Dedicated 20 amp circuit - Electrician laughed!

A couple of times I have tried a transformer between my panel and my dedicated run to the stereo, using a Topaz 5 kVA, 0.0005pF model.  I never really heard sonic improvements, frankly, and the thing did buzz nicely (was in a separate room!) and wasted a lot of energy in the form of heat.  But they do kill any DC on the line.  I took it out both times, and have found actual sonic improvements with the PS Audio P20 (P10's before that).

Your electrician is an idiot.  Don’t let him change a switch or receptacle.  Without an understanding of the NEC he is dangerous.

just sayin’...

This discussion is excellent.

I have my basement gutted and need advice on wiring since this will be my listening room.  I’ve investigated soundproofing thoroughly. But really don’t understand wiring the basement, what to tell the electrician, or where I should go to learn about it.  
I talked to one electrician about wiring with respect to an audio system. He looked at me blankly and had no idea what I was taking about. 
”Running one normal dedicated line”: does that mean the wiring is from the circuit box to the outlet then directly to the audio equipment?  You can see I’m a little lost here.  

Where should I go to learn the basics?  
Thank you in advance.  

Now, I'm getting confused. Nearly every post on a dedicated breaker that I can remember has cautioned that a separate ground rod is a code violation? What gives?

A separate grounding electrode is legal per NEC 250.54 but ultimately the separate electrode must be connected to the ground of the main service per NEC 250.4 (A)(5).

An isolated ground receptacle basically means that the ground terminal on the receptacle is isolated from its yoke. In theory if you install an isolated ground receptacle and run the ground wire back to the breaker box, the ground wire will be isolated from the other ground wires and metal boxes on that circuit - up to a point.

Ultimately, every ground wire terminates at the same bus bar. Additionally, every single neutral wire is also eventually connected to the same ground back at the service. With that in mind, the only way for your audio system to be truly "isolated" from everything else in your home is to install a separate service.

That being said, having a dedicated circuit for your rig, as well as utilizing isolated ground receptacles, and paying mind to which circuits are connected to which phase in your breaker box can go a long way towards reducing unwanted noise, but it's not a cure-all or a magic bullet.

...take all of this with a grain of salt - I'm just a dumb electrician who builds amplifiers...

A separate grounding electrode is legal per NEC 250.54

Well that's a relief. 

but ultimately the separate electrode must be connected to the ground of the main service per NEC 250.4 (A)(5).

So... the electrode that goes into the ground must be connected to.... the electrode that goes into the ground. 

I must admit it sounds a whole lot more official with a bunch of letters and numbers but in plain English: 2 ground rods connected together. Right?