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Questions on mutiple dedicated lines

119.237.11.138
Posted on October 26, 2009 at 00:05:37
andy2667
 Hi,

Having heard the great difference in good power cords and conditioners, I have recently been in search for upgrading power lines/supply to my gears/listening room.

I intend to install 4 dedicated lines for audio use. Each one will be terminated with a twin socket so that I can get totally 8 sockets. Thus
- one line with 2 sockets for my 2 tube power amp mono block
- one line with 2 sockets for my 2 SS power amps for sub woofers
- one line with 2 sockets for analogue front ends (e.g. tube pre)
- One line with 2 sockets for my digital front aend (i.e. a DAC and a CD transport).

I note that this arrangement would be less costly compared with buying a exotic expensive power strip.

The above plan seems to be perfect in my mind but I have the following questions need to be cleared before triggering the work.

1. Ground loop problem
I have read some where before that all equipment should be plugged inone outlet to reduce ground loop. Is this true? Can I just link the ground lines of these 4 dedicated line to achieve similar aim?

2. Shielid vs not shield
It is much easier to do the work by PCV conduit than metal conduit. Is metal conduit a benefit for shielding?

If the ground loop problem is not an issue, I will go for this project.

Thanks in advance for your advices/inputs.

Andy

RE: Questions on mutiple dedicated lines, posted on October 28, 2009 at 09:13:11
andy2667
 Hi All,

Thank you for your information and advices. I decide to go the 4 or dedicated line route and use a parallel filter for each line. Of course will try adding filter to one line first.

Don't know if the cable type for the dedicated line be matters. I may use Pirelli PVC cable for the line. It is available locally, inexpensive and famous for its netural charactor.

Note that in USA the Romex cable is more propular and there are Cryogenically treated version. Not certqain if Cryogenically treated be have differences in sound quality but shipping one lot to Hong Kong would be too expensive.

Thanks

Andy

RE: Make sure each of the lines are on the same phase in the breaker box., posted on October 27, 2009 at 09:42:37
reb
Audiophile

Posts: 1621
Location: NY
Joined: January 28, 2002
 Otherwise you may experience some unwanted "sonic" compromises.

RE: Make sure each of the lines are on the same phase in the breaker box., posted on October 29, 2009 at 06:41:29
andy2667
 Too bad that we can only get one phase in general grade apartment in Hong Kong. Unless it is a luxury apartment or house, we are not able to have 3- phases supply. Thus, we can only get a single phase with all equipment and appliance supplied by this phase.

Dedicated lines are fed by individual MCB (fuse) only. I note that some users have their dedicated lines fed by power line upstream of the main fuse (MCB) but this violate the local supply rules and are not safe.

Thank you for your recommendation.

Confusion over the use of the word, "phase.", posted on October 29, 2009 at 15:37:51
Al Sekela
Audiophile

Posts: 8279
Location: Northern California
Joined: February 18, 2002
 The USA domestic users also have single-phase power. What they are talking about is the way the power is connected to branch circuits.

We have 240 volt power that comes from the utility transformer. This transformer secondary winding has a center tap which is grounded at the transformer. Three wires feed the house: one from each end of the secondary winding (considered hot), and one neutral wire connected to the center tap.

At the house, this neutral wire is grounded again. Heavy appliances (240 volt) are fed from both hot wires, while branch circuits for lighting and convenience outlets (120 volt) are fed from one or the other of the hot wires and the neutral wire. A separate "ground" wire is also used in newer construction as a safety measure. This safety-earth wire is connected to the neutral at the earthing point at the circuit breaker panel.

Because the two hot wires are taken from the ends of the utility transformer secondary winding, both have 120 volts to neutral, but the AC voltage waveforms are 180 degrees out of phase with respect to each other. Many people refer to the two hot wires as "phases." Experience shows that audio systems with more than one branch circuit sound better if all the branch circuits are fed by one of the hot wires, and this was the recommendation above. I don't think this applies to your wiring standards.

