Neumann Vintage U87 Clone : Build Thread.

[poctop]

Something is wrong the output should remain constant trough , do you happen to know how this is happening
afer power on for a short period -- intermittent --  is it sytematic,

if you set the drain at 11V what is happening the 51pf cap should not be used for biasing but you actually inject the signal there ,

if you can find out in wich context this is happening this will be the first part of your problem solved,

hope this helps,
D

 

[poctop]

Heya guys,

does anyone ever tried Marik's trafos in this build?

http://samaraudiodesign.com/BobbinTransformers.html

How do they sounded?

I was unaware of them. Do you know where they are located?

would also be happy to see SAMAR chime in as well,
all doors open ,
D.

 

[drAk]

Has anyone tried the Peluso P-T87 yet? I'm looking to go with either the T13 or the Peluso and would be great to hear comments if someone's tried it.

 

[mateus]

I was unaware of them. Do you know where they are located?

Sorry, I have no idea. I just suggested since I've heard and read some hi praise about Samar's products.

Thx

 

[mrcase]

Something is wrong the output should remain constant trough , do you happen to know how this is happening
afer power on for a short period -- intermittent --  is it sytematic,

if you set the drain at 11V what is happening the 51pf cap should not be used for biasing but you actually inject the signal there ,

if you can find out in wich context this is happening this will be the first part of your problem solved,

hope this helps,
D

Alright. So the output should remain the same, whatever value I set the trimmer to? And I thought I inject the signal for scope biasing at R6? Hmm I think I got it all wrong...
Dan, could you explain it for dummies again how I should bias my mic?  thank you!!!

 

[poctop]

Something is wrong the output should remain constant trough , do you happen to know how this is happening
afer power on for a short period -- intermittent --  is it sytematic,

if you set the drain at 11V what is happening the 51pf cap should not be used for biasing but you actually inject the signal there ,

if you can find out in wich context this is happening this will be the first part of your problem solved,

hope this helps,
D

Alright. So the output should remain the same, whatever value I set the trimmer to? And I thought I inject the signal for scope biasing at R6? Hmm I think I got it all wrong...
Dan, could you explain it for dummies again how I should bias my mic?  thank you!!!

I mean the output will change as you increase the voltage to the drain but at a certain point it wil not change anymore this is about the bias point,  i mean once you have set the symmetry the output is not suppose to change when using the mic,  hope this help
Dan,

 

[sirblue52]

hi, first time posting, having a lot of fun building this particular project.  (thank you Dany!)

I am trying to perform the fet bias, having trouble understanding how to setup.

The sine waveform I get is not symmetrical, wide bottom and narrow top, nor does the clipping ever get symmetrical - forgot to take screenshots.  I am using a software o-scope and sound card.

I must not be setup correctly.
Any help much appreciated!!

See my photos:

 

[HellfireStudios]

First, disconnect the other transformer primary. Second, I can't tell what your FET gate is hooked to. If your gate is hooked up properly, it could be just the transformer being half hooked up.

-James-

 

[wave]

Hello fellow DU87 builders!
So I recently finished a mic for a client and I'm having an issue. The mic sounds great in cardioid but in figure 8 the back side of the capsule sounds like there's a low pass filter engaged. The capsule is working correctly (I'm using one of Eric's awesome K87 capsules).
He put it into his test mic and ruled out any possibility of it being the problem.
I'm wondering which components I should test to fix this issue.

Thanks!
Dave

 

[HellfireStudios]

Hello fellow DU87 builders!
So I recently finished a mic for a client and I'm having an issue. The mic sounds great in cardioid but in figure 8 the back side of the capsule sounds like there's a low pass filter engaged. The capsule is working correctly (I'm using one of Eric's awesome K87 capsules).
He put it into his test mic and ruled out any possibility of it being the problem.
I'm wondering which components I should test to fix this issue.

Thanks!
Dave

I woukd check C2. If it is styrene, alcohol, high heat, or long heating times could have taken it out. R4 would be next, but highly unlikely.

-James-

 

[Marcocet]

I finally got the parts together to build my other three U1671. All the optional caps are styrene, and all three have original neumann transformers. As of now one has a brand new Neumann K87, one has a Peluso P-K87 (albeit a slightly used one), and one has a Microphone Parts RK-87. The bodies were provided by microphone-parts.com along with the capsule stands which he graciously customized to work with the other capsules.

