GoodSoundClub - Romy the Cat's Audio Site - Daisy chaining of ground wires

11-21-2015

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JOHNR
Posts 24
Joined on 10-12-2015

Post #:	1461
Post ID:	22232
Reply to:	22230

Suggestions

I can only offer a simple solution to this problem.
Decide on which row you wish to place digital services. I would also include anything that has a switched mode power supply because of the Y capacitor thing. Assume Row 1 will be used for digital services.
Assign the central sockets nos 3 and 4 on the top row as the feeder location for sockets each side.

In the top row connect sockets 1 and 2 to socket 3 using individual wiring. I use a flat Nordost speaker wire, single strand for this. On a 110 volt power system insulation should not be an issue here. Fit shrink down tubing if this makes you nervous.

Wire socket 4 to sockets 5 and 6 (Row 1) using dedicated wiring.

The incoming power feed is to be taken directly to the Row 1 socket 3. I use a USA supplied 30 amp rated cooker wire for this, cross linked polyethylene type (XLPE and 27 strand). Never use PVC insulation.

Repeat this for the second row.

Connect row 1 socket 3 to row 2 socket 3 and again for sockets 4.

Rather obviously this will be an elaborate Star system.

The principle is to force noise coming in off each socket to take the shortest route to the feeder cable using its own wire.
Also to avoid sharing of noise artifacts except on the main feeder cable.

I live in a condo and have to suffer 200 air conditioners, lifts, main water pumps and booster water pumps directly above my head.
I also use a 2kVA 230 volt/110-0-110 isolation transformer for safety and noise control.

The 100-0-100 emulates the USA system of using a single phase 9 to 15 kilovolt feeder into a pole mounted transformer, aka "open delta" where the 2 outer taps will provide 220 volts for larger loads. Explains why 110 volt power is always dirty because of the mixed loading giving weird phasing artifacts.

A CAUTION:
When using this type of power supply I would strongly advise against using a house ground.
You can become the prefect ground path for lightning and any surge on ANY building anywhere that is served by this external transformer.
We used these in the Caribbean cellular radio sites and well member such an incident. We always fitted a 100 Joule surge arrestor system and it blew this such that it turned everything inside the steel box into charcoal.

Use an isolating transformer always. - then decide upon your grounding method.

Hope this helps,
Regards
John

11-21-2015

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N-set
Gdansk, Poland
Posts 616
Joined on 01-07-2006

Post #:	1462
Post ID:	22234
Reply to:	22232

The Alternatives

Guys, thank you!

Avoiding ground loops is self understood and actually my question was more
trivial than that: Shall I arrange all receptacles for all my 3 lines in one box
or take the dirtiest line into a separate one? A dedicated ground is unfortunately
impossible in my circumstances.

Here are the alternatives.
A) 1Box 3 lines 1 Ground

Boxes.jnt-page-001.jpg

B) 2Boxes, 2+1Line I show two separate grounds but can of course use just one

Boxes.jnt-page-002.jpg

John, thank you for taking the time to explain the wiring. I do plan to star
connect all receptacles within a line using such distribution blocks. Line comes in
and then each outlet is individualy connected to the block. I wanted to use an
ordinary solid core wire but you suggest something fancier even for such a short
connections?

Thanks,
N-set

Edit: We all know it but I just leave these grounding basics here: https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf
FYI, slide #38 shows real-life spectrum of a power line.

Cheers,
Jarek
STACORE

11-21-2015

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Paul S
San Diego, California, USA
Posts 2,644
Joined on 10-12-2006

Post #:	1463
Post ID:	22235
Reply to:	22234

Phase

John mentioned phase issues. In the US, a residential service it typically referred to as "single phase 240V". For hi-fi it is well to note that US (and similar) 240 is "split" at the service panel into 2X 120V rails that have 180 degree phase shift. For most of what we do with electricity this is not an issue. However, it can be in issue for hi-fi. It tends to work best for us if we can bring in either one "heavy" circuit, or, in the event of 2 or more circuits, we use the same 120V "leg" for all circuits that serve the system, As for grounding, I'm presently settled with all components on a single "neutral" wire back to the mains ground, along with 1 dedicated "bleeder" ground for cable and SUT shielding. In other words, I do not use the house "safety" ground" wire for hi-fi (this wire being the usual US green "third wire" at each modern outlet). Of course, there might be problems with induction (and resultant noise) any time there is more than one path to ground. And the only way to be sure is to try it. It's also helpful to use a dielectric at mechanical ground connections (those that are not soldered).

