hospital grade or commercial grade receptacles ?

Saki70..There isn't any shielded conductor in common 12/3 wire used in houses. What makes you think that green tape will stop "interference" better than bare wire? (Have you tried red tape?) Why not use the bare ground wire? This conductor carries no current except for leakage resulting from a fault in the neutral (white) wire. A safety issue.

Quality outlets are desirable because the elcheapo ones wear out and the contacts get loose. If the contacts get loose, so that the plug tends to fall out, then you do have a problem.

Search the archives for posts on power by Lak and Psychicanimal. You'll find ideas that go a good way beyond what you have planned, but if isolation is important to you, you might be happy to know about them.

One key point for me was the return or neutral (white) connection. When the electrician installed my dedicated line, he ran a separate hot wire from the breaker box for it but connected the neutral to a common bus. The isolation was only partial and I had to have it redone.

Getting back to the original post, I hate hospital grade wall plugs. Their only purpose is to not spark when cords are unplugged. They are not as conductive and sound terrible. I have bags of them.

On the question of whether wall plugs sound different, I will say try them. If you hear a difference, ignore those who say you cannot. You are not delusional; they are.

Eldartford;
What I was refering to, was the use of the insulation on
the third wire as a means of insulating against possible stray interference from outside forces, maybe not totally but of some use as compared to the bare ground. The green tape was to identify it as a ground wire should anyone else
get in there.

Tobias;
Please excuse my ignorance, but what did you have to have redone with the neutral wire ? What was the procedure ?
Is that the same as a seperate ground ? Did it require further equipment ?

Hi Saki70, the thing is just to make sure that both hot (black) and neutral (white) sides of your dedicated line are truly independent, all the way from your system outlets back to the circuit breakers at the point where the electrical service enters the house.

My dedicated line was installed at the same time as other parts of the house were rewired. The electrician set up a central bus connection for neutral on the first floor. Nothing odd there, since the breaker box is on the second floor and it made connections easier for him. But the sound system is on the first floor. He ran the sound system's hot wire directly back to the breaker, but he only ran the neutral back to the first floor bus.

The problem then was that the bus connection was shared by all the ground floor circuits, so my system line was no longer entirely independent. Any noise on the neutral wire was shared. It made having a dedicated line sort of pointless.

The electrician had assumed that the reason I wanted a dedicated line was to keep the whole 15 amps of service on that circuit available to the sound system and nothing else. He didn't understand that the most important reason for having the dedicated line was to isolate the system from noise generated by sources in the house like the refrigerator, the computers and the washing machine.

To make the isolation point even more clearly, I'll mention that when I replaced the standard 3-conductor, plastic-insulated 12 gauge wire in the dedicated line with Belden 83802 double-shielded (to cut radio-frequency noise pickup), the background noise level dropped even more. My ears liked that a lot.

I got my Belden wire from the Subaruguru (Ernie Meunier), here at Audiogon.