[Christof]

It's time for me to specify the electrical layout in my new loft.  I would like to ask you folks a couple questions about dedicated lines before I make any decisions.  

Here is a little background information on my project.  This is a commercial building which is part of a historic downtown gentrification project.  I had 30A service to my building but requested a 400A upgrade (2 lofts @ 100A each + storefront/workshop @ 200Amp).  My local power provider requires me to set (pay for) a new utility pole with a dedicated transformer which will feed the 2 lofts, my storefront and wood shop. This should minimize any 'junk' being put into my power source from other businesses or residences.  All electrical must be in metal conduit.

I will occupy one loft and rent the other.  Each loft and the storefront will have their own electrical meter and service panel.  I will not install dimmers in the rental loft or my storefront, hopefully minimizing noise being introduce into the main power line.  Overkill, I'm not sure?

Now before I ask my questions let me tell you about my personal loft/listening area.  My room is essentially 23'w x 50'd x 13'h and I plan to orient my system half way down the 50' wall firing across the 23' wide area. This will make the side walls about 20' away from the speakers.  At the halfway point along the 50' wall I will install a dedicated audio circuit.  I would also like the flexibility of being able to move the system to the 23' wall and orienting the speakers so they fire down the 50' length so I will install another dedicated circuit midway on the 23' wall.  

Q's:

1. In your opinion is it worth the big price tag to buy Belden 83803 too run these circuits?  I will need 75' to get to the 23' wall site and another 50' to get to the 50' wall site.  Thats about $500 just in wire

2.  I will be running 4 Odyssey mono block amps to biamp a pair of SP Tech speakers.  While I'm at it should I run a dedicated line just for the amps and a seperate line for my pre/cd/TT?  This would double the amount of wire needed (83803 = $1K...yikes!!!!).

3.  Is there a prefered isolated ground outlet?  I'm already over budget so I'm not really considering cryo treated $50-$100 outlets....I have to be (somewhat) realistic.

4.  I should request that my electrician keeps all appliances with motors and any line with a dimmer on the opposite buss bar, correct?  Is there anything else I should ask him to keep opposite the Audio circuits?

If you have taken the time to read through this long winded post I sincerely thank you.  This project is a major undertaking for me and I really appreciate the input you folks are giving me along the way.

Thanks!
Christof

[JoshK]

Congrats!  Sounds like a really killer place.  If you read csero's comments recently about large live spaces you'll realize this is a very good thing for your sound.

1. In your opinion is it worth the big price tag to buy Belden 83803 too run these circuits? I will need 75' to get to the 23' wall site and another 50' to get to the 50' wall site. Thats about $500 just in wire

No, just stick with 12-2 equivalent of shielded NBX or whatever its called.  It is basically already OFC copper. Much cheaper and just as effective.

2. I will be running 4 Odyssey mono block amps to biamp a pair of SP Tech speakers. While I'm at it should I run a dedicated line just for the amps and a seperate line for my pre/cd/TT? This would double the amount of wire needed (83803 = $1K...yikes!!!!).

I might put two lines, especially if you ever consider putting a video system in too.  Much easier to plan ahead then try to retrofit.  Important! Make sure they are on the same phase!  If they aren't you will have a ground problem like nobodies business between components.

3. Is there a prefered isolated ground outlet? I'm already over budget so I'm not really considering cryo treated $50-$100 outlets....I have to be (somewhat) realistic.

If you are required to run the shielded cable, you are in an industrial code zone, so you need to find out what kind of grounding is required, iirc it is a bit different than for residential.

4. I should request that my electrician keeps all appliances with motors and any line with a dimmer on the opposite buss bar, correct? Is there anything else I should ask him to keep opposite the Audio circuits?

No idea, but couldn't hurt.

[bubba966]

Being a sparky myself I'll try to answer your questions for 'ya...

1. I wouldn't really bother with the Belden for the dedicated lines. I'd just use 12-2 Romex (NM-B) and spend the $ saved on room treatments. A 250' roll of 12-2 Romex is currently running about $65. Sure, the Belden is better wire and would make some difference. But not much difference, and certainly not as much of a difference as room treatments make.

