the AMI T67 corrected wiring,
this is what you can expect with this ,

https://io.groupdiy.com/file/gdiy-2017/u/39511/58d02819941dd.wav

Best,
Dan,

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on May 20, 2014, 12:53:09 PM
Quote
Isn't the M269 an inherently brighter microphone than a U67?

-c version, yes (self bias); -b version, no (fixed bias, like the U67).
From what I know.
But an AC710 tube doesn't sound exactly like an EF86, of course.

They all have the de-emphasis circuit, mind. That includes the M269c.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: stitch-o on May 20, 2014, 04:09:52 PM
DANY RAWKS!!!

Thank you again for all your amazing attention to detail and work.
I hope to make a pair of ELAMs if the money tree starts flowering... ;D ;D

Cheers!

-s

Hi Dan,
Thanks for the astounding amount of dedication to this project!
And to be fair: YES, the mic as is sounds VERY good.
My bar is just a bit more finicky as this mic was being built for a client who want
an exact (as possible) reproduction of a U67 and has used and had access to the best conditioned ones. The IO transformer obviously doesn't quite deliver that sound.

So two questions: is this a matter of tuning of parts around the IO transformer to
tweak the response or should I look to replace the transformer with an AMI brand?
Second - if I do go with the AMI transformer, but already have PCBs for the IO,
is there any way to make the AMI transformer work in this configuration?

CHEERS and many many thanks!!

-s

IMHO you will need an AMI PCB and then you will be able to reach what you were hoping and  need,
Best,
Dan,

Thanks To dandeurloo a  sound sample with the AMI T67 corrected wiring,
this is what you can expect with this ,

https://dl.dropboxusercontent.com/u/43869772/U67/Feedback%20winding%20Correction/Corrected.wav

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: ruairioflaherty on May 20, 2014, 11:12:15 PM
I don't have a horse in the AMI vs IOAudio transformer race but I've owned a U67 for years and used quite a few, both original and the early 90s re-issue.  U67s are not known for being bright or airy, they are also not know for being dark.  A working u67 is wonderfully balanced and has great mid range body and detail, it can take eq really well and if you want airy you just open it up with eq.

I just wanted to point that out for those that have never used one or heard and original.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: stitch-o on May 20, 2014, 11:30:08 PM
Because of the semantic nature of many of these recent response/posts, I'll say I too have used a few U67s.
They have a defined and articulated high end.
I used the word airy because in direct comparison to the two immaculate original U67s -
the IO audio D67 sounded dark and the U67s sounded like there was a distinct high end extension and articulation not present in the IO audio fitted D67, confirmed by two other engineers beside myself.
I called it 'airy'. Guess that word stuck in some jowls... :-X (see tag)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on May 21, 2014, 04:03:10 AM
I hear you.  :)

And I'll repeat that I personally don't consider the U67 a dark microphone.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: ruairioflaherty on May 21, 2014, 12:44:54 PM
Because of the semantic nature of many of these recent response/posts, I'll say I too have used a few U67s.
They have a defined and articulated high end.
I used the word airy because in direct comparison to the two immaculate original U67s -
the IO audio D67 sounded dark and the U67s sounded like there was a distinct high end extension and articulation not present in the IO audio fitted D67, confirmed by two other engineers beside myself.
I called it 'airy'. Guess that word stuck in some jowls... :-X (see tag)

As I say I don't have a opinion on the transformer issue, it seems people are losing hi end somewhere.  If you are saying that the 67s you heard were airy next to non functioning mics then I guess that makes sense but in the wider mic world a 67 is not airy. 

It's not a big deal at all but I'm thinking about builders out there who won't have access to originals, if they are expecting a very open top end they might think they have an issue when they don't.

In very broad terms -
Dark - AEA R84, Beyer
Neutral/balanced - U67/U47
Bright/Airy - Manley Reference, C12/24, C251
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: stitch-o on May 21, 2014, 12:51:56 PM
I think you meant the ELAM251. I've used those, and original C12's, and RCAs and everything you have mentioned.
Again, the D67 with the IO transformer is NOT non-functioning. It function's fine.
Again, in comparison of orig....eh, whatever   :-X

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: ruairioflaherty on May 21, 2014, 12:55:36 PM
Yes Elam!  Sorry, no green tea yet.

I'll stay out of the transformer conversation, I haven't read enough to even know what's going on.

I spent some time really looking inside my 67 yesterday, perhaps one day I'll build it a brother.

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mickdundee63 on May 22, 2014, 02:56:34 AM
On a (sorta) related point – I have the AMI board and have stuffed it ready to go but ended up getting the AMI BV12 classic which I understand is a drop in replacement for the original tranny and so wound the same way. Is there going to be a workaround with the AMI tranny board or if the IOaudio tranny is also a drop in replacement should I just re-order the ioaudio board, dremel off the transformer portion and re-wire the severed traces?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 22, 2014, 08:55:51 AM
On a (sorta) related point – I have the AMI board and have stuffed it ready to go but ended up getting the AMI BV12 classic which I understand is a drop in replacement for the original tranny and so wound the same way. Is there going to be a workaround with the AMI tranny board or if the IOaudio tranny is also a drop in replacement should I just re-order the ioaudio board, dremel off the transformer portion and re-wire the severed traces?

If you have Have Stuff the AMI board this one is made to have room for an external transformer just install the transformer in the cavity wihout the AMI adaptor board and wire it to the main mic pad as per the corrrected wiring note and you should be able to go ,
Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kaguenpituak on May 25, 2014, 08:32:20 AM
I have placed with a switchboard the possibility of putting in parallel with the transformer of exit a small condenser. This way I make  less brilliant u67 (Ami) if I wish it:)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: kaguenpituak on May 25, 2014, 08:37:13 AM
I had ground connected across the plug to electrical net and across the xlr (3pin). Due to it the electromagnetic interference was appearing :)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mickdundee63 on June 08, 2014, 11:41:45 PM

This is AMIs BV12C transformer. I have requested a data sheet but haven't heard anything back - has anyone installed one before? As you can see in the picture the wires are arranged

white ------------ blue
         ------------black
yellow------------red

grey  ------------white
        ------------black
green------------orange

I'm operating on assumptions: the left hand side is the primary so yellow and grey should be linked and green and white used - polarity i'm not sure but have to hope that the physical orientation has been setup to match the schematic. The blacks are to be grounded, blue and white are audio same as in the original schematic and therefore red and orange are the feedback windings.

Anyone able to offer any guidance?

(http://s21.postimg.org/k76qu423r/bv12c.jpg)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on June 09, 2014, 07:55:47 AM

This is AMIs BV12C transformer. I have requested a data sheet but haven't heard anything back - has anyone installed one before? As you can see in the picture the wires are arranged

white ------------ blue
         ------------black
yellow------------red

grey  ------------white
        ------------black
green------------orange

I'm operating on assumptions: the left hand side is the primary so yellow and grey should be linked and green and white used - polarity i'm not sure but have to hope that the physical orientation has been setup to match the schematic. The blacks are to be grounded, blue and white are audio same as in the original schematic and therefore red and orange are the feedback windings.

Anyone able to offer any guidance?

(http://s21.postimg.org/k76qu423r/bv12c.jpg)

you need to ask Oliver a complete and exhaustive datasheet on this one ,
as i understand this is the wired version of the T67 but I have never used it before ,
you could take a DMM and start measuring DCR to know more but you also need to know the polarity on this one as it is important for final wiring ,
Please when you have it please post it here as well,
Best,
dAN,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on June 09, 2014, 01:56:52 PM

This is AMIs BV12C transformer. I have requested a data sheet but haven't heard anything back - has anyone installed one before? As you can see in the picture the wires are arranged

white ------------ blue
         ------------black
yellow------------red

grey  ------------white
        ------------black
green------------orange

I'm operating on assumptions: the left hand side is the primary so yellow and grey should be linked and green and white used - polarity i'm not sure but have to hope that the physical orientation has been setup to match the schematic. The blacks are to be grounded, blue and white are audio same as in the original schematic and therefore red and orange are the feedback windings.

Anyone able to offer any guidance?

(http://s21.postimg.org/k76qu423r/bv12c.jpg)

you need to ask Oliver a complete and exhaustive datasheet on this one ,
as i understand this is the wired version of the T67 but I have never used it before ,
you could take a DMM and start measuring DCR to know more but you also need to know the polarity on this one as it is important for final wiring ,
Please when you have it please post it here as well,
Best,
dAN,

here is the documentation you requested,

https://io.groupdiy.com/file/gdiy-2017/u/39511/58d028199420e.pdf

Best,
dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on June 10, 2014, 10:06:57 PM
I built a u67 inside a u87ai last month using that bv12, the mic sounds COMPLETELY different to the du67 with t67 in a GREAT way. i don't know why but ill make a separate post v soon! at the moment i'm loving this mic.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on June 11, 2014, 04:27:54 AM
Quote
I built a u67 inside a u87ai last month

Interesting.

