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

[fgan81]

Hey, got some questions about PSU Resistor values:
R9: there is no 536 R / 0.3W Resistor in that BOM. Is it right to use this one? 560 R 1 W:
http://eu.mouser.com/Search/ProductDetail.aspx?R=MOS1CT52R561Jvirtualkey66000000virtualkey660-MOS1CT52R561J

R8: is it ok to use 1 W instead of 0.3 W?
http://eu.mouser.com/Search/ProductDetail.aspx?R=PR01000105108JR500virtualkey59420000virtualkey594-5073NW5R100J

R1: is it ok to use 1 W instead of 0.3 W?
http://eu.mouser.com/Search/ProductDetail.aspx?R=MOS1CT52R682Jvirtualkey66000000virtualkey660-MOS1CT52R682J

Thanks for help!

 

[Phrazemaster]

Hey, got some questions about PSU Resistor values:
R9: there is no 536 R / 0.3W Resistor in that BOM. Is it right to use this one? 560 R 1 W:
http://eu.mouser.com/Search/ProductDetail.aspx?R=MOS1CT52R561Jvirtualkey66000000virtualkey660-MOS1CT52R561J

R8: is it ok to use 1 W instead of 0.3 W?
http://eu.mouser.com/Search/ProductDetail.aspx?R=PR01000105108JR500virtualkey59420000virtualkey594-5073NW5R100J

R1: is it ok to use 1 W instead of 0.3 W?
http://eu.mouser.com/Search/ProductDetail.aspx?R=MOS1CT52R682Jvirtualkey66000000virtualkey660-MOS1CT52R682J

Thanks for help!

It's totally OK to use a higher  resistor wattage rating here, and in almost any circuit. If they will physically fit.

Sometimes larger wattage resistors were used on purpose to reduce resistor noise, if using carbon comp.

 

[fgan81]

It's totally OK to use a higher  resistor wattage rating here, and in almost any circuit. If they will physically fit.

Sometimes larger wattage resistors were used on purpose to reduce resistor noise, if using carbon comp.

Thanks Phrazemaster!!!

R9 = "Note: BOM include 560R for R9"

 

[CiaoPatsy]

There's now a 10 week lead for this 60M resistor (R2E, R9, R16E)  seems pretty much impossible to find too...

http://www.mouser.com/Search/ProductDetail.aspx?R=RNX02560M0FKLBvirtualkey61300000virtualkey71-RNX02560M0FKLB

Next to the 60M in the BOM for the mic there is a customer number and it leads here on Mouser, would this resistor be an ok replacement?

http://www.mouser.com/ProductDetail/KOA-Speer/GS1-4LC686J/?qs=y9aipCsCAreuTrYpJqEQBw%3D%3D

 

[wave]

There's now a 10 week lead for this 60M resistor (R2E, R9, R16E)  seems pretty much impossible to find too...

http://www.mouser.com/Search/ProductDetail.aspx?R=RNX02560M0FKLBvirtualkey61300000virtualkey71-RNX02560M0FKLB

Next to the 60M in the BOM for the mic there is a customer number and it leads here on Mouser, would this resistor be an ok replacement?

http://www.mouser.com/ProductDetail/KOA-Speer/GS1-4LC686J/?qs=y9aipCsCAreuTrYpJqEQBw%3D%3D

You could use 2 of these in series...
http://www.mouser.com/ProductDetail/Ohmite/MOX-200003005JE/?qs=sGAEpiMZZMsPqMdJzcrNwsJljJEG6YukRuwZPlwJKN0%3d

Dave

 

[jrasia]

Can someone help me out on how to wire and incorporate a separate fuse and lamp light for this psu diagram?

 

[jrasia]

anyone?

 

[Murdock]

Can someone help me out on how to wire and incorporate a separate fuse and lamp light for this psu diagram?

You put the fuse between the hot (or live) side from your power plug connector and the power on switch. 
And concerning the lamp, it depends on what type of lamp you want to use. Either 120V or 6.3v or something else?

 

[jrasia]

It's a fender type lamp rated for 125v

Thanks!!!

 

[tamtamstudio]

what does it means? is it a polarized styroflex?
I can't find it anywhere, could u explain me, thank you. :-[
all the best.

 

[HeavyHand]

any opinions on the Cinemag transformers?

 

[tamtamstudio]

testing my build, i've got:

+213V at B+
-6.3V at H-

but at A i've got +210V
I still not attached the tube, but seems too high, right?

 

[jrasia]

After months of putting this off I finally got around to finishing off the mic and psu build.

PSU uses the 16V Bell transformer Dany recommended for new builds btw.
Everything powered on, no smoke, and measured the following, unloaded

AC voltages
17.9 for the 20VAC ( I guess because of the new 16v transformer?)
270VAC for HT

DC voltages
-16VDC for H-
around 250VDC for B+
seems good.

What worries me are two things;

1.
R2 (22r 5w) and D1 ( 15v Zener) are super hot.  Like almost can't touch them.  Especially the diode. This after only being on for a few minutes.