RE: Confusion over the use of the word, "phase.", posted on November 3, 2009 at 06:02:02
Jerry P
Audiophile

Posts: 599
Joined: June 17, 2000
 Our power distribution system in the US is called a 3-wire, single-phase, mid-point neutral system.
Sony SCD-777ES >> Silver Audio SB 4.0 >> AI M3A >> Silver Audio Hyacinth >> Odyssey Stratos >> Tice 416A Bi-wire >> MG 1.6QR

I like that. Short, sweet and and perfectly descriptive. n/t, posted on November 3, 2009 at 13:27:53
Ugly
Audiophile

Posts: 1420
Location: Des Moines, WA
Joined: August 22, 2006

180 degrees? Isn't it 120 degrees so that the sum of the three phases..., posted on November 1, 2009 at 10:07:18
jeffreybehr
Audiophile

Posts: 3833
Location: Phoenix, Arizona
Joined: December 10, 2004
 ...sometimes available is 360 degrees?

Or maybe in a 2-phase system, that is where 3-phase power is not available on the power company's distribution system, the phases are indeed 180 apart.
-------------------------------------------------------
Tin-eared audiofool and parttime landscape fotografer.
http://community.webshots.com/user/jeffreybehr
RE: 180 degrees? Isn't it 120 degrees so that the sum of the three phases..., posted on November 2, 2009 at 20:25:44
jea48
Audiophile

Posts: 3544
Location: Midwest
Joined: January 5, 2005
 >>

180 degrees is equivalent to a sign inversion., posted on November 1, 2009 at 12:11:21
Al Sekela
Audiophile

Posts: 8279
Location: Northern California
Joined: February 18, 2002
 Domestic power is simply single-phase. The use of the word, "phase," is inappropriate for domestic power when discussing the two hot legs. This is how the confusion arises.

Three-phase power does indeed have 120 degrees between the phases. The power company generates and distributes three-phase power, but domestic users are attached to only one of the phases. The transformers are the clue: they have a single core instead of a triple core.

I don't think so. My house is fed with 3-phase power..., posted on November 4, 2009 at 14:12:31
jeffreybehr
Audiophile

Posts: 3833
Location: Phoenix, Arizona
Joined: December 10, 2004
 ...(the neighborhood is now 50 years old), and my domestic service has 3 lines plus neutral coming from that big transformer. The 2 physical halves of the breakerbox are fed by 2 of the 3 legs, while the 3rd (it's a 3-phase-delta system) runs to the AC system. As a result, my 2 120VAC legs are 120 degrees out of phase.

And I believe where 3-phase power is not available, the 2 120VAC legs that do arrive from the transformer are 180 degrees out of phase. Else how does one have 240VAC for one's waterheater and oven?

But maybe you'll tell me. :-)


-------------------------------------------------------
Tin-eared audiofool and parttime landscape fotografer.
http://community.webshots.com/user/jeffreybehr
RE: I don't think so. My house is fed with 3-phase power..., posted on November 4, 2009 at 22:07:36
jea48
Audiophile

Posts: 3544
Location: Midwest
Joined: January 5, 2005
 3-phase-delta system

Arizona..... Had to be the only state that ran 3 phase power to a residential occupancy.

Are you sure it is a delta and not a WYE? If it is a 3 phase 4 wire delta it will have what they call a "wild leg". From two hots to the neutral the voltage will be 120V nominal but from the other hot to the neutral it will be around 208V. And usually out on the utility pole you will see one big transformer and two smaller ones.
Sometimes only one big transformer and one small transformer. In this case it is called an "Open delta".

At any rate if it is a delta the 120/240 is single phase fed from the bigger transformer and there is not a 120 degree phase angle.

