This is a simple project circuit for mixes two or more channels into one channel (eg. stereo into mono). The circuit can mix as many or as few channels as you like and consume very little power. This is the figure of the circuit. This circuit is based on or built by FET 2N3819. The circuit can be powered by a single 9 volt battery. As many or as f
ew channels as are required can be added to the mixer. A shielded case is probably needed to reduce hum and help stop oscillations.