I have always had my amp plugged straight into the wall and use a power conditioner to isolate the rest of my gear. I currently use a Furman Elite 15 PFI and it works well with my Audio Research equipment. It also protects my gear from spikes and noise while not having a negative effect on the sound. I don't know what ARC models you have. My Ref 110 has a max of 800 watts and the rest of my gear maybe 400 watts at most. There should be no problem with everything plugged into a 15 amp outlet. An extension cord can effect the sound. The only way to find out for sure is to try it and see.
Amp and preamp on same outlet?
Just how much of a no-no is this? ARC goes as far to print in their manual to say to have the amp and preamp on their own circuit. I live in an apt. and I'm forced to have both plugged into the same outlet. Cords just don't reach....How much sound quality is lost by doing this? It sounds great as is, but is there a major detriment to this? I'm curious.