that's good and all for the alternator whine (which, btw - I've fixed in my car by running 4 gauge wiring to the amps, hooking up JUST the empeg's side of the rca-ground cables, hooking up a ground loop isolator between the amp and the empeg...)

But the problem that's also there isn't related to the ground loop... find an adapter and hook up regular headphones to the empeg while plugged into the AC power; you'll hear a noise semilar to crunching up aluminum foil... in higher-end systems w/ good speakers this unfortunately gets very amplified...
-mark

...proud to have one of the first Mark I units