Installing a dedicated AC line

Incus,

1) Don't put in a subpanel if you're 10' away from your new breaker box. The situation for a subpanel would be where a long run is required. Then running 6 gauge to the subpanel might help reduce the voltage drop.

2) 10ga minimizes the potential voltage drop along the run. Definitely use it for the curcuit your amp will plug in to. For your preamp and source equipment, 12ga might be just fine. After using 10ga for all my dedicated circuits I met Lloyd Walker (of Walker Audio): he's one of the people who'd recommend using 12ga for the source equipment. His comment to me was that the 12ga better matches to the current being pulled across the circuit, smaller diameter, less resistance, less skin effect. I'm not clear on the explanation, I just remember he was quite clear in his opinion, and I trust his knowledge about audio and electronics.

3) Silver contact enhancers do work and will make a difference. I strongly recommend using Extreme SST from Walker Audio for both your AC connections and all the rest of your audio cabling connections. The difference can be dramatic. (Lloyd Walker offers a full refund if you're not satisfied with the results.)

4) Some of the Square D stuff is very well made and some units use a full copper bus, not aluminum. The copper bus is the critical difference for our purposes. (I believe that Square D today makes a broader range of "built to a price point" panels, so the quality may not be the same across their entire line of panels as was once the case.) In my installation, we used a commercial Siemens breaker panel with copper bus. Whatever brand you use, use the the same brand for your circuit breakers - not good to mix and match here.

Good luck!

"His comment to me was that the 12ga better matches to the current being pulled across the circuit, smaller diameter, less resistance, less skin effect. I'm not clear on the explanation, I just remember he was quite clear in his opinion, and I trust his knowledge about audio and electronics."

Skin affect at 60Hz?

If you are willing to pay the extra money for 10 gauge wire, then go for it. You will have less voltage drop, less surge drop, and a more robust system. You need to make sure all of your circuitry, such as breakers and receptacles, support 10 gauge wire; as some do not and you DO want this to meet NEC.

Regardless of which gauge you use, make sure you use a good quality receptacle, such as a Hubbell. See http://www.hubbell.com/

Actually, if you are a real glutton for punishment, you can bring in 220 VAC and rewire your transformers in all of your equipment! This quadruples the efficiency and halves the surge currents.

Oh, I forgot to mention, put in a dedicated earth ground for your system. I have done this several times in several homes and it has always helped reduce EMI interference and made a whopping difference in FM reception. That being said, I wouldn't do the work for the sonic improvement, but it sure is worth it for FM.

I didn't think about this when I first installed it, but FM, as with all broadcast, is transmitted with respect to the earth, so a solid earth ground really cleans up reception.