Neumann Vintage U87 Clone : Build Thread.

[S-O]

Hey there, been following these builds for a while! I am about to take the plunge, but I will admit I am still a little ignorant of how to get some of the parts from the Mouser BOM that are out of stock or are no longer carried. Without asking someone to hold my hand the whole time, where would one find these? Are all of them necessary, or were some parts swappable?

Thanks for any help, and with any luck I will be placing an order soon!

 

[wave]

Hey there, been following these builds for a while! I am about to take the plunge, but I will admit I am still a little ignorant of how to get some of the parts from the Mouser BOM that are out of stock or are no longer carried. Without asking someone to hold my hand the whole time, where would one find these? Are all of them necessary, or were some parts swappable?

Thanks for any help, and with any luck I will be placing an order soon!

Hi,
I have an updated Mouser BOM I can share with you. The only parts they don't have are the styrenes. You can buy these from Dany when you get your PBCs tho...

If you shoot me a PM with your email, I'll share the BOM with you

Dave

 

[fazeka]

If you are working on the Blue Version of the pcb you should adress your question in the other thread for this one ,
I have posted in the opther thread for this one.

OK, I replied there but wanted to ask here as it is still pertinent as well:

A) i would defo check if you have proper isolated backplates,

I missed how to check on properly isolated backplates. Can someone enlighten me? This is a tskguy (Eric's) capsule, FWIW.

If the backplates are not properly isolated, is this fixable?

Thanks,
Chris

 

[fazeka]

Only means I could think of to check if the backplates were isolated was to check with my Fluke 73III DMM.

On continuity, I hear a short single (not continuous) "beep", although I don't know what this means vis-a-vis the backplates if they are touching or not...

 

[rob61]

If the plates are isolated, there should be 4 wires coming off the capsule. If they are not isolated, there are 3 (for a front and back version capable of omni). If you touch the two backplates with your continuity tester, it should not beep - no conduction between the backplates if they are isolated.

 

[S-O]

Hey there, been following these builds for a while! I am about to take the plunge, but I will admit I am still a little ignorant of how to get some of the parts from the Mouser BOM that are out of stock or are no longer carried. Without asking someone to hold my hand the whole time, where would one find these? Are all of them necessary, or were some parts swappable?

Thanks for any help, and with any luck I will be placing an order soon!

Hi,
I have an updated Mouser BOM I can share with you. The only parts they don't have are the styrenes. You can buy these from Dany when you get your PBCs tho...

If you shoot me a PM with your email, I'll share the BOM with you

Dave

PMed! Thanks a ton, expect an order soon Dany!

 

[dreadheaded]

Sorry this took so long, I kept forgetting to bounce the files out  

So this is basic shootout of 2 U87 clones, one with a beezkneez k8 the other with a peluso k87i against a Neumann U87ai on a female vocalist.

So I should preface all of this by saying that I believe the beezkneez is actually faulty and has been sent back to Aus for a little tune up and the mic that had the beezkneez capsule actually had c6 removed entirely to try and give back some high end.

There is obviously a slight compromise in the setup we used as to micing in the perfect position, resulting in all of the mics being slightly off axis. I would normally have put the low pass on but we felt for testing it was best to leave it off, because we went further later with using some EQ tests and such.

The mics are running through  neve 1073LBs  straight into ssl alpha link converters recorded at 96/24 no editing or mixing has been done at all to the files, except for a level match, that is just done on the faders and peak level, which obviously has slight issues in this set up, but I think the difference is minimal enough that it should be insignificant.

I have uploaded the raw wav files and for some reason cant get them to actually stream of anything, so unfortunately it looks like they have to be downloaded (I am guessing because of the sample rate).

I doubt very much this will be our last test, We most definitely will be looking at the Beezkneez capsule again once we get it back. I would also like to make it clear that despite issues with the capsule we recieved from them Beezkneez have been excellent to deal with and the customer service is a different class to most places we have dealt with (plus their emails have a nice Australian twinge that is endearing!)

