Yea, the input gain is +5 and the gain is up all the way. Lowering it does lower the hum a little bit but it is still noticable at quite moments in a movie.
What do you mean twisted cable?
The construction of the cable. Instead of a coaxial design with a single conductor inside a dialetric, it uses twin cables, twisted, crossing each other at near 90 degrees many times. This allows cancellation of electromagnetic inducted noise. Switching to twisted pair cables eliminated the hum with my EP2500 as I had some induced noise into the system.
It also sounds like you may have a ground loop as well. This may be more difficult to diagnose. The key here is to diagnose which connected component is introducing the loop. to make this determination you will need to remove one component at a time from the receiver. Cable boxes are usually a good place to start as a common culprit.
Set your receiver's subwoofer output at +5 of 10 or so. Lower your input gain on the DCX to flat. Set the amplifier's gain to 50% and see if that helps you out. If it is not enough, then bump up the output gain on the DCX as necessary keeping it below clipping.
