Dedicated power

@spenav How to wire your house for good power is excellent. It should be required reading.

Adding a whole house surge protector (or go Taurus, etc.) to your to do list something to consider.

There's a Torus on HI FI Shark today. For wire use JPS Labs Power in wall cable. It's 10 gauge but probably one of the best for noise rejection.
When I set up my system originally there was noise that you couldn't hear but it did a number on my high efficiency speakers. Brittle is the best way to describe. Very disappointing to say the least. The Balanced Power Technologies 3.5 Sig + introduced was a huge relief. Later found an Equi=Tech 5KVA wall unit. And balanced power doesn't wear out.

What most of you big gauge gurus fail to realize is that musical transients are asynchronous to the power line frequency. Low E on a bass is 41.2 Hz. The lowest common multiple with 60Hz is 6180 or every 103 line periods for bipolar supplies and every 51.5 for unipolar.

@ 120 BPM there are 30 line cycles per beat. The power supply is topped up on every line peak which almost never coincide with an audio transient.

Clean connections and no computer junk on the audio circuit solve the vast majority of power problems. Note that many wall-warts for 'audio' devices are SMPS and should not be used.

Running a dedicated line for your system is a major upgrade that does not cost a fortune and the sound can improve as much as a component upgrade.