simple condenser mic preamp circuit - ElecCircuit.com
Dynamic Mic Preamplifier Circuit
Low Noise Balanced Microphone Preamp
Circuitdiagram.org - Here is a schematic of a very sensitive microphone preamp circuit, which can be used to increase gain of microphone or boost the audio signals coming from microphone. Read more...
preamp - What is the best preamplifier circuit for electret condenser microphone? - Electrical Engineering Stack Exchange