Paul S

11-21-2015

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Romy the Cat

Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #:	1465
Post ID:	22237
Reply to:	22234

I think it is wrong division.

I do not think that this division on analog and digital is right. The true division should but not about type of frond end but about a type of PS. If you have any switching PS then I would isolated them in a dedicated line. The division also might be by ground loop type in case some of your equipment use single-ended interconnects and some use balanced.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

11-21-2015

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Paul S
San Diego, California, USA
Posts 2,644
Joined on 10-12-2006

Post #:	1466
Post ID:	22238
Reply to:	22236

Bleeder

I run a 12 gauge "bare" copper line from the system to a copper ground rod that is driven into the ground under the window behind my system, The main, system-end connector and the wire/rod connection are both soldered, and the bare wire is routed to avoid "incidental" grounding before it gets to the ground rod. In my system, I get hum if I try to ground a bleeder to the house ground, which - of course - shares a bus with the neutral wire at the main panel, per typical residential protocol. Even in cases of a "split bus" for neutral and ground, the wires therefrom typically route to the same ground, whether UFER (underground ferrous electric), or (rare in US) a driven ground rod or rods (Code presently requires 2).

While I agree in principle with a dedicated (same pole) circuit for digital/switching gear, in the end, the ground is usually shared, and this may be a problem that needs dealing with, in and of itself. Again, it seems to be a good idea to at least have "home runs" for hi-fi circuits. meaning, all dedicated circuit wires are unbroken between the outlets they serve and the main breaker box.

N-set, I also like a nice, tightly connected, "buttered" fuse in lieu of a magnetic or vacuum breaker for hi-fi circuits; but for most people this feature would be either redundant or a Code violation.

Best regards,
Paul S

11-21-2015

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drdna
San Francisco, California
Posts 526
Joined on 10-29-2005

Post #:	1467
Post ID:	22239
Reply to:	22237

Purpose of ground

The ground simultaneously serves as the source of all electrons entering the system and a common voltage level that establishes a baseline for the system. Thus, the ground should be simultaneously as large a homogenous metal source as possible while also being as small as possible to minimize internal resistance. All ground paths should be as short as possible and isolated from each other, ultimately coalescing in a central common point with minimal resistance within the physical ground. This is, of course, well known to us all. However, it serves the discussion in approaching the idea of isolated lines for digital or switching circuits. All circuits introduce noise into the AC waveform, but these circuits in particular have been described as particularly nonmusical in their action here. In theory, all such circuits should be isolated to the greatest extent possible (back to the panel), but because all physical circuits are calculated compromise with the potential for flawed execution, it ultimately depends on the specifications of your own system.

You may, for example, find better results with digital circuits attached to an isolated output from a PurePower APS versus a completely dedicated line. Ideally, you would have a dedicated line leading to a PurePower APS for each device, but the size and expense of this venture would be prohibitive. I suggest you have a few fully dedicated lines installed, which will give you the flexibility to experiment with different equipment configurations to find the one which works best for your application.

In my system, I have dedicated lines back to the panel, but have found the results to be just as good with everything plugged in to the PurePower APS connected to a dedicated line. In my previous house, I had used a "separate copper rod in the backyard" ground solution, but this has not been necessary at my current location.
Adrian

11-22-2015

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Romy the Cat

Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #:	1468
Post ID:	22241
Reply to:	22239

My PP configuration in system.

