I build speakers and try to build amps(tube type). So far fair results with the speakers and miserable results with the amps. I have been able to rebuild and or modify a few amps. I have about 15 tube amps, 3 SS amps and 3 preamps. Most of the amps are integrated or have gain controls and many are mono blocks, and 4 are stereo recievers. 2 tube tuners. I use DVD HDCD players for CDs as well as movies. 6 speaker pairs and close to 50 raw drivers(most of these are medium quality). I make my own speaker cables and will soon make my own interconnects.