Originally Posted by Mojo
Isn't it strange, that with your AVR and DSP off, and the ADA to DSP cable connected, the hum is still there? But when you remove the ADA to DSP cable, the hum subsides.

Oh, this is why I thought I should clarify. When you first said amp to DSP cable, singular, I assumed that meant the cable from the AVR to the DSP, since there are five cables connecting DSP to ADA. Let me try that out as well, disconnecting at the DSP all of those cables, and I'll report back.