Did you use Dany's PCB, and if so, how did you make it fit?

Also, did you use the U87ai's capsule?

Henk
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on June 11, 2014, 06:06:05 AM
Quote
I built a u67 inside a u87ai last month

Interesting.

Did you use Dany's PCB, and if so, how did you make it fit?

Also, did you use the U87ai's capsule?

Henk

Hi henk,

I built it all point to point on perfboard from scratch as a almost identicle to original u67.

I measured all internals of original using digital calipers. Used danys psu though. I used the original hwadbasket and capsule. Just changed the low cut cap value as per u67 but added ground pin hookup to pass through to headbasket like u87ai

Best

J
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on June 11, 2014, 06:47:57 AM
Cool, Jess!

Be prepared, though.
Once the word spreads, your inbox a.o.t. might overload quickly.



Henk
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on June 11, 2014, 09:23:09 AM
I built a u67 inside a u87ai last month using that bv12, the mic sounds COMPLETELY different to the du67 with t67 in a GREAT way. i don't know why but ill make a separate post v soon! at the moment i'm loving this mic.

Do you mean you have built it with this new Classic Series BV12 From Oliver ?

LEt me know ,
Best,
DAn,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: MetalD on June 11, 2014, 12:30:50 PM
I built it all point to point on perfboard from scratch as a almost identicle to original u67.

I measured all internals of original using digital calipers. Used danys psu though. I used the original hwadbasket and capsule. Just changed the low cut cap value as per u67 but added ground pin hookup to pass through to headbasket like u87ai

Best

J

I think we're going to need to see some pictures because that sounds awesome and I want to see
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mickdundee63 on June 16, 2014, 10:42:13 AM

This is AMIs BV12C transformer. I have requested a data sheet but haven't heard anything back - has anyone installed one before? As you can see in the picture the wires are arranged

white ------------ blue
         ------------black
yellow------------red

grey  ------------white
        ------------black
green------------orange

I'm operating on assumptions: the left hand side is the primary so yellow and grey should be linked and green and white used - polarity i'm not sure but have to hope that the physical orientation has been setup to match the schematic. The blacks are to be grounded, blue and white are audio same as in the original schematic and therefore red and orange are the feedback windings.

Anyone able to offer any guidance?

(http://s21.postimg.org/k76qu423r/bv12c.jpg)

you need to ask Oliver a complete and exhaustive datasheet on this one ,
as i understand this is the wired version of the T67 but I have never used it before ,
you could take a DMM and start measuring DCR to know more but you also need to know the polarity on this one as it is important for final wiring ,
Please when you have it please post it here as well,
Best,
dAN,

here is the documentation you requested,

https://dl.dropboxusercontent.com/u/43869772/U67/BV12.pdf

Best,
dan,

Perfect. Thankyou Dan. I am installing this very soon in a DU-67 then just have to sort a tube. I am V jealous of Jess Jackson's p2p model. I instead have smashed a KK87 capsule and head basket on an sty-5 body. Oh boy will it be ugly :). I am also building a second with standard sty-5 body/head grill and t67 transformer so will be interesting to hear the difference.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on June 16, 2014, 10:59:50 AM

This is AMIs BV12C transformer. I have requested a data sheet but haven't heard anything back - has anyone installed one before? As you can see in the picture the wires are arranged

white ------------ blue
         ------------black
yellow------------red

grey  ------------white
        ------------black
green------------orange

I'm operating on assumptions: the left hand side is the primary so yellow and grey should be linked and green and white used - polarity i'm not sure but have to hope that the physical orientation has been setup to match the schematic. The blacks are to be grounded, blue and white are audio same as in the original schematic and therefore red and orange are the feedback windings.

Anyone able to offer any guidance?

(http://s21.postimg.org/k76qu423r/bv12c.jpg)

you need to ask Oliver a complete and exhaustive datasheet on this one ,
as i understand this is the wired version of the T67 but I have never used it before ,
you could take a DMM and start measuring DCR to know more but you also need to know the polarity on this one as it is important for final wiring ,
Please when you have it please post it here as well,
Best,
dAN,

here is the documentation you requested,

https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281994237.pdf

Best,
dan,

Perfect. Thankyou Dan. I am installing this very soon in a DU-67 then just have to sort a tube. I am V jealous of Jess Jackson's p2p model. I instead have smashed a KK87 capsule and head basket on an sty-5 body. Oh boy will it be ugly :). I am also building a second with standard sty-5 body/head grill and t67 transformer so will be interesting to hear the difference.

Not Sure if understand the Smashed KK87 capsule or the syt-5 mic ,  did you dropped it if so i am sorry for you ,
if you do have a KK87 make sure you have the backplate shorted togheter to render it in a K67 style capsule ,

you will also need a schematic complement of the AMI pcb pad connection to make sure you wire te new BV12 transfo correcty , i will post it later tonight for you ,
as per the T67 please consult the first page for proper corrected wiring for the feedback loop to work correclty.


Best,
dan,


 
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mickdundee63 on June 17, 2014, 03:02:07 AM
No that is just my colourful language the kk87 isn't broken i just mean it looks a bit awkward with the two put together as they are a bit of a mismatch. I do know to short the backplates together and thanks very much for posting the AMI pcb pad document later.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on June 17, 2014, 08:23:11 AM
Hi All,  This is the Pad transformer relationship for the AMI transformer on the AMI mic pcb , if you have looked upon the datasheet i have just published there is an error on the specsheet from Oliver there is actually an inversion on the 2nd audio tap from  his datasheet i will get in touch with him today to ask him to correct that one the 2 black wire from the transformer will be grounded as those one are the core shield

the pad number on the mic pcb will used to wire the transformer accordingly.

(https://dl.dropboxusercontent.com/u/43869772/U67/AMI%20transformer%20Mic%20PCB%20Hookup.jpg)





(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d028199425d.jpg)

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mickdundee63 on June 17, 2014, 09:49:42 PM
The data sheet also lists two grey wires and one white whereas the transformer has one grey wire and two white.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: OPR on June 17, 2014, 11:21:36 PM
I just wanted to thank you Dan For another awesome Project!! The 67 is heavenly!! 8)

(https://scontent-b-hkg.xx.fbcdn.net/hphotos-xfp1/l/t1.0-9/10393979_663365533740658_4259943446879154896_n.jpg)
(https://scontent-a-hkg.xx.fbcdn.net/hphotos-xpa1/t1.0-9/10359532_662787363798475_6318633315995045372_n.jpg)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on June 18, 2014, 02:46:32 PM
The data sheet also lists two grey wires and one white whereas the transformer has one grey wire and two white.

i'll show you what i did to hook up the bv12. who knows.. we may have feedback backwards! lmao
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mickdundee63 on June 19, 2014, 02:29:49 AM
The data sheet also lists two grey wires and one white whereas the transformer has one grey wire and two white.

i'll show you what i did to hook up the bv12. who knows.. we may have feedback backwards! lmao

That just means your mic could get even better ;). I would appreciate your hookup info and hopefully all will be clarified with a corrected data sheet.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Graph on July 10, 2014, 03:25:58 AM
Hi, i have finished some months ago the D87 project, and i really love how it sounds :)

I was looking and make a tube mic, and decided for the D67. I wanted to know, which transformer is better? BV12 from AMI(the expensive option), from IOAudio(not so expensive) or T67 from AMI(the cheap one)?

And another question: D87 was pretty easy going project. Well.. i didnt run out in any several problem, it started worked with no issues. Is the D67 more difficult to build?

Thanks :)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mickdundee63 on July 11, 2014, 07:20:02 AM
Hi, i have finished some months ago the D87 project, and i really love how it sounds :)

I was looking and make a tube mic, and decided for the D67. I wanted to know, which transformer is better? BV12 from AMI(the expensive option), from IOAudio(not so expensive) or T67 from AMI(the cheap one)?

And another question: D87 was pretty easy going project. Well.. i didnt run out in any several problem, it started worked with no issues. Is the D67 more difficult to build?

Thanks :)

There is actually two BV12 versions from AMI as well. One has NOS laminations and is more expensive. From memory the "Classic" model uses new lamination material and is around 300 - 350 USD whereas the authentic version with NOS lams is more like 500 USD. AFAIK no one has used the AMI BV12 in the D-U67 although Jessjackson used one in a P2P U67 build. As soon as I get my tubes in and the correct data sheet I will install one and do a comparison with a T67 D-U67. As for Iaudio v t67 I think the consensus is that neither is significantly better. They both give a slightly different flavour that is possibly less important to the final sound than your choice of tube and capsule.

