Dedicated Line, Surge and Safety

That's right. But more importantly, I suggest that you set up TWO dedicated lines, in order to isolate digital components from analog...or at least use your pre-existing house line to maintain isolation. I also believe that using better cable (Teflon insulation) results in better performance most of the time. Many folks know that a cheap-insulation NEW dedicated line can take a long time to burn in, and that an OLD house line, if dedicated, will sound better. (DISCLAIMER: I sell Teflon-insulated Belden cable for dedicated line use). A good compromise might be to set up one Teflon 12AWG line and one 10-12AWG Romex one. Barring that, I'd install two 12AWG Romex instead of one 10AWG...again to allow separation of digital and analog....

Rex, the longer the loop distance between the dirtier digital onto its ac line to the analog preamp's input the lower the expected noise floor....
Gs5556, nice post. So why does the 10AWG sound better? It's TOTAL inductance is actually higher than the 12AWG, but maybe not as a ratio to its resistance, or current-handling capacity. If it sounds better I postulate that it's because it stays isothermal through those instantaneous current demands. Yes, 10AWG is overkill in these circuits, as even tiny temperature fluctuations won'y occur except perhaps with the very largest amps. There's some work to do here, as the normal electrical specs allow ratings that reflect a fairly large temperature rise...maybe WELL past what's audible! Is it the voltage drop that's audible or the fact that it fluctuates...or some other consequence?

Shopsmartjazz, The Belden 83000 Series cables can be bought in 100'+ spools from a couple of industrial/commercial suppliers. I do just that, "cure" the Teflon insulations with my EST process, then chop them into custom lengths to resell to you guys on A'gon. It's a whore's business, taking over my office workshop with various unspooled lengths everywhere. Ellen won't even go in there anymore (hmmm....), but I figure somebody's got to do it. This cable is very expensive as commercial stuff goes, given its complete Teflon construction and double-shielding. Even the outer jacket is Teflon, so it's an installer's dream. Belden explains that the 9AWG costs nearly double the 12AWG because there's no real cost saving in doubling the materials because it's offset by the difficulty in making such a hefty cable with fluorocarbon insulations. Teflons sell for $7/lb, vs a few percent of that for PVC. And as we know, oftentimes you CAN hear the difference. I'm not sure that the benefits of using the 12AWG version cable on big amps will offset the possible advantage of 10AWG, but that's why having the 9AWG version is nice, especially for short PCs on my PoBoxes, for example. But using the 12AWG on a dedicated line for preamps, DACs, etc., can be quite beneficial.
(Disclaimer, etc.) Cheers...and Happy Holidays.

Tom, I use the same SPDT 30/30A switch on both the 12AWG and 9AWG PoBoxes, so EACH outlet has overkill 30A rated contacts. Cheers, Ern