Sound samples to come as soon as I can get a minute in the studio.

 

[Volume11]

I finally got the parts together to build my other three U1671. All the optional caps are styrene, and all three have original neumann transformers. As of now one has a brand new Neumann K87, one has a Peluso P-K87 (albeit a slightly used one), and one has a Microphone Parts RK-87. The bodies were provided by microphone-parts.com along with the capsule stands which he graciously customized to work with the other capsules.

Sound samples to come as soon as I can get a minute in the studio.

Interesting, looking forward to hearing the capsule comparisons.

 

[poctop]

+1

 

[mateus]

I can't find a good U87 body that I like... When I discover that M-Parts have one I like... It's not for sale anymore.
I guess I'll keep looking.

 

[geekmacdaddy]

Greetings Builders of Beautiful Microphones.
I started hearing a noise that could have a been a burnt (even though I took all precautions when soldering) styrene...then I remembered burning my XLR connector with the iron..burnt some plastic and the cable doesn't latch properly into the connector. Sure enough, I wiggled the  cable at the mic, and that's the problem. Does anyone happen to know the mouser part # for that piece of plastic with the 3 pins and screw?

Thanks!
Jeff

 

[Marcocet]

Greetings Builders of Beautiful Microphones.
I started hearing a noise that could have a been a burnt (even though I took all precautions when soldering) styrene...then I remembered burning my XLR connector with the iron..burnt some plastic and the cable doesn't latch properly into the connector. Sure enough, I wiggled the  cable at the mic, and that's the problem. Does anyone happen to know the mouser part # for that piece of plastic with the 3 pins and screw?

Thanks!
Jeff

I don't know if you can buy just that part, but any switchcraft style male xlr insert will usually fit. \

Happens to me all the time by the way, especially with switches. I forget to turn the heat down and the plastic melts before I can even get the solder to bond.

 

[geekmacdaddy]

Thanks. I went back in and had a look. I did a crap job soldering one of the pins. All better now.

 

[Marcocet]

Well, here they are.

DISCLAIMERS: This was, due to time constraints, an extremely brief test. The mics were put up in one corner of the room in a line, and the sources were recorded at least 4 to 5 feet away in order to get some sort of even dispersal. No attention was paid to mic placement. The three mics are identical builds with vintage U87 transformers. The FETs all tested extremely close IDss (almost exactly 10mA for those interested). The Microphone Parts and Neumann capsules were brand new, but the Peluso had been used in a previous incarnation of this same mic. It may have had a little bit of dust on it.

As a side note I also set up one of my original builds, and there was a HUGE difference in noise floor. Paying better attention to keeping the boards and inside of the head basket clean seems to have caused a significant improvement, not that I should be surprised.

Anyway, enjoy the improvisational arts of my partner and co-engineer Daniel Schlett.

https://www.dropbox.com/sh/v89qi3xsafsr7uo/4dbKzVX_bb

I'll save my own opinions for a few days.

 

[burglar]

2x MXL 2010 mics currently on eBay:

http://www.ebay.co.uk/itm/261112577064?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649

 

[poctop]

Well, here they are.

DISCLAIMERS: This was, due to time constraints, an extremely brief test. The mics were put up in one corner of the room in a line, and the sources were recorded at least 4 to 5 feet away in order to get some sort of even dispersal. No attention was paid to mic placement. The three mics are identical builds with vintage U87 transformers. The FETs all tested extremely close IDss (almost exactly 10mA for those interested). The Microphone Parts and Neumann capsules were brand new, but the Peluso had been used in a previous incarnation of this same mic. It may have had a little bit of dust on it.

As a side note I also set up one of my original builds, and there was a HUGE difference in noise floor. Paying better attention to keeping the boards and inside of the head basket clean seems to have caused a significant improvement, not that I should be surprised.

Anyway, enjoy the improvisational arts of my partner and co-engineer Daniel Schlett.

https://cdn.groupbuilder.com/groupdiy/u/39511/58d0281993916

I'll save my own opinions for a few days.

Hey Marcocet, Thanks For taking the time in doing This experiment and Share with us , I did not listen yet but i can tell you that it is on my plate now as i am back from a work trip and did not have my SennHP
Best, 
D.