Dominic Marsh continues with his personal thoughts on mains cables and why he believes they can make substantial improvements in the sound of your hifi.  

Hifi Pig does not advocate anyone making ANY unauthorized or unsafe changes to their mains supply or equipment in ANY way! Always consult a professional and qualified electrician. 

In part one I dealt with the basics of mains cables, their construction and some basic metallurgy, so in this part I will offer my explanations of why I think an after-market mains cables brings improvements in sound quality that you can hear through your hifi system.   But I will reiterate . . .

As a safety note at this point, Hifi Pig does not advocate anyone making ANY unauthorized or unsafe changes to their mains supply or equipment in ANY way. Always consult a professional and qualified electrician.  Be safe out there in audiophile-land folks.

I will say yet again though that none of this in based on absolute scientific evidence, mainly because I don’t believe any truly exists in any detail and my own personal observations have been repeatable and consistent enough for me to rely upon for many years.  I am not asking anyone to take what I write at face value, it is not the Holy Grail of mains cables or The Gospel According To The Wise One Dominic Marsh, it is merely me making my private opinions wide open for you to read and if you see any sense in it at all, it has been worthwhile writing it for you.

First up then is the old cry I have heard so many times over the years and this is it;  “There are countless miles/kilometers of cable between the power station and my wall socket, so how can a mere one meter of it from the wall socket make any kind of difference?”   Yes it is indeed true that there is indeed miles of cable from the power station to your house and you should stop thinking about that because it is mostly irrelevant in my opinion.  The cable from the power station’s diameter is huge, greater than the thickness of your arm for most of the distance and losses have been calculated for in their design, using the best materials available within budget constraints.   “Aha, but if pure silver cables are so wonderful, why don’t they use them in the grid?”  They do and have done for quite a few years now.   Liquid cooled as well no less.  I will bet that has surprised you – it did me.  In the larger conurbations of the USA like New York or Los Angeles which consumes a LOT of electricity, they were faced with adding more and more, bigger and bigger cables to meet demand, so they have capitalised on silver’s conductivity to build more efficient power transmission lines.

In the illustration below, there is a brief sketch of the average electricity power grid which applies to almost any country in the world.  We are concerned with what is happening within the red box, from the nearest local substation or transformer to the consumer unit or fuse box inside your home.  Whether the power enters your home through underground cables or overhead power lines makes no difference, the vital component in this scenario is that last transformer before it reaches your house.

Mains_path_PNG1

When the supply enters your home it will pass through a meter and a fuse/distribution panel, then via copper cables to your wall socket.  I won’t be discuss ring mains wiring or radial spurs, because as long as the wiring is of good quality it still plays no major part in that final one metre or so from the socket to your hifi component.  In the UK we have ring mains wiring with each having its own fuse or breaker unit to cut the power in the eventuality of a fault arising, plus we have a mains fuse in the 3 pin input connector plug which does (I believe) have an effect within the subject we are discussing here.  On the continent with the Schuko connection system there is no additional fuse in the line, the same as the USA, Australia and many other countries too.  The fuse, being of a thin resistance wire is designed to rupture during current excursions beyond its amperage rating and I think it as being a large bottleneck with regards to current flow, given that the cabling either side of it has considerably less resistance than the fuse itself.

The actual “business end” of an aftermarket upgrade mains cable lies between the transformer of your hifi component and that last transformer outside of your home.  These two components form a circular AC loop between them and we need to look for components within that loop that are the weakest link in the chain and I have already highlighted the mains fuse in the plug as being one of them.  The fuse located within the mains plug is there to protect the power cord in the case of a fault condition, there are (or should be) fuses within the component to protect that component in a fault condition situation.  If you find a fuse blows repeatedly, there is a permanent fault condition present and under no circumstances should a higher rating fuse be fitted…get it to a competent and registered repair shop, or back to the manufacturer.

As a safety note again at this point, you must not fit fuses of a higher amperage, or bypass/override the fuse altogether.  Be very safe out there in audiophile land folks.