The D67 is certainly more difficult but not significantly so. You also need to build a power supply so it's a lengthier build.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Graph on July 12, 2014, 04:12:07 AM
Thank you! No problem, i have already made several projects :) what really bothers me is the chance to make a simple mistake and connect the wires incorrectly so everything might blow up :P

But, is it possible to use the BV12(the 300-350, not with laminated NOS) in this build right? It fits correctly?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: wave on July 15, 2014, 01:37:28 PM
Hi, i have finished some months ago the D87 project, and i really love how it sounds :)

I was looking and make a tube mic, and decided for the D67. I wanted to know, which transformer is better? BV12 from AMI(the expensive option), from IOAudio(not so expensive) or T67 from AMI(the cheap one)?

And another question: D87 was pretty easy going project. Well.. i didnt run out in any several problem, it started worked with no issues. Is the D67 more difficult to build?

Thanks :)

There is actually two BV12 versions from AMI as well. One has NOS laminations and is more expensive. From memory the "Classic" model uses new lamination material and is around 300 - 350 USD whereas the authentic version with NOS lams is more like 500 USD. AFAIK no one has used the AMI BV12 in the D-U67 although Jessjackson used one in a P2P U67 build. As soon as I get my tubes in and the correct data sheet I will install one and do a comparison with a T67 D-U67. As for Iaudio v t67 I think the consensus is that neither is significantly better. They both give a slightly different flavour that is possibly less important to the final sound than your choice of tube and capsule.

The D67 is certainly more difficult but not significantly so. You also need to build a power supply so it's a lengthier build.

According to AMI's website there is a BV12 with NOS lams and the T67.
The BV8 comes in modern lams and NOS lams...

http://www.tab-funkenwerk.com/id53.html

I built my DU67 with the T67 and I think it sounds great!

-Wave
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mickdundee63 on July 18, 2014, 11:33:44 PM
The other product is called the BV12 classic. It's not on their main price list page yet. You can see it in the photos above. It can be used in this build but it's not as straightforward as using the T67.

Shouldn't be too difficult once we have the corrected data sheet - any movement on that Dan?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on July 19, 2014, 11:16:23 AM
The other product is called the BV12 classic. It's not on their main price list page yet. You can see it in the photos above. It can be used in this build but it's not as straightforward as using the T67.

Shouldn't be too difficult once we have the corrected data sheet - any movement on that Dan?

i would suggest using the AMI adaptor board and drill 2 holes for mouting the transformer on it :)
as per the error on the datasheet all it is is the inversion of the original referenced color from the neumann schematic on the second audio tap on the left side it should be white and green but his color are correct,

if you compare the datasheet above from oliver and this piture it will be clear,

(https://dl.dropboxusercontent.com/u/43869772/U67/MaxBV12%20Parrallele.jpg)

SpecSheet for the New BV12 Classic Series From AMI https://io.groupdiy.com/file/gdiy-2017/u/39511/58d02819942d5.pdf

let me know if it helps,
Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mickdundee63 on July 20, 2014, 05:15:52 AM
OK so it's only the original neumann colours in brackets that are wrong. So to be sure: the second audio tap blue wire on the AMI BV12 transformer has the polarity dot (green on the original schematic) and is 9 on the DU67 schematic?

My other problem is that the data sheet lists two grey wires and one white whereas the physical transformer has two whites and one grey. One of the white's has continuity with the green so I'm presuming this is the audio tap and the other white is the grey on the data sheet if that makes sense.

Also just to clarify - If I wire the AMI BV12 to the AMI t67 board i should still use the corrected wiring hookup (and NOT the original wiring hookup) as the error discovered was in the board not the t67 transformer, so the error will still be present with the BV12 if using the t67 board.

I realise I don't need to use the t67 pcb for wiring purposes but I think it will make it simpler for me.

Thanks for all your help looking forward to finishing soon!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on July 20, 2014, 11:20:53 AM
OK so it's only the original neumann colours in brackets that are wrong. So to be sure: the second audio tap blue wire on the AMI BV12 transformer has the polarity dot (green on the original schematic) and is 9 on the DU67 schematic?

My other problem is that the data sheet lists two grey wires and one white whereas the physical transformer has two whites and one grey. One of the white's has continuity with the green so I'm presuming this is the audio tap and the other white is the grey on the data sheet if that makes sense.

Also just to clarify - If I wire the AMI BV12 to the AMI t67 board i should still use the corrected wiring hookup (and NOT the original wiring hookup) as the error discovered was in the board not the t67 transformer, so the error will still be present with the BV12 if using the t67 board.

I realise I don't need to use the t67 pcb for wiring purposes but I think it will make it simpler for me.

Thanks for all your help looking forward to finishing soon!


you should not be using the wiring pad on the aMI adaptor board then it will just create more confusion and extra labor,
as far as i can tell the error on Oliver datasheet was just in reference to original neumann color ,
i would suggest you wire it direct to the mic pcb using this as a guide,

the pad number on the mic pcb will used to wire the transformer accordingly.

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d02819942e8.jpg)

as far as the 2 grey wire i bet Oliver could explain better , i would suggest you call directly or send an email ,
you could also use your DMM and inject a sine tone in the transformer to confirm what it is ,
maybe if you connect it the way you think it is it might just be correct as well ,
I tried contacting Oliver for this but he is extra busy lately


hope this helps,
Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mickdundee63 on July 21, 2014, 04:29:16 AM
Ok thanks Dan I will wire direct to the amplifier PCB, I'm sure it will be pretty straightforward once I have figured out the windings. I'm sure you have seen the very sad news that Oliver Archut has passed away. I will figure out the transformer by asking Jessjackson who has one wired in and by trial and error. Once I have it in and functioning I'll post the results here. Cheers.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jeannot on July 22, 2014, 12:34:07 PM
I'm very very interested by this project! do you think how long does it take to succeed?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on July 27, 2014, 06:25:51 PM
I'm very very interested by this project! do you think how long does it take to succeed?

there is actually no good answer to this one , it really depends of your understanding and soldering skills and comprehension of basic electronics and the ability to follow instruction correctly :)

but as an advice it is always better to take your time and suceed the first shot rather than go fast and spend time in debbugging mode,

Best,
Dan,


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Barton on September 13, 2014, 03:22:46 PM
I just finished my D-U67 and have a few questions.  The volume on the mic is extremely low.  To the point where I have to turn the gain on my  my mixer almost all the way up.  Below are the voltages I'm getting.  i removed the 56k resistor on the psu trim because I couldn't get any higher than about 194v  at B+ on the mic pcb.  The below measurements were measured after I removed the 56 k.

PSU Not loaded

B+ = 284v
H = -6.3v

PSU Loaded

B+ = 245v
H = -6.3v
a = 78.5V

Pin 1 = 330mV
Pin 2= 330mV
Pin 3= 1.7mV
Pin 4= -6.4 V
Pin 5 =  246V
Pin 6 =  -10.4mV
Pin 7 = -0.1 mV

FD = 0.933V
BD = 0.933V (Cardiod), 3.5V (Omni), 3.5V Fig. 8)
BCK = 7.9 V

XLR 1 = -0.2mV
XLR 2 = 347 mV
XLR 3 = 345 mV

Please heeellp.  This is driving me crazy.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mickdundee63 on September 14, 2014, 06:22:03 AM
I have twice had mics passing audio but very low. Both times it has been a capsule wiring error. Once I had one of the capsule wires shorting to ground, the other time I hadn't bridged the backplates which were isolated.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Barton on September 14, 2014, 09:05:18 AM
Well given that this is the first I've ever heard of bridging isolated backplates, I'm going to venture to guess that is the problem.  My next question will clearly indicate how new I am to this.  How do you bridge the backplates?  The capsule I have is the HK67 from tskguy.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mickdundee63 on September 14, 2014, 11:35:03 PM
Sorry that was probably misleading, you only need to bridge the backplates if they are isolated in the first place. For example, if you have Neumann's k87 capsule (built for the u87 which requires you to keep the backplates isolated) you can convert it for usage in a u67 by electrically connecting the backplates so they are no longer isolated. All this means is that you create an electrical connection between the two backplates, either with a short piece of wire between the wire terminals on the backplates of the capsule itself, or simply by connecting the wires that are attached to each backplate.

