PocTop D-elam 251 Repair. White Noise Issue never resolved...

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SparkleBear

Well-known member
GDIY Supporter
Joined
Jun 21, 2016
Messages
308
Location
Santa Cruz, CA
Greetings All,

I've been on and off trying to track down the white noise in my D-251 build for about a year now. I have noise tested the 6072a and its super quiet, Replaced the CT12 capsule, de-soldered the whole thing, cleaned it, re-soldered it up again, changed the output caps, twisted the audio wires in the power supply and kept them from the filter caps, tried filtering the B+.... all to no avail. The white noise makes it pretty un-usable for any voiceover/vocal or acoustic guitar application as the hiss is too noticeable.  I am going to post a few sample recordings, perhaps anyone has any ideas. Listen to the lead in before the guitar comes in... I am posting a recording with my D251 and next with my IO Audio U67. The 67 is dead quiet in the lead in...

251 link: https://www.dropbox.com/s/doga2sonunml4u6/Will%20She%20Be%20Gone%20%28251%29.mp3?dl=0

u67 link: https://www.dropbox.com/s/1dmqcloash2avqx/Will%20She%20Be%20Gone%20%28u67%20no%20filters%29.mp3?dl=0

At this point I am wanting to hire someone to track down and fix this problem for this mic system. Anyone feel up to the challenge and have the knowledge and experience with such a job!?

Thanks a ton!

-Eric
 
Can I ask what resistors you used and if you double checked the values, also what cable are you using between the mic and PSU and how long is it?
 
Have you tried substituting a good quality fixed capacitor for each side of the capsule (in the 50 to 70 pF range) and listened for noise?
 
gyraf said:
Are you sure you have high noise, not just low sensitivity (these are different entities with very different origins)?

Jakob E.

I was going to ask the same question in a different way. What were the mic pre gain setting for the D251 and the U67?

Cheers

Ian
 
Very interested in hearing how it turned out for you, I have similiar issues with mine!
 

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