It can be dangerous to float the ground, particularly if tube equipment is involved given the high voltages. I have a very high efficiency system using single ended RCA interconnects. I found the Jensen Isomax transformers were the trick. I have monoblocks so they are placed just before the amps and they are connected to the amps with high quality short interconnects. The bottom line is dead quite for the first time after accepting a low level of noise for 15 years.
