Search for 'alternator whine' in these bbs or possibly 'grounding', there's a ton of good info and if your installers were worth their salt they'd have more of a clue. It sounds like they aren't interested in doing the tough part of the job, just taking your $$ for making a few crimps. Grounding & alternator whine aren't unique to the empeg, just a little touchier. I cleared up my alt. whine by separating the power wires into the empeg from the speaker wires & preamp outs. Good luck, it can be sticky.

-Zeke

just say you weren't paying much attention...