I had a bad rectifier that was an old Russian unit cause the 807 to blow a fuse.when you plug the unit in without it being turned on there's loud humming through both speakers I'm going to try an earth ground. I don't know what else to do with it.
After living with this 807 amplifier I'm very pleased with it thanks Hi-Fi Exquis. At first I had a hum issue figured out it was my subwoofer.