I'd personally be more picky about the electrical panel & breakers than what wire is being used. Square D QO series panels/breakers are the best. But they're also not cheap...

2. Yes, I'd personally run 2 dedicated lines. And I'd do it using Romex 12-2-2 which is essentially like 12-4. Meaning that it has 4 12awg conductors in one cable. So not only is it easier to pull, but it also has a cable geometry that would be of some benefit as far as noise rejection is concerned. And it's much easier/quicker (aka cheaper) to run a 2 lines using one run of 12-2-2 than it is to run 2 lines using 2 pieces of 12-2. Been there done that.

3. The Eagle/Cooper IG8300RN 20A Hospital Grade Isolated Ground outlet is very good (I've used a bunch of these in many different setups and had great results with them each time) and is only about $10 each. The Hubbell IG8300 is the same spec as the Eagle/Cooper but is about twice as much. Either of them would be what I'd use.

4. Correct, I'd ask to keep that stuff on the opposite buss/phase. And if you end up running 2 lines to your listening room make sure to get them both on the same buss/phase as each other. As far as anything else that should be kept on the opposite buss I can't think of anything that you didn't list. Dimmer's & things with motors (fridges, washers/dryers, AC, etc.) are what usually puts noise back into the line. I suppose you might want to keep computers on the opposite buss as well if possible. Though I'd put that on a lower priority than the other stuff.

[bubba966]

Sorry, I forgot you said that all wire had to be in conduit.

Depending on how it'll have to be run your sparky probably wont want to run NM-B (12-2 or 12-2-2) in conduit. He'll probably use THHN as it's much easier to pull through conduit than NM-B is.

I know you can get 12-2 in BX which is just Romex in a flexible metal cunduit. Don't know if you can get 12-2-2 in BX though. But if it's not too difficult of a run (not too many tight bends) you could get him to put the 12-2-2 in a piece of flex long enough and them put the 12-2-2/flex combination in the wall.

[Dan Banquer]

I would recommend that all of the audio and video circuits be on the same phase. Other than that bubba has a lot of good advice.  Bubba: I didn't know until now that you're a sparky
                     d.b.

[PhilNYC]

I might put two lines, especially if you ever consider putting a video system in too. Much easier to plan ahead then try to retrofit. Important! Make sure they are on the same phase! If they aren't you will have a ground problem like nobodies business between components. .

FWIW, even putting them on the same phase doesn't insure against ground loops.   I have two dedicated lines in my room, and every time I plug my amp into one and everything else into the other, I get a ground loop hum.

3. Is there a prefered isolated ground outlet? I'm already over budget so I'm not really considering cryo treated $50-$100 outlets....I have to be (somewhat) realistic.

I use Pass & Seymour 6300IG isolated ground outlets.  Admittedly, I have never A/B'd them against anything else on the same line...but my dedicated line with these outlets sound a LOT better than my non-dedicated line using silver/cryo'd AcmeAudioLabs outlets.  The P&S 6300IG outlet was recommended to me by my electrician who has done hundreds of dedicated lines for high end home theater users.

4. I should request that my electrician keeps all appliances with motors and any line with a dimmer on the opposite buss bar, correct? Is there anything else I should ask him to keep opposite the Audio circuits?

More important that on the opposite bus bar, make sure they are below/above the audio lines in the panel (below if the powerline from the street comes into the top of the breaker panel, above if the powerline comes in from the bottom)...basically you want any high power-draw circuits to come after the audio circuits in your panel.

[maxwalrath]

thread about outlets...Gregg Straley did a comparison and preffered Porter Ports which can be found on A-gon, but I don't know if they meet your specifications.

http://www.audiocircle.com/index.php?topic=23756&postdays=0&postorder=asc&start=10

[kfr01]

FWIW, even putting them on the same phase doesn't insure against ground loops. I have two dedicated lines in my room, and every time I plug my amp into one and everything else into the other, I get a ground loop hum.

