As an experiment, I'd suggest putting the entire stereo system, including both sets of power amps, on the same dedicated port (assuming it has sufficient current capability).
I'm thinking that there could be voltage offsets between the ac safety ground and/or neutral of each of the dedicated ports and those of the other dedicated ports, as well as between them and the ac safety ground and/or neutral of the regular port. Those offsets would then appear between the chassis of the various components, since they are connected to ac safety ground, and also to a small but possibly significant extent are coupled to ac neutral due to leakage paths. That in turn would cause small ac currents to flow in the shields of the interconnects that connect those components, in common with signal returns which also flow through those shields.
That could account for both the hum and the sensitivity to which interconnect is used, since the shield resistance (and consequently the amount of unwanted current flow) would be different between the two sets of cables.
And the current drawn by the lights when they are turned on could very well be increasing the voltage offset between the regular port and the dedicated ports.
Use of multiple dedicated ac ports for different parts of the same audio system, while having potential advantages that are well documented, has this kind of potential downside as well.
Hope that helps,
-- Al
I'm thinking that there could be voltage offsets between the ac safety ground and/or neutral of each of the dedicated ports and those of the other dedicated ports, as well as between them and the ac safety ground and/or neutral of the regular port. Those offsets would then appear between the chassis of the various components, since they are connected to ac safety ground, and also to a small but possibly significant extent are coupled to ac neutral due to leakage paths. That in turn would cause small ac currents to flow in the shields of the interconnects that connect those components, in common with signal returns which also flow through those shields.
That could account for both the hum and the sensitivity to which interconnect is used, since the shield resistance (and consequently the amount of unwanted current flow) would be different between the two sets of cables.
And the current drawn by the lights when they are turned on could very well be increasing the voltage offset between the regular port and the dedicated ports.
Use of multiple dedicated ac ports for different parts of the same audio system, while having potential advantages that are well documented, has this kind of potential downside as well.
Hope that helps,
-- Al