Installing dedicated 10 gauge lines

WOW...  Lots of opinions here on power wiring etc...  I do agree that confiding in a good electrician especially one with re-modeling experience is a reasonable thing to do.  I re-modeled a retirement cottage last year and was easily able to install 10-gauge cryo'd Romex to Pangea outlets which accept the 10-gauge wire easily to a 20-amp breaker at the panel 30-ft away.  With no-load on that circuit, then powering up all of my equipment (including class-A amps) the voltage drop was ~1-volt no load to full equipment load.  My audiophile friend with roughly similar equipment and 14-gauge wiring with similar distance to the panel with full load experiences a ~3 - 4 volt drop.  So I feel that 12-gauge Romex would be fine unless you're going a good distance from the panel.  Then 10-gauge in my opinion would be better.  This was not a scientific experiment...  Just an observation on our parts with voltage-drop.  

Again, if you can measure your no load to full load voltage drop with existing wiring, you may not have any problem at all.  Using better quality outlets just makes the connections a lot more secure.  

I have been planning a dedicated AC line for some time and it should be installed within a couple of weeks. At first, I thought of using the man as a consultant who did M.Fremmer’s which was a major fix including a new meter box, new incoming outside line and junction, two outside grounding poles, etc. Since code in my area doesn’t allow anything outside to be changed, I decided on a more basic rework of my inside line.

For that, I bought 50’ of Oyaide high end cable and two Oyaide outlets with heavy faceplates. Just this was $4500. And my electrician will be able to run the wiring through the attic for about $800. Waits to be seen if I will still need my top line Shunyata conditioner. It is recommended that the amps go into the wall outlet.

I will see if the preamp is better to the wall or to the conditioner.

My current AC for the system is on the same line as the fridge. I expect that the new line will bring the whole system up to a new level. More present? Hope so.

In an empty house we were moving to I had two outlets, of 4 plugs each, installed of 20 amp wire. The room had a common wall with the garage, and the wire went to a breaker box in the garage far wall. So the wire only ran to the ceiling and down a wall to access the room at the floorboard. 
 

It cost me $400, but this was in 2010. And I hired an unemployed electrician who did the work. So it was a win/win. Hardly near $15k. 

Did exactly this in 2 houses.  Two different electricians ran dual 10 gauge from the box to dual quads so I could separate tube/SS for ground loops or noisy power supplies.  Less than $800 both times without any holes in the sheet rock other than cutouts for outlets.  An electrician should be able to notch the sheetrock to jump over a stud if necessary, which is easy to patch. As for 10g vs 12g…while you are in there it isn’t much more expensive on a short run, and it isn’t going to sound worse.