Thanks for all the input, guys. Chashas1, howdy again. You are right, I'm still looking. From the input you all are giving me, I may end up wasting money. The amp sounds great, but I just can't help but wonder - more quiet space between notes, more definition, better soundstage? - just by adding a power cord. Maybe I am an idiot led astray by all the power cord hoopla.
Regarding AC power, I do know that plugging amp and preamp into a PS Audio Power Plant Premier made a significant difference, as did swapping the stock PS Audio cord for a DCCA Reference Master. But then, the PC that came with the PPP was not of the same weight as the PC that came with the AR.