Given that tskguy produces both a 67 and an 87 capsule I'm presuming his hk67 doesn't have isolated backplates so this is unlikely to be the problem.  Hopefully someone else can confirm this.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Barton on September 15, 2014, 08:47:13 PM
Still seems that the overall volume is pretty low.  I'm running the mic through an EZ1073, which I have to set the input gain to about 60.  I have an AKG 414 EB that I've never cranked higher than about 40.  Is this usual for the U67?  The tone of the mic is good, no popping, etc., it's just that with the volume so low, you begin to pickup some of the noise from the preamp when raised to usable volumes for the mic.  I checked the capsule connections to make sure they weren't going to ground in any way.  Here's a couple of pics of the mic and psu.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Barton on September 15, 2014, 08:48:25 PM
Another pic.  Also not sure that it matters, but I'm using a JJ EF 806s tube.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Barton on September 15, 2014, 08:49:13 PM
And the PSU.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 16, 2014, 08:25:12 AM
I just finished my D-U67 and have a few questions.  The volume on the mic is extremely low.  To the point where I have to turn the gain on my  my mixer almost all the way up.  Below are the voltages I'm getting.  i removed the 56k resistor on the psu trim because I couldn't get any higher than about 194v  at B+ on the mic pcb.  The below measurements were measured after I removed the 56 k.

PSU Not loaded

B+ = 284v
H = -6.3v

PSU Loaded

B+ = 245v
H = -6.3v
a = 78.5V

Pin 1 = 330mV
Pin 2= 330mV
Pin 3= 1.7mV
Pin 4= -6.4 V
Pin 5 =  246V
Pin 6 =  -10.4mV
Pin 7 = -0.1 mV

FD = 0.933V
BD = 0.933V (Cardiod), 3.5V (Omni), 3.5V Fig. 8)
BCK = 7.9 V

XLR 1 = -0.2mV
XLR 2 = 347 mV
XLR 3 = 345 mV

Please heeellp.  This is driving me crazy.

First I would consider adding a resistor back on the B+ line to get the corret voltage on B+ if 56K is too much then go for 27K you should then be able to get the proper 210B+ with the mic connected ,

start by checking all the important voltage on the mic as well not just on psu,
measure backplate voltage before the High Meg resistor because it will fool your meter , should be arround 58V
double check the connection and check bias on tube should be somthing like 1.6V at the cathode,
double check your wiring , the D-67 is a high gain mic so there is no way you need that much of gain so somthing is defo wrong with your build ,  Make sure nothing is touching somthing it is not suppose to touch in the HZ bridge between the socket board and the main board this is a critical area and since everything is floating ......  check for cold solder at the grid point (isolation teflon pin on both side and also to the floating tube grid point.

if you can hear something , that mean you are not that far off but only a small details is preventing the output to go Glory,
verify capsule connection and make sure it is correct , you can also replace the capsule with a 50pf and inject a 1K sine tone from there and check the output to transformer then work you way down from there ,   I already had a similar problem where the tube was bad also. replace to make sure , and also use any stock capsule also to confirm that it is not a problem. Like said you are very close.....

it feels like a little something is missing or the grid connection might be touching something ,
hope this helps,
Best,
Dan,


Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Barton on September 16, 2014, 06:11:09 PM
Thanks for the help.  I ordered some different resistors for the trim which should be here in a day or so, as well as another tube.  We'll see what happens.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: friesdan on September 22, 2014, 05:46:57 PM
Hi guys, quick question here.. I don't see  a PSU lamp in the BOM or mouser cart - does anyone have a part number or recommendation? I'm getting Dan's case (realized I'm not too good a cutting square holes in metal) so hopefully it will be one which fits in the pre-cut holes, or is bigger.

Thanks so much for the project - It's the first non-chunger-tutorialized mic build I've tried, and it has been more challenging and different. I'm hoping it'll fire up once it's turned on!

Thanks!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: wave on September 25, 2014, 07:09:53 PM
Hi guys, quick question here.. I don't see  a PSU lamp in the BOM or mouser cart - does anyone have a part number or recommendation? I'm getting Dan's case (realized I'm not too good a cutting square holes in metal) so hopefully it will be one which fits in the pre-cut holes, or is bigger.

Thanks so much for the project - It's the first non-chunger-tutorialized mic build I've tried, and it has been more challenging and different. I'm hoping it'll fire up once it's turned on!

Thanks!
What kind of lamp do you want? A jewel lamp?
Also, Where are you located?

In mine I used a jewel and lamp holder from antique electronic supply and got a lamp that runs off of 120-130V AC and tied it into the power switch

Dave
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: dmp on October 24, 2014, 10:09:05 AM
Quote
In mine I used a jewel and lamp holder from antique electronic supply and got a lamp that runs off of 120-130V AC and tied it into the power switch

Do you know the bulb number? I know #47 is the 6.3v variety, but I'm not sure where to get a 120v version. This is a good idea.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: stitch-o on October 26, 2014, 08:47:08 PM
I am in need of a third screw to hold the pattern, pad, shelf switch PCB to the underside of the headbasket
of my DU-67. I have the ShuaiYin SYT-5 donor.
Could anyone tell me the size and length of screw I need to buy?

Cheers!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: wave on October 27, 2014, 09:16:40 AM
Quote
In mine I used a jewel and lamp holder from antique electronic supply and got a lamp that runs off of 120-130V AC and tied it into the power switch

Do you know the bulb number? I know #47 is the 6.3v variety, but I'm not sure where to get a 120v version. This is a good idea.

This is what I got,

http://www.mouser.com/Search/ProductDetail.aspx?R=8-3995virtualkey60600000virtualkey606-CM8-3995

Dave
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Mahasandi on November 27, 2014, 07:54:02 PM
I bought a great DU67 build from a member here - He wanted to find the right fuse on the power supply (iyt has a wrong value one in there)
we could never find a time to meet - (busy lives)
he also wanted to re-wire the x former.
It sounds great- but would a x former rewire change the sound much? does any one no where I can get the correct fuse value for the power supply?

Any and all help appreciated!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on November 28, 2014, 08:55:25 AM
I bought a great DU67 build from a member here - He wanted to find the right fuse on the power supply (iyt has a wrong value one in there)
we could never find a time to meet - (busy lives)
he also wanted to re-wire the x former.
It sounds great- but would a x former rewire change the sound much?

See here for complete relationship between pad number and transfomer on the AMI and various transformer mic pcb version
http://groupdiy.com/index.php?topic=50021.msg720336#msg720336

if you Have the T67 AMI transformer (Rewire is only valid for the AMI T67 of D-67 or D-269c any other transformer can be wired correctly from the wiring guide of the pcb ) yes it will make the sounds better the top end will be much sweeter with the corrected feedback wiring as seen in this thread,

does any one no where I can get the correct fuse value for the power supply?
i usually stick a 0.3A if you are in north america,

Hope this helps,
Dany,


with wiring error
https://dl.dropboxusercontent.com/u/43869772/U67/Feedback%20winding%20Correction/Orginal.wav

With wiring correction  WoW :)
https://io.groupdiy.com/file/gdiy-2017/u/39511/58d028199444d.wav


Any and all help appreciated!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on November 28, 2014, 11:36:25 AM
Quote
Hope this helps,
Dany


I would think so.  :)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Mahasandi on November 28, 2014, 10:37:17 PM
Thanks Dany! Yes it was the T67 AMI - and I'm in North America!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Mahasandi on December 01, 2014, 08:54:15 PM
So i'm not gifted with this stuff I looked at the diagram and wasn't positive what i would be soldering?
can anyone identify from my pictures what needs changing - this would make the diagram more useful to me...
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Mahasandi on December 01, 2014, 08:54:48 PM
and the back side
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Mahasandi on December 01, 2014, 08:59:51 PM
see I'm only good at making the outside look good .... :P
(thanks to my wife for hand modeling)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on December 02, 2014, 05:30:22 AM
Hey Mahasandi, good to "see" you.
So, you got the bug so bad you are now rolling your own.  :)
Brave guy.

Do be careful with them high voltages, will you?
They can be lethal, you know.

Oh wait!
You're modding the one you bought.
My bad; I should have scrolled back.

Time for coffee.



Henk
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on December 02, 2014, 08:19:01 AM
see I'm only good at making the outside look good .... :P
(thanks to my wife for hand modeling)

Just Make sure of this connection Scheme,

AMI T67 Corrected Wiring to main microphone pcb

From transformer board to mic PCB

Pad 5 ----->  mic pcb pad T1212
Pad 12 -------> mic pcb pad T55
Pad 1 --------> mic pcb pad T44
Pad 4 --------> mic pcb pad T11
Pad 7 --------> mic pcb pad T1010
Pad 10 ------> mic pcb Pad T77

Thanks For the Pictures,
Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 03, 2014, 05:34:54 PM
HI Guys,

just thought id post a little mess around groove with my newly tweaked U67.
U67 as room mic put it through my LA2A and through SSL 9k pre amp. Mic about 6-8 foot away at chest hight.
not great upload quality unfortunatly :(

https://soundcloud.com/spencer-lee-horton/sleepy-groove

regards

Spence.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on December 04, 2014, 08:30:21 AM
HI Guys,

just thought id post a little mess around groove with my newly tweaked U67.
U67 as room mic put it through my LA2A and through SSL 9k pre amp. Mic about 6-8 foot away at chest hight.
not great upload quality unfortunatly :(

https://soundcloud.com/spencer-lee-horton/sleepy-groove

regards

Spence.

