MeanGene brings up a good point. A lot of units, in addition to any kind of noise filtering that they do, also provide for switched and unswitched outets (TV and VCR always on, but then you can turn on the entire rest of your system with one button), and some even have delayed powered on outlets, such that the source components & pre/pro are turned on *before* the power amps(s) to prevent turn on thumps through your speakers.