A bit more information. The primary reason for the AC change was to future proof the pieces. What happens if Vinnie gets out of the hifi game? Then we have no way of accessing his batteries.
I'll admit, I was skeptical when I had him do it as to if there would be any sonic changes, but since it it utilizing a completely external power supply there was no noise added to the signal - dead quiet. That was a very pleasant surprise. The conversion was simple, so it would be relatively straight forward and inexpensive if you wanted Vinnie to convert them back.
A friend brought over his battery powered units and they sounded the same.
Price drop to $2,000 + shipping/paypal fees