Thanks Spencer,  Really like the shim of the cymbals on this one ,  8)
Best ,
Dan,
 
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on December 05, 2014, 04:34:46 AM
Just want to post back here and say how incredibly pleased I am with my D-U67. Dany, it's the best mic I own! It beats out my U87 by a mile! It manages to have a big, full warm presence, with tons of gain. Captures male vocals incredibly well (haven't used them on female yet).

I'll be tracking a female vocal soon, and I'm sure it will be terrific. I'm so proud of it; sounds wonderful, is solid as a rock, and comes with the pride and joy of having built it myself! (with a little help from my friends)!

Thanks Dany and friends! And if you're on the fence about this mic, don't be! It's awesome!

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on December 05, 2014, 05:14:02 AM
Just want to post back here and say how incredibly pleased I am with my D-U67. Dany, it's the best mic I own! It beats out my U87 by a mile! It manages to have a big, full warm presence, with tons of gain. Captures male vocals incredibly well (haven't used them on female yet).

I'll be tracking a female vocal soon, and I'm sure it will be terrific. I'm so proud of it; sounds wonderful, is solid as a rock, and comes with the pride and joy of having built it myself! (with a little help from my friends)!

Thanks Dany and friends! And if you're on the fence about this mic, don't be! It's awesome!

Mike


 8)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on December 05, 2014, 09:20:33 AM
Just want to post back here and say how incredibly pleased I am with my D-U67. Dany, it's the best mic I own! It beats out my U87 by a mile! It manages to have a big, full warm presence, with tons of gain. Captures male vocals incredibly well (haven't used them on female yet).

I'll be tracking a female vocal soon, and I'm sure it will be terrific. I'm so proud of it; sounds wonderful, is solid as a rock, and comes with the pride and joy of having built it myself! (with a little help from my friends)!

Thanks Dany and friends! And if you're on the fence about this mic, don't be! It's awesome!

Mike

Thanks Mike for this post ,
you just made my day ,
what is the configuration of your mic ,
Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on December 05, 2014, 09:26:58 AM
Quote
what is the configuration of your mic ,

Yeah, I wondered, too.

As a matter of fact, I was so curious, I weeded through all the pages to find out.

OK, I could have asked Mike, too.
But I didn't know how long it would take for him to answer.  :)

Max (ioaudio) BV12
Phillips Mullard tube
Shinkoh resistors
Stock capacitors from build
BeesNeez K6 capsule
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on December 05, 2014, 12:31:52 PM
MicAddict,

You just earned your moniker man! Even I would have had to go digging! So...yeah, Thx!

Truly a superb sounding mic!!!! Very very smooth!

And thank-YOU Dany!

I've still got an M49 to put together - waiting on getting a body. And a  U47 clone so....yeah, I'm a mic addict too!

Happy day gang!

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Spencerleehorton on December 06, 2014, 03:12:33 AM
Hi guys,

I would also like to add that my U67 sounds really, really good now. Have adjusted  B+ and H+ to 210v and -6.3v as for some reason they were a bit off.
My mic has Eric's capsule in there and sounds very sooth, have got some choices with tubes and at the moment I have a electro harmonics EF86 in there but I have a telefunken red dot, winged C and some mullards.
Transformer wise I had Sowter make me  one, sounds amazing.
Sounds great as room mic, acoustic guitar, vocals and electric guitar.
It's a real goto mic for me in the studio, if you don't have one I would order one right now you won't regret it.
Big thanks to Dany for everything.

Regards

Spence.

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Mahasandi on December 06, 2014, 04:28:55 PM
Thank you Dany ! db is the mic king!!!

see I'm only good at making the outside look good .... :P
(thanks to my wife for hand modeling)

Just Make sure of this connection Scheme,

AMI T67 Corrected Wiring to main microphone pcb

From transformer board to mic PCB

Pad 5 ----->  mic pcb pad T1212
Pad 12 -------> mic pcb pad T55
Pad 1 --------> mic pcb pad T44
Pad 4 --------> mic pcb pad T11
Pad 7 --------> mic pcb pad T1010
Pad 10 ------> mic pcb Pad T77

Thanks For the Pictures,
Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gevermil on January 02, 2015, 02:18:35 PM
Finally had time to finish , Besides chasing a simple ground issue  , it is now
 nice and quiet with any tube .

Max BV12
telefunken Ef86  via Christian Whitmore
New Neumann Capsule .
Initial listing tests while
switching tube types offers interesting results

Telefunken Ef86 and Amperex 6084/E80F
Have similar top end with the tele having a bit more low end .
The Electro-harmonix certainly more harsh .
Obviously need time for tubes to burn for awhile but all in all very interesting .
Hopefully I can hear more differences soon and Maybe get my hands on a Mullard for Kicks .
Thanks Dany for the cool Kit
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gevermil on January 02, 2015, 02:29:14 PM
Here are the tubes
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: gevermil on January 02, 2015, 02:30:43 PM
mic
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: rjuly on January 09, 2015, 09:46:20 AM
Does anyone know where I can source the WIMA caps from the mouser BOM - Film Capacitors 400V 2200pF 5% (MKP2G012201B00JSSD)   - here in Europe? They don't seem to be available until later this year from Mouser and elsewhere. Alternatively, can anyone suggest a replacement cap?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on January 09, 2015, 10:37:26 AM
Does anyone know where I can source the WIMA caps from the mouser BOM - Film Capacitors 400V 2200pF 5% (MKP2G012201B00JSSD)   - here in Europe? They don't seem to be available until later this year from Mouser and elsewhere. Alternatively, can anyone suggest a replacement cap?

you can try to get the 10% instead from mouser ,
those are RF caps filtering so the tolerance is not really an issue,
Best,
DAn,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: rjuly on January 11, 2015, 12:25:26 PM
Does anyone know where I can source the WIMA caps from the mouser BOM - Film Capacitors 400V 2200pF 5% (MKP2G012201B00JSSD)   - here in Europe? They don't seem to be available until later this year from Mouser and elsewhere. Alternatively, can anyone suggest a replacement cap?

you can try to get the 10% instead from mouser ,
those are RF caps filtering so the tolerance is not really an issue,
Best,
DAn,

Hi Dan,

Do you have a mouser code for this? I couldn't locate it on their site. Will another manufacturer do the job as well?

Also, received my boards, sockets and polystyrene caps - thanks.

rjuly
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on January 11, 2015, 12:43:30 PM
Does anyone know where I can source the WIMA caps from the mouser BOM - Film Capacitors 400V 2200pF 5% (MKP2G012201B00JSSD)   - here in Europe? They don't seem to be available until later this year from Mouser and elsewhere. Alternatively, can anyone suggest a replacement cap?

you can try to get the 10% instead from mouser ,
those are RF caps filtering so the tolerance is not really an issue,
Best,
DAn,

Hi Dan,

Do you have a mouser code for this? I couldn't locate it on their site. Will another manufacturer do the job as well?

Also, received my boards, sockets and polystyrene caps - thanks.

rjuly

the 10% in is in stock,
D
http://ca.mouser.com/ProductDetail/WIMA/FKS2G012201A00KSSD/?qs=sGAEpiMZZMv1cc3ydrPrF2CPLAojp4yWb8qnuRrIr78%3d

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on January 25, 2015, 04:23:39 AM
Question about PSU for Dany:

The 0V connection on the PCB - this goes to the chassis (earth) ground? I got confused because AC circuits have Neutral as return path.

Or is the 0V only for the audio shielding?

I'm trying to design an add-on board for my Dany PSU and I got confused when to use earth ground (chassis) or do I ever use AC neutral for AC ground?

Thanks much,

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on January 25, 2015, 03:23:52 PM
Quote
The 0V connection on the PCB - this goes to the chassis (earth) ground?

Yes it represent the reference voltage in this case 0V, it will also tie up to the chassis and earth at the end.

Quote
Or is the 0V only for the audio shielding?
audio shielding will also go there ,  nothing to do with the neutral return path ,

Best,
Dan,

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on January 25, 2015, 10:14:42 PM
Thank-you Dany.

So to ask a more pointed question then. I want to put a switch to add a load to the PSU, so it's really easy to test over time.

But where do I ground the switch to then? Earth/Chassis ground? Certainly not through the AC mains neutral! I'm just confused because I am reading that Earth ground should never have a voltage signal applied, but if I put a load across B+ with a resistor and tie it to earth ground, wouldn't that be wrong? But how else would I do it correctly?

Sorry if this is obvious.

