Stereo microphone amplifier circuit with gain control.
The circuit has been tested with the POM-5238P-R microphone capsules:
http://www.puiaudio.com/product-detail.aspx?categoryId=4&partnumber=POM-5238P-R
CNC manufacture files (gerbers, FlatCAM project & gcodes) are available in the Gerber folder.
Click here for the full assembly instructions
Aprox milling time for 0.8mm drill: 4 minutes
Aprox milling time for 1.2mm drill: 2 minutes
Aprox milling time for 0.3mm copper etching: 20 minutes
Aprox milling time for 2mm edges routing: 3 minutes
This circuit is a derivation from the following -very useful- Texas Instruments guide:
Single-Supply, Electret Microphone Preamplifier Reference Design by John Caldwell
Gain control is achieved by replacing R2 (75k) with a 100k dual potentiometer.
Author: Carlos Garcia Saura (http://www.carlosgs.es)
License: CC-BY-SA (http://creativecommons.org/licenses/by-sa/4.0/)