From Eric

Contents 1 Micro amplifier 2 Mixer 3 Filter 4 From split supply to mono supply

Micro amplifier

Mixer

Filter

I use an active Sallen-Key second order filter.

From split supply to mono supply

In my initial configuration, I used a dual power (-12v,12v), but this is not very practical if I want the device to be portable.

For info., here is a classical way to build such a symmetric power supply (from https://circuitdigest.com/electronic-circuits/12v-dual-power-supply-circuit)