Ultra-Simple Mono-in Panning Mixer
http://www.musicfromouterspace.com/
Here is the schematic, PC board layout, and parts placement. Always breadboard first! Have fun.
Ultra-Simple Mono-in Panning Mixer Circuit Schematic
Ultra-Simple Mono-in Panning Mixer PCB Layout (component side shown)
Ultra-Simple Mono-in Panning Mixer Parts Layout