Speakers cut out when car is on or running. Ideas?

I bought a new head unit and subs for my '92 Jimmy a couple months ago. My roommate wired up the head unit for me and I wired up the amp and subs. The way my roommate wired up the head unit is strange because it's on as long as the faceplate for the CD player itself is on, whether the car is on or not, and he swears it's wired up to the battery.

Anyway, everything ran well until I left the faceplate on for three days while I was on vacation, so the thousand watt amp and everything else related to the sound system ran my battery down to shit. Got it jumped and now the car starts just fine again, but the speakers only work when the car is neither on or running. With the faceplate on and the car off things sound as they should, but as soon as I turn it on all of the speakers cut off
except the subs. Replaced the blown radio fuse and I still get the same problem.

Any ideas?