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Ray Thomas[_2_] Ray Thomas[_2_] is offline
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Default Rumbling SD condenser mic problem

Hi all,

I have a Behringer B-5 condensor mic, long out of warranty, that has
developed a 'stomach rumbling/rolling thunder' sound behind the audio, which
peaks erratically every 5-10 seconds as a 'shorting/fizzing' sound that
drives the signal into the red. The audio itself is not distorted, but fails
to mask the rising background rumble. It does this no matter whether the
omni or cardioid capsule is fitted, in fact even does so when no capsule is
installed. Since I have little to lose by investigating the innards, what
components would you suggest I test or replace in a repair attempt....it's a
"cheap-end" mic after all !
Thanks,
Ray


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Mike Rivers Mike Rivers is offline
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Default Rumbling SD condenser mic problem

Ray Thomas wrote:

I have a Behringer B-5 condensor mic, long out of warranty, that has
developed a 'stomach rumbling/rolling thunder' sound behind the audio, which
peaks erratically every 5-10 seconds as a 'shorting/fizzing' sound


Probably an electrolytic capacitor but it could be a bad solder joint.
Not a chance of getting a schematic of it, so you'll just have to draw
one out yourself. Shouldn't be too hard as long as you can get it open
in a way that will let you put it back together. There aren't going to
be a lot of parts in there.

--
If you e-mail me and it bounces, use your secret decoder ring and reach
me he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)
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Scott Dorsey Scott Dorsey is offline
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Default Rumbling SD condenser mic problem

Ray Thomas wrote:

I have a Behringer B-5 condensor mic, long out of warranty, that has
developed a 'stomach rumbling/rolling thunder' sound behind the audio, which
peaks erratically every 5-10 seconds as a 'shorting/fizzing' sound that
drives the signal into the red. The audio itself is not distorted, but fails
to mask the rising background rumble. It does this no matter whether the
omni or cardioid capsule is fitted, in fact even does so when no capsule is
installed. Since I have little to lose by investigating the innards, what
components would you suggest I test or replace in a repair attempt....it's a
"cheap-end" mic after all !


It's contamination. Disconnect the capsule from the electronics... if the
noise goes away, it's gunk inside the capsule or on the insulating ring of
the capsule.

If the noise stays, first hit the board with flux remover, then try shorting
the FET gate to ground. If the noise still stays, replace the FET. If the
noise goes away, look for stray fingerprints on the leak resistor or a leaky
input cap. If they used a film cap, fingerprints on the film will do it too.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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Ty Ford Ty Ford is offline
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Default Rumbling SD condenser mic problem

On Fri, 31 Oct 2008 18:26:49 -0400, Ray Thomas wrote
(in article ):

Hi all,

I have a Behringer B-5 condensor mic, long out of warranty, that has
developed a 'stomach rumbling/rolling thunder' sound behind the audio, which
peaks erratically every 5-10 seconds as a 'shorting/fizzing' sound that
drives the signal into the red. The audio itself is not distorted, but fails
to mask the rising background rumble. It does this no matter whether the
omni or cardioid capsule is fitted, in fact even does so when no capsule is
installed. Since I have little to lose by investigating the innards, what
components would you suggest I test or replace in a repair attempt....it's a
"cheap-end" mic after all !
Thanks,
Ray



Maybe junk on the diaphragm. Connect it, and exhale slowly into it. If it
sounds like a distant thunderstorm afterwards for a while, you have junk on
the diaphragm that's become conductive with or above a certain humidity
level.

Overly humid environment?

Drying the mic out with dessicants (sp?) in a sealed bag might be all you
need.

Regards,

Ty Ford

--Audio Equipment Reviews Audio Production Services
Acting and Voiceover Demos http://www.tyford.com
Guitar player?:http://www.youtube.com/watch?v=yWaPRHMGhGA

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Mike Rivers Mike Rivers is offline
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Default Rumbling SD condenser mic problem

Ty Ford wrote:

Maybe junk on the diaphragm.


He did say that he heard the same noise with either capsule. They could
both be cruddy, but the odds are better that the problem is with the
guts. Could be dirt and moisture on the circuit board along an ultra
high impedance path, it could be the contact point for the capsule, or
it could be a faulty component on the circuit board.



--
If you e-mail me and it bounces, use your secret decoder ring and reach
me he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)
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