Choice of Wire for Dedicated Line

Use MC type cable. This is similar to BX/AC only it provides better EMI noise suppression and uses a dedicated grounding conductor. Run the grounding conductor to the ground bar of the main panel; NOT the neutral bar. If the panel does not have a seperate ground bar, any electrician can install it. It's also a relatively easy DIY. This cable doesn't cost a small fortune.

Low impedance balanced interconnects are a must. RCA's will pick up the electric field radiated by the RF antenna and cause some serious humming.

Consider a power conditioning shielded (isolation) transformer for your dedicated circuit. Use a 2.0 or 3.0 kVA. Your other circuits will pick up the elecric field and infect your system. This adds many degrees of isolation.

Consider MIT power cables such as the Z-1 or Z-II. Yes, they dont have the heavy gage super-duper exotic copper and have molded rubber plugs - but they are probably the best in keeping out EMF/RFI noise, which sounds like your top priority. And, keep the cables (power and IC) as far away from each other as practical. Doubling the distance decreases noise by 6db.

That's how I would go about it. Hope this helps.

I have experimented over the last 6 months with various wires to use for dedicated 20-amp circuits. I have the following wire in use in no special order:
1) 10 gage Romex
2) 10 gage UV
3) Belden 83802
4) Virtual Dynamics 10 gage BX Cryogenically treated with Cryoed circuit breaker. *

I have not tried the following but I’m sure it works, 10 gage solid THHN (white/black/green) manually (electric drill) spiral twist and snake through conduit.

To my ears on my revealing system I hear NO difference between (1-4)! I think simply using a dedicated circuit with 10 gage copper makes the biggest difference. I also think Gs5556 over the year’s gives excellent electrical advice.

I hope all that read this find it helpful, it’s cost me about $500 (out of my own pocket) to complete the testing for my own peace of mind.

* There might be other positive factors to using cryogenically treated wiring besides sonics. It might lower the operating temperature of equipment.

Lak, thanks for your work as recall when I tested various duplexes over a decade ago it was like watching paint dry......10ga Romex is highly inductive and best to just install it and use all that inductance to separate digital from analog gear using separate lines on the same phase. RF is best treated externally with a box of caps across the line.....

I agree with Lak and Rcrump. Having dedicated lines of around 30A (for the 230V supply here) appears from my experience to be all that is required in the wall - OFC etc makes no discernable difference. Using 5 to 10 feet of good power cord seems to do the rest. Note that having dedicated lines will accentuate the differences between good PCs and stock PCs. Using significantly longer lengths of power cord or more costly cable in the wall have no great effect. One often overlooked issue is that even the standard Romex is VERY directional. Try it both directions before you put it in the wall. The difference is large - so don't gamble. A further overlooked issue is the mains fuse. A poor mains fuse will do more damage than any noise the cable will pick up. The best in my opinion are the ceramic fuses. The glass ones are hopeless. The breakers sound OK until they get 6 months or more old. One of the big advantages of the ceramic fuses is also you can take them out and clean and tighten the contacts. This makes a big difference, as does getting you electricity supplier out to clean and tighten the contacts where your drop feeder is joined. An then there is the grounding arrangement...

I would use 10 gauge romex.

Chuck