Dedicated circuit for each outlet pair?

DonH50

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Jun 23, 2010
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I’m struggling with this, Ron, as I noted above. I’ll admit a bigger room would be better. 14x21x9 sounds pretty nice. :confused:

Look up "golden ratio" or "prime ratio" when deciding on room dimensions and use them if you can. Dimensions that are multiples of each other, or have common submultiples (e..g 2x7 = 14 and 3x7 = 21), increase the magnitude of room modes that are challenging to control. If you can make the dimensions all relatively prime to each other, if not irrational multipliers, then it is a little easier to correct the bass.

When we finished our basement I had a nice prime-dimension media room all planned out. Then we added a bedroom, and it plus the associated hallway killed my plans so I have ugly dimensions and about 1/3 less area. Better for resale, and of course my younger son loved his new bedroom, but every time I have to recalibrate the room or want to get real theater seating that won't fit I sigh just a little...
 

tony22

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Understood, Don. Unfortunately I’m not going to be able to get 23’ out of the long dimension. Before I bought this house I was looking at one that, with two adjoining rooms combined, would have gotten me 13 x 20-1/2 x 8. Just about perfect. But the house was otherwise not ideal for many more important reasons. With respect to room modes and primes, it seems like 14 x 16 x 9 might actually be better.
 

Alrainbow

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Any pics for of the proposed system to share ?
 

twitch

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Jun 17, 2010
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In hindsight, I wish I had installed mine upside down. That is with the ground on the top of the socket. Then the weight of the power cord would force the AC pins into the socket.

LOL, just like old women with saggy boobs, audiophiles with 'saggy PCs' need support !
 

Kingrex

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Al has the best design. I would dispense with the romex, mc cable. I would run all ofc cord surface from the sub panel to equipment. Its significantly better.

Having said that, if the walls are open, go ahead with adding in wall power. I personally would go pipe and wire. Or ofc in wall wire. You want your wire runs of similar length.

Al had a pretty good description of how to handle the main feeder to the subpanel..

If you want it to sound good, you have lots of work to do in your main panel as well as proper grounding.
 
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treitz3

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@DonH50 - I was not being sarcastic but after your explanation, it is crystal clear why you would say that. I read that statement and assumed something else. It was this misinterpretation that I found surprising. Thanks for clarifying.

Tom
 

DonH50

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Jun 23, 2010
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@DonH50 - I was not being sarcastic but after your explanation, it is crystal clear why you would say that. I read that statement and assumed something else. It was this misinterpretation that I found surprising. Thanks for clarifying.

Tom

No worries. I realize my opinions are diametrically opposed to most here and try to behave and stay out unless I feel I have something technical to contribute. Even then I usually just dig myself a hole, often when a question I thought was technical was not really the ask. Need to learn to not post unless it is in the technical area. In the end, I need to reread my signature, and remind myself what's really important is the music. OK, and maybe the movie, and the family, and the dog (R.I.P.)...

On-topic, one thing I have learned over the years, and keep re-learning the hard way, is that it is easy to underestimate how much power you'll need in ten years or whatever. I had three 20-A lines placed along the front wall where the gear went, letting the sides and rears be handled by a normal 15-A loop. Then several years later added a couple of subs in the back, and wish I had stuck a couple of 20-A lines back there...

One thing that can cause problems with multiple lines is that the potential for ground loops is much higher when you are plugging a bunch of components into different outlets with isolated lines back to the service panel. I was cognizant of that and went with balanced (XLR) equipment where I could, including the AVP, amps, and rear subs. No hum, thankfully.

Building a room it is also worthwhile to consider lighting. Having a track system or two to aim light where you need it (and keep it from where you don't want it) can be helpful. Avoiding dimmers, or at least getting low-noise types, is helpful. LEDs are great but can actually radiate a fair amount of noise, especially the cheaper ones (IME). A friend of mine took a cue from the RF screen room at work and went with DC lighting in his media room powered by a supply in a shielded cabinet (rack) outside the room.

Finally, if you are building a new room, floating walls and ceiling (and floor if not on concrete and if possible) can be a big help in isolating the room from outside noise, and letting the rest of the house remain quiet when you decide to crank up the system or watch a movie late at night. Don't forget the ducts; the HVAC system is a great path for sound transmission into or out of the room. I went with a minisplit unit so there are no ducts to the rest of the house in my media room. I did add an external duct and fan for air circulation; we are in a rural area so a bit of fluffy pink insulation in a box is sufficient to reduce noise transmission. In a more congested area I'd've had to build a studio box for the inlet and outlet ducts (multiple layers and staggered baffles, much like the muffler on a car).

I be shut up now - Don
 

Ron Resnick

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I’m struggling with this, Ron, as I noted above. I’ll admit a bigger room would be better. 14x21x9 sounds pretty nice. :confused:

Do you have a den? Maybe you can sacrifice the bathroom near the listening room and convert part of your den into a replacement bathroom?
 

Ron Resnick

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By the way, I agree that all wire runs to duplex outlets should be the same length to avoid ground loops.

