It’s relatively straightforward, but it consists of removing common-mode and normal-mode noise. I use a -31 series 1kVa Topaz Ultra-Isolation Transformer (0.0005 pF) that all my networking components and their linear power supplies are plugged into via a common power strip. It looks something like this:
Wall Receptacle > APC LE1200 Voltage Regulator > Topaz 1kVa > Tripp-Lite (PS-602-HG) Strip—>Hynes SR4/EE8 Switch; Teddy 15/2/Google Nest
My networking scenario is somewhat different than others, so one may or may not require the voltage regulator (even I likely don’t need one). Also, if you’re placing any digital components like a DAC into the strip, there’s the option that many use to plug a balanced iso-tranny (like a B&K 1604A) in series with the Topaz. The DAC, for instance, would plug into the balanced; the balanced into the Topaz to mitigate any backwash noise from the DAC or an SMPS. There are lots of different options to fit a given scenario. Mine is quite simple but effective.
My current system is nice, but I’ve owned better performing (at least if expense is any indicator), yet none of those so-called better ones is/was even close noise-wise to what this achieves in mitigating or eliminating any of the above CM and NM noise, which in turn really elevates a mid-to-hifi system like mine to something quite special, IMO. It is so quiet it can be staggering. I’m convinced it is because so much of the noise issues have been addressed, versus throwing money blindly at the problem. So much of it is cumulative as well, meaning each addition such as star-quad DC cables where applicable and using purposefully implemented ferrite cores within the proper range can really benefit as well. It might be overkill, but noise and the prospect of gound-loops isn’t really a concern for me anymore.