During RMAF 2008 the presentations in the Nordost room and the Tuning & Setup seminar hosted by HiFi+ (Roy Gregory) emphasized the importance of the house power supply in audio systems. Not only is the electric source noisy but house appliances and indeed even audio devices themselves add noise to the house power grid. Dedicated electrical lines from the main electrical panel to audio systems and the use of power conditioners can greatly improve the power source. But are they alone enough? A completely separate line and accompanying electric meter is not practical in my case. But I am considering installing a separately grounded electrical sub-panel dedicated to the current dedicated electric circuits that drive my audio system. However, I'm not sure if this change will actually improve my audio system power source. If I run separate main electrical cables from the meter (or the primary electric panel) will this additional cable ultimately be contaminated by "back-flow" from the main panel (since everything is interconnected? I would very much appreciate any wisdom on this subject.