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Dedicated Power Lines

Been thinking about running dedicated Romex circuits from my circuit breaker box for my rig. No . . . I decline paying for specialty wire, Romex will do. The question is how many discreet lines and the amp capability of each line. I'm still trying to figure out how to do the installation in accordance with Code, without tearing my finished basement apart. For that, I'll consult a licensed electrician.

My rig consists of the following gear: (1) self powered sub that is rated at 1500 "Class D" watts; 4500 watts on a surge; (2) ARC tube CDP; (3) ARC tube line stage; (4) ARC tube power amp rated at 120 wpc - supposedly draws 700-800 watts when driven hard; (5) ARC tube phono pre; and VPI TT. I have a large screen plasma TV and a DVD player. I think that stuff can run off the house circuits.

Right now, everything I just listed is sucking juice off the same line. I gotta believe no good is coming from that set-up. Funny story -- one day my kid was playing Rosetta. I think it's a band that plays music, or at least that what my kid says. Tons of bass. When the band kicked into "low gear," first the basement lights dimmed, then the circuit breaker tripped.

Oh, my house is tied into the utility lines with a 100 amp service. If I change that out, that's the next project. But not right now. Other than Rosetta, no other power delivery problems noted.

Thanks
bifwynne

Showing 2 responses by almarg

almarg's avatar
almarg
9,670 posts
 
Is the smart move to use same phase dedicated lines, BUT ask the electrician to move other house circuits to the other hot phase rail to keep the house load balanced??
Hi Bruce,

Most likely redistributing other loads is not worth worrying about. See the last two paragraphs of Jim's post just above.

Best regards,
-- Al
almarg's avatar
almarg
9,670 posts
 
05-14-13: Bifwynne
My concern is whether powering my gear with different phase hots could in some way change the output phase of my gear.
As Jim (Jea48) indicated, the answer is no. AC phase has nothing to do with audio signal phase. As you will realize, the audio signal path is powered by DC, which is created from the AC by the power supply of each component.

Regarding the issue of splitting the load between two AC phases, as is usually the case I am in complete agreement with Jim (and Foster_9 and Pbnaudio who expressed similar positions), at least in situations where the AC draw of the system is not unusually large.

I looked through the ExactPower paper Jim referenced, the relevance of which is captured in its subtitle, "A practical guide for AV designers, installers, and electricians."

As an EE with extensive background designing analog and digital circuits (not for audio) I find the paper to be authoritative and credible. Which is to be expected, considering its authors. Among them, Henry Ott (biography here), is a world renowned authority on numerous aspects of electrical and electronic design. Bill Whitlock (biography here) is certainly no slouch either. Some excerpts from their paper:
Less than 300 microamps of ground loop current can cause hum as it flows in an unbalanced audio interconnect cable. However, harmonics of 60Hz that are generated from lighting dimmers or switch-mode power supplies sound like “Buzzz” mixed with a bit of “Hummm” and are more easily coupled by even smaller currents. Harmonics can add together when equipment is powered from different phases, so clearly there is an advantage to specifying same-phase electrical service to power the electronics systems in most cases....

Any leakage currents on the safety ground wires of split single phase load circuits fed by different phase legs will add together due to the 240V potential difference....

Power conditioners do not solve any of these common problems: Cross phase coupling (doubles hums & buzzes) .... What actually does solve them: Same phase power.
Also, regarding ground loops, I would commend this paper by Bill Whitlock to everyone's attention, particularly the first page. It seems to me that if leakage current finding its way to the chassis (and safety ground) of a given component, via stray capacitance in the power transformer, EMI/RFI filters, etc., is out of phase with leakage current in another component that it is interconnected with, inter-chassis current flow between the two components, and therefore susceptibility to ground loop-related hum and noise, will have been maximized.

Regards,
-- Al
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