So I came across a mostly useless power supply (from PABX UPS?) with a chunky heatsink and simple chassis. It measures 20 cm wide by 9 cm high and base to fin tip about 7 cm. I was wondering if there was a PSU/amplifier combo that would fit. It would be to use as an electronic keyboard practice amp so it can be mono. If stereo it would be used to drive a speaker and subwoofer. Solid state class A would be nice, otherwise a chip amp would be fine. I don't have a large budget. Please some advice would be interesting to read.