[rollo]

  Great info here. We found that useing three separate circuits consisting of two 20 Amp and one 15Amp. Having an individual dedicated line for Amps, Preamp and CD made a significant difference.
   If only two dedicated lines can be had then by all means separate the Digital fron the analog devices. We used 8Ga Romex to feed cryoed outlets. From each outlet an Uberbuss is used. We then tried isolation trannies for digital and all else but the Amps.
   What was achieved is a dead quite background, no hums, buzzes or the like. Music just emerges from silence. Dynamics were improved and every subtle inflectio was now more evident in the recordings.
    Is this the "best" way. Frankly who knows as direct comparison to another method is just not practical. Some tips we founf desirable:

 Use solid core wire.
 Use Progold or equal to clean all connections
Polish all connections before tightening down
Make sure the grounding connection at panel is tighter than a crabs arse
Use cryoed outlets
10Ga wire at a minimum
Use same manf of IEC and plug for tight fit if possible
Use isolation trannie for Digital
Install as many dedicated lines as possible [ two minimum ]

    There are many products available to achieve ones goal. Which one ? Ah the$ 64,000 question. If yyou cannot or decide not to use any power conditioning or power correction devices the dedicated lines alone will make a substantial difference for the good. Especially for digital and Amps. Have fun trying.


charles

 
 

[jarcher]

I was given this advice from the design engineer of a well known Audiophile Power Conditioner manufacturer.

"Use round Romex 10/3 or 12/3. Inside are 4 wires,  a black, white, red and bare wire(s). Use black for hot, white for neutral,  the red and the bare are both for ground (using 2 wires for ground gives you a much lower impedance path to earth ground resulting in a quieter system with a lower noise floor).

I'm considering doing 10/3 but was wondering if Lokie's source or someone else could comment about the connections for the ground.  The receptacles I'll be using (Oyaide R1's) do not have dual ground straps - just hot, neutral, and one ground.  How would the second ground / bare be connected at each end of the circuit?  On the receptacle end both red & bare to the same ground strap/screw?  How about on the panel / breaker end?

Secondly, an electrician I was speaking to the other day suggested considering a separate ground for the dedicated power lines if I was concerned about RFI.  Is their any practical way to measure for this?  Honestly to me it's hard to determine how much to be concerned about EMI / RFI and what measures are worth taking.  In general (2) lines will be about 40 feet and another (2) about 25 feet, both running in the basement along the 1st flr joists.  I live in a medium density suburban location of single family homes.  At least about half a dozen wifi's going (including my own). 

Does a dedicated ground make sense, and if so any practical suggestions about installation?  Does it need to be to earth?

[Speedskater]

"jarcher" is the power cable 10/3 Romex®(NM) or individual wires in a metal conduit?  The "Isolated Ground" wire is only functional if the installation has metal conduit or the outlet boxes are connected to metal wall framing.

[jarcher]

At first I had thought about using 10/3 Romex NMB, which can be had for about $200 for 250 feet. 

http://www.homedepot.com/h_d1/N-5yc1v/R-202316277/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=10-3+southwire&storeId=10051#.UEJB6lR40ZY

Then maybe putting it in flexible metal conduit:

http://www.homedepot.com/h_d1/N-5yc1v/R-202316476/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=flexible+metal+conduit&storeId=10051&superSkuId=202891058#.UEJCIVR40ZY

I see that flexible metal conduit w/ 10-3 inside is sold, but the only asking prices I find are much more than the combo above:

http://www.grainger.com/Grainger/SOUTHWIRE-COMPANY-Metal-Clad-Armored-Cable-2VGG1

I.e. $640 vs $200 for the NMB + under $100 for the conduit.

I do not have metal wall framing.

Sorry for the ignorance here, but just don't know how to implement the additional ground in the 10-3 cabling, and whether it makes sense or not to implement an isolated ground. "Talking down" here would be helpful. I'd ask the electrician, but what I'm asking is pretty far from routine I think for him - and I get the feeling that first dedicated line was done wrong & will have to be re-done.

[Speedskater]

The 10/3 (plus ground) Romex® NMB is typically used for split phase 240V circuits. But the 3 conductor (+G) has a virtue when used in 120V circuits (one wire is not connected) that virtue is that it has a natural twist which reduces interference.

If you are using conduit (solid or flexible)(metal or plastic) then Romex® is not needed.  Use 3 individual wires. If you find an electrician that will do it, twisting the Hot and Neutral wires is good.  Many electricians have little interest in doing a job this way and often get it wrong.

