Dedicated line: 10 gauge solid core or 8 gauge stranded

My son is an electrical contractor. He installed 2 x 10 gauge solid lines with 20 amp breakers for my Home theater. 12 gauge is minimum 20 amps.

@ jrwaudio, Any 20 amp or 30 amp electrical outlet will connect to, 10awg wire. The point of all that (mojo) is you can not "tax"the circuit out. Now all your audio gear gets all the power it needs. And the cost is very low ..Hope that helps...

Thanks for all the responses. I'm planning to install just 1 receptable for the entire system connected to a Nordost power strip. Turntable, phono preamp, preamp, 2x140W monoblocks, 2x800W subs, nothing too crazy. I know folks sometimes have multiple lines installed to split the amps from lower powered components, but I'm trying to avoid ground loops.  Sounds like I'll be just fine with 10 gauge, twisted.   

@galpi i did basically the same. 10 gauge line (cryo’d Romex) to a quad receptacle, synergistic line filter box for for front end and direct from wall for monoblocks. No noise no complaints. Yet.

@galpi If you can justify it, particularly if it’s new construction (as opposed to remodel), I might try to separate out your subs from the rest of the system...unless you never listen above half your available amp power (at half amp power - not halfway on your volume control). Especially if it's going to be a long cable run from your breaker box.

If a remodel, ask your electrician to explain how much rerouting, if any, he might have to do in order to balance the 2 phases (assuming you have 2 of them), because all your system circuits will have to be on the same electrical phase in order to avoid hum. But, just adding 2 system legs onto one of your existing phases and letting it go at that will likely result in the 2 phases now being out of balance (unless you plan to add 1 or 2 non-audio legs of roughly similar amperage on the opposite phase to balance it all out)...and barring that, then you’d have to look at taking an existing breaker or two and removing them from the system-side phase and move them over to the opposite phase to balance against the amperage of your system (routine work for any electrician). He should be able to estimate that ballpark cost for you.

@gs5556 Finally found the Lowes brand of twisted 10/3 in solid core (hiding from me in plain sight), which I’m considering for an upcoming remodel. That may be all I’ve seen so far, but the price is right and (I’m supposing) I can connect the extra wire to ground along with the bare conductor and get the best noise rejection without causing any noise problems, as opposed to letting the 4th conductor remain unconnected??