This was my first electronics project that involved soldering. It’s a guitar pedal that acts as a master effects loop. It has 2 inputs and 2 outputs: the guitar is 1 input, the amp is 1 output, and the remaining input and output go to and from all the other guitar effect pedals one may have. This lets you turn on/off all your pedals with one switch, and also lets you decide how much signal to feedback into the effect loop. Made from a schematic originally from Beavis Audio Research.