I have an old PA amp that cooked itself. The power supply is okay and puts out 75 VDC. Its a heavy duty steel 3 rack unit case, so plenty of room. I'd love to find some inexpensive amp modules, preferably prebuilt, to drop into it. Good sound quality and fairly robust output into 8 ohms stereo is the goal. I'd rather not spend more than about $150 if possible - plenty of other amps out there I could just replace it with if I get over that price range. Any suggestions?