Anyone have the Answer?

Using an oscilloscope is the best way I know of.  Unfortunately they will still put you out around $300-$400, and if you don't have a background in electronics are going to be difficult to set up, and interpret.

Preach it Brother Carbon.. LOL You've pointed out the demon, and it seemed to need an exorcism.. Be gone. or is the A Gone..

https://www.youtube.com/watch?v=f0ZS9sImoOE

These two had it easy, only the one demon at a time.

They make products to measure your ac lines for sure but i can tell you that a good conditioner will improve the sound of your system whether the line is a good one or a noisy one and you do not have to spend thousands to hear the difference.

First things , I had installed dedicated 20:amp lines awg 10
with and this is key 4 wire ,dual ground one common the other a insulated isolated ground with copper gold plated outlets .
a night and day difference in detail as well as silence. That was the
best value per $$ spent in Audio ,and I hav3 had a friends AQ5000
line conditioner ,slightly better then my line by maybe 2-3% 
if it is a great recording .

What I been saying for years, the single most cost-effective power improvement is to replace the standard outlet to outlet circuit with a dedicated line. The details of wire, gauge, etc are very minor compared to this one thing.