Thanks for all of the info guys.  Greatly appreciated!  we have just decided to move to the burbs and I will build a room from scratch!  best.

@theaudioamp that is all good and correct, and we should minimise ground loops, and using one outlet or circuit is a help.

But every one in town is rattling their noise onto the power line, and those fields are going into other circuits in our house, say to another parallel circuit in our house… and out of our house into the next house… etc.

And I doubt that a 12ga romex brand wire bundle is much different from some off brand of 12ga copper wire.

Having the LEDs on different circuits makes their effect at least need to travel further to get to the circuit that our gear is on. Ideally that is on a different phase of 120v, so it needs to effectively go to the pole where the transformer is at in order to loop any fields back. (It is that way if we ignore coupling between the two phases.)

So I am more inclined to trust the electrician (aka “a sparkie” in Australia), and then put the investment of power conditioning into the gear which is generally designed better to mitigate noise entering in.

But a dedicated circuit and grippy outlets are never a bad thing… just it is doubtful that some fancy copper will change anything.

Lots of lore in audio @holmz.

It is inaccurate to say there is no benefit of a dedicated line in all installations. It will significantly reduce the impact of high instantaneous draw sources (dimmers, etc.) by putting them a different AC run. If it is on the same run, you are exposed to the the instantaneous drops on that run. If it is on a different run, those drops are buffered by the incoming feed, and filtered by the inductance of the dedicated run. Value depends on how susceptible your equipment is.

If a high current dedicated run allows you to plug everything into a single outlet box sharing the same ground as opposed to multiple outlets, that is a benefit as well. About the worst thing you can do is multiple runs and multiple outlets. I have seen that suggestion often on audio forums. It is a bad idea.

Noise does couple from line and neutral currents into ground and that can also generate noise in your system. A dedicated run with better wire, not expensive, just better will help for this.

As always, YMMV. Your electrician is not right or wrong. Don't assume you have a noise issue. If you play something analog or digital and cannot hear noise in quiet passages (silent sections), then it is highly unlikely you have a noise issue. There is a slight chance that noise could create more jitter if you are using a coax digital cable. If you are worried about that, get a better DAC. For analog, the noise in the silent parts is everything.

I brought my electrician out to my house today to show him where I would like to install a dedicated 20a circuit for my system.  He laughed and said that's the stupidest thing he's heard and laughs when people talk about it.  It said, if you're going to do it, you have to have it separately grounded (shoving a new 8 foot rod into the ground) but even then, he sees no way there can be an audible improvement.

Now, he's not just an electrician though. He rebuilds tube amps on the side and tears apart amps and such all the time so he's quite well versed in audio electronics and how they operate.

He basically said anyone who thinks they hear a difference is fooling themselves.  

He sounds trustworthy so far.

Personally, I'm still not sure, I'm no engineer, my room's not perfect,

Then I would trust an engineer.
 

I'm not taking a side here but I thought it was interesting how definitive he was that this not only WILL not make a difference but ALMOST CANNOT make a difference. 

If we start with, say, Benjamin Franklin, and go through Chas. Augustine Coloumb, Faraday, Maxwell, etc… we pretty much end up with the basis for all electrical theory that is rooted in science.
The other theories are rooted… in something else.

Food for thought

Dedicated 20 amp circuit - Electrician laughed!

I brought my electrician out to my house today to show him where I would like to install a dedicated 20a circuit for my system.  He laughed and said that's the stupidest thing he's heard and laughs when people talk about it.  It said, if you're going to do it, you have to have it separately grounded (shoving a new 8 foot rod into the ground) but even then, he sees no way there can be an audible improvement.

Now, he's not just an electrician though. He rebuilds tube amps on the side and tears apart amps and such all the time so he's quite well versed in audio electronics and how they operate.

He basically said anyone who thinks they hear a difference is fooling themselves.  

Personally, I'm still not sure, I'm no engineer, my room's not perfect, and I can't spend hours on end critical listening...  But, he does kinda pull me farther to the "snake oil" side and the "suggestive hearing" side (aka, you hear an improvement because you want to hear it).

I'm not taking a side here but I thought it was interesting how definitive he was that this not only WILL not make a difference but ALMOST CANNOT make a difference. 

Cardas used to offer a 10 AWG 3 unshielded in wall product @ approx $17. per foot but it is listed as no longer available by their dealer Cableco.
 

JPS Labs also offers an in wall product with 2 10ga power leads + one 12ga ground lead

Beldon has their 83803 12 AWG 3 with a both a foil & a braided shield 

JPS Labs Power AC IN-Wall Cable

https://www.enjoythemusic.com/magazine/equipment/1002/jpslab.htm

Summary

If your system is toward the lower end of the high end, or you're likely to move within the next few years, and the installation is relatively easy, I'd probably recommend just going with a standard wire dedicated line. For a hundred dollars, and an evening playing with an electric drill, a dedicated line is a true bargain. 

On the other hand, if you've got some nice mid-to-top quality components, and if your life is pretty stable, and if the installation is not too complex, the $1000 to $1500 upgrade to the In-Wall is highly recommended. That's a lot of "ifs", but you could easily spend a lot more upgrading a single component. With the installation of the In-Wall you can improve your entire system, getting the best from every component--now, and when you upgrade them in the future. It is not a "jaw-dropping" improvement, but one that audiophiles with educated ears will easily appreciate. The path to the highest levels of music reproduction is not simple, and rarely inexpensive. The JPS Labs Power AC In-Wall cable definitely took me higher up the mountain and gave me a better view. And for the high rollers out there, building new homes with built-in home theaters and dedicated music rooms, this wire should be considered standard equipment. Don't think twice.