I have the Sony CDXGT550UI
I also have the Crunch P1400.4
The way I currently have it wired is this:
The Sony has two(2) pre-amp outs.. Front and Back/Sub
I ran two sets of RCA cables to the Crunch and plugged the "front" RCA's into Channels 3/4 on the Crunch, and the Back/Sub into Channels...