If you only use Romex® or plastic conduit, then no additional Ground wire or special receptacle is needed.

If you use metal conduit, then IG receptacle's are needed.  Depending on how it's done an additional EGC ground wire may be needed.

[ctviggen]

10/3 is two hots, a neutral and a ground.  If you wanted to do isolated ground, then you'd have to have isolated ground outlets. I'm looking for a good description and can't find one that's great, but here's one that's not bad:

http://communities.leviton.com/servlet/JiveServlet/previewBody/2099-102-1-3203/Spec%20All%20HG%20IG%20Receptacle.pdf

Theoretically, you'd use one hot wire as a hot, the neutral as a neutral, the ground as a ground, and the other "hot" as the isolated ground (with proper marking at both ends).  That's only one circuit, though.  If you need two circuits, you'd need 10/4 or you'd have to run a separate ground.

The isolated ground by itself is really not useful unless you combine it with a metal box and metal conduit and metal cover.  Then, the body of the outlet is connected to the metal of the cover and the metal of the box (and to the isolated ground), and there's an entire grounded "shield" around the wires and the outlet.  Without that grounded "shield", the isolated ground isn't useful.  And this only prevents/reduces electromagnetic coupling into the wires; any "garbage" that's on the wires to begin with isn't effected. 

[ctviggen]

Or it is "affected"?  Can't remember my grammar right now.  Gotta go cut some more grass/weeds in this intense heat.

[jarcher]

Thanks speedskater - don't think I'd want to pay my electrician to do a lot of manual labor twisting conductors - he's cheap, but I think the NMB route would be cheaper.

For the 10-3 NMB, if the hot / neutral / ground are all connected to the receptacle, would the bare wire then just be capped off at both the receptacle end & the load center end? So basically you're doing 10-2, but just getting the advantage of the twisting of the hot & neutral?

[jarcher]

If you need two circuits, you'd need 10/4 or you'd have to run a separate ground.

The isolated ground by itself is really not useful unless you combine it with a metal box and metal conduit and metal cover.  Then, the body of the outlet is connected to the metal of the cover and the metal of the box (and to the isolated ground), and there's an entire grounded "shield" around the wires and the outlet.  Without that grounded "shield", the isolated ground isn't useful.  And this only prevents/reduces electromagnetic coupling into the wires; any "garbage" that's on the wires to begin with isn't effected.

I'd run one line per circuit. I.e. one line to reach receptacle.

Do you think there's any significant advantage to doing the isolated ground as you described vs just running the 10-3 NMB straight & plain?  I'm willing to do it w/ the metal box / plate / conduit if there's really going to be a benefit.  How would the hook up be done on the load center side?  I.e. what if anything would the bare wire be connected to?  Would the ground & the bare wire have to be connected to a completely seperate ground wire apart from the load center to get the benefit? Thanks.

[Speedskater]

With the exceptions of big basic amplifiers, big powered sub-woofers (or powered speakers) and big video projectors I would run everything on one circuit. The main goal is to reduce the length of the AC power runs from component to component.

If your in-wall AC power line run near your A/V rack then metal conduit might be helpful.  Distance is the best preventive.

Your dedicated circuit should start at the main panel-board (load center) that's where the Neutral, EGC ground and IG ground all get connected together to the power company and the ground rods.

[jarcher]

In the basement the receptacles are right behind the built in rack.  So I don't know - maybe the metal conduit is a good idea.  There's a lot of stuff on that rack, including noisy stuff such as wifi, bluetooth, etc stuff.

BUT - everything but the amps are plugged into a Furman line conditioner. 

The amp is a monster : Krell Showcase 7 w/ 1500w total peak potential power consumption.  Yes - I doubt I'm ever going to get near that, though the maggies are power thirsty, but the manual does suggest a dedicated 15A min line. I do have a projector (JVS DLA RS1) but it is not super power hungry (300W max maybe?).

The power cable runs are all kept quit short &  similar, w/ the exception of the projector.

As for the living room, the power amps needs may be slightly less, though some tube amps are pretty thirsty : up to 300Ws.  In other words, does seem that there are enough power hungry products to merit a separate line for them.

And all the gear is fairly close to the receptacles - i.e. within 3 feet.

And so I'm guessing at this point it does make sense to do metal receptacle boxes & metal conduit...........