Is this normal, and is it safe to proceed with plugging in the mic?

2.
My lamp isn't turning on.  Everything seems to be wired correctly.  Replaced the bulb even.  Afterwords I realized I'm using a lamp rated for 125v. 
http://nextgenguitars.ca/products/lamp-front-panel-indicator-light-relampable.html

Is this the issue and if so what 'fender' type lamp and bulb are people using in their builds?  Links?


Attached is the hookup for the 16v transformer primary in case anyone is wondering ,or is a dolt like me.  For 120v.

 

[TLRT]

After months of putting this off I finally got around to finishing off the mic and psu build.

PSU uses the 16V Bell transformer Dany recommended for new builds btw.
Everything powered on, no smoke, and measured the following, unloaded

AC voltages
17.9 for the 20VAC ( I guess because of the new 16v transformer?)
270VAC for HT

DC voltages
-16VDC for H-
around 250VDC for B+
seems good.

What worries me are two things;

1.
R2 (22r 5w) and D1 ( 15v Zener) are super hot.  Like almost can't touch them.  Especially the diode. This after only being on for a few minutes.

Is this normal, and is it safe to proceed with plugging in the mic?

2.
My lamp isn't turning on.  Everything seems to be wired correctly.  Replaced the bulb even.  Afterwords I realized I'm using a lamp rated for 125v. 
http://nextgenguitars.ca/products/lamp-front-panel-indicator-light-relampable.html

Is this the issue and if so what 'fender' type lamp and bulb are people using in their builds?  Links?


Attached is the hookup for the 16v transformer primary in case anyone is wondering ,or is a dolt like me.  For 120v.

It is better to test the PSU with testload, put 33ohm/2W between terminal pin 3-4(heater) and approx 230kohm/0,5W for the anode simulation between pin 5-7. Leave it on for some hours an see if the voltages drift or not. You can measure the voltage drop also R2 and calculate the dissipation(should be around 3watts normally). I think 60-80 celsius for R2 should be fine, if you see the datasheet it is tolerationg quite high temperatures above 150C.

 

[jrasia]

It is better to test the PSU with testload, put 33ohm/2W between terminal pin 3-4(heater) and approx 230kohm/0,5W for the anode simulation between pin 5-7.

Thanks TLRT!  That's a really good suggestion and thanks for clarifying about the resistor.

Now all that's left to sort is the lamp.  Basically I followed the d67 psu build guide wire hookup.  The exception being the new 16v transformer and then i put the lamp in between the IEC neutral and the line on the switch.  no light though

 

[TLRT]

Thanks TLRT!  That's a really good suggestion and thanks for clarifying about the resistor.

Now all that's left to sort is the lamp.  Basically I followed the d67 psu build guide wire hookup.  The exception being the new 16v transformer and then i put the lamp in between the IEC neutral and the line on the switch.  no light though

Our chinese friends making perfect E10 LED lamps, I'm just using the 240V version directly wired from the IEC Switch.
But you can also use a 24V one,and get the voltage from the heater line terminals.

 

[jrasia]

Thanks everyone for your help. She's alive and well.

I used a Neumann K67 capsule, AMI BV12 classic, Phillips e80f tube, vishay dale resistors, vishay polyprop caps.
Can't believe how quiet and lovely it sounds.

About the only thing to tweak is that I'm at max rotation on the H- pot and it only gets to about 6.2v after warming up for about an hour.

Which resistor should I reduce to get a little more play out of the pot? R2?

 

[TLRT]

Thanks everyone for your help. She's alive and well.

I used a Neumann K67 capsule, AMI BV12 classic, Phillips e80f tube, vishay dale resistors, vishay polyprop caps.
Can't believe how quiet and lovely it sounds.

About the only thing to tweak is that I'm at max rotation on the H- pot and it only gets to about 6.2v after warming up for about an hour.

Which resistor should I reduce to get a little more play out of the pot? R2?

E80F heater needs more current (approx 300-350ma compared to the EF86's 200ma)the question is that the mains transformer is capable to supply it. The mic will sound different with E80F too, it is pity as I have a big box of E80F's...

 

[jrasia]

E80F heater needs more current (approx 300-350ma compared to the EF86's 200ma)the question is that the mains transformer is capable to supply it. The mic will sound different with E80F too, it is pity as I have a big box of E80F's...

Ahh, thats a shame.  I have an EF86 on hand as well.  The e80f definitely sounds more 'sparkly' than the ef86, but maybe thats the lack of heater supply.

 

[fgan81]

EDIT: It sounds great, found that error, Main-Mic PCB wasn´t soldered to the little small bridge to connect to Tube PCB. Only the two big bridges where soldered.
----
Hey, i finished everything and the measurements are fine. But I only get a really silent signal, i mean really silent like nearly nothing. Is it possible that i changed sides at t67? I can measure correct values at B+ and H-( at mic pcb). At t67 I can't find a black sign, only a silver one, I am not sure if t67 is correct mounted. How I can control that? How I get sure if the tube is not bad? Any additional idea?

Thanks for help...