To complement my system's phalanx of SR Black fuses, I just ordered a second Black outlet for my second dedicated line. It was gonna be kind of a pain to replace even one of them as the two lines share a double outlet box back in a corner, so I figured replacing both at the same time will be easier than not and regretting it later. I should have the two outlets some time next week and will hook them up as soon as possible (they will be replacing PS Audio Power Ports).
This second line powers the REL along with some noisy bits (and noisy bits on each circuit are all plugged into Blue Circle Audio PLC FX-2 filters). Because the system spans the two circuits(via the REL high-level connection from the amps). I have been worried about ground potential differences and ground loop problems. I did have a hum when the REL was first connected with its three wires, the solution from the REL distributor was to leave the ground wire unconnected. The REL played just fine and the hum was gone, so it was clearly getting its ground reference from somewhere. After I installed the Black fuse into the REL, I decided to try tying the chassis ground of the REL to the star ground post on my Nordost QBase which powers the main components on the other line.
The two circuits are on a tandem breaker (not two separate breakers ganged) and my guess is that they were wired on two different hot phases relative to neutral/ground. I'm seriously considering hiring an electrician to check the box and change things around so that both circuits are on the same phase. The grounds seem to be fine, as the 22ga. REL chassis ground wire doesn't get warm at all suggesting there is no meaningful difference in ground potential at the outlets, which is good since I have tied the grounds of the two circuits in two places--at the breaker box and at the outlets. If code allows, I will also ask the electrician to drive another ground stake to connect to the star ground on the QBase
It shall be interesting to see whether the Black outlets can enhance the sound beyond the dramatic changes wrought by the Black fuses. It's kind of addictive (OK, it is addictive). We shall see...