From somewhat long experience, but not with every brand, I’d say the first step is to run dedicated lines. There are many threads here on the subject.
I found that most of the conditioners I used back in the day did not improve the sound directly from the wall (with dedicated lines) but could see a situation where, for example, you are in an apartment (condo or ’flat’) and cannot do much.
I would only do a try before you buy deal, though you’ll pay more that way through retailers that permit this.
I’ve had very good luck with isolation transformers. My tone arm uses a large (1/2 HP or greater) air compressor which created a nasty snap on the lines, crossing into the audio signal. (Part of the problem was that my electrician bundled the feeds for the dedicated lines). The thing that eliminated it was an isolation transformer. (Granted, this was not connected to sound producing gear, but suppressing a electrically powered device ancillary to the system).
I’ve since moved, and had dedicated lines installed using best practices, and in addition, have a large (10kVa) isolation transformer that feeds the system subpanel. Dead quiet (I have 104db sensitivity horns and use all tube equipment).
At a minimum, I would start with the dedicated lines if you can, get some direction on best practices from some other threads or those more technically inclined with a knowledge of the Code and go from there. I’ve found that commercial electricians often understand audiophile needs better than the garden variety electrician. You want the work to meet applicable Code at a minimum. Even with the cost of pulling a permit, not terribly expensive, particularly compared to many magic black boxes.
