Very small variable dummy load, no protection so be aware of the load you put on it. Only 40 Watt to be on the safe side. If the MOSFET smokes the load was to high ;-) (yes I did smoke one, had no cooler on it :-( ). Primarily build it to test a bunch of unknown transformers I had lying around, and it seemed and is a fun project.
A breadboard-compatible dual non-inverter audio amp built around an opamp.
Exposes most of its internals on pins for more versatility (variable gain, simple filter, ...). Some parts are optional.
Can be stacked to create a mixer with 1 board per stereo channel and 1 board for a master volume.