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

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.

I am also a believer in feeding audio equipment, (that is connected together by wire interconnects), from the same Line, leg. I do not subscribe to the theory the equipment must be plugged into the same outlet to prevent the chance of ground loops though.

I have two 20 amp dedicated branch circuits that are 75ft each. Wiring is 10/2 NM cable, (Romex Trade Name). Both circuits are fed from 20 amp breakers that are directly across from one another... My system is dead quiet.
(Tube power amp and tube preamp).

Dedicated circuits get a bad rap and are wrongly blamed for ground loop hum, imo...
Things to blame:
1) Poorly designed audio equipment that uses an EGC where the circuit designer directly connected the power supply B- / signal ground to the chassis/EGC.
2) The wrong type of branch circuit wiring was used.
3) The wrong wiring method, installation, was used.


See page16 and read pages 31 thru 36.
An Overview of Audio System Grounding and Interfacing

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I've never encountered a ground loop from running more than one dedicated outlet, it would be rare. I think some mistake noise in the system to a ground loop.

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.