 

MAINS_CIRCUIT_PNG1

The table below shows the effects of cable diameter on current handling capacity, the larger the diameter of the cable, the greater the current load that can be safely drawn through it.

Core size
mm2
             Current
(Amperes)
     Wattage (kW)
at 240v
     Typical applications
1.0          14       3.25       lighting
1.5         18       4.25       lighting
2.5         24       5.75       power circuit
4.0         32       7.75       power circuit, shower
6.0         40       9.75      shower, cooker
10         53      12.9      cooker

These figures relate to current rating of copper cables in “free air”, that is in installations where the cables are not bunched or confined in an environment where cooling air cannot circulate to dissipate any heat the cables produce internally.  And yes, they do produce heat even during normal use.

Despite many hours of searching, I haven’t been able to locate a table similar to the one above which translates the power ratings of pure silver cables, but the more knowledgeable amongst you could probably work the increased conductivity of silver over copper and formulate a rough guide.

And therein lies the reason why the ubiquitous freebie 5 amp rated mains lead with a 1mm core (I won’t call it a “kettle lead” because that is a total misnomer) simply isn’t up to the job of delivering the high currents and fast transients a large amplifier demands when driven hard.  In Part One I mentioned metallurgy and purity, so the greater the impurities in the cable wire, the less the amount of power can be drawn before the cable heats up and saps energy flowing through it.  How can we tell this is actually happening?  If your bass is slow sounding with a booming overhang, you need a better quality mains cable and fitting an aftermarket mains cable with a high current rating makes this booming sound vanish instantly in my experience and my systems.  So many people over the years have told me they have put up with this booming sound believing it to be “normal”, blaming it on their speakers, their room dimensions, their amplifier, but never once considered a mains cable is responsible – until they try one.  By putting in a better mains cable, you have not ‘improved’ anything at all, you have in fact removed an inadequate performing component and installed another one with less flaws than the one that you have just taken out.  Remember what I wrote in Part One about this?  I thought not, so I will clarify this point before we move on.

If I start with the “freebie” cable which is of generally indeterminate parentage and quality, rated at 5 amps maximum then replace it with a £30 after_market mains lead it tends to sound “better” and so I assume the £30 cable has less flaws than the freebie cable because it sounds better.  If I spend £100 on an after-market upgrade cable and it sounds “better” than the £30 one, which to me says it is less imperfect than the £30 one.  Then if I spend a £1,000 on an after-market cable and it sounds “better” again, it suggests to me it has less imperfections than the £100 one.  Even though you have spend £1,000 on a cable it is still not perfect because there is no such thing as the “perfect cable” to begin with and with each cable purchase in that scenario above you have bought one with presumably fewer imperfections than the previous one, so it sounds ‘better’ at each advance.  Does that make sense to you?  I sincerely hope so, because that is the foundation of all cable related discussions and in my experience applies equally to interconnects, speaker cables and even more surprisingly, digital interconnects too.

To screen, or not to screen, that is the question, whether it is nobler to suffer the slings and arrows of outrageous fortune . . . . . . “  (apologies to the Bard here). Why would you have metal screening on a mains cable you may ask?  Dominic will now give you the answer as I see it.  I believe it to be a complete and utter waste of time. If the makers suggest that screening a mains cable will “reject RFI” (Radio Frequency Interference) then I will eat one whole if they are correct.  In a small signal, high sensitivity conductor like a phono cartridge interconnect I can see the virtues of keeping out airborne interference, although it has been many a long year since a local taxi firm has intruded into my listening pleasures with a call for driver Bert to go to 34 Acacia Avenue to pick up Betty to take her shopping.  For a radio signal to imprint itself onto a cable carrying mains voltages it would have to be so powerful the fillings in your teeth would be glowing red hot long before any actually entered a mains cable carrying 13 amps or more.  Ooer, that’s going to ruffle a few feathers I bet, but show me otherwise if I am mistaken. I recall an amateur “hifi reviewer” wheeling his motorcycle indoors and running the engine in close proximity to his hifi system to test for “RFI rejection” to mains cables under test.  His needlepoint work was outstanding and he loved his pet slugs with a passion too, so I believe.

