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In this project guide, we show you how to use your Desktop PCB Milling Machine to make an electret mic preamp. This circuit, based on an LM358 operational amplifier, is essential for a number of audio-reactive projects. Lets dive in!

- Bantam Tools Desktop PCB Milling Machine
- Computer with Bantam Tools Desktop Milling Machine Software installed
- Flat end mill, 1/32”
- Flat end mill, 1/64”
- Alignment bracket
- Soldering iron
- Diagonal wire clippers
- USB cable
- Bit fan

- PCB blank, FR-1, single-sided
- Nitto tape, high-strength, double-sided
- Resistors, 100K (2)
- Resistors, 10K (2)
- Resistors, 1K
- Ceramic capacitor, 0.1uF
- Electrolytic capacitor, 470uF
- Electrolytic capacitor, 10uF
- Screw terminal, 1x2
- Dip socket, 2x4
- Potentiometer
- Horizontal audio jack LED
- Electret mic

- Electret-Mic-Preamp.brd file downloaded”

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