I'm also going through this planning stage right now.  

Is there any way to get around this dedicated lines / ground loop problem?

Karl

[Dan Banquer]

Gentleman: Dedicated lines really don't cause ground loops, the grounding scheme or lack there of in the equipment will!
                       d.b.

[PhilNYC]

Gentleman: Dedicated lines really don't cause ground loops, the grounding scheme or lack there of in the equipment will!
                       d.b.

Just curious then...why would I not get a ground loop when all gear is plugged into the same outlet (front end gear into a power conditioner plugged into the outlet, amp directly to the outlet), yet when I move the amp to the other dedicated line, I do get the ground loop?

[PhilNYC]

Just curious then...why would I not get a ground loop when all gear is plugged into the same outlet (front end gear into a power conditioner plugged into the outlet, amp directly to the outlet), yet when I move the amp to the other dedicated line, I do get the ground loop?

And btw - this happens in my place with many different combinations of components and brands...

[Dan Banquer]

It may well have to do with the power conditioner, which may have enough isolation so you don't get a ground loop under those circumstances.
                        d.b.
P.S. Do I need to re post an earlier post of mine on grounding and consumer audio equipment?

[PhilNYC]

It may well have to do with the power conditioner, which may have enough isolation so you don't get a ground loop under those circumstances.

But the amp is not being plugged into the power conditioner in either case...all that is different in each case is where the amp is plugged in (same outlet vs. a different dedicated line)...

                       d.b.
P.S. Do I need to re post an earlier post of mine on grounding and consumer audio equipment?

Sure...post a link to it...

[Dan Banquer]

Try using a Jensen Audio Isolator between the power amp and everything else. The model# is CI2RR if I remember correctly and available from Markertek for about $120.00


GROUNDING PRACTICES IN CONSUMER AUDIO

As many of us have observed over the years grounding practices in consumer audio have for many of us been a frustrating experience. Compatibility/Synergy are consistently major issues, as well as safety, reducing ground loops, noise and interference. Designers are equally frustrated by this problem. Some of us wish it would go away and others attempt to deal with as best as we know how. There does not appear to be much of any standardization that I, and many others are aware of. Many of us who work in the electronics industry outside of audio who have observed the posts from audiophiles, designers and dealers scratch our heads in near disbelief.
The following is not only an outline for reducing these problems, but a wake up call to this end of the industry. The following is for the application to consumer unbalanced audio, and could well be a possible outline for positive discussion and direction. It is also a way to use Earth Ground to our advantage instead of a problem.
Chassis Grounding:
The following is a technique used in instrumentation for low frequency applications.
The chassis will be earth grounded via the earth ground at the three-prong outlet. The audio signal ground contained in the chassis is not connected to the chassis ground. This will require the design to be electrically isolated from the chassis ground which is easily solved by using nylon stand offs to mount pc boards and isolated bulkhead RCA jacks. (I am going to break this rule later on but bear with me for the
 moment). The above forces the design to be star grounded at the return of the power supply, which is always good practice to reduce noise and ground loops. However, this does leave the present configuration susceptible to interference from the inputs. This interference can be reduced by the using a simple common mode ac line filter at the AC input and using either a well shielded coax or microphone cable at the line level input. This configuration also poses an additional problem due the fact that we now have two different grounds with two different potentials. In the past I have observed this problem when using a certain brand of rotary switch for a volume control. The rotary switch was not well isolated internally and had enough of a leakage current so that noise was developed when it was used. Moving to a different vendor with higher isolation devices corrected the problem. I have not observed any problem with standard switches for on off applications or anything similar.
I have applied this technique to basic audio chain of equipment consisting of an outboard DAC, line level pre amp, and power amps using the chassis and grounding design I outlined above. The transport that I presently use is a modified consumer device and is equipped with a two-prong plug. The system also has an FM tuner and an old pre amp that is used as a phono pre amp. Both of these devices are standard consumer issue with a two-prong plug. I have observed no compatibility issues with the older style units.
As I outlined earlier I am going to break this rule at one point. The line level pre amp now has a connection from the return of the line stage pre amp power supply to the chassis of the unit. I have now connected earth ground to the analog “center point of the system.” This did not cause a ground loop at all, and to be more precise, for CD playback the inherent ground loops that are typical for unbalanced circuitry simply disappeared. The FM tuner and the old pre amp appear to be unaffected by the center point earth ground. A welcome addition was that the rotary switch that had a leakage problem because of the two different potential levels described earlier no longer had the problem due to center point earth ground.
The use of the system center point earth ground for low frequency applications has been in the textbooks for at least 30 some odd years and has been applied to other low frequency applications. Applied at this level to a simple chain of audio playback equipment. CD playback now has reduced hum and hiss to levels more akin to balanced design than unbalanced design. Playback of FM tuner and Phono pre amp remains unaffected.
One thing that has surprised me relates to the issue of low frequency applications. I was expecting to find problems with the digital portion of this playback chain. I have not found one to date but I think this needs to be investigated further when time allows.
A note to all of the tweakers who read this: I am not recommending any changes to existing designs; in fact I would discourage it.
To DIY folks: You may wish to rethink some of your present chassis/grounding schemes.
To the rest of the industry; this is a subject that not only deserves discussion but an active participation to reach acceptable standards.
The grounding system described above will not address the problem of toroidal transformers mechanically vibrating due to either DC on the AC lines or as I have observed on occasion, low frequency oscillations.
Dan Banquer
R.E. Designs

