Anyone have the Answer?

There is a whole suite of measurements you can make to assess power quality, using devices such as this. The extent to which any of these factors actually influence the sound is a matter of some debate, obviously.

One power quality factor that is often overlooked - and which can have a definite, measurable influence on your system - is Power Factor. It can be measured with something like this.

Measuring the AC mains noise isn't really that important as ALL electronics that are certified will have internal filtering. If it makes you feel better then use something like a Panamax but I wouldn't spend over a few hundred dollars they give you plenty of outlets and even some of the less expensive ones now show your voltage. Watch the first video I posted it explains why internal filtering is mandatory for certification as the internal noise is worse than any incoming on the mains and since it travels both ways the internal filtering is required to keep noise from being injected to the mains line. This is one of the least understood issues and most oversold as far as cleaning products for your mains.

Great answers, here, mostly! I had the same question.

Easiest method is buy a Power Plant try it. If it doesn't work return it.

I use one, works according to my ears and eyes(TV).

tablejockey

Easiest method is buy a Power Plant try it. If it doesn't work return it.

This is such great advice that it is hard to understand why it is not a more common practice. In this instance, PS Audio offers, "Free shipping & free 30-Day returns for all US customers, including Hawaii and Alaska," according to its website. So it seems there is zero risk, other than your time and energy.