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How To Do You Measure the Quality of Your AC Power?

What is the best way to measure the quality of the AC power feeding your listening room? Is there a device you can plug into an outlet that will give you the voltage, frequency, the total amount of distortion relative to a perfect sine wave, etc.? Furthermore, how would you measure the ability of your AC main to deliver transient currents?
It seems like there may be a scenario where you could measure your power quality to be excellent but somewhere in the line you could have a loose or poorly made wiring connection which under heavy load (such as powerful bass notes) you could run into trouble with power delivery. In this scenario, an AC regenerator would not help you, or would help very little.

Just curious what methods people have come up with to systematically analyze their power and how they use those measurements to drive buying decisions or repair work, if needed.

Edit: My apologies for the title typo.
128x128mkgus
mkgus's avatar
mkgus OP
324 posts
 
It’s fed underground. 
Another update:

The electrician came out and repaired the bad neutral lug and tightened everything up. The utility turned the power back on. The first thing I did was run some “tests.” Dimmable lights that used to buzz loud are quieter, the treadmill no longer dims the lights with each footfall (it does a little bit but it seems normal now whereas before it was like being at a rave), and best of all the sound quality of my audio system improved! No wonder - I’m sure the current flowing through the bad neutral lug wasn’t helping in any way with power delivery!

I’m really glad I put in the effort to follow through on this. I am very thankful for all the good advice from this community! I knew something was wrong with the power. I am happy that I didn’t go off on tangents with dedicated lines or power regenerators. I still plan on doing those things, but they would not have completely solved my problem in this case.
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rikkipuu's avatar
rikkipuu
268 posts
 
I had 3 dedicated lines installed a year ago and now wish I had 5.  Each line had a new breaker, I wish I had replaced all the breakers.

I have a PS Audio P10 Powerplant.  I never get 0 % distortion but the readout says it is better.  I have noticed the P10 adds its own distortion to the line depending on various settings.  It can be a very detrimental effect.  I only use the P10 for my digital gear and it is on its own dedicated line.

The P10 is very susceptible to line noise from the components on it.  I had to remove 2 SMPS's as they were injection an awful distortion.  

On the subject of SMPS's I found a great benefit taking them off all of my dedicated lines.
mkgus's avatar
mkgus OP
324 posts
 
Interesting. I am in the same situation as you. I have a couple SMPS’s on the same circuit as my other gear. I could power them off a 12V battery using a 120V AC inverter or run a dedicated line for them. I wonder if my amplifier would sound better without those SMPS’s on the same circuit. I also wonder if they interfere with each other.
helomech
1,634 posts
 

 I wonder if my amplifier would sound better without those SMPS’s on the same circuit. I also wonder if they interfere with each other.

Not if your amplifier is competently designed.

Save your money. Power regenerators do absolutely nothing for sound quality unless your components are very poorly designed. You’ll be better off upgrading your system components. When you own good gear you’ll find that distortion on your grid has absolutely no bearing on sound quality. Companies like PS Audio thrive off hawking such garbage because they’ve realized most audiophiles don’t have any clue how their gear works. 
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