I have ais very much the same configuration as Adrian has and I find work the best for me. I have PP plugged in a single dedicated line and it is plugged with all 3 pins, including the ground. The PP shall not work with lifted source ground, it gives to it a bunch of operational instabilities that derives from PP's topology. On the load side my ground are completely lifted and I use my own ground. It is beautiful for noise. Loops and beautiful for sound. I disagree with Adrian regarding that it would be "ideally" to have dedicated PurePower APS for each device. In my experience it is not goof to have more than one PP in system as the PPs are impact each other. When I am listening my main system I always shut down my PP in Opera room as the difference is very audible.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche

11-22-2015

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N-set
Gdansk, Poland
Posts 616
Joined on 01-07-2006

Post #:	1469
Post ID:	22244
Reply to:	22241

1Box,1Ground

I think I have mentally resolved my question: since all of the
equipment powered from my lines will work in a chain,
there must be one ground and outlets should be quite compactly
placed. This minimizes potential differences between the "grounds"
and their influence via common impedance of the power lines.
All the TT motors etc will be powered from my normal household line,
they are not parts of the chain.
PP and other power regenerators-maybe, but not now.
Actually the guy in the presentation I posted above (the president of jensen transformers)
puts forwad an interesting thought: many benefits of power conditioning
are actually due to tight cluster of the power outlets.

Cheers, N-set

Cheers,
Jarek
STACORE

11-22-2015

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drdna
San Francisco, California
Posts 526
Joined on 10-29-2005

Post #:	1470
Post ID:	22245
Reply to:	22244

Isolation of turntable motors

I think this is all fine, but since you are building it all, why not make it so that you have the flexibility to experiment with different configurations to see what works best in your system? I think it's fine to have a theory about clustered power outlets, but you should always test out the theory in real life.

N-set wrote:

All the TT motors etc will be powered from my normal household line,
they are not parts of the chain.

I would use caution in making this assumption. My experience is that the regulation of the AC current to the turntable motor is one of the most important aspects of reproducing Sound. Some people even go so far as to having a separate isolated DC battery source for the motor. Even simple filtering is helpful in my experience; you should experiment with this a bit.

Adrian

11-22-2015

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N-set
Gdansk, Poland
Posts 616
Joined on 01-07-2006

Post #:	1472
Post ID:	22247
Reply to:	22245

True

Adrian, very true but being a theoretical physicist I like to have an initial hint
on what's going on. Moreover, in my situation the dedicated lines physically
are cables sticking out of the wall so I have to organise and connect the outlets somehow.
I will actually make two alu boxes which I can bolt together or unbolt, and two ground runs will
give me a chance to test my theories.
The motor of my TT (emt930) is getting a dedicated microprocessor controlled 3-phase power synthesizer
with linear output amps. There are leakages and mag couplings of course but in principle all the
coupling from the motor is parasitic and not part of the chain like e.g. data from the transport
referenced to the same ground as the rest of the chain.

Cheers,
N-set

Cheers,
Jarek
STACORE

11-23-2015

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JOHNR
Posts 24
Joined on 10-12-2015

Post #:	1473
Post ID:	22249
Reply to:	22244

Daisy chaining of ground wires

You should take care that you do not daisy chain the ground leads. Refer to following text.

From my perspective, you should treat the L and N leads as one type of circuit and the PE as a separate circuit. Electrical codes, rules etc do not insist that the PE is always carried along with the L+N.
Very often amplifier builders are sloppy as to how the PE is connected. Sometimes the PE is used as a part of the audio return path to for example, a line amplifier. To get around the hum that will result, they use a ground lifter device eg 10 ohm resistor even a pair of diodes back to back.

A point to note is that line and neutral generate noise of one type whilst a PE should not be carrying noise at all unless you use one of the clever high cost power cords.

A system that can work well is to create a single node or terminal where all ground leads are terminated. This terminal is then connected in turn to the electrical panel.

Noise can come down any wire but cannot go back up any other wire so there cannot be any passing of noise from one piece of apparatus to any other.

The choice of wire to be used is important since stranded wire has much higher inductance than a single core. This is important since one can inadvertently create a high frequency TANK circuit.
Thus, this central ground terminal should be connected using the thickest single core wire that is available. Here, in a metric cable environment, single cores are not available. Tip - go and look for plenum rated fire system cabling supplies. Generally XLPE insulation which is better anyway than standard PVC type BUT costly.

On an earlier posting, i recommended using USA cooker cable since this cable is unusual in that all of the 3 conductors are the same size. Generally electrical codes require the ground conductor to be 1/3 to 1/2 of the line conductor size. In effect you obtain a double sized ground path which is useful to have.