What about RFI leaking OUT from a mains cable?  RFI certainly not unless someone deliberately creates the equipment to make it happen and even then, not much if any chance unless you enjoy a mouth full of red hot fillings if you are stood nearby.  A mains cable does however emit EMF forces, screened or unscreened.  Beg, borrow or steal an EMF meter and wave it around near a mains cable and the meter needle will give full deflection even a few inches away from it.  This is because “electricity” is electromagnetic force generated at 50 cycles per second, so every 35 centimetres  or so (I cannot recall the exact distance) along the length of the cable the meter needle will swing to full peak.  If the cable is wrapped in copper close-weave screening  (no matter how dense) it will offer no resistance at all, nor will steel screening, nor will silver screening either.  What did shock me was when I waved the EMF meter over an amplifier which had no less than three layers of solid steel screening over the mains transformer and still had a full scale deflection on the meter.  To the best of my knowledge, the only metal impervious to EMF energy penetration is Mu-metal  and I don’t know of any cable manufacturer that uses that unique and not inexpensive metal in this particular application.

“Night and day differences, with blacker blacks!”.  You been on the old home brew again Dominic?  Many people have reported a much quieter background noise level from an aftermarket mains cable upgrade, so what’s all that about?  It is generally attributed to grain boundaries in the crystalline composition of the metal itself, but rather than bore you to death typing page after page of science, I will use analogy to explain what’s going on.  Imagine if you will that your mains cable is like a stream or small river and the electricity is represented by water flowing along it.  If the bed of the stream is littered with rocks and boulders, the water will have a tortuous route along it, with the rocks creating lots of noise as the water flows over them.  Take all the rocks out of that stream and what happens to the water?  It flows smoothly, without ripples and completely silently doesn’t it?   The “experts” said for years that is complete rubbish, more a case of wishful thinking than having any basis in science.  I had a furious row with a leading light in the hifi press years ago about a pure silver mains cable having significantly less hiss heard through a sensitive horn speaker  than a copper mains cable did.  He went off on an aggressive and indignant diatribe about the hiss originating from “semiconductor transistor junction conductance breakdown” or some such and  I was deluded if I thought a mains cable could be responsible for any hiss reduction heard through the speakers.  He was so busy being indignant and outraged; it had slipped his mind that a VALVE AMPLIFIER was being used in the trial.   I didn’t argue the point, but glad to say I have since been vindicated by a very nice man from Japan called Professor Atsumi Ohno.

Professor Ohno took a very long hard look at the crystalline structure of metals and deduced that electricity flowing through a metal is very much like a river flowing along with too many rocks littering the river bed and impeding the water flow, creating noise.  Where have I heard that before?  His answer was to rethink the way the metal wire is drawn through the die during the manufacturing process and rather than do it in an uncontrolled manner, he devised a strict regime of metal temperature, draw speed and cooling routine which resulted in a wire than had far fewer grain boundaries at the crystalline level of the metal.  In other words, he removed the rocks from the river bed and made the water flow smoothly and silently, the process commonly known today as Ohno Continuous Casting, or OCC for short.  Anyone who uses and has compared an OCC manufactured cable will attest that it does have a lower noise floor than a standard copper or silver wire using conventional drawing and production methods.  More about this process by clicking on this link:   Ohno Continuous Casting Patent
or look up the filed Patent:  US5074353 A

Well there you are then, that concludes Part Two of this tome and in the next issue I shall be talking about power supplies and what happens when you create alloys or hybridise with various metals to manufacture mains cables.

Hifi Pig does not advocate anyone making unauthorized or unsafe changes to their mains supply, cables or plugs in ANY way. Did we make that clear? Always consult a professional and qualified electrician. 

Dominic Marsh

 

 

 

 

 

 

 

 

 

 

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