Re: Neumann Vintage U87 Clone : Build Thread.
« Reply #3120 on: May 07, 2019, 01:48:18 PM »
Hey guys. I am having a problem with one of my builds. I have A his that sounds like White Noise.I have clean this board multiple times serious I remove the poly styrene capacitors to clean the board. I am at a loss. I am using a 797 capsule from a 1st gen c1. And Cinemag transformer. This capsule and tranny worked fine and n another Dany pcb. Anyone else have this issue or had it? I have 23.34 v at the zener. 40 v to the capsuleR14 21.2  r12 11.6


Re: Neumann Vintage U87 Clone : Build Thread.
« Reply #3121 on: May 07, 2019, 04:13:22 PM »
Hey guys. I am having a problem with one of my builds. I have A his that sounds like White Noise.I have clean this board multiple times serious I remove the poly styrene capacitors to clean the board. I am at a loss. I am using a 797 capsule from a 1st gen c1. And Cinemag transformer. This capsule and tranny worked fine and n another Dany pcb. Anyone else have this issue or had it? I have 23.34 v at the zener. 40 v to the capsuleR14 21.2  r12 11.6

Ricardus

Re: Neumann Vintage U87 Clone : Build Thread.
« Reply #3122 on: May 07, 2019, 08:54:08 PM »
No,  figure 8 is not working.

OK, but why were you talking about Omni mode then, a dozen messages back?
Audio mastering for hire..

HosaMogami

Re: Neumann Vintage U87 Clone : Build Thread.
« Reply #3123 on: May 08, 2019, 07:14:42 PM »
OK, but why were you talking about Omni mode then, a dozen messages back?

Every other one of my posts was talking about figure 8, I did mistype one post which is now corrected so my apologies.

Ricardus

Re: Neumann Vintage U87 Clone : Build Thread.
« Reply #3124 on: May 08, 2019, 10:40:11 PM »
Every other one of my posts was talking about figure 8, I did mistype one post which is now corrected so my apologies.

Oh, OK. No worries. It did throw me off a little but, that's all.
Audio mastering for hire..

Delta Sigma

Re: Neumann Vintage U87 Clone : Build Thread.
« Reply #3125 on: May 10, 2019, 12:36:17 PM »
Every other one of my posts was talking about figure 8, I did mistype one post which is now corrected so my apologies.

I'm not familiar with the project - never built a U87 - but I took a quick look at the Schematic. If your voltage is fine (looks like C9/R13 junction to 0V is the place to measure) and there's no shorts between backplates and diaphragms check C2. If Omni and Cardioid are fine, there's not much that can be wrong. Also, remember that in the hi-z sections, all work should be done with gloves (non-powdered nitrile) because oils from your hands may be enough to cause problems in the hi-z sections.

Use the original Neumann schematics along with Dany's for troubleshooting. They paint a pretty clear picture of a not-so-simple hi-z and pattern switching section.

Re: Neumann Vintage U87 Clone : Build Thread.
« Reply #3126 on: May 10, 2019, 01:15:13 PM »
I think I may have the same issue, Omni and Cardioid work flawlessly but Figure of 8 has crackling noises on both of my builds...

TLRT

Re: Neumann Vintage U87 Clone : Build Thread.
« Reply #3127 on: May 11, 2019, 02:41:42 AM »
I think I may have the same issue, Omni and Cardioid work flawlessly but Figure of 8 has crackling noises on both of my builds...

Check shorts between the 2 capsule backplates. Maybe your mount screw shorting the 2 backplates together(those needs to be separated)

Re: Neumann Vintage U87 Clone : Build Thread.
« Reply #3128 on: May 13, 2019, 09:13:39 PM »
D-U87 Build Thread


To Bias Fet, make sure you install R6 backward in reference to the silk screen like this:



I noticed that the picture you showed was of board V1.1 .  Does the reverse R6 still apply on V1.2?

Re: Neumann Vintage U87 Clone : Build Thread.
« Reply #3129 on: May 14, 2019, 02:27:30 PM »
Can you guys see this post? I’m not sure that they are being seen.


Ricardus

Re: Neumann Vintage U87 Clone : Build Thread.
« Reply #3130 on: May 14, 2019, 11:29:07 PM »
Can you guys see this post? I’m not sure that they are being seen.

Yes.
Audio mastering for hire..

Delta Sigma

Re: Neumann Vintage U87 Clone : Build Thread.
« Reply #3131 on: May 15, 2019, 02:17:20 PM »
Hey guys. I am having a problem with one of my builds. I have A his that sounds like White Noise.I have clean this board multiple times serious I remove the poly styrene capacitors to clean the board. I am at a loss. I am using a 797 capsule from a 1st gen c1. And Cinemag transformer. This capsule and tranny worked fine and n another Dany pcb. Anyone else have this issue or had it? I have 23.34 v at the zener. 40 v to the capsuleR14 21.2  r12 11.6

Try replacing your capsule with a similar value cap. May help you narrow down the source of your issue. Make sure you wear gloves when working on the hi-z sections of the mic.

Re: Neumann Vintage U87 Clone : Build Thread.
« Reply #3132 on: May 15, 2019, 07:20:11 PM »
Thank you! I’m gonna give that a shot. I just finished matadors c12 build today. It Went pretty smooth and sounds great but this 87 hiss issue is kicking my butt.😀


 

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