Dedicated line w/ upgraded parts or power cond?

When we put a new addition on the house a few years ago, we had to upgrade our panel. At the time, I added 3 dedicated lines for my new listening room. Ran 10 gauge Romex and used FIM receptacles.
The one thing we made sure of and this is very important, is to keep motors, refrigerators, dishwasher, and microwave circuits on the different leg from the dedicated listening room circuit(s).
You have two power legs (combined they are 220/240 volt) feeding your panel. You use a single hot leg to get 120 V. We made sure we pulled all the noisy circuits from one leg and the dedicated circuits from the other leg. Your electrician can advise you on this.

I have never felt the need for any kind of power conditioning. All my circuits are dead quiet

Whart - have you tried a floating shield approach on your power and interconnect cables?

All good advice from the previous posts, and in my opinion it can be an individual system dependency and/or local AC power company issues.
I remember reading posts from past topics where some said dedicated power circuits made an improvement and others said they did not notice a difference.
Years ago I first used a power conditioner which was an improvement.
Next, I installed several dedicated 20 amp circuits with high end outlets, which was another big improvement.
I actually removed the power conditioner and injoyed the dedicated circuits and AC outlets, however I finally installed two Xentek Extreme Isolation Transformers which make up my major AC power filration system.
I use two 5 KVA Isolation Transformers into sub-panel that feeds all the dedicated AC power into my systems.
A picture of my power filtration system is shown in my virtual systems.

Willie- I haven't really fooled around with the interconnect pin configuration or wiring- I run XLR from phono stage to line stage, and xlr from line stage into Lamm ML2 amps, but the latter is not a true balanced input. I have floated grounds on power cords in the past to sort 60hz hum issues but try to ameliorate without any ground-lifting. I think some problems may arise from how individual components are internally grounded, but i'm not expert enough to determine that. The external star grounding approach has worked in some set-ups using the horns, although right now, the system is extremely quiet without it. I will occasionally hear noise over the system that comes from a power anomaly on the line, or a microphonic tube, but I've been pretty lucky. I did find that having separate dedicated lines created more potential grounding problems, but right now, fingers-crossed, the system seems to be in fine fettle.
I'll be interested to see how the Equi=Tech performs once I'm set up in a new room. That may be a while, though.