I know this thread appears to have gone dormant, but I thought I'd share some improvements that were suggested to me that have appeared (sonically) to have removed every shred of noise present in my system and done wonders for my noise floor as a whole…
Each of these bullet points represents one very good upgrade, taken together, they are really impressive to me in terms of how my system came to sound after completing them....they certainly together address the OP's question (IMHO).
*note the items below assume you don't have a higher-end solution like one of those monster Equitech or Torus house panels with own Isolation transformer, etc....
- reorganize main house panel so the dedicated circuit(s) for my audio system (in my case a split-off for a sub-panel) is the very first drop on the first leg of the main house panel (left leg as you look at panel)
- reorganize main house panel so all high draw and/or noisy power devices (washer, dryer, refrigerator, electric oven, microwave, heat pump/AC units, etc..) are on 2nd (right leg) of the panel
- balance rest of circuits so that left and right leg of house panel have equal/near-equal loads and you don't exceed code in any way
- ensure you have solid copper busbar(s) in your main house panel and sub-panel if you have one
- note the above may require some rerouting of incoming leads to each circuit breaker, while you are at it, ensure all your breakers are good quality and if necessary replace them with new to assure that…
- have an ENVIRONMENTAL POTENTIALS EP2050 WAVE-FORM REGENERATOR/SURGE SUPPRESSOR unit on main house panel (see my system listing here and on Audiogon for more details on EP units)
- apply one ENVIRONMENTAL POTENTIALS EP2750 GROUND FILTER to each dedicated circuit for your system in main house panel or sub-panel if you have one....; these are installed in the house panel or sub-panel as appropriate
- For outlets, after a lot of years/using many others, I prefer AVATAR ACOUSTICS AFTERBURNER8 duplex outlets....
- ISOTEK EVO3 TITAN power conditioner for main amplifiers (up to 2); in my case, my stereo amp and a bespoke HDPlex custom-built DC power supply for my WAVELET processor
- "tether" using a power cord with Neutrik "PowerCon" connectors, an ISOTEK EVO3 SIGMAS power condition to the EVO3 TITAN; all front-end/other equipment gets power from the SIGMAS....
- tethering the TITAN and SIGMAS together was recommended to me by the US Isotek distributor; I've not seen this solution applied in many systems but the results for me were extremely impressive to say the least
- use a star-grounding device of your choice for all equipment; I have used Granite Audio's "Ground Zero" for years. I cannot see my way clear to move "up" to one of those uber 5-figure grounding solutions that are out there (5-figure when you add up all the uber-expensive grounding cables that they tend to push you to purchase....they may be superior but I have not found a clear and compelling explanation from anyone as to what they actually provide that is "better" than the Granite Audio solution...
Any questions on the above, please let me know and I’ll be glad to help in any way that I can. As I’ve mentioned specific products above strongly, I want to be clear that I am not affiliated with any manufacturer, dealer or distributor as I am only a fellow “audio nut” and simply love this hobby!