K1803 gain falls after a few seconds

Kits Audio Hi Fi Projects
1

Hi,

I just put together a K1803 and connected it to a microphone I’m trying to use (digikey.com/1/parts/831-micr … 63prt.html). It seems that when I power the PCB (20VDC), I get a good output for about 3-4 seconds… and then the gain falls off immediately and I get no output. Is there something I’m hooking up incorrectly?

Thanks!

Jeff

2

It seems that you are using an Electret Condenser Microphone.
The K1803 is for dynamic microphone.