Stereo mic input to mono socket. How should I transform it?

I made contact mic with JFET preamp circuit(very basic). It works fine. Then I tried to use my stereo microphone with same setting, so I plugged my stereo microphone(cheap one) to input of preamp but I can't listen any sound. Nothing noisy or no cranking sounds..neither.

What I've noticed I used my socket with mono socket (GND/+) as input, but the mic uses 3.5mm stereo jack with 3 poles. As I knew it has (GND, -, + in order) so I expected I could just plug? Or can I just select GND/+ and solder on mono plug?

Electret condenser mics have to be powered. Laptops & soundcards provide power for "computer mics". [u]Here[/u] is a circuit I found.

With the steeo mic, benerally, you shouldn't "short" left & right outputs together. If you want mono you can just use one side or you can make a passive mixer by running both mic-outputs through a resistor, then you can connect both resistor "outputs" to the preamp input.

You need a lot clearer explanation of what you are doing. :astonished:

Paul__B:
You need a lot clearer explanation of what you are doing. :astonished:

Like, a schematic.