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

Let's disambiguate. (is that  word?)
Typically we worry about Noise. MC went on (correcly) on noise. The only solutions involve various type sof filtering, including normal filters and (better) isolation transformers. Bear in mind that YOU are likely the biggest polluter with your PC, TV, etc right there in your house.  Make sure you have filters between those noises and your sensitive analog components.

Now on to some things you said about lights dimming etc. under loads. This is a very different issue, that comes from a hgih impedance of the AC line - maybe from the utility, but also maybe your own wiring.  I have two "home run" outlets from my listening room to the 200A service in my garage that is on 12 AWG copper and bypasses all the other house wiring.  I also have several filters (all home made). But they do jack $H1T for hgih impedance (aka: low current capability - same deal).  An electrician ought to be able to find this - basically you load test it just like you load test your batter y and alternator in your car. Apply load; measure voltage drop.


BTW noise on the line changes every minute, second, hour, day and season. One measurement means little.

@jea48 :
Careful. You're talking mostly about things that impact the power company and/or maximum utilization of your step down trans.  Nice, but not huge sonic issues.  The reason that many (including me) say that equipment ought to be on one leg, is that in fact I say it must be plugged into the exact same outlet (with outlet strips as needed. This is the only way to minimize ground loops.

Since  your equipment in aggregate is probably drawing 100-400 watts maximum, its really no big deal.

I'm simply saying that i have used this in many systems to remove a ground loop hum.  Sometimes you have the same reference on two outlets, sometimes you don't.  But the simple fact that they are not the same places violates the principle of star grounding out of the gate.

I think some mistake noise in the system to a ground loop.

Let me preface with "not trying to be argumentative" - you both seem to know what you're doing and have things under control. But let's nto tell others that up is down or up isn't really high enough to matter.

I’ll answer to both of you guys (immediately above) that a star ground is the gold standard. And while you may claim things are "good enough" or "not a big deal" any divergence is in fact wrong -- less than ideal. period.

Any resistance between reference points can result in noise of various kinds - in AC power typically 60Hz or 50 Hz (outside ’murica). Why bait fate? You are simply arguing that you can sometimes get away with it. we can get away with many things, until we’re caught.


Now, when you move all the plugs/grounds to one circuit,and the hum decreases, you know its source. Its a reference differential. So there ought to be no mistake if you follow the golden rule: don’t change anything else, one variable per equation please.