Adding an aux input to a microphone

[riccardo]

Hello,

I have a small PA unit that has a wireless microphone. The mic seems not to be very sensitive as I have to put it right to my mouth and speak loudly for any sound to come out at all.

I'm wondering what the best way is to a) improve the mic sensitivity. b) Is there a simple circuit I can use so I connect an external audio source to the PCB with the mic?

 

[aliarifat794]

You can use a simple op-amp like the TL072, with resistors to set the gain to an appropriate level for your microphone.