"My control, signal, and power lines are a rat's nest, and I know I need to work on that."
I would start with that rat's nest. Disconnect and bundle like-wires together with cable ties - audio with audio, etc. Get any AC wiring away from audio cables. If you cannot keep AC wires completely separate from audio cabling, cross them at a 90 degree angle - do not run them parallel to audio cabling.
As Musiclover said, I would also invest in some quality balanced cabling. Good luck.
Regards,
Bob
p.s. I hope I'm not being condescending and telling you something that you already know.
Last edited by 90 dB; 09/16/14 04:54 AM. Reason: p.s.