R1 powers a single electret mic from a filtered voltage. If you want more mics then two or three can be connected in parallel then the value of R1 should be reduced.So, audioguru, I'm going to take a crack at your electret mic preamp. I do have two questions before I start my electronic adventure, though.
Does your circuit provide power for the electrets?
My preamp has plenty of adjustable gain. With a 9.0V supply its max output before clipping is 2.3V RMS which is much more than an MP3 player.Also, because the Zen has NO amplifying at all, it requires quite a loud input to be just under clipping. If you'll excuse the non-precise comparison, it requires something similar to an MP3 player on 2/3 volume. So, because your circuit is a pre amp, it'll also need another amplifier afterwards, correct? Or will your circuit amplify the mic quite a bit more than I'm thinking?