Originally Posted by spinaltap
You may find this detailed explanation useful.
Not really. it seems to claim that the mains cable acts as a filter. Much better ways of filtering are available but it seems to ignore the fact that it is the power supply that actually provides power to the amplifier, for example, will have filtering of a much better quality than a cable.

ROON Rock on an NUC across the systems
Sitting room: 218, DSP7200SE
Study: 218, Quad 303, Spendor BC1
Bedroom: Musical Fidelity A3CR, Chartwell LS3/5a
Various Sonos boxes in bathroom and spare rooms