AKG C5900 humming

J

jenschristian

New member
Hello
I have a problem with my AKG C5900 microphone.

When connected to my Yamaha power mixer the microphone will make a destinct humming when you touch the micropone "grill".

It will come and go with the touch.
That leads me to believe it is something with a ground-failure, but I can not find any bad connections.

Phantom power is on and I have tried and tested cable and mixer channel with a different microphone -no problems.

What should I look for when I have the microphone disassembled?

When the humming is not there and you are carefully NOT to touch the "grill" -then the microphone is working perfectly.
But if you slightly touch in the wrong place - the humming is back.

Let me know if you need further information!
I hope that someone has got the needed experience that I do not :-)

Thanks
Jens Christian
Denmark
 
I have one, I can get the ohm meter on it later but I'd guess the grill, case and xlr case ought to be as one? What about when those are touched- or on a different cable or input?
 
mixsit said:
I have one, I can get the ohm meter on it later but I'd guess the grill, case and xlr case ought to be as one? What about when those are touched- or on a different cable or input?
Click to expand...

Thanks - that would be great.

I can touch the case without problems -only the grill...
I have tried different cables and different inputs - only this microphone has the fault.

Thanks
Jens Christian :-)
 
Hello Mixit - I never heard from you.
Did you get a chance to "ohm" your microphone for comparison?

Thanks in advance.
Best regards from Denmark
Jens Christian
 
Well hello check this out. I just learned something about this mic! Today I was thinking 'ya know, the last time I used this -was on an up right bass, it had an intermittent hum'. And at the time I remember now thinking it seemed at the time to be position sensitive (like maybe single coil pu's can do?
I scratched a spot on the grill- to get past the paint, and it is 'zero ohms to the case.

Tonight, it was dead quiet even with the gain jacked up... until I started to twist on the grill.
Shure frikin enough it was easy to mess that up and get hum. It could be bad enough for a little w/o even touching the grill. Or.. not so much until you touched it.

So, what we have here is a not so solid shield path.

I found there's two, the '5900 and the 5900m. I have the non-'m triangular- no threads - i.e. it's probably got some little tabs in there for the connection.
C5900 (discontinued) - Microphone | AKG Acoustics
C5900 M (discontinued) - Microphone | AKG Acoustics
'Service / blow-up' docs and stuff..

And so thank you Jenschristian :)
 
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