I definitely have made some decisions on what I like more but I am quite keen to hear what other people think before I muddy the waters with my opinions

Link can be found here: https://www.dropbox.com/sh/2zrzquskpb1m28k/AAAbQPaq8jmL7ckwx3-sxuwwa?n=79612

 

[dreadheaded]

It seems that the mic that contained the beezkneez capsule also has an issue, now that it has been removed I thought I would chuck the peluso capsule in there to make sure it was just the capsule behaving oddly and Omni is about 20db quieter then everything else on that mic, I notice that intermittently the polarization voltage seems to drop to around 17v, although I understand there are issues actually reading the voltage there with a DMM, I have on several occasions measured there with my 2 different DMMs and they give completely different readings,

 

[andyfromdenver]

Hi all 

I know I got all excited @ the first of the year about making another, then dropped off the planet. 
Well, I've made a lot of progress:
Got my boards loaded
Blingy Polystyrenes and tants,
All continuity checks good and teeth brushed.
Selected a 9.3-ish IDSS 2N3819

Then, I was about to message tskguy, when I was strolling the capsule choices and guess what!?!?  Zenproaudio is having a black friday wknd sale 10% off peluso and free shipping, so I bought another P-K87i.
I was hoping he'd have the T13 too, but no luck so I still need that.

Anyhoo, I have nix'd my LED idea for now and just want simple quality. Though I may paint the body.

Was I getting to something??? Yes!  So, I realize this will elicit some eye rolls and cricket sounds amidst silence  :

But I am reading Matador's tut on using the meter to bias cause I want to do it right.  I borrowed my friends meter, but it was a gift and he's never used it either!  But it has all the connections and works.
Would anyone with the grace of a saint care to hand hold me through it's use?  I see I can bias prior to txfmr load in by visual and I'd like to hard wire the resistor eventually.
I have the 50pfd cap too.

If not no biggie, I am reading etc. but I just don't want to damage anything.
If this one turns out well I am going to maybe trade it for a painting by my favorite musician/artist Will Cullen Hart. 
I biased my last by ballpark and ear and it's a mega success, but I'm trying to improve my skills.

Take care all!
Andy

edit update:  I thought this scope had a signal generator that I could use as well.  I see it doesn't.  I'm going to finish the build completely and try the method of placing it a foot from a speaker with a 1khz sine wave and then observing on the scope   gonna be a couple weeks while waiting for parts.
edit update #2: just placed an order from the only vendor currently listing the Tabfunken T13, Audio Power Tools (cyberMonday!!); also read the sad news about Mr. Oliver Archut   my sincere condolences to the family.
edit update #3:  ok I demystified this scope and have a plan for a signal generator.  Back on track lol.

 

[useme2305]

here's my build.

finished it with pretty much no problems at all.
biased it with my scope.
output is on the lower side though.
while selecting the FET it read 7,5mA when testing it.

just to re-assure that i have a perfectly working mic...i need 45db of gain from any of my preamps to get a decent signal with about the usual 10db of headroom in my UFX when speaking into the mic in cardioid 15cm away from the headbasket.

i have the lead reversed version of the T13..so yes, i know about this issue. i installed it both possible ways anyways before settling for the correct way with a near healthy amount of output level.

the capsule is from microphone-parts dot com

 

[poctop]

here's my build.

finished it with pretty much no problems at all.
biased it with my scope.
output is on the lower side though.
while selecting the FET it read 7,5mA when testing it.

just to re-assure that i have a perfectly working mic...i need 45db of gain from any of my preamps to get a decent signal with about the usual 10db of headroom in my UFX when speaking into the mic in cardioid 15cm away from the headbasket.

i have the lead reversed version of the T13..so yes, i know about this issue. i installed it both possible ways anyways before settling for the correct way with a near healthy amount of output level.

the capsule is from microphone-parts dot com

Yeps ,  totally normal with 45db,  The vintage U87i has about 10db lower gain than modern mics,
but the colour is beautifull,
thanks for the post ,
8)
Best,
Dan,

 

[kante1603]

Yeps ,  totally normal with 45db,  The vintage U87i has about 10db lower gain than modern mics,
but the colour is beautifull,
thanks for the post ,
8)
Best,
Dan,

Confirmed ;D


Best,


Udo.

