The most fundamental difference between now and when the problem was not present, aside from the different amps, is that previously there were balanced connections, and now there are single-ended connections.
As Jim's "myths" link makes clear, the shields of single-ended interconnects, while serving as the return path for signals that are transmitted between the connected components, also conduct extraneous currents caused by ac ground differentials between the components (since the shields tie together the chassis of the components, which in turn are connected to both signal ground and ac safety ground). The common path causes coupling of ac-related noise into signal, since the receiving component has no way of distinguishing between the two. Balanced interfaces are a completely different story, and are essentially immune to this kind of effect.
So my first suggestion, if you have not already tried it, would be to connect EVERY component in the system to the SAME dedicated line, to minimize ground offsets between the components.
Beyond that, it IS very conceivable to me that a better quality interconnect would help, because it would presumably (although not necessarily) have lower shield resistance, which would tend to "short out" voltage offsets between the chassis of the connected components. As well as providing better immunity to airborne rfi.
Regards,
-- Al
As Jim's "myths" link makes clear, the shields of single-ended interconnects, while serving as the return path for signals that are transmitted between the connected components, also conduct extraneous currents caused by ac ground differentials between the components (since the shields tie together the chassis of the components, which in turn are connected to both signal ground and ac safety ground). The common path causes coupling of ac-related noise into signal, since the receiving component has no way of distinguishing between the two. Balanced interfaces are a completely different story, and are essentially immune to this kind of effect.
So my first suggestion, if you have not already tried it, would be to connect EVERY component in the system to the SAME dedicated line, to minimize ground offsets between the components.
Beyond that, it IS very conceivable to me that a better quality interconnect would help, because it would presumably (although not necessarily) have lower shield resistance, which would tend to "short out" voltage offsets between the chassis of the connected components. As well as providing better immunity to airborne rfi.
Regards,
-- Al