A 3 phase 4 wire WYE transformer configuration has three equal voltage hot phases that have a 120 degree phase angle with respect to one another. Usually phase to phase is 208V nominal and from any of the three phases to neutral is 120V nominal. If the 3 transformers are mounted on a pole or platform, the transformers will be the same size. A 3 phase 4 wire WYE pad mount transformer will have all three coils inside one enclosure.
Jim

RE: Confusion over the use of the word, "phase.", posted on November 1, 2009 at 06:43:30
reb
Audiophile

Posts: 1621
Location: NY
Joined: January 28, 2002
 Excellent post. You did a perfect job of explaining what I was thinking and how I have my dedicated lines set-up.

RE: Questions on mutiple dedicated lines, posted on October 27, 2009 at 05:46:32
jimmyjames
Audiophile

Posts: 3176
Location: Raleighwood
Joined: February 20, 2001
 unless you are using humongous power amps, can't see the need for more than one 20amp dedicated ckt. I have a fairly expansive a/v system (see my system in the asylum inmates systems page) and am using one 20amp circuit on #10awg wire with extensive power filtering. Whether you do one or 8 ckts, the EC should run all grounds back to common point in panel. Also, stress to the EC to install "home run" cable from panel to recepts with NO SPLICES and NO WIRENUTS anywhere.

"E pur si muove...And yet it moves"
The advantage of multiple circuits..., posted on October 27, 2009 at 10:39:14
Al Sekela
Audiophile

Posts: 8279
Location: Northern California
Joined: February 18, 2002
 Most audio power supplies do not draw sinusoidal current from the AC. The supply circuit impedance converts power supply current into a noise voltage. This noise voltage can have a very broad frequency spectrum. Any other audio components on the same circuit see this noise, and may not be able to filter it effectively with their power supplies.

Passive power conditioners that provide as much isolation as separate dedicated lines have to use series inductance with at least some of the outlets, and this can affect performance. Active conditioners are quite a bit more expensive than typical AC circuit installation costs, even with top-notch outlets.

RE: The advantage of multiple circuits..., posted on October 29, 2009 at 14:31:04
lacee
 I was using two dedicated lines, one 30 amp for my power amps and a 20 amp for everythingelse.

I went back to just one 30 amp dedicated line.
I run it directly into my Furman 20 amp input with a 20 amp Wattgate receptacle.

The Furman balances the power to a Hydra 2(amps) and a Guardian 2 for the pre and cd.

It sounds better with everything into the Furman and off one line than separate runs .

Why this is so i don't understand.
In theory the way I had been doing it(separate runs) should have been better.

And yes, I was on the same phase at the panel.

Have you tried running the CD player by itself from the second circuit?, posted on October 29, 2009 at 15:21:01
Al Sekela
Audiophile

Posts: 8279
Location: Northern California
Joined: February 18, 2002
 The CD player may be affecting the preamp, or vice versa, if they share the same conditioner.

still sounds like overkill to me, posted on October 27, 2009 at 14:29:36
jimmyjames
Audiophile

Posts: 3176
Location: Raleighwood
Joined: February 20, 2001
 but then so do $250,000 loud speakers. I would rather spend the money that all those dedicated ckts would cost on a decent power filter/distribution center. Noise coming in on the power line doesn't care how many ckts you run. Not sure what having those lines on different phases might do either but I guess you could put them all on the same phase bus bar if he was going to have 8 circuit breakers. Most 20 amp c/b's are rated for 2 wires max under the lug.

"E pur si muove...And yet it moves"
I know by experience, posted on October 28, 2009 at 15:53:43
Al Sekela
Audiophile

Posts: 8279
Location: Northern California
Joined: February 18, 2002
 that my system sounds a lot better when my Wadia 861 does not share an AC circuit with a power amp.

You don't need $250,000 speakers to hear the difference.

Damping the dedicated circuits also helps, and costs little. The circuits and parallel filters are much cheaper than a fancy conditioner.

I know by listening, posted on October 29, 2009 at 05:51:51
jimmyjames
Audiophile

Posts: 3176
Location: Raleighwood
Joined: February 20, 2001
 that my system sounds better with the MIT Z filtering in the system than without. Whether or not dedicated lines for digital and power eqpt in my system would make it sound better or not would need to be tried. Along with that experiment, I would want to try the digital and power gear on different and same phase legs in the panel to see if that made a difference but that is a whole lot of trouble.

