How do you tell how dirty your power is?

A scope is the only way to assess the non-60 Hz information on your ac. I doubt if anyone rents them, however. Don't be too certain that ac filtering, etc. while getting rid of some of the noise will sound better. Most such devices hurt the sound more than they help it.

TBG makes a good point. There are several types of power filtering, from transformers to chokes to capacitors to active re-generating devices. Each has its place and results in different trade-off's. Some can work together and others can't. Some work better for source components but not for amps. There's more to this science (yes, science, because each has a provable result on dirty power sources) than just buying something and saying "it helps" or "it makes things worse".

There's a lot posted about power conditioning on many forums. Do some searching and read up a bit. Then by all means, buy something used that makes sense and try it out. But just because that may not work doesn't mean that the correct type of power conditioning isn't needed in your room.

Enjoy,
Bob

I didnt know the PS Audio product has a light that can tell you how it is working, I have a Blue Circle Noise gizmo but cant tell any benefit, thanks all.

A different way to consider the question is 'how can you tell how robust your equipment is?'. The better your components internal power supplies are designed, the less neccessary or detectable any type of ac power fiddling will be. I really like Elizabeth's note about using lights for a cheap sensitivity test, cept I'd go for high wattage (more current draw, less resistance, more dramatic effect).

One of the worst culprits, and very easy to assess, is fluctuating line voltage. It's a serious problem if you use a tube amp with manual bias. Just stick the probes of a simple volt/ohm meter into your wall outlet at different times of the day and see what it reads. If it's always low (118-ish) or fluctuates between 118 and 123, then you're going to need a regenerator like an Exactpower. No conditioner will help, but a regenerator in addition to holding a steady 120, will do everything else a conditioner will do but without ruining dynamics, etc.
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