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.
@invalid wrote:
I agree! I have four dedicated lines for audio, one for each monoblock amp, one for analog and one for digital. I do not have any ground loop problems or hum. 😎 Mike See article below:
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I had a classic ground loop problem. I had one dedicated line to my power conditioner. When I would plug my amp into a nearby duplex receptacle I would get a hum. The circuit my amp was plugged into had a number of outlets on them… I never fiigured out which. Solutions included replacing all the duplex receptacles on the non-direct line or just adding another direct line. I added another direct line. Problem gone. There was ever so slightly greater resistance in the original installed line which serviced many recepticals than the direct line… hence a trickle of electricity. A second direct line solved the problem. |
Different potentials always try to equalize to the same potential thus there will be current flowing between the two (or more). It will always use the path of least resistance. Because parasitic current is not only a single frequency like 50/60Hz but a band of frequencies we need to consider not only resistance (DC) but impedance (AC) which makes it even more complex. The goal of correct grounding is to give different potentials in different audio components a path of least resistance to earth ground so that it wouldn't flow through the interconnect and cause hum or buzz. Power cables have impedance and that's why it is not a good idea to connect the earth ground of two or more lines in the breaker box. The ground of the interconnect might be an easier path for the current. One dedicated circuit and all audio components connected with short and low impedance power cables in one power strip for digital/one for analog to the outlets of a good power conditioner would fulfill most necessary conditions. It can have different reasons If one doesn't hear any hum or buzz. Sometimes the potential difference is so small that it isn't audible (you got lucky!). Or the sensitivity of the speakers is too low. But as long as some currents are flowing through the interconnect there is a modulation of the audio signal and depending on the strength it will have some neg. effect on the SQ. If an audio system should theoretically sound better than it does (considering the expenses and efforts) I would always start measuring potentials and consider correct grounding.
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The current will take any path that is provided... As for using more than one dedicated circuit, to feed audio equipment where signal feeding other equipment is by wire interconnects, in most causes where there is a ground loop hum problem the reason is the wrong type of branch circuit wiring was used and or the method of installing the branch circuit wiring was done incorrectly. Another problem can be the dedicated branch circuits were not fed from circuit breakers connected to the same Line, leg, in the electrical panel. FWIW, I have two dedicated branch circuits that feed my 2 ch audio system. One for the analog equipment the other for digital. I installed 10/2 with ground NM cable, (Romex is a trade name). Length of the two runs are 75ft each. My system is dead quiet... The OP’s three 12/2 NM cable dedicated Lines are 35ft each. IF he installed them correctly he shouldn’t have any problems at all. . |
The article form E. Juaneda which I posted earlier really explains the problem of possible ground loops. Anyone who is interested to understand causes and how to fix it will find the answers there. 'The current will take any path that is provided' but like in any voltage divider more current will flow through the branch with less resistance. If that's the interconnect it will still cause a problem.
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