Neumann Vintage U87 Clone : Build Thread.

[MetalD]

Edit: never mind stupid question

 

[soulitude]

I'm thinking of building myself a D-87.
I haven't got any possible mic donor bodies laying around so I need to buy one, and I want it to be as cheap as possible.
The suggestions mentioned in this thread aren't that easy to find here in Sweden. Or Europe I guess.

So (sorry for being a newbie) now I'm asking if any of you guys know if the cheapest U87 looking mics on Thomann would do the job for me?
Like this one:
http://www.thomann.de/gb/the_tbone_sc400_grossmembranmikro.htm

Or maybe any other suggestions?

Thanks!

 

[melomane]

I'm thinking of building myself a D-87.
I haven't got any possible mic donor bodies laying around so I need to buy one, and I want it to be as cheap as possible.
The suggestions mentioned in this thread aren't that easy to find here in Sweden. Or Europe I guess.

So (sorry for being a newbie) now I'm asking if any of you guys know if the cheapest U87 looking mics on Thomann would do the job for me?
Like this one:
http://www.thomann.de/gb/the_tbone_sc400_grossmembranmikro.htm

Or maybe any other suggestions?

Thanks!

Buy directly the kit from mic&mod: http://micandmod.com/en/diy-mics/45-u87-diy-kit.html
They are from France, so fast shipping and no customs for you ;D

 

[jimmytillier]

Hi everyone,
I'm french so I apologize for the mistakes.

I bought a pair of u87DIY kit from mic and mod, and I have some issues with them, I'd like you to help me if you can.

- On the first, I have a directivity problem. It seems to have the three polar patterns, but they don't match with the pattern of the switch. Mic and Mod told me to check the conductivity of the wires when using the switch, and here are the results:
switch in 8 position: conductivity between the cardioid and 8 wires
switch in cardioid position: no conductivity between the cables
switch in omni position: conductivity between the omni and cardio wires.
The question is: why do I get the cardioid pattern when I choose the 8 pattern ?

- On the second microphone, it's a bigger problem, I have no sound.
Here are my voltages, with the transistor plugged and the potentiometer R11 set to 0
Phantom power is 46.8v
top of L1 - 46,7v
top of L2 - 46,7v
top of R18 - 46,7v
top of R19 - 46,2v
bottom of R17 - 46,2v
top of R17 - 23v
Zener 23v
FET drain pad 0,5v
FET source pad 0v
top of R12 18v
top of R13 43v
top of R14 19v
top of R8 39v
Top of C14: 46,2V
When I raise the resistance R11, I hardly get 6,5V of Drain voltage, but it's impossible to have more.

Thanks for your ideas...

 

[jimmytillier]

Hello everyone,
I solved my problems, so for those who could have the same problems:

- The directivity problem was caused by a short circuit near the directivity switch, the "omni" wire was shorted to the ground.
- On the second mic, the transistor was broken. I replaced it, and everything went fine.

 

[Maddin89]

hello guys,

thanks for that great project. i build a u87 from micandmod and got stucked with a problem.
when i pluged the micro in the preamp i get no sound, only crackle, noise and pops. (kindar hythmic clacks?!)
here are my voltages with everything connected (trafo,capsel)

phantom power: 45,3V
top of L1 : 42V
top of L2 : 42V
top of R18: 42,8V
top of R19: 42,7V
top of R17:  22,5V
bottom of R17: 42,7V
Zener: 22,5V
FET drain: 2,08V  !!!!!!!!!
FET source: 1,3V ???????
top of R12 : 2,0V !!!!!!!!! <<<< i think there is the problem. i checked the resistor- 45 k
bottom of R12: 18,8V
top of R13: 34V
top of R8: 32V
top of R6: 30V
bottom of R6: 32V

it would make me so happy when you could help me out.

best regards martin

 

[poctop]

hello guys,

thanks for that great project. i build a u87 from micandmod and got stucked with a problem.
when i pluged the micro in the preamp i get no sound, only crackle, noise and pops. (kindar hythmic clacks?!)
here are my voltages with everything connected (trafo,capsel)

phantom power: 45,3V
top of L1 : 42V
top of L2 : 42V
top of R18: 42,8V
top of R19: 42,7V
top of R17:  22,5V
bottom of R17: 42,7V
Zener: 22,5V
FET drain: 2,08V  !!!!!!!!!
FET source: 1,3V ???????
top of R12 : 2,0V !!!!!!!!! <<<< i think there is the problem. i checked the resistor- 45 k
bottom of R12: 18,8V
top of R13: 34V
top of R8: 32V
top of R6: 30V
bottom of R6: 32V

it would make me so happy when you could help me out.

