If you are going to the trouble to add a dedicated circuit, go ahead and use 10 guage wire and a 30 amp breaker. You will never be sorry. On a 20 amp circuit with only one light and my system, when the four amps (2 dual monos; I run mains and subs on matching amps and preamps.), all occasionally draw power at the same time, and the light dims for an instant. My amps only have one chip per channel. It regulates the power supply. Occasionally, I believe, all four channels of transformer filling current fill a total of 16 giant caps, which causes the flicker. It does not happen now that I ran the 30 amp wiring. Remember, a 20 amp circuit is really only 15, because 75% is what triggers the breaker. If you look at extension cord packaging, the ratings for 14 guage and 12 guage are 13 (Legally rounded from 12.5) and 15 amps, or 75%. My amp transformers are 500 watts x 4. Add in a good sized power supply for the two preamps and the 25 pound cd player (big transformer), then say we have 2200 watts divided by 110 volts and we have a possible draw of 20 amps, one third more rhan a 20 amp circuit is designed for. The chips regulate cap filling, so it does not blow breakers at turn on.
