It's a simple project to build a stereo preamplifier using electret microphones and the cheap operational amplifier LM358  

This project uses the dual channel operational amplifier LM358. Each channel is used to increase the signal of one electret microphone and it helps to manage a stereo output.

 

To build this project you will need:

LM358 x 1

Electret Microphones x 2

Resistors 10K x 8

Resistors 47K x 2

Electrolytic Capacitor 10uf x 2

Electrolytic Capacitor 220uf x 2 (or 10uf x2  depending on noise)

2 pin Header x 2 (or minijack or any connector you want)

1 Stereo minijack (3.5) female connector (the output connector)

Battery Holder (you can use any power supply between 5V and 32V. I used two battery joined to produce 6,6V)

 

The PCB is designed for 20mm battery and has a size of 42 mm x 28 mm on two sides board.

 

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ivanneira 4 years, 6 months ago

hi. i see in the list 2 electrolitic capacitors 220uF but it's not in the project.