An audible ground loop happens when you have two or more paths to ground that are of different potential (voltage). That's what causes the hum. If all your grounds are at the same potential - which isn't difficult to do when using proper dedicated lines - you'll suffer no ground loop issues.
Another dedicated circuit question
(I just wrote a novel, and I tried to paste a couple of links, and the whole thing disappeared, so as I type slowly and poorly, I am going with the condensed version this time.)
About 25 years ago I put in three dedicated circuits for my gear. (That was before I had a PC & internet, so I am sure that I must have gotten the idea from Stereophile, and as with all things, I thought bigger was better and more was best.) Recently I have been reading a number of dedicated circuit threads and discovered that I had made numerous errors. Therefore I have been up in my attic and into my panel for the last week or so removing, replacing, and rerouting and I was about done
and then
I found out that three dedicated lines was another mistake I made. No biggy: I bought a lot of Romex and other stuff I didn't need and spent some extra time I didn't need to spend, but I can rectify the three-circuit-RFI that I introduced by turning 'off' two of my three system circuit breakers. Right?
But my question is: since I need four outlets (digital source, pre, amp, powered sub) is the BEST solution to put another outlet in series with my one dedicated outlet?
Are there any power-strip solutions that are of an acceptable grade? After the last dedicated circuit thread, I wound up discussing this (to some extent) with @millercarbon and I told him about a power conditioner I bought around 25 years ago called the Promethean Audio Products Power Flo (sorry MC, I got the name slightly wrong) and he suggested that in the interim I use that as my strip. What I neglected to tell him was that it occasionally arcs at the outlet when unplugging/plugging it in, and I am a bit leery of it.
Here is where my previous novel I had typed disappeared on me, so I am not going to try to pate any links this time, but price is a consideration and MD sells the Furman PST-*D Power Station (8 outlets) for $269 + tax which is withing my range, but it says to use only on 15A circuits (meaning I would have to put a 15A outlet & breaker on either end of the 12-2 that makes up my one dedicated circuit.
MD also sells, for $40 + tax, the Audioquest IEC-3 power strip (three outlets) and I guess I would need two of them (plus two cords) as one of the reviews say that the outlets are too close together to use all three of them at once.
Are either of these an acceptable (meaning minimal degradation) method to add outlets to one dedicated circuit? Are there any other methods (excluding multiple hundreds or thousands of dollars on a power conditioner) that I could consider?
In a reply to this post, I am going to attempt to paste links to the two options I just mentioned.
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A poor ground, say with 100Ohms of resistance to the outside ground rod, will still have ZERO volts unless a current is applied. A poor ground point and a perfect ground point with no current will have the exact same voltage: 0 V. Connect a piece of gear to each and then have them connect together and there is still no ground loop until one of those pieces of gear causes actual current on the ground to flow. One of the best ways to do this is often a laptop or PC power supply. It is for this reason that USB isolators are IMHO something often needed to get the best out of a PC based music system. |
This article gives a good explanation of the problem why there is ground current: Because of the way a power transformer is constructed the parasitic capacitors have different values and because the neutral power line is connected to the safety ground, the amount of noise on the two sides of the power line is different. Ideally the connection of all the power plugs would be in a star ground configuration (analog and digital gear connected to separate isolated power outlets of the power conditioner) . Power strips is the next best to star ground. I use horn speakers (105dB sensitivity) which are unforgiving of the tiniest noise problem in the system but even if you don't hear hum or buzz with less sensitive speakers the noise will modulate the audio signal and will produce too much brightness and/or less dynamic sound.
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Why did you see the need for 3 dedicated circuits ? What is your power requirement ? This has been addressed above already in a few posts but just to re-iterate: Connecting different sources to different power outlets MAY cause earth loops and is therefore it is much better to connect ALL your gear to ONE outlet, to reduce the stray resistance between their earth points, which otherwise may cause hum. So in fact, use of multiple outlets increases the possibility of introducing earth loops.
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@cakyol , well, as I started this thread by typing, I originally did this 25 years ago before I had a PC and the internet, so I am sure that I probably read something in Stereophile about a dedicated circuit (or maybe more than one) for the gear, and with this, as with everything else in my world, I thought that if one is good more was better. At the time I had a pair of ARC mono blocks, my pre, three pieces of digital separates, and a powered sub. This has changed, and I now am running a two channel Cary amp, a pre, a Maranzt SA10 as my digital source, and the same powered sub. In this thread I posted I have read both sides of this coin, and I guess by flipping a couple of breakers to ’off’, I have the option of experimenting & trying it both ways. I pretty much finished up in the attic today, and tomorrow I have a couple of things to change around at the panel, and then I will start testing some stuff out. I appreciate your interset & I thank you for your input.
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