This is a device that can be plugged into a dual-trace O-scope, and will display the high freq noise, on your incoming AC(both line to neutral and neutral to ground): (http://pdf.textfiles.com/manuals/STARINMANUALS/ETA/Manuals/Power%20Probe.pdf) Here's a demo of it's display and the noise on an AC line: (http://www.youtube.com/watch?v=vOO89uHEprM) There are three parts to the demo on Youtube. Of course everyone's AC quality varies, depending on what's connected to the their local source(everything operating on your side of the neighborhood's single phase distribution transformer). ie: In your own home; anything digital that's operating is polluting your AC with very high freq noise.
Analyzing the power from the outlet
I've been reading threads on the various methods of power cleaning -- filters, regenerators, dedicated lines, etc. But I don't see a thread that explains a systematic way of evaluating the condition of the power at the outlet. Is there a thread or a link that instructs on how to analyze the power for noise, voltage consistency, etc from the point of view of an audiophile?