Unfortunately, I could not figure out how to accomplish this in my particular situation, as the audio sub-panel was outside the listening room just past the front left corner of the listening room, and the front-end equipment is diagonal from that corner and is past the rear right corner of the listening room into an adjacent equipment room all the way on the other side. :rolleyes:

From the sub-panel the length to the near duplex outlet is about 7 feet, and the length to the far duplex outlet is about 70 feet. (I have 3 to 2 prong AC adapters ready in case I need to lift any grounds.)
 
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LenWhite

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I suppose the electrical power coming into a house can differ by locale. In my case the #12 wire lengths from the 100A subpanel with four breaker circuits vary depending on where the Furutech GTX-D duplex receptacles are placed. I had two dedicated 20A circuits placed on the front wall, one each on the side wall and back wall. The front wall circuits are used for my sub and stereo amp, the side wall for all my ancillary equipment, and I'm not currently using the back wall circuit.

Twisted pair wiring (#12) is used for each circuit with the neutral and hot wires wrapped on 2" centers and the ground wire placed parallel in PVC conduit. A white paper presented at the 2010 AES 129th Convention shows this method has the lowest ground voltage induction tested.

At idle my main speakers are dead quiet and I've had no ground loop issues.

I've discovered how one treats the electrical power speakers use to create the sound should be very high priority. This was an key part of the dedicated room design as was the acoustics.
 

tony22

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Do you have a den? Maybe you can sacrifice the bathroom near the listening room and convert part of your den into a replacement bathroom?

If only. The house is in Florida. That means a solid concrete pad (finally! my system and speakers on a concrete floor!). Even if I had a spare spot for one, I’m not prepared to have to rip up floors and jack hammer into the concrete for a new bathroom drain line. :(
 
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LenWhite

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That's exactly what I did in 2015 when an addition was added. I didn't have a suitable room for dedicated listening and my wife encouraged me to leave the FR. I'm certainly glad I did as the new dedicated room has given me many hours of sonic bliss, not to mention the movies we've watched on the big screen in there:)
 

tima

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By the way, I agree that all wire runs to duplex outlets should be the same length to avoid ground loops.

Unfortunately, I could not figure out how to accomplish this in my particular situation, as the audio sub-panel was outside the listening room just past the front left corner of the listening room, and the front-end equipment is diagonal from that corner and is past the rear right corner of the listening room into an adjacent equipment room all the way on the other side. :rolleyes:

From the sub-panel the length to the near duplex outlet is about 7 feet, and the length to the far duplex outlet is about 70 feet. (I have 3 to 2 prong AC adapters ready in case I need to lift any grounds.)

Two separate dedicated circuits w/ two breaker boxes? No doubt you thought of that, Ron, but chose not to go that way.
 

Alrainbow

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DaveC951

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Just to reiterate in case it has gotten lost in the thread:
For those not installing a separate sub-panel, please be sure all audio system breakers are on the same phase. In general, this means the breakers for the audio outlets must be every-other slot.
I ran 4 outlets (digital, analog, turntable, amp). Separate turntable was a bit overkill, but I liked having all equipment types fully separated.
Foolishly I ran 8 gauge wire, which was a genuine pain to terminate, even in hospital grade / audiophile duplex outlets. 10 gauge is adequate for 20 amp outlets, no problem.
 

tony22

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For those not installing a separate sub-panel, please be sure all audio system breakers are on the same phase. In general, this means the breakers for the audio outlets must be every-other slot.

I spoke to an electrician a little while ago and this came up. He remarked that a “proper” (whatever that means) electrical distribution from the breaker box would have the phase load balanced. I should have asked him why, or what bad things could happen if it wasn’t, but I didn’t.
 

DaveC951

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Aug 20, 2018
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I spoke to an electrician a little while ago and this came up. He remarked that a “proper” (whatever that means) electrical distribution from the breaker box would have the phase load balanced. I should have asked him why, or what bad things could happen if it wasn’t, but I didn’t.
Yes & No
He is correct in that the best way to draw electricity from the power company, which feeds you 240v, is to draw equally from both 120v rails (phases). Fine.
But, that has nothing to do with how you arrange your breakers to accomplish that. In other words, for your stereo, the best is unquestionably to be on a single phase. In other words, you can place your breakers for your stereo feeds in every other slot to keep them on one phase, and perhaps "re-balance" by moving something previously on that phase to the other.
In general I find a very poor job of balancing in most breaker boxes, so this could give you an easy opportunity to redistribute the breakers to improve that at the same time.
So... - what he said does NOT apply to balancing the feeds to your stereo, it applies SOLELY to your overall house load.
Hope this makes sense and clarifies.
 
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tony22

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So... - what he said does NOT apply to balancing the feeds to your stereo, it applies SOLELY to your overall house load.
Hope this makes sense and clarifies.

Yes it does. Thanks Dave. It leaves me in a bit of a dilemma. My existing 200A service box has every single slot (or two slots for high current circuits) taken up with a breaker. So part of my wanting to add a separate box for my listening room is practical. I may free up one or two 15A breakers in the existing box going to the room, but that will be more than offset by the likely 6 to 8 breakers I would wind up adding to the listening room box.
 

Ron Resnick

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Two separate dedicated circuits w/ two breaker boxes? No doubt you thought of that, Ron, but chose not to go that way.

I don't think I thought about that explicitly, but wouldn't that create another possible source of different potentials to ground?
 

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