Neumann U67 Clone : D-U67 Tube Microphone Build Thread.

[poctop]

D-U67 Build Thread

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

The D-U67 Tube Mic

Mic Assembly Tutorial
https://cdn.groupbuilder.com/groupdiy/u/39511/58d1402a0351f.pdf

PSU Assembly and Tips
https://cdn.groupbuilder.com/groupdiy/u/39511/58d1402a03549.pdf

http:// Check this First: Project Files for The D-U67 Build 
https://cdn.groupbuilder.com/groupdiy/u/39511/58d1402a0356c.zip


The Safety Manual and Considerations.
https://cdn.groupbuilder.com/groupdiy/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
Note: BOM include 56R For R20

D-U67 PSU Parts : 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=49675.40



PSU Schematic
https://cdn.groupbuilder.com/groupdiy/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

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

AMI sent me the updated schematic with these details below.

The circuit:

... and the reference image:

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://cdn.groupbuilder.com/groupdiy/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://cdn.groupbuilder.com/groupdiy/u/39511/58d1402a035d6.doc



Not inclued in the Mouser Bom are:

• Switches for Switch board.
• 1X 270pf Styroflex/630V
• 1X FeedBack Cap (80-160pf) styroflex/630V

Styroflex Capacitor Available Here :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

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

The D-U67 Build

All Of it, 100% original Circuit , No Exception  Include Calibration Check Port & Internal LC shift Switch

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/
or Here: http://www.groupdiy.com/index.php?topic=41963.0

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

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 

AMI T67 Example.

 

[Studio Mollan]

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

 

[HellfireStudios]

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-

 

[Studio Mollan]

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.

 

[poctop]

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,

 

[JessJackson]

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.

 

[Dylan W]

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?

 

[Volume11]

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

 

[dmp]

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

 

[poctop]

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,

 

[Volume11]

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.

 

[poctop]

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,

 

[mrcase]

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

 

[Sredna]

Depends on your budget, you have to buy several to test for noise and microphony.

 

[kpearsall]

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.

 

[Sredna]

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....

 

[kpearsall]

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.

 

[poctop]

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. 

 

[Volume11]

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?

 

[ktfstudio]

Curious about your  "EXCEPTION 1" pic. What am I missing?