Please do not float any ground. I understand your situation, but floating grounds is quite simply defeating the circuit protections designed to save your life. You are now a better ground than house ground because it isn't there anymore and you are toast. Find the problem and fix it. One suggestion is to place all your lower level electronics through the same device/power conditioner/isolater and the amps through their own separate dedicated line back to electric panel. In other words, if you have two amps, each amp should have their own dedicated line to the panel and they should be on opposite sides of the input line. Most houses have 220volts coming in and separated in the panel. Therefore, one amp runs to one 120 input and the second one goes to the other side and do not share neutrals in the outlet boxes. Also, the other electronics should have their own separate dedicated line. So, the pre-amp, tuner, turntable, cd player, etc, plug into a conditioner and that has a dedicated line to the panel. Also, check your cables, sometimes the shield is tied to the signal return, not good, or the signal return is lifted and floating also. Sometimes the manufacturer ties electronic's signal ground to house ground and that is not right and there is your ground loop. But floating ground is simply dangerous and if a fault happens there will be major problems. Fix the problem, don't mask it.