[PhilNYC]

Gentleman: Dedicated lines really don't cause ground loops, the grounding scheme or lack there of in the equipment will!
                       d.b.

Looked up the Jensen audio isolator, and part of the text described a cause of ground loops here:

"The result is that the neutral or ground side of the two circuits can be at a slightly different potential.  It can be because one of the circuits is loaded more heavily than the other, or because one run is longer than the other, or any number of other reasons that are beyond the scope of this article."

So it does appear that there are causes of ground loops that are somewhat independent of the grounding scheme in the equipment...

[Dan Banquer]

I think you need to read a little further there Phil. It's not as simple as it appears. You also have to think about the direct application we are talking about here, In any case there is also plenty of information on Home Theater wiring at www.audioholics.com
                  d.b.

[PhilNYC]

I think you need to read a little further there Phil. It's not as simple as it appears.
                  d.b.

Yep, I know its not simple.  If it was, I wouldn't have a ground loop problem...  But I was simply asking for more information regarding your comment that dedicated lines are not part of the cause of ground loop problems, because based on what you said, it would seem unlikely that I would be experiencing what I'm experiencing (ie. only getting a ground loop hum when the amp is plugged into its own dedicated line; if it was inherent in the design of the component's grounding scheme, I would get it in both cases, and not just one?)...

[Dan Banquer]

Here’s a few more links to help you out with grounding issues.
http://www.audioholics.com/techtips/setup/avhardware/groundloopcableTV.php

http://www.audioholics.com/techtips/audioprinciples/interconnects/filename123.php

http://www.audioholics.com/techtips/audioprinciples/interconnects/WholeHouseWiringP2.php

http://www.audioholics.com/techtips/audioprinciples/interconnects/APCPowerConditioners.php

Hope this helps
 d.b.

[Christof]

Thanks for all the responses!!!  I'm meeting my 'sparky' this A.M. and I'll pass this information on to him.  I'll report back here later and maybe  post some pics of the project.  I have numerous acoustic/room questions as well.  Thanks again for taking the time to help me out.

christof

[Christof]

Guys

I met with my electrician and discussed numerous things all seemed well until I got to dimmer switches...without saying anything he kind of gave me that 'what the hell are you thinking' expression.  You know, the head gets a little cocked, one eyebrow lifts followed by a slight nod. Am I being an overly paranoid freak by not allowing dimmers in my new buiulding? The power company is setting a new pole and transformer just for my building to deliver 400amp service.    It would be nice to offer dimmers on all lighting in the second loft but I don't want to cause a ripple in still water...

here is a pic: