HellfireStudios

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #120 on: March 29, 2012, 03:30:13 AM »
mrcase, the easiest way to remove the stamped logos is to fill it with epoxy (kneaded type works best for me, but requires more paint to look totally smooth). On the cheap side, Mighty Putty comes to mind. There is an equivalent (more expensive) available at ACE Hardware stores that is grey.
Just overfill the logos, and wait for it to cure. Sand flush (down to 220 grit), and finish with desired color. Be patient with dry times and everything should turn out fine.
"Tommorrow is just yesterday in reverse. Just like friends are enemies in reverse." -Gary Busey


kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #121 on: March 29, 2012, 04:24:04 AM »
loog great! how did you get rid of the stupid behringer engraving? or did you just paint it and its still there?
mrcase, the easiest way to remove the stamped logos is to fill it with epoxy (kneaded type works best for me, but requires more paint to look totally smooth). On the cheap side, Mighty Putty comes to mind. There is an equivalent (more expensive) available at ACE Hardware stores that is grey.
Just overfill the logos, and wait for it to cure. Sand flush (down to 220 grit), and finish with desired color. Be patient with dry times and everything should turn out fine.

Hi,

I have done that with 2K glue (for metall connections),worked superfine on a t-bone mic with really deep engravings.
BTW:The B2 I bought is not engraved,just painted,so pretty easy to handle.

Cheers,

Udo.
« Last Edit: March 29, 2012, 04:27:15 AM by kante1603 »

mrcase

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #122 on: March 29, 2012, 04:32:04 AM »
Great info! Thanks all. what kind of paint would you recommend? and should I sand the whole body as a preparation for the painting process?

sincerely yours
mrcase  ;)

mrcase

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #123 on: March 29, 2012, 04:34:21 AM »


I have done that with 2K glue (for metall connections),worked superfine on a t-bone mic with really deep engravings.
BTW:The B2 I bought is not engraved,just painted,so pretty easy to handle.

Cheers,

Udo.

strange. mine has a quite deep engraving - I bought mine used. did you buy yours new?

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #124 on: March 29, 2012, 04:49:30 AM »
Hi,

for kante,
 I will try to take other photos of the inside. The pcb is just in place with a little cord, I have to make new holes in the pcb to fix it. The transformer just sit between the pcb and the XLR connector, it isn't fixed but don't move at all.
For the switch, if you take a look at the B2 head of the mic, you will see that there are 6 pins wich connect the head to the body. You will use 4 of them for the capsule, so the 2 others can be use for the low cut or the pad. For the other one and the polarity switch, you have to put cables. I don't connected them to the switch and prefer open the mic for changing the polarity of the mic (I use cardioide 90% of the time)  If you find another solution, I'm open to it!
Hi Adrien!

thank you for the fast reply.
As said I haven't opened the mic yet,but I want to use the switches from the outside as "normal".
Concerning your mounting solutions of the pcb as well as for the transformer I must say that I'm not lucky with it(thinking of the possibility of parts moving inside a condenser mic makes me very very nervous).
Let's see how this works out when I open up mine,I'm sure there are some things doable a "better"way,hahaha.... :)

Have fun,

Udo.

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #125 on: March 29, 2012, 04:52:17 AM »
strange. mine has a quite deep engraving - I bought mine used. did you buy yours new?
Hi,

yes,bought mine 3 days ago at Thomann germany,definitely not engraved!

Cheers,

Udo.

pavthefiddler

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #126 on: March 29, 2012, 04:54:43 AM »
strange. mine has a quite deep engraving - I bought mine used. did you buy yours new?

Yeah I bought mine new just now and there's no engraving, just paint. But I used B2 maybe 8 years ago or so and I remember it had quite deep engravings.

kante1603

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #127 on: March 29, 2012, 05:55:28 AM »
Great info! Thanks all. what kind of paint would you recommend? and should I sand the whole body as a preparation for the painting process?

sincerely yours
mrcase  ;)
Hi,

I have done my "T-Bone"(containing max┬┤s MK47 of course ;D) as follows:
*Filled the engravings with 2k glue for metall connections and let it dry well
*Sanded the whole body and controlled the formerly engraved parts with my figer tips
*Cleaned it to get rid of any dust and fat parts
*Used a 1K primer (spray) first
*Put "Hammerite" laquer on it to give it a vintage look
*Let it dry very well before proceeding assembly

I should mention that it is very important not to put any laquer on the top and bottom parts where the metall tube is touching the head basket and the bottom part!This would destroy the propper shielding against rf.Simply measure from head to bottom after assembly,your DMM reading should end up very close to 0 ohms.

Have fun,

Udo.

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #128 on: March 29, 2012, 08:06:57 AM »
I really recommend the aurycle 460 body or the MxL type as they are a perfect fit but well this is diy after all ;D
Dan,

HellfireStudios

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #129 on: March 29, 2012, 10:24:47 AM »
Great info! Thanks all. what kind of paint would you recommend? and should I sand the whole body as a preparation for the painting process?

sincerely yours
mrcase  ;)

Hammered finish paint tends to be one of the stronger paints. Self-etching primer isn't a bad idea beforehand either. You should google search how to paint/bake the finish on DIY guitar effects pedals. It is supposed to make the paint even tougher.
Sand the body down, in increasing grits on the engraved bits, and with 220 grit on the rest. Prime, paint, bake, label(optional), and clear coat as many times as needed with baking in between coats. There is a lot to it, but it looks great when done right.
"Tommorrow is just yesterday in reverse. Just like friends are enemies in reverse." -Gary Busey


Re: Neumann U87 Vintage Circuit Build Thread
« Reply #130 on: March 29, 2012, 03:56:48 PM »
The black wire at the top of the microphone Aurcycle 460 between the pad and the high pass gets connected to what on new boards?  Does it get connected to the ground link or Cground? 