 

[ctviggen]

The turn on rush current will be what kills you.  I had so many amps at one time that I had to stagger turn on for a 15 amp line.  In my current system, I have two 20A circuits, though I'm sure I come nowhere close to that when running.

[Wayner]

I've read a number of posts here at the AC on this very subject, and to me, most guys go way overboard.

Sure it's nice to have a couple of dedicated lines, but hooking amps to one branch and preamps and other stuff
to another branch, asks for trouble. Good grounding (to eliminate possible hum issues) involves a single point,
not spread over several branch circuits. If you have 3 prong grounded equipment, this may lead to problems.

While I do endorse having 1 dedicated branch circuit for your system, the outlets your system is plugged into
should be isolated from each other. Toroidal transformers like to influence each other (even with the device off)
and at least for me, this is the main issue with any systems electrical supply.

Many brands of power conditioners offer duplex to duplex isolation. This is the direction I would go. Perhaps
1 20 amp branch circuit for the system, and get a power conditioner that has isolated outlets.

Pretty much problem solved with not much invested.....

Wayner 

[rollo]

  Although conventional wisdom says one 20 Amp circuit is enough which I agreed with until we tried multiple circuits. Having two was an instant improvement in dynamics and clarity. Adding the third was the icing on the cake. Why ?? got me. No going back from what we now hear.
    Please I am not disagreeing with anyones findinings just stateing our own.


charles
   

[jarcher]

If anyone is curious what a stock MRI / hospital grade Leviton @ $21 from Amazon looks vs a Oyaide R1 "flagship" receptacle at $175 retail looks like, here's your chance. I ordered both, but there was no way I was gonna pay $175 for a receptacle - got it for way off of that from a dealer looking to clear out old stock.

The R1 has of course the "Highly (twice) polished beryllium copper" and the mounting plate certainly seems a bit thicker & definitely shinier / prettier.  The Leviton is made in the good ol USA.

I doubt I will go as far as trying to A/B the plugs - the R1(s) will go in the main listening room.  The leviton for another room for less critical listening. For the less OCD, I get the feeling that the Leviton MRI82 is sufficient at almost a tenth of the cost retail of the Oyaide.

[drummermitchell]

Rollo,I agree totally.I have multiple dedicated lines(two are 240v)Total silence ,also which I have three Torus connected(also dead quiet).
All Torus receptacles  feed off the main Torus supply(no dedicated digital receptacles)again dead quiet.
Gotta say if any component,conditioner,interfered with my listening to music it would be out the door.

[ctviggen]

I've read a number of posts here at the AC on this very subject, and to me, most guys go way overboard.

Sure it's nice to have a couple of dedicated lines, but hooking amps to one branch and preamps and other stuff
to another branch, asks for trouble. Good grounding (to eliminate possible hum issues) involves a single point,
not spread over several branch circuits. If you have 3 prong grounded equipment, this may lead to problems.

I have two 20A dedicated circuits on the same phase.  Zero hum, zero issues.  I have amps plugged into one duplex outlet and everything else plugged into another.  Now, both my 20A dedicated circuit wires run in the same conduit and are within probably an inch of being the same length, which may not be true for anyone else.  I do have hum in a sub on a different circuit, but I've been able to alleviate that, and the sub is across the room, so it has to be on a different circuit. 

[Wayner]

I have two 20A dedicated circuits on the same phase.  Zero hum, zero issues.  I have amps plugged into one duplex outlet and everything else plugged into another.  Now, both my 20A dedicated circuit wires run in the same conduit and are within probably an inch of being the same length, which may not be true for anyone else.  I do have hum in a sub on a different circuit, but I've been able to alleviate that, and the sub is across the room, so it has to be on a different circuit.

It's not hard to have the 2 circuits in phase as the 240 volt service to your house is single phase.

Wayner

[srb]

It's not hard to have the 2 circuits in phase as the 240 volt service to your house is single phase.

Although "phase" is commonly used in error when talking about residential 240V service, I'm fairly certain that what ctviggen is referring to is having circuits on the same 120V leg or side of the panel.
 
Steve

[mjosef]

Multiple lines are not a absolute requirement for zero noise/hum imo.
I live in the heart of Brooklyn ( amidst 2.7million 'other' peoples), and use one 20A line which could be over 4 decades old(the panel uses fuses) and there is zero noise, hum, buzz in my system.

I power the whole system on this 20A line, with a competent power conditioner of course, with isolated outlets for each digital source(2+1-DAC), power amps (2), X-over, turntable  and preamp.

<just another voice in the wilderness of audiophilia>