If you wish to check out ground currents etc, purchase, hire, beg, borrow or steal a clamp on "Hall effect" ac/dc meter. This will tell you that line and neural are correctly balanced and if there is any current in the ground path.

regards
John

11-23-2015

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clarkjohnsen
Boston, MA, US
Posts 298
Joined on 06-02-2004

Post #:	1474
Post ID:	22250
Reply to:	22249

The AC polarity problem

This may have been mentioned already. . . if so, it escaped me. But here's the thing: Each component has its own AC chassis leakage characteristic. This can be measured, and lining every component up by the same polarity produces less noise & hum and better sound. The best article on this appeared in Bound for Sound, but I cannot find it. So here's one with only a couple minor errors, so listen up!

http://www.gcaudio.com/resources/howtos/acpolarity.html

11-23-2015

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N-set
Gdansk, Poland
Posts 616
Joined on 01-07-2006

Post #:	1476
Post ID:	22252
Reply to:	22249

No daisy chain!

JOHNR wrote:
You should take care that you do not daisy chain the ground leads.
[...]
A system that can work well is to create a single node or terminal where all ground leads are terminated. This terminal is then connected in turn to the electrical panel.

This is exactly what I want to do: all the outlets star grounded to a single terminal within the box (max connection length
would be about 10cm) and then this connected with a single cable to the ground at the panel.
As I understand the last connection is for safety only (planes or satelites have no reference
to the ground and ultraprecise scientific equipment works there no problem). The most important is to have
a compact arrangement of outlets with thick, short, star-connected grounds.

JOHNR wrote:

The choice of wire to be used is important since stranded wire has much higher inductance than a single core. This is important since one can inadvertently create a high frequency TANK circuit.

This is interesting and I did not know that. Do you have any data comparing same cross-section stranded and solid-core impedances vs. freq?
I have to my disposal stranded 16mm2 or solid-core 6mm2 run to the ground. Solid core due to the skin effect has a nice feature of presenting high impedance for AC currents, the thicker the higher the impedance. If i get it right, this is a natural mechanism blocking some of RF rubbish from propagating along thick solid core power lines.

Cheers
N-set

Cheers,
Jarek
STACORE

11-23-2015

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drdna
San Francisco, California
Posts 526
Joined on 10-29-2005

Post #:	1477
Post ID:	22253
Reply to:	22252

Solid core versus stranded wire

N-set wrote:
Do you have any data comparing same cross-section stranded and solid-core impedances vs. freq?
I have to my disposal stranded 16mm2 or solid-core 6mm2 run to the ground.

At one time I experimented quite a bit with different wire configurations: solid core, stranded, etc. ... even very thin sheets of copper foils for AC wiring. My best results were with 5 mm2 solid core copper hand wound into a triple helix configuration so that the individual wires were always at 90 degrees to each other at all points. This being said, the effects were very subtle and easily overshadowed by variations in construction, insulation, shielding, etc. In my opinion, it is far better to use the easiest wires to work with to minimize any issues with the physical and mechanical construction and installation of the wires. Installation is never ideal, and it is more important to ensure that it can be accomplished in such a way that there is no compromise that may more significantly impact the system.

Adrian

11-24-2015

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JOHNR
Posts 24
Joined on 10-12-2015

Post #:	1480
Post ID:	22257
Reply to:	22252

Solid core wire

This is a fact but, you need to review literature relating to lightning/surge arresting systems. It is given in books such as the FURSE system because stranded conductors DO NOT WORK in that application. Flat tapes and small solid core wire should be installed between the equipment and the ground rod or MD panel. It must also be insulated to prevent contact with concrete, soil etc.

Here in Malaysia, we have daily lightning problems and I do not recommend using a domestic ground rod system not for technical or safety reasons but because the contractors will not do as you instruct and they get it wrong. Here, ALL installations have to have a Residual Current Circuit Breaker (RCB) that will trip if a Line to Neutral imbalance occurs occurs above 15 mA. They really do save lives and I strongly recommend fitting one in series with the main feed to your system. They do not require a ground to function.

Your solid core 6mm2 is correct. Not available here which is why I use fire system plenum rated wire; it will not burn either which is useful if you do have a problem.

John R

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