I also connected the xlr wires like this hopefully this is right.  I don't do this everyday.

red = hot
white = cold
black = ground

When I start to check the bias of the mic I don't have the capsule in right?

I need to look back in the treads and find out how to do it again.  But i do plug it into a mic cable hook up to a preamp with phantom power right?

thanks
-Scott

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #131 on: March 29, 2012, 05:18:03 PM »
Ok So I read the fet and adjusted the r11 to 10.53 volts from 10.8.  The R11 value goes from 15.77 - 15.92 resistance on my DMM each time it seems to be different.  Could be me i guess.  What resistor should i buy to replace the pot?   My zener is reading 22.82.  The overall phantom power reads 46.3 volts.  I guess this is why my numbers are a little off. 

Questions is should I go ahead and install John P capsule.  Is it ok to do this without hurting it?

Secondly what resister should I use to replace the R11 pot

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #132 on: March 29, 2012, 05:32:43 PM »
Ok So I read the fet and adjusted the r11 to 10.53 volts from 10.8.  The R11 value goes from 15.77 - 15.92 resistance on my DMM each time it seems to be different.  Could be me i guess.  What resistor should i buy to replace the pot?   My zener is reading 22.82.  The overall phantom power reads 46.3 volts.  I guess this is why my numbers are a little off. 

Adjust the pot to get about 11V on the drain pad if you dont have any other way as a sine tone or scope, you can leave the pot inside if you already solder it to the board,  if not then the resistance from the Pot to replace with a specific resistance must be measured completely out off circuit this is why your meter is confused.

Questions is should I go ahead and install John P capsule.  Is it ok to do this without hurting it?

I would make sure all the voltage are right before installing the capsule,  you should get about 40V from the (bdy) pad on the (FC)  connection
the really best way to tune the FET is with an input signal in , 
Secondly what resister should I use to replace the R11 pot

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #133 on: March 29, 2012, 05:33:07 PM »
The black wire at the top of the microphone Aurcycle 460 between the pad and the high pass gets connected to what on new boards?  Does it get connected to the ground link or Cground? 

I also connected the xlr wires like this hopefully this is right.  I don't do this everyday.

red = hot
white = cold
black = ground

This is Correct

When I start to check the bias of the mic I don't have the capsule in right?

I need to look back in the treads and find out how to do it again.  But i do plug it into a mic cable hook up to a preamp with phantom power right?

thanks
-Scott

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #134 on: March 29, 2012, 05:34:19 PM »
The black wire at the top of the microphone Aurcycle 460 between the pad and the high pass gets connected to what on new boards?  Does it get connected to the ground link or Cground? 

I also connected the xlr wires like this hopefully this is right.  I don't do this everyday.

red = hot
white = cold
black = ground
This is Correct

It may Vary from mic to mike ,  the best is hot = pin 2   cold =pin 3 GND pin 1 with this you never get it wrong unless you are in the middle of the 60's


When I start to check the bias of the mic I don't have the capsule in right?

I need to look back in the treads and find out how to do it again.  But i do plug it into a mic cable hook up to a preamp with phantom power right?

thanks
-Scott

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #135 on: March 29, 2012, 05:37:21 PM »
Quote
The black wire at the top of the microphone Aurcycle 460 between the pad and the high pass gets connected to what on new boards?  Does it get connected to the ground link or Cground? 

Is this black wire the Mic basket ground or mic body grnd or simply grnd ,  if it is you can connect to Gndlink,
GndLink are at the same level of gnrd,   one is designed for Traffo core Gnrd and the other one for linkin mic Body parts to grnd if needed,

Dan,

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #136 on: March 29, 2012, 05:50:42 PM »
Do I pull the gold tape off of the backplate/body of John's Capsule.  Its in the way of the screw holes.  I can push the screws threw the tape but I think it should come off.  Just wanna make sure. 


Re: Neumann U87 Vintage Circuit Build Thread
« Reply #137 on: March 29, 2012, 06:02:52 PM »
Dont Remove the Tap in any case ,

just use sharp tool pointy to pierce it and then screw ,  refer to thread for the capsule mounting ,
D

Marcocet

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #138 on: March 29, 2012, 06:28:07 PM »
Fair warning: If you are using the aurycle mic bodies (or prob many others) do NOT store the microphone in the box it came in. I opened up one of mine to enact a quick repair and the capsule was already thoroughly covered in foam dust. Luckily most of it came off with some careful and distant use of canned air, but there's still more than I'd like. Stupid foam...

JamesW

Re: Neumann U87 Vintage Circuit Build Thread
« Reply #139 on: March 29, 2012, 07:28:21 PM »
Is there away of selecting a good sounding fet out of the circuit? Is there any thing we learn from the Idss like high current good low current bad?
Subject to change with out notice


 

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