Best,

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: rjuly on February 01, 2015, 06:58:24 AM
I am trying to get my head around the AMI BV12 classic transformer  connections and I have a few questions. I hope you will take pity on me and give me some pointers. First of all, does my general diagram make sense, and have I made any errors in my assumptions?

AMI's schematic:
(http://i1300.photobucket.com/albums/ag85/rjuly/AMI_BV12Schemeatic_zps9f580994.jpg)

My diagram of the AMI BV12:
(http://i1300.photobucket.com/albums/ag85/rjuly/BV12diag_zps16074ff4.gif)



As mickdundee63 noted earlier in this thread,  the AMI schematic differs from the actual transformer in that the AMI schematic shows  two grey wires and one white wire, whereas the actual transformer has two white wires and one grey wire. As he noted, white wire (G) has continuity with green wire (A), so it would seem that the other white wire is one of the ones marked as grey on the AMI schematic.

Question: Which destination should grey wire(B) be connected to? R28 or C3 ? This would indicate  where white wire (D) should go.
Question: What are the 2 black wires (F and I) for, and where should they be connected in the circuit?

Any help would be appreciated.

Regards,
Richard
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on February 02, 2015, 02:55:54 PM
I am trying to get my head around the AMI BV12 classic transformer  connections and I have a few questions. I hope you will take pity on me and give me some pointers. First of all, does my general diagram make sense, and have I made any errors in my assumptions?

AMI's schematic:
(http://i1300.photobucket.com/albums/ag85/rjuly/AMI_BV12Schemeatic_zps9f580994.jpg)

My diagram of the AMI BV12:
(http://i1300.photobucket.com/albums/ag85/rjuly/BV12diag_zps16074ff4.gif)



As mickdundee63 noted earlier in this thread,  the AMI schematic differs from the actual transformer in that the AMI schematic shows  two grey wires and one white wire, whereas the actual transformer has two white wires and one grey wire. As he noted, white wire (G) has continuity with green wire (A), so it would seem that the other white wire is one of the ones marked as grey on the AMI schematic.

Question: Which destination should grey wire(B) be connected to? R28 or C3 ? This would indicate  where white wire (D) should go.
Question: What are the 2 black wires (F and I) for, and where should they be connected in the circuit?

Any help would be appreciated.

Regards,
Richard

please send a email to [email protected] to ask for a corrected datasheet and clarification for your question
and please post your findings here ,
thanks,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on February 02, 2015, 03:23:46 PM
I have just spoke with Dennis at AMI andhe is looking into it ,
Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: rjuly on February 04, 2015, 07:36:43 AM
I have just spoke with Dennis at AMI andhe is looking into it ,
Best,
Dan,

Dany,

Many thanks for that. I have also sent an email to the support team as you suggested. Hopefully they will come back with something.

Regards,
Richard
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on February 04, 2015, 08:26:44 AM
I have just spoke with Dennis at AMI andhe is looking into it ,
Best,
Dan,

Dany,

i should be getting back today with a full configuration diagram for the bv12 classic series,
stay tuned,
Dan,

Many thanks for that. I have also sent an email to the support team as you suggested. Hopefully they will come back with something.

Regards,
Richard
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: rjuly on February 05, 2015, 07:31:03 AM
AMI sent me the updated schematic with these details below.

The circuit:
(http://i1300.photobucket.com/albums/ag85/rjuly/imagejpg1_zps7ff60568.jpg)

... and the reference image:
(http://i1300.photobucket.com/albums/ag85/rjuly/imagejpg1_zpsfa3e1910.jpg)

... still wondering if anyone here can tell me what the black wires connect to? Not sure what the dotted-dashed line with the "&" symbols in the circuit diagram denote.

Best,
Rich
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on February 05, 2015, 08:08:56 AM

Here is the correspondance on the pcb pad for the U67 Mic pcb


(https://dl.dropboxusercontent.com/u/43869772/U67/AMI%20transformer%20Mic%20PCB%20Hookup.jpg)


AMI sent me the updated schematic with these details below.

The circuit:
(http://i1300.photobucket.com/albums/ag85/rjuly/imagejpg1_zps7ff60568.jpg)

... and the reference image:
(http://i1300.photobucket.com/albums/ag85/rjuly/imagejpg1_zpsfa3e1910.jpg)

... still wondering if anyone here can tell me what the black wires connect to? Not sure what the dotted-dashed line with the "&" symbols in the circuit diagram denote.

Best,
Rich
:)
yes i got it this morning , cant wait to start a new build with this traffo. i really like my D-EF47 with the BV8 classic series.
let get this bv12 classic series going :)
the 2 black wire are actually shiedling of the core, take those 2 wires to a gnd pad onm the pcb,
Also note that the Blue wire (4) is the +audio out and the White (3) is - audio out

https://io.groupdiy.com/file/gdiy-2017/u/39511/58d02819944ac.pdf
best,
Dan.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: rjuly on February 05, 2015, 10:14:11 AM
Yes, I'm looking forward to getting back to work on my pair. I have looked at my finances, and I can't afford to rectify the error I made ordering the ioaudio bv.12 version pcb's. I am going to try and make them work if possible, with the AMI bv12's. I believe they will just fit in the mic bodies I have. When I drill the holes in the pcb to attach the trafo, should I try to avoid the ground plane or try to intersect it?

Regards,

Rich
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on February 05, 2015, 10:18:49 AM
Yes, I'm looking forward to getting back to work on my pair. I have looked at my finances, and I can't afford to rectify the error I made ordering the ioaudio bv.12 version pcb's. I am going to try and make them work if possible, with the AMI bv12's. I believe they will just fit in the mic bodies I have. When I drill the holes in the pcb to attach the trafo, should I try to avoid the ground plane or try to intersect it?

Regards,

Rich
just put a small layer of large heat shrink tube under the core that sit on the pcb ,
that will do it and give a little extra dampening effect,
Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on February 05, 2015, 01:30:59 PM
Finally documentation for the BV12 AMI classic series is here ,
see first page or 2 post back on this page,

 8)
Best,
Dany,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: micaddict on February 05, 2015, 04:33:47 PM
Very curious how it compares to the T67.



Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: JessJackson on February 11, 2015, 01:34:47 AM
Thats exactly how I said to wire it.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: saint gillis on February 28, 2015, 01:51:22 PM
Hey Dan,
Here the voice has been recorded with a D-U67
https://www.youtube.com/watch?v=D1Q5n5KGic8 (https://www.youtube.com/watch?v=D1Q5n5KGic8)
Hope its not bad publicity !  ;D
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on February 28, 2015, 03:18:46 PM
Hey Dan,
Here the voice has been recorded with a D-U67
https://www.youtube.com/watch?v=D1Q5n5KGic8 (https://www.youtube.com/watch?v=D1Q5n5KGic8)
Hope its not bad publicity !  ;D

Love it , the song is very cool, influential work indeed, thanks for taking the time to post this , I really love the vocal track  ;),
Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: saint gillis on February 28, 2015, 08:06:27 PM
AMI Transformer + capsule from TSKGuy !    ;)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on March 04, 2015, 04:47:24 PM
To help For transformer Connections, updated first post as well,
A nice tutorial for this project  is coming soon. :) 

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0813d.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a035b4.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281994524.jpg)

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: potstweaker on April 02, 2015, 01:00:33 PM
finally getting around to finishing this mic build. however i cannot for the life of me figure out how to hook up the capsule. any pics that could help?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 02, 2015, 01:39:21 PM
(https://dl.dropboxusercontent.com/u/43869772/U67/1-1.jpg)
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d028199455d.jpg)
Hope this helps,

Refer to M269b build thread for pattern switch and low cut and pad,
Dan,

Yes you need to have the backplate ( metal part of the Capsule connected via a screw eylet) and then wired to middle pin of pattern switch , what i usually do is to have a pre existing lead on the switch board that goes up to the basket ,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: potstweaker on April 02, 2015, 01:44:10 PM
what about the wire thats on the side of the capsule?where does that connect to?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 02, 2015, 02:34:39 PM
what about the wire thats on the side of the capsule?where does that connect to?

Where the arrows point in the pictures  ;),
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: potstweaker on April 02, 2015, 09:23:01 PM
sorry, I suppose my confusion lies in which is the backplate......would i be safe in assuming that is what the cable thats screwed onto the side of the capsule would be?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on April 03, 2015, 09:52:01 AM
sorry, I suppose my confusion lies in which is the backplate......would i be safe in assuming that is what the cable thats screwed onto the side of the capsule would be?

