2. misc-audio
  3. 151779-122613

Dedicated Power Line Project

I’m going to be adding a dedicated AC line to feed my audio system. Currently, the system is fed by a 75 foot run of 14 gauge romex that is likely daisy chained a few times in the wall between outlets. Needless to say when I turn the volume up, dynamics suffer and the overall sound quality is much less than I know my system is capable of. At louder volumes, bass notes will make the lamps dim and if I go louder, it seems like the system struggles and the bass notes get rounded off or sound “fuzzy.” My calculations tell me that with 75 feet of 14g romex, the voltage at the end of the line could be dropping by 5-10 volts, maybe more, during transient peaks. What I think is happening is that the power amps’ power supply caps are draining and there isn’t enough current to recharge them quickly enough and the amps start to draw directly from the AC line which causes a large voltage drop. 

Initially I was looking at a 10 gauge or 12 gauge line with a 20 amp breaker. After running the numbers, even a 10 gauge run could see some significant voltage sag at 75 feet during transients. At that point I considered 8 gauge, but the problem with that is that no electrical outlets will accept anything larger than 10 gauge, so I’ll have to do something fancy like place a junction box and step down to 10 gauge at the breaker panel and just before the outlet. Then I thought if I’m going to that much trouble with an 8 gauge, why not run 6 gauge? My calcs tell me 6 gauge could have a volt or two less variance than an 8 gauge and it wouldn’t be much more cost. So as of now, the plan is to run a 6/2 solid core romex line and run all the equipment of that. (I could run another line for the front end in the future but that isn’t the plan right now).  I have a few questions if anyone would be so kind to reply:

1) Are there any foreseeable issues with running “too large” a power line? I’m not sure if it’s accurate, but I’ve heard that large gauge is good for bass and small gauge is good for treble. Since I’ll be running everything (including the low current draw components like sources, preamps, etc) off this one line, is there any chance I’ll change the sound signature in a negative way?

2) What is better? In-wall romex or THHN inside a grounded conduit? I’m leaning towards romex because my gut tells me having the wire surrounded by something could hinder transients or hurt clarity but I’m not sure that’s accurate - that may just be from my personal experience with low level signal cables where too much insulation can be a bad thing. 
3) Are there any other “gotchas” that you can think of?

I’ve read the MSB Technology article and I’m subscribing to that theory which is this in a nutshell:

“It is the subject and goal of this paper. The gauge of the wire is FAR MORE IMPORTANT than the fact that the line is “dedicated”. The subject of this paper works on the theory that the varying musical demands of your amplifier are actually modulating the incoming power line, divorced from the utility (power company) by some resistance (12 or 14 gauge wall wiring at some length from the breaker panel has too much resistance for audio purposes).”

Thank you and wish me luck!
128x128mkgus
dhite71
316 posts
 
I too will soon be upgrading my circuits. I have done a lot of electrical work in my two homes over the years and wanted to say first of all that 14ga wire is not typically used for outlets. That should only be used for lighting circuits. I know codes vary but thought that was a universal code to have at least 12 ga for any receptacle. You may want to have an electrician asses your panel and house design while you are doing this upgrade to ensure you don't have any potential hazards.  

I have everything plugged into a Monster power center then going into an outlet that has a few other items on the circuit, but nothing major. I have another receptacle in the area so plan to upgrade both and try running the amps into one while the Monster is on the other. I was leaning to simply going 10 ga and cannot imagine dealing with 8, 6 or 4 in a wall box!! In my experience any Romex is solid...none of these products are stranded. Whatever ga you choose, I would stick with a single run direct from the breaker to the receptacle...don’t try to change wire within that same circuit.
dhite71
316 posts
 
correction from my comment above...just went to Lowe's and checked out the Romex.  10ga is a single solid conductor per wire, but the 8, 6 & 4 were stranded except for the ground.
mkgus's avatar
mkgus OP
324 posts
 
I was confused by that too. It didn’t help that I found an online Lowe’s listing for 8 gauge solid core Romex. It was an error: 8 and larger seem to be only sold as stranded.

I am not familiar with the code. I know I’ve seen 12 gauge and 14 gauge wiring used in a number of houses and in many cases, have seen one breaker turn off outlets AND lights. Perhaps codes vary or some houses just aren’t up to code.
millercarbon's avatar
millercarbon
12,531 posts
 
dhite71-
I was leaning to simply going 10 ga and cannot imagine dealing with 8, 6 or 4 in a wall box!!

Ahh, I see this is the thread where noromance instigated me to putting my system on-line. Here it is: https://systems.audiogon.com/systems/8367

Look close, that is 4 ga wire coming into the step-down transformer. At one point it went from there into an outlet box. So you do not have to imagine, I have done your imagining for you, as in actually did it, and no it is not anything I would recommend. In fact I would not recommend anyone do anything I have done. I am not an electrician. I am an audiophile. Who knows a little something about electricity....

Please read my first post in this thread. I just read it again and wouldn’t change a word. People are running around fretting over stranded vs solid and what gauge, when its been clearly stated what really matters is that the line be run direct. Its not that these tiny little details don’t matter at all. Its that they matter so little that in the big scheme of things you could be doing stuff that makes a huge easy to hear difference instead of struggling to figure out which wire might be a tiny little bit better- a difference you will never hear because unlike me you will do it only once.

Look at it this way. There’s things you can do to your existing wiring that will be a whole lot faster, easier, and cheaper, and make a whole lot bigger improvement, than anything you will ever get from any wire you can buy at Lowe’s.
More to discover