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[T12]

Hi there,

This is my first post on this forum so maybe this topic was already covered, although I could not find it :
I own several KM84 mics for more than 30 years and still use them regulary.
Last week I did a setup and noticed that 3 of them show what I would describe as
microphony but I never expected it with a non tube device...
The sound character is rather sinusoïdal in the mid range ( 1 - 3 kHz.)
Can anyone help me out on this ?

Best regards,

[klaus]

Please let us know what kind of microphonics we are talking about, once have you read this post:
https://repforums.prosoundweb.com/index.php/topic,37339.0.html

[T12]

Sorry for not describing this in my first message :

The pinging sound is heard while soft knocking on the housing/tube and the decay time is rather short.
Hope this helps ?

Best regards.

[klaus]

I addressed that symptom in my opening post: discrete components on the circuit board that are not secured can resonate when excited, and transmit the resonance into the audio of the mic.

The cure: After taking the housing tube off, hold the mic against your ear, ping the body with a finger of your other hand, or a plastic screwdriver, and identify the ringing sound. Now judiciously hold a finger from the hand that is holding the mic to your ear over components until the ringing stops.Identify and locate the component and secure it with a dab of Eclectic E6000.

[T12]

I addressed that symptom in my opening post: discrete components on the circuit board that are not secured can resonate when excited, and transmit the resonance into the audio of the mic.

The cure: After taking the housing tube off, hold the mic against your ear, ping the body with a finger of your other hand, or a plastic screwdriver, and identify the ringing sound. Now judiciously hold a finger from the hand that is holding the mic to your ear over components until the ringing stops.Identify and locate the component and secure it with a dab of Eclectic E6000.

Thank you very much Klaus for your suggestions.
Last weekend I was able to "glue" capacitors C1, C2, C9 with a few drops of  Eclectic E6000
Ater that problem solved !

[klaus]

That's the spirit! Anyone can stop components inside mics from resonating with that same method. Just ping the body while the mic is plucked in, and listen for ringing.

Then hold the mic (unplugged) to your ear and duplicate the ringing that way, then hold down individual components with a free finger while you continue tapping the mic, until you find the culprit(s)

The great thing about E6000 is the ability to peel it off in one pull, leaving no residue, if you ever need to.