0AndyGadgetBest Answer 8 years ago ReplyUpvoteSimplest way is to follow the speaker wires back to get to the audio section, but . . . Once upon a time, most equipment was nicely subdivided and you could see each functional section quite easily, but nowadays the manufacturer will make use of chips which may pack several functions into one package, with maybe a few passive components and transistors around it. This makes it almost impossible to re-purpose it for your own ends. If you're looking for a small amp, you can buy encapsulated pre-amps and power amps for only a few pounds / dollars.