My point about $250K speakers being overkill along with 8 dedicated ckts is just that. IMO you don't need either to have a great sounding system. If you have unlimited resources and time then go for it. I realise that some posters here are after the ulimate sound and want to constantly tweak and spend money but I have grown beyond that stage. Life is too short. I get more enjoyment out of listening and finding components and tweaks that perform way beyond their price point and downsizing my system accordingly.

"E pur si muove...And yet it moves"
Metal conduit is an open question., posted on October 26, 2009 at 15:14:56
Al Sekela
Audiophile

Posts: 8279
Location: Northern California
Joined: February 18, 2002
 Yes, metallic tubing offers some shielding (but not much against low frequency magnetic fields), but it can act an independent resonator for electrical and acoustic energy.

I would avoid ferrous (steel) tubing or armored cable. Also avoid steel wiring boxes. I think we are stuck with steel circuit breaker boxes.

Each separate line should have some sort of parallel filter to damp its resonances.

Separate lines provide the ultimate separation to keep each power supply's noise away from the other components. As you found, they are usually much cheaper than the sophisticated conditioner that would be needed to provide as much isolation. The ground loops are larger, as they now extend back to the breaker panel. This could be a problem if the cables have to pass near a strong source of magnetic field.

RE: Metal conduit is an open question., posted on October 26, 2009 at 17:54:41
banpuku
Dealer

Posts: 127
Joined: January 19, 2006
 Hi Al,

What parallel filters do you like/recommend? And where do you install them (ie at the panel or the outlet box)?

Thanks, Pat

My experience is with DIY designs., posted on October 27, 2009 at 10:28:04
Al Sekela
Audiophile

Posts: 8279
Location: Northern California
Joined: February 18, 2002
 The filters are installed at the dedicated outlets.

These are R-C circuits developed with the participation of others, so I can't share the details.

We've found that subtle recipe changes are quite audible, and that there are interactions with the system setup details. Thus, a single recipe would not give optimum performance in all applications.

The easiest way to start would be with Alan Maher's lower end products such as the PE v3 or Reference II as plug-and-play, or Hammond chokes as DIY alternatives. If these don't give major improvements, then the setup is not sensitive to resonances or induction on the dedicated lines and there is no point in pursuing more expensive or elaborate devices.

My advice..., posted on October 26, 2009 at 10:08:45
mkuller
Audiophile

Posts: 15929
Location: SF Bay Area
Joined: April 22, 2003
Contributor
  Since: December 28, 2003
 ...if your box has room, get a separate line for each component.

At least for each amp because of their power draw.

And separate one for your DAC because of the digital hash it will put back into the line.

It won't cost you much more in electrician time and materials.

A power conditioner will still make an improvement.

Not to discourage you, posted on October 26, 2009 at 06:13:01
bartc
Audiophile

Posts: 3514
Location: SF Bay Area
Joined: November 25, 2002
 Of course, I'd like to do something similar and only cost keeps me from it. But this doesn't necessarily obviate the value of and need for additional filtering, in my observation.

Another inmate whose system is superbly resolving and who is an EE has both dedicated lines and still needs to use parallel AC filtering for best results. He does NOT use the usual commercial conditioners, however, and many of these may not help without their own compromises.

I don't have the dedicated lines, but I find that there are tweaks all the way to the breaker box that still help much. The outlets you use are of great importance (I use Oyaides). I'm having a terrific time with Alan Maher's Infinity Circuit Breaker device - a $25 passive filtering unit placed on the breaker box itself.

Make sure you do all you can at the breaker box, as advice here on dedicated lines delineate.

YMMV.

get unswitched outlets, posted on October 26, 2009 at 05:55:06
dave c
Audiophile

Posts: 28377
Location: Ferny Hills
Joined: April 17, 2000
 It's not a huge difference in my experience, but why wouldn't you?
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