 

[fazeka]

Hi,

I finally (I think, see below) figured out how to wire up my (Eric's/tskguy's) capsule...

I noticed in figure 8 that the back capsule is slightly brighter/louder than the front capsule (what I call "front" for cardioid). In omni, front and back are equal in tonality/output.

Anyone else notice similar?

Cheers,
Chris

 

[patxiplg]

Hello everybody!

I have just biased the JFET of my U87 with an oscilloscope (Matador's way) and I'd like to ensure that the results are normal, because even I am able to get a symmetrical flat part of the output sine wave, it's slightly different on its upper part (and I can't modify that by adjusting the potentiometer). Also I'm getting a gain of around 20 which is way more than what I've been reading here (9...6...etc).

Is that normal?

I uploaded two captures of the scope so you can see the wave!

Thank you in advance!

 

[andyfromdenver]

I got to the point of the transformer-stuff-debacle and wanted to share my "never leave the bench" mod!
I'm going to pretend in a magical world I am offering some small shielding in the process.

For me to have a nice mic for my recordings and keep the $ amount low ($5 for the donor at the flea market, hello!) is just...i'm speechlessly grateful to all

it'll be interesting to have the Peluso trans (in my 1st) and Ami to cross examine the witness.

Sushi roll
1 of 2

 

[andyfromdenver]

Oh yeah, takes four hands
2 of 2

 

[andyfromdenver]

Hi gents and ladies (?)
I need help
Still experimenting, but wanted to ask.
I figured out how to use my old loaner scope.
I had to improvise on the 1k sine wave though.  I am using my microkorg.  I can't get the volume to cause the wave to clip.
I think everything is set up right.  Is it just that for this set up i need a boost pedal as well?  Wanted to ask before I get too experimental.
Plus, I wired in the lil 50pf cap, but see that this is unnecessary, is that any contributing factor?

Thank you!!

*big edit, that was the old...er..two hours ago me  : 8)

So!  I figured out my diy method to get the signal generator and work the scope and bias correctly.
I'd be happy to help any newbstinatrixs sort out this part as I was able to finally teach myself
The cool thing is, with the transformer in, you can hear when the tone is in the "sweet spot" pretty easily I thought, and visually confirm with the scope.
I used the microkorg into a preamp to deliver the level necessary to get the clipping.*

 

[andyfromdenver]

Hello everybody!

I have just biased the JFET of my U87 with an oscilloscope (Matador's way) and I'd like to ensure that the results are normal, because even I am able to get a symmetrical flat part of the output sine wave, it's slightly different on its upper part (and I can't modify that by adjusting the potentiometer). Also I'm getting a gain of around 20 which is way more than what I've been reading here (9...6...etc).

Is that normal?

I uploaded two captures of the scope so you can see the wave!

Thank you in advance!

hope to help.
That is roughly how my waveform appeared.  Although, I felt it was soo helpful  to actually hear the output, because the sweet spot when the clipping is symmetrical is fairly unmistakable in my experience.  So if you haven't added the capsule yet, and can wire in the transformer, I think it would be worth a listen.
But, on both my old and the new build I did, when the sound was "sweet" (as you dial the pot you can hear the distortion lessen, then if you keep dialing it comes back) it corresponded exactly to the image I showed in my pic, so I believe you can trust your eyes too

I'm not sure what you mean exactly about the gain, so hopefully someone else can elucidate.

 

[Nyquist]

Looks totally fine to me.  Time to plug it in and record some stuff.

 

[kante1603]

@patxiplg:


looks quite nice,I've digged in the old posts and  found my reply #305 on page 16:


http://groupdiy.com/index.php?topic=48030.300


Look at the last pic,the clip symmetry is slightly "odd" too.
Remember this is already the range where the mic is clipping,you won't listen to this in reality.
Since your sine waves look asolutely fine I'd say it is listening time now!


Have fun,


Udo.


Edited for typo.