Hi, I plan to make a 4 chanel audio amplifier. Im not going too fancy, no volume control etc. I just want a PCB with 4 phono inputs and 4 speaker outputs. The inputs will be from a PC's soundcard and the speakers i have i think are about 5W. The speakers are for my pinball machine (yep, back on that project for a while).

Ive not really done anything with audio before. Google finds a lot of schematics but they are all different and im not sure what would be best so my question really is where do i start learning about these kind of circuits?