@dookieshooter I don't have a lot of programming/code experience to help people here, but I do have a fair amount of audio expertise and this is a fairly simple issue to solve. It's called an "audio ground loop" and it's because the audio signal isn't grounded to the same ground as the rest of your components. Perhaps it's plugged into a different outlet or surge protector. The reason your second amp worked is because it probably has a ground loop filter built-in and the first one didn't. The easiest and cheapest way to minimize or get rid of the hum is to buy a Pyle PHE300 or similar device that (depending on the model) either connects to the signal that's going to the speakers or to the audio OUT from the Pi. It intercepts the signal and 'cleans' the hum from it by grounding the signal again.