Well this was different, so everything that runs on electric in your home give out interference when its plugged in the wall outlet and the only way is to shut down the power in your home except for the power running to your system...interesting. So then I won't need thousands of dollars in cables for my system.Or then again I do....hmmmmmm .I live in a complex and my town house has a neighbor to my left and one in the rear connected units......so I guess I never will have silent sound.
Get the best from your system while listening without any cost
Turn off your solar systems inverter while seriously listening, as it puts very high frequency s***t back into your house mains wires, as does your microwave and anything with a smp (switch mode power supply) which ends up in your system, I’ve seen it on the oscilloscope.
And if the missus want to cook with the microwave, tell her to get take out delivered
Simple way to test if you don’t have a oscilloscope, is get a portable AM radio that does not mute if "off station", and tune down to around 700khz on AM and turn up the volume and go near any smp power supply and listen to it squeal it’s head off, this noise is getting injected into you home mains wiring and your system..
Cheers George