Here is a C&P from one of my customers that has done extensive listening tests on all things power. He is a power professional and a long time music lover and listener:
"The Uberbuss is now sounding rather incredible, after I experimented with some new isolation feet under it. Herbie's frost-semi clear Iso-Cups with lampblack balls under it (3 of them). Holy moly, things are getting amazingly neutral its ridiculous. I personally find that having the 2 different types of outlets in there, the NCF Furutech plus the polished unplated FPX, is quite an amazing balance. I prefer the digital source into the polished FPX, pre-amp into the NCF. Sounds better that way to me than both in the NCF for some reason. Chalk it up to "everything has a signature no matter how good something is", and, therefore, when you use 2 difference types of outlets, you completely avoid any of the weaknesses of one type, no matter how small, and can *potentially* achieve a more balanced, neutral, transparent result (which I believe I have)."
The polished FPX he is referring to is the Furutech FPX(Cu) that I disassemble and polish the beryllium copper to a mirror finish.
Once again: highly polished electrical contacts are lower noise. Oh, graphene is turning out to be a hit, too.
People keep asking me about tweaks for BUSSes, so please post your favs for the rest of us to see>