Use of CY cable for radial dedicated mains wiring

A (Linn) dealer once suggested to me that fire alarm cable was good for dedicated HiFi use, because, like CY cable, I believe, it is shielded. Weather or not this is good advice, I don't know, and in any case, you would need to ascertain that the installation conformed to the UK or other relevant regulations.  

The resistance for 6mm2 conductors is 3.3 Ohms/km which is extremely low. The cable was recommended by an audiophile who does commercial electrical installations. My electrician was happy to use it. It is used where control signals need to be free of interference, hence the screening. The earth is same size as the L&N conductors, which must be an advantage. 

Each wire in a bundle is 0.31mm diameter. I calculated the a 6mm2 cable would have about 20 strands.

Good old 10mm2 armoured cable running through the flowerbeds works for me. If these CY cables were particularly good, I'm sure many more people would be using them, but they don't appear to be. That probably says something. 

Low resistance is a must but i do wonder about the value of screening the dedicated mains supply feed in a domestic environment (unless you are running a whole bundle of cables together etc)

If your electrician is happy to fit and certify it and it's not some daft price over normal T&E then i can't see a reason not to use it. 

I'm inclined to agree James,  & thats coming from a person who's a bit OCD about screening and/or separating.  If a dedicated cable is running around/through a normal domestic house,  it probably runs alongside other power cables on the same supply & voltage for some of that route,  then there is nothing that requires a screen.  Whatever,  it will do no harm.

CY cable is simply a category of multi-core flex with a wire braid screen intended to work in areas of EMI & tough conditions.  They are intended for use as a flexible cable, not fixed installations,  but again will do no harm.

Another upgrade would be to put a wattgate evo iec plug straight on the equipment end, rather than using a plug and socket. You'll be surprised at the difference it makes. 

According to my electrician "the price for 6mm 3 core SWA cable is £2.11 and the CY was not a lot more (Feb 2016)". I needed 12m. The use of armour clad was not an option because it could not be buried in the flower border or under my concrete path. CY is also flexible and was installed in external conduit with a total of three bends.

Having studied a reasonable number of threads on the subject, the objective of a dedicated radial is to provide the power supplies with as near to a sinusoidal supply as possible.

Cheap SMPS (chargers, fluorescent bulbs and possibly even the rectifiers of LED bulbs) introduce significant spikes which propagate through the mains and the air both in ones own property and to neighbouring properties. The incoming mains is frequently bad. For some a noisey mains coming in will make the difference between exceptional replay and the rest. We buy Naim for the exceptional replay it can achieve in ideal circumstances. Listening in the early hours is an alternative if the mains is bad.

The voltage spikes have frequency components across the audible spectrum. Assuming the cases of our expensive Hifi electronics are housed in do a good job of screening electromagnetic fields, then the weak point will be the cables and the non metal parts of the case.

It really makes sense to the screen a radial supply to ensure that in places like the location of the consumer unit(s) the close proximity of cables some carrying the noise is not transferred to the radial we want to be free of noise generated within the property transferred through electromagnetic induction (think of a sort of inverse square effect and the cumulative effect when wires run parallel, which is why the advice for interconnects etc to cross at right angles is given). 

We all know that the Naim PowerLines make an immense improvement. I'm not aware of it being a magic effect (perhaps connected to spending lots of money), so one assumes that they do what they do by

1. the tight fit at each end which reduces contact impedance and arcing

2. any screening they provide

3. cable quality 

4. have I missed anything?

The separate consumer unit advice is based on making it more difficult to transfer noise from one circuit to another within the CU by keeping the dirty stuff further away.

My intuition makes me think the reasons racking has an effect on SQ is because vibrations applied to things carrying electric currents create induced currents (in much the same way generators work) with some slight delay. Another use is to reduce mechanical shock on the circuits.

I've only just discovered how good even one Powerline is on the SuperCap DR powering my 282 so my radial must be ok.

I'm sure Naim know lots about all this which they keep as trade secrets.

Surely the whole point of SWA is that it can be buried in the flowerbed? That's where mine is. It's 10mm2 and about as thick as your thumb. 

Hungryhalibut posted:

Surely the whole point of SWA is that it can be buried in the flowerbed? That's where mine is. It's 10mm2 and about as thick as your thumb. 

It would not work for me though as there are no borders and only concrete path on the route. 

Ah, I see. 'Could not' rather than 'cannot'. My mistake. 

I used 10mm SWA from a spare terminal in my consumer unit round the outside of the house and back into my lounge. Sounded bloody awful, much worse than plugging it into a standard socket on the downstairs ring main.

Ray

thebigfredc posted:

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I used 10mm SWA from a spare terminal in my consumer unit round the outside of the house and back into my lounge. Sounded bloody awful, much worse than plugging it into a standard socket on the downstairs ring main.

Ray

Ray

As a research physicist once upon a time, I strove to get answers. In my last forum post to this thread I tried to put out some possible answers that make some sense to me although I have not got the stuff Naim have to do the testing. I striped out all my ethernet over mains stuff, paid attention to the cabling rules, experimented with box positions and plug in order in the 5 double sockets and more recently a PL on the SuperCap DR. Cumulatively each made a difference but the iceing was the PL. 

Its hard to experiment with radial spurs. So ones tries to get info from others.

Phil

@Ray, fat & long globs of copper take ages to break in before they start to sound good.

thebigfredc posted:

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I used 10mm SWA from a spare terminal in my consumer unit round the outside of the house and back into my lounge. Sounded bloody awful, much worse than plugging it into a standard socket on the downstairs ring main.

Ray

If you read this Wikipedia article https://en.m.wikipedia.org/wiki/Inductor you will find out more about AC current flow. A large monofilament cable will not achieve a uniform current flow through its cross section because of the laws of electromagnetism. 'Skin Effect' means that the electrons are forced towards the surface and away from the centre. Other problems are the Oxygen content and the crystalline structure of the copper creating unequal paths for the electrons.

In a Hifi system the time dependent energy output to the speakers must reflect the music being played. This energy comes from the mains and despite the power supply designers doing all they can to smooth out the demands there will always be a small time lag so the energy transfer through the mains cable will always be a smoothed out version of the music.  When the Hifi cannot get all the electrons it needs from the PS the music will not be faithfully reproduced. Voltage regulation helps but in the end it's a demand and supply issue. