Here the simple mic pre-amp circuit design based on single IC LM358. The circuit is very simple, inexpensive and easy to built. This mic pre-amplifier circuit operated with 9V DC voltage, you may use 9V battery for this circuit.
Component Parts List:
R1, R3, R4 = 10K
R2 = 1K
R5 = 100K-1M Potensiometer
C1 = 0.1uF
C2 = 4.7uF/16V
IC1 = LM358 dual op-amp single supply
Mic = Electret Microphone
Notes:
- Use R5 to adjust the gain of op-amp LM358.
- The LM358 has dual op-amp module, you may build stereo audio pre-amp using single LM358. These devices consist of two independent, high-gain frequency-compensated operational amplifiers designed to operate from a single supply over a wide range of voltages.
Download PDF document of LM358 datasheet from below link:
LM358 Datasheet 1.21 MB
Download Datasheet
The simple mic pre-Amp based LM358 circuit designed by Tony van Roon