A simple DC blocker ( Emotiva makes a good one) will take care of any LED or dimmer DC issues if you detect adverse hum coming from usually toroid core transformers. No impact to the sound from the speakers though. Nothing more than a ferrite on a power cord is all that is needed for noise. Providing of course the equipment plugged in is not garbage. For protection of your equipment, a decent surge suppressor/filter is not a bad idea. Protection, not magic. Panamax, Isotrip etc. Even Monster made some decent ones.
I ran a line back when I had three modified Parasound 1200's and two subs. 10 Ga, 20A. I still had to run a Furman sequencer to get everything powered up as the surge was tremendous. Valid reason for designed current draw. No magic.
A lot of hub-bub is made about power by folks trying to sell something and folks who do not understand electronics. I have no fancy power cords, dedicated circuits, regenerators etc. I can put my ear right to my tweeters, crank up the volume knob to higher than I normally listen to and guess what I hear? Nothing. Not a darn thing. Black as black. If you hear something, then track down your problem instead of grasping for straws. You can buy some really nice speakers for what an electrician costs.
OH my gosh, terrible sound. Entrance cable is... ALUMINUM! Can we get the power company to run a mono-crystal directional line from the transformer to our house?🙄