best regards martin

I strongly suggest you contact Mic and Mod For Support then,
regards,
Dany,

 

[Maddin89]

hello guys,

thanks for that great project. i build a u87 from micandmod and got stucked with a problem.
when i pluged the micro in the preamp i get no sound, only crackle, noise and pops. (kindar hythmic clacks?!)
here are my voltages with everything connected (trafo,capsel)

phantom power: 45,3V
top of L1 : 42V
top of L2 : 42V
top of R18: 42,8V
top of R19: 42,7V
top of R17:  22,5V
bottom of R17: 42,7V
Zener: 22,5V
FET drain: 2,08V  !!!!!!!!!
FET source: 1,3V ???????
top of R12 : 2,0V !!!!!!!!! <<<< i think there is the problem. i checked the resistor- 45 k
bottom of R12: 18,8V
top of R13: 34V
top of R8: 32V
top of R6: 30V
bottom of R6: 32V

it would make me so happy when you could help me out.

best regards martin

I strongly suggest you contact Mic and Mod For Support then,
regards,
Dany,

They suggest my to write in this thread 
I would be glad if you could give a tip me what to measure.

regards Martin

 

[poctop]

They suggest my to write in this thread 
I would be glad if you could give a tip me what to measure.

I am Sorry but I Cannot Provide Free Advice and troubleshooting Tips for Mic and Mod,
Mic and Mod should be able to Provide is own Support Channel ,
Best regards,
DAn,

 

[poctop]

Hi Am working on to Revisit The D-87 Mono-Block for the new SYt-5 mic body,

I had a Spare original Transformer and i will be reskinning myself my own vintage K87 capsule Very soon,

Stay tuned,
dD

 

[kante1603]

Cool stuff brother Dan!
And reskinning on your own......WOW!!!

Best from munich,germany,

Botsf Udo.

 

[MetalD]

I'm in for one of those mono-blocks. Gonna have myself a stereo pair of u87's.

 

[Aleks]

Hi Everyone, I am new to the group and have a quick question.

I'm in the process of building two U87 clones on Dan's platform. I don't have a pre-amp with phantom power. Can I use a standard bench top power supply which has the option to leave the output floating at 48VDC? This is just for test purposes while I set up the FET, not for actual use with a pre amp.

I have an oscilloscope and a HP3585b spectrum analyser with tracking generator for setting the FET bias with the aim to getting the maximum output with minimum distortion products. When i get the time I will test a few FETS with different IDSS and post the distortion product plots, be interesting to see for real how this FET behaves.

Great group, I really like the community concept with the sharing of ideas and technology.

Cheers,

Aleks

 

[shabtek]

@Aleks--yes a bench supply will work, build a "y" cable/mic cable that will allow you to inject +48vdc to the +/- signal wires via matched 6.8kΩ r's and connect - output of p.s. to cable sheild.

 

[Aleks]

Thanks very much for the info.

 

[pryoga]

Hi guys, I am about to start 2 of these using the v1.1 batch of the pcb's.  I feel a bit like the tortoise just getting off to a start when the race has already been run and won.

My question (and I my have missed a reference to it) in my read of the 114 pages of this thread is whether there is any things I need to be aware of with the v1.1 version of the pcb as the current boards are at v1.2.

Thanks in advance.

 

[poctop]

Hi guys, I am about to start 2 of these using the v1.1 batch of the pcb's.  I feel a bit like the tortoise just getting off to a start when the race has already been run and won.

My question (and I my have missed a reference to it) in my read of the 114 pages of this thread is whether there is any things I need to be aware of with the v1.1 version of the pcb as the current boards are at v1.2.

Thanks in advance.

the first version is almost the same , in version 1.2 the trim post package was added near the resistance package for better support of the trim pot,
that about it, 
Best,
Dan,

 

[sr1200]

Dan, sorry, late to the party yet again,
whats the difference with the monobloc design and the regular one (just 1 board?) or are there other component level differences?

 

[poctop]

Dan, sorry, late to the party yet again,
whats the difference with the monobloc design and the regular one (just 1 board?) or are there other component level differences?

it is the same component as the original version the addition or the goal to this one was to have everything on a single pcb and have all the HI-Z connection Floating so in total there will be 6 floating connection on teflon isolated pin to emulate the original design as the HZ modular headbasket performance of the original. in addition to this it will have on board transformer support, I am still looking for a SYT-5 mic body kit to test it out , i should have a little run made of 10 untis in about 2 weeks ,
the other goal with this one is to have a bench testing circuit for my new capsule reskinning work as well.

Best,
Dan,

 

[sr1200]

you forgot about the part about you separating me from more of my money once those bodies come in...