sevestan
Just turn off all your breakers except for audio and then listen...DUH
This exactly what I do when I want to listen seriously and the missus is out, takes a few seconds, but many here don’t have dedicated audio lines to do that with.
I do run all my system components through power conditions/filters for protection from transient spikes. No hums, no electrical noise at all.
I have not yet seen a good power conditioner/filter that doesn’t detract from explosive transients compared to when a power/amp is plugged direct into mains, but they are great for source equipment. I use my own using isolation transformers and expensive Siemens large block filtering brick sized cans that are used in medical theater equipment, one for each source piece, that way they have some isolation from each other as well.
Cheers George