Man, I feel like a dork!

IIRC, there are two wires that have to be switched... I vaguely remember tracing the wires from the empeg, into the adapter, and then to the stock setup. I *think* two of them had to be switched. We took the adapter and popped the little silver connections out, moved them to the right spots, and pushed them back in. No way I can remember which ones, but we had to move some.

The markings on the stock radio can help ID the wires. I know we got it figured out eventually, but it took a while.

I also know that the only way we got decent sound was via use of a ground loop isolator. We put one on the front, and it solved everything there. The rears sounded bad, but not as much so. Nothing ever ended up in the back.

This was mafisto's TT. Since then the car is being lease-paid by a friend, as he now owns a brand new Celica GTS. (He started thinking long-term and got tired of paying for a car that was never going to belong to him). The stock radio was put back in and the whole problem went away in an instant...

Now we get to put the empeg into the Celica! I'm looking forward to this one, I'm great at installing from scratch, just not leased Audis aparently.