OBI, I must admit that anytime you are fortunate enough to have friends that went to M.I.T. you are going to benefit from it for sure. I can also say that my going to Motorola school didn't hurt me either.
The noise in my home was actually bad enough that you could actually hear it in the light switch located at the top of my stairs! I was surprised as well as thankful when it turned out to be as simple as a loose ground in my service panel!
One other thing that you touched on was interconnect routing.. Another simple thing that certainly can't hurt is taking the time to make sure that your interconnects are separated from all of your power cables and speaker cables. Try to run them as far away from the other cables as possible. This can be a little frustrating and time consuming, but it doesn't cost you any money to do except for some zip ties etc. It's also just one more thing you can do to eliminate a potential problem......
Question: Do you know why turds are tapered on the ends? Answer: So your asshole doesn't slam shut..
Carver- SDA490t, SDA450, 2 TFM45's, TFM15, CT23, CT28v, CT27v, Linn Kaber speakers, Sunfire crm2's, PS Audio Statement speaker cables and I/C's, A.P.C. power