The metal portion of the capsule is the backplate,
the gold film portion of the capsule are the diaphrgames,
hope this helps,
Dany,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 08, 2015, 02:42:53 PM
All New Build guide available trough the website Web and PDF version

Thanks To Steven Jensen For this Build Guide.
available here:
http://www.vintagemicrophonepcbkit.com/DU67.html

I will be receiving next week adaptor pcb for the AMI Classic Series BV12 as well,
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d02819945c5.jpg)

Best,
Dan,




Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on May 11, 2015, 06:52:58 PM
Hi All, I am pleased to announce another Transformer Support Options for the D-67 Tube Mic .
this announce and explain how to install the AMI Classic series BV12 to your D-67 PCB Kit,
please request separately with the AMI and external Transformer PCB Kit Style not on web store yet


First , install the transformer with M1.6 screw and nuts , use little plastic washer to make sure the transformer is not in contact with the screw. I haven't put them for the demonstration but use them ,

A) Slide Fit the Transformer in The cutout and screw the adaptor pcb in place
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a082ee.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a082ff.jpg)

B)  Very Gently snip a little bit of thre plastic corner  Make sure you don't damage the transformer wire close to it ,
Use this kind of precision Snippers,


(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a08310.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a08321.jpg)

C) This will looks like this after the Snips
(https://dl.dropboxusercontent.com/u/43869772/AMI%20BV12%20installtion/IMG_0786.JPG)

D) Then Close the Shell and it will slide in with no interference at all,

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d02819945f2.jpg)

Enjoy and continue your build.


best,
Dan,




 
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Phrazemaster on May 17, 2015, 07:22:13 PM
Thought I would chime in again and thank-all you guys for amazing projects like this!

My D67 is hands-down my favorite mic! I used a Max Kirscher transformer, and a Sneezby K6.

Here's a link to a recording I did of a great singer and song, on YouTube:

https://www.youtube.com/watch?v=cPUvqEH0_ZE (https://www.youtube.com/watch?v=cPUvqEH0_ZE)

Chain was D67-->SCA N72 (I think) -->Lavry Blue-->Sonar X2.

Using Lexicon Reverb plug.

Best,

Mike
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jonathanmorbin on June 09, 2015, 05:45:33 PM
Hi, quick question for anyone in the know. I have built two of these microphones and they sound great. However I'm finding that in certain places (My Studio) i am picking up noise from the mains power (Lights/LED). The noise is in the form of fizzles and hum, fairly low but audible if your doing voice overs. At my house there is no noise at all. has anyone else encountered this? i have other valve mice in my studio that don't have noise on them, have i just got my grounding wrong?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: rjuly on June 17, 2015, 08:19:07 AM
Yes, I'm looking forward to getting back to work on my pair. I have looked at my finances, and I can't afford to rectify the error I made ordering the ioaudio bv.12 version pcb's. I am going to try and make them work if possible, with the AMI bv12's. I believe they will just fit in the mic bodies I have. When I drill the holes in the pcb to attach the trafo, should I try to avoid the ground plane or try to intersect it?

Regards,

Rich
just put a small layer of large heat shrink tube under the core that sit on the pcb ,
that will do it and give a little extra dampening effect,
Best,
Dan,

I have finally found some time to make a bit of progress on the build of my two mics. I have managed to mount the B12 classics onto the circuit board meant for the T67(since I accidentally ordered the wrong boards). I found some nylon bolts that have worked well:

(http://i1300.photobucket.com/albums/ag85/rjuly/photo%201_zpsptnijg0b.jpg)
(http://i1300.photobucket.com/albums/ag85/rjuly/photo%202_zpsajfetsr7.jpg)

I now need to make sure that I have the correct connections for my jury rigged build... This is what I think it should be:

(http://i1300.photobucket.com/albums/ag85/rjuly/BV12%20diag%20plain%2003_zpsptzx1mbc.png)

Can anyone confirm that I have these connections correct? I understand that the green and yellow need to tied together.

Many Thanks,
Richard
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on June 17, 2015, 09:21:07 AM
Hi, quick question for anyone in the know. I have built two of these microphones and they sound great. However I'm finding that in certain places (My Studio) i am picking up noise from the mains power (Lights/LED). The noise is in the form of fizzles and hum, fairly low but audible if your doing voice overs. At my house there is no noise at all. has anyone else encountered this? i have other valve mice in my studio that don't have noise on them, have i just got my grounding wrong?

try using ( removing)  the SHLF jumper on the psu and lift the cable shield to see if it helps,
this was  actually  designed for those  scenario where RF issues is present.
hope this helps,

Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on June 17, 2015, 09:25:23 AM
Yes, I'm looking forward to getting back to work on my pair. I have looked at my finances, and I can't afford to rectify the error I made ordering the ioaudio bv.12 version pcb's. I am going to try and make them work if possible, with the AMI bv12's. I believe they will just fit in the mic bodies I have. When I drill the holes in the pcb to attach the trafo, should I try to avoid the ground plane or try to intersect it?

Regards,

Rich
just put a small layer of large heat shrink tube under the core that sit on the pcb ,
that will do it and give a little extra dampening effect,
Best,
Dan,

I have finally found some time to make a bit of progress on the build of my two mics. I have managed to mount the B12 classics onto the circuit board meant for the T67(since I accidentally ordered the wrong boards). I found some nylon bolts that have worked well:

(http://i1300.photobucket.com/albums/ag85/rjuly/photo%201_zpsptnijg0b.jpg)
(http://i1300.photobucket.com/albums/ag85/rjuly/photo%202_zpsajfetsr7.jpg)

I now need to make sure that I have the correct connections for my jury rigged build... This is what I think it should be:

(http://i1300.photobucket.com/albums/ag85/rjuly/BV12%20diag%20plain%2003_zpsptzx1mbc.png)

Can anyone confirm that I have these connections correct? I understand that the green and yellow need to tied together.

Many Thanks,
Richard


there is all the information for the pinout of the bv12 directly in the T67 pad on the board,
Actually all the info you need is on the previous page of this thread  , or here

http://www.vintagemicrophonepcbkit.com/D67B/D67B/D-67%20Build%20Guide.html
(end of the page)

I have designed a special adaptor now for the AMI BV12 Classic series.
see here ,
(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d028199466d.jpg)

hope this helps,
Best
Dan,

Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: rjuly on June 18, 2015, 06:09:47 PM
Just taking a look at the PSU build guide on http://www.vintagemicrophonepcbkit.com ... Is anyone else getting blank pages after page 12?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on June 18, 2015, 06:20:36 PM
Just taking a look at the PSU build guide on http://www.vintagemicrophonepcbkit.com ... Is anyone else getting blank pages after page 12?

yep this is just a formatting error I did not fix yet , but on my plate ,
you are not missing anything so there is no worries,
Thanks for pointing this out ,
best,
dAn ,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: rjuly on June 18, 2015, 06:32:48 PM
I'm building the UK version and was hoping there would be a wiring diag for 220. Also I notice that I am getting 270 AC coming out of the transformer rather than 210. Is that acceptable?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on June 18, 2015, 06:43:24 PM
I'm building the UK version and was hoping there would be a wiring diag for 220. Also I notice that I am getting 270 AC coming out of the transformer rather than 210. Is that acceptable?

A)  For input transformer toroid the primary needs to be in series for 230V input ,  (see datasheet)
B)  The heater transformer is the same logic see picture in the thread ,  (see datasheet)
C)  Don't worry about the High Voltage until you know what it is with a load,
D) Follow instruction for dummy load in this thread to test psu ,
E.........njoy this part  of the build

hope this helps,
Best,
Dan,



Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mrerdat on June 25, 2015, 09:51:01 PM
Just got around to finishing a mic a few days ago.  The studio I used to work at had a pair of vintage 67s that sounded a bit different from each other and though I haven't gotten a chance to get back in there to do a direct comparison, the one I built sounds much closer to the one I remember liking more!   It sounds fantastic, and I'm definitely going to order parts for #2 very soon.

I used the tskguy HK67 capsule, AMI T67 transformer, and a silver shield Telefunken EF-86.

The only anomaly in my build was that I had to use a 44k ohm resistor with the B+ trim pot to get 210v, because with 56k I was getting 208v max and with 22k I was getting 216v with the trim all the way down.  Everything else measured fine right away.

Thanks to everyone on the board who made this possible!  You're the best.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: friesdan on July 13, 2015, 03:21:10 AM
Hi guys,
I'm hoping someone might give me some ideas about some trouble I'm having with my mic.

First thing is that I get a "windy" sound which goes down after a couple days of warming up, but is still noticeable even then. I've changed the tube 3 times, and now have a price NOS telefunken in there. The mic sounds great, but that windy sound is pretty annoying. Any ideas?

Another thing I've just noticed seems to be an issue with the pattern switch.
Figure 8 seems fine. When I switch from figure 8 to cardioid, that works fine. Then I switch to omni and the sound shuts out. I still hear handling noise, but it's like the capsules aren't picking up what they're supposed to, or maybe they're cancelling each other out. THEN, if I switch to cardioid from omni, same thing - no real volume to speak of. If I put it back to figure 8, it starts working again, and I can then get cardioid to work again.
weird, huh?
Ideas?

