Condenser Mic Test Jig?

[pinebox]

I dont go out of my way to work on many microphones, but they do come across my desk sometimes and I would like a more consistent way to test them. Years back I asked some people if I could remove the capsule and feed a very low oscillator signal into the circuit at that point to trace the signal flow quickly through the components. The consensus was yes, I could, but I have long forgotten the recommended capacitor value and expected signal level, does anyone use a method similar to this?

 

[callgrlmusic]

i would also like to know how to do this.

 

[johnsonic]

Matador did an awesome job walking me through injecting a signal to trace a fault - the saga begins on this page of the thread and goes for a page or two: ELA M251 Inspired Microphone - Build Thread

 

[abbey road d enfer]

I have long forgotten the recommended capacitor value and expected signal level,

Ideally, the capacitor should have the same value as the capsule it replaces, so typically 50-70pF for LDC, 25-40pF for MDC and 10-20pF for SDC.
Signal level should be high enough for noise not polluting readings and not too high for avoiding clipping.
A value between 10-100mV should wotk usually.

 

[MicUlli]

If you need to to some deeper measurements my thread may be helpful:
https://groupdiy.com/threads/a-poor-wo-mans-microphone-measurement-equipment.84375/BR MicUlli