This is one way to switch audio signals without the use of a mechanical relay. It takes the input of two buttons to switch between two stereo audio sources. The circuit uses a 4066 CMOS chip as the actual switch and a BJT transistor gate to handle the buttons. This can be incorporated into a preamp or something that is supposed to process multiple audio inputs.
******* In the schematic I erroneously swapped the control pins and the output pins on each of the channels. Pin 2 and pin 4 are the output pins and pin 13 and pin 5 are the control pins. *******
Improved Audio Signal Switch: https://youtu.be/93teJFpJiZU
Improved Audio Signal Switch Kit: https://thetuberoaster.com/products/cd4052-four-channel-audio-switch