Thank you!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mrerdat on July 13, 2015, 09:29:54 PM
Another thing I've just noticed seems to be an issue with the pattern switch.
Figure 8 seems fine. When I switch from figure 8 to cardioid, that works fine. Then I switch to omni and the sound shuts out. I still hear handling noise, but it's like the capsules aren't picking up what they're supposed to, or maybe they're cancelling each other out. THEN, if I switch to cardioid from omni, same thing - no real volume to speak of. If I put it back to figure 8, it starts working again, and I can then get cardioid to work again.
weird, huh?
Ideas?

Thank you!

I came across a similar issue but not quite the same.   I was getting a lot of loud pops when changing patterns, handling noise, low hum, and something I think was the "windy" sound you mentioned, but I double-checked my wiring and found that I somehow forgot to connect the backplate to C2/R2 even though it was wired to the pad switch.  Everything worked after fixing that one connection.  It turned out I was not as thorough as I thought I was.

I'm sure you have already, but go through the build guide again slowly and recheck your connections, especially between the Hi Z network, capsules, and switches .
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: friesdan on July 18, 2015, 06:18:56 PM
turned out the connection to the backplate on the capsule had come loose. Thanks for the reply!
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mrerdat on July 29, 2015, 10:27:42 AM
I was wondering if any of you have had issues with hum using the mic in some places but not others.   I've been trying to troubleshoot this buzz/hum that's been driving me crazy when I've attempted use the mic at two of the places that I freelance at.  The hum is so loud that the mic is unusable at these places, but elsewhere it's fine.  I've done some experimentation with redoing the ground scheme like connecting pin 3 of the 7 pin XLR to pin 1 of the 3 pin XLR in the PSU, which helps a bit but doesn't get rid of all of the noise. The only thing I do that seems to get rid of the hum completely is to lift the safety ground on the PSU (yikes, I know).  This seems like there is a ground loop inside the mic somewhere. 

For now, I have reset the mic to exactly the way it says to build it in the build guide as a starting point for troubleshooting.

An interesting thing is that with the PSU powered off and my mic preamp gain cranked, I can hear this hum come and go as I move the mic around.   This does not go away when I power the mic on.  Unplugging the 7 pin XLR while the PSU is powered off  however makes the hum go away completely.  Any clue as to where the ground loop in the mic might be coming from?  I'm quite sure I wired it exactly as it says to do it in Dany's guide.

Edit: I wanted to add that the jumper in the PSU to tie/lift pin 3 and 7 has no effect.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mrerdat on August 09, 2015, 04:37:48 PM
So here's an update on the grounding situation.  I've had some time yesterday at the place where the hum issue is the worst to do a bit of soldering.   I've been doing some reading about the "pin 1 problem" and surmised that the mic had that at first, but when I tried tying the output XLR3 pin 1 directly to the chassis and nothing else, the ground hum becomes audibly worse.

Using a pair of headphones , I experimented with connecting/disconnecting different ground schemes using a short wire until I found the one that undisputedly had the lowest audible level of hum.   The cable shield from XLR7 pin 3 is connected to XLR3 pin 1  directly AND to the PCB ground point (see attached picture).This was the result of some trial and error so let me know if any of you experts see anything really wrong with this.

Again, the SHLF jumper in the PSU has no effect on this issue.

Now what was strange is that in certain tie panel inputs is that hum was eliminated almost (if not) completely, but was still quite audible in others.  The XLR tie panels have ground lift switches, but the hum is actually worse when the XLR ground is lifted there.  What still gets rid of the problem 100% is lifting the AC safety ground, which I am not ok with as a permanent solution. 

The noise/hum in the space is clearly audible in DIs as well, which need to be ground lifted in order to get rid of the hum.   The house's Neumann M149 does not have any sort of audible hum whatsoever though. 

Can anyone offer some advice or insight on this issue? It's been driving me crazy for the last few weeks.

here is what the hum/noise sounds in the space sounds like:
https://drive.google.com/file/d/0B1BmrLv1U3XQZzB5cm94Q3UzVWM/view?usp=sharing

Meanwhile in most other places the mic still sounds absolutely wonderful and problem free.  8)
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Banzai on August 10, 2015, 12:07:14 PM
Mrerdat, how is your 7-pin cable wired?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mrerdat on August 10, 2015, 12:21:27 PM
My 7 pin cable is wired the way it says to do so on page 1.

Pin 1: signal +
Pin 2: signal -
Pin 3: shield (I clipped off the black cable and wired just the shield, as per the guide) and it is not connected to the connector shell.
Pin 4: heater
Pin 5: b+
Pin 6: calibration
Pin 7: 0v
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Banzai on August 10, 2015, 03:03:51 PM
Did you attach the shield of the multi-wire cable between XLR7 and XLR3 to ground? Hard to see from your pic. Also just in case, double-check the XLR7 and XLR3 connectors themselves to see if they're properly grounded (worth re-checking all metal to metal contacts are good). Then see if you get a constant ground from the XL3 casing to the GND pin on the IEC, and same to the headbasket of the mic etc.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: mrerdat on August 10, 2015, 04:11:00 PM
Did you attach the shield of the multi-wire cable between XLR7 and XLR3 to ground? Hard to see from your pic.

Yes.  I'm following the wiring chart so the short run of cable inside the PSU has the black wire connected to pin 3 of the XLR7 (which after the connector now carries the shield signal from the long cable) and is soldered directly to pin 1 of the XLR3 connector.

Also just in case, double-check the XLR7 and XLR3 connectors themselves to see if they're properly grounded (worth re-checking all metal to metal contacts are good). Then see if you get a constant ground from the XL3 casing to the GND pin on the IEC, and same to the headbasket of the mic etc.

All continuity checks out fine.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Banzai on August 10, 2015, 06:29:01 PM
This part is unrelated to the wiring scheme: the short run of cable you have inside your PSU has its own shield. You want to connect this somewhere on the chassis (on one side only), otherwise it's just a loose antenna and the wires inside aren't shielded. Won't solve your problem, but good practice to tie up all loose ends.

Yes.  I'm following the wiring chart so the short run of cable inside the PSU has the black wire connected to pin 3 of the XLR7 (which after the connector now carries the shield signal from the long cable) and is soldered directly to pin 1 of the XLR3 connector.
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on August 30, 2015, 11:10:29 AM
Hi All, I have been working With Dave at Cinemag For about a year now and Dave Came up with this awesome little new Toy ,

I Proudly Present the CM-15701 in other word the Cinemag (BV-12), I have just tested compatibility with my kits and it can be easily mounted on the bottom bell  8) and leave enough room for the Tube  8) this transformer is compatible with the External Transformer Version of the D-67 Kit available here
www.vintagemicrophonepcbit.com

you can contact Dave here http://www.cinemag.biz/

Here is a little Mounting Demo Proposition .

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0857a.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0858b.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a0859c.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a085ad.jpg)

(https://dl.dropboxusercontent.com/u/43869772/U67/Cinemag%20BV12/IMG_0005.JPG)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d02819946fa.jpg)

Best,
Dan,
www.vintagemicrophonepcbkit.com







Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: Jim50hertz on August 30, 2015, 11:50:01 AM
Price?
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on August 30, 2015, 12:19:43 PM
Hi All, I have been working With Dave at Cinemag For about a year now and Dave Came up with this awesome little new Toy ,

I Proudly Present the CM-15701 in other word the Cinemag (BV-12), I have just tested compatibility with my kits and it can be easily mounted on the bottom bell  8) and leave enough room for the Tube  8) this transformer is compatible with the External Transformer Version of the D-67 Kit available here
www.vintagemicrophonepcbit.com

you can contact Dave here http://www.cinemag.biz/

Here is a little Mounting Demo Proposition .

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a085e2.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a085f3.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a08604.jpg)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d1402a08614.jpg)

(https://dl.dropboxusercontent.com/u/43869772/U67/Cinemag%20BV12/IMG_0005.JPG)

(https://io.groupdiy.com/file/gdiy-2017/u/39511/58d0281994709.jpg)

Best,
Dan,
www.vintagemicrophonepcbkit.com

Not sure yet about the price of the Cinemag BV12 , I will try and ask Dave ,
and report back ,
Best,
Dan,
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: jandoste on September 27, 2015, 02:04:24 PM
Hi Dan,
I already bought this tranx http://www.mouser.fr/ProductDetail/Hammond-Manufacturing/186B20/?qs=CoAU%2fpHVZXz4H1LQS1Hn0w%3d%3d and I'm in Europe so do you think it'll work or I have to get new one?

Thanks

Jandoste
Title: Re: Neumann U67 Clone : D-U67 Tube Microphone Build Thread.
Post by: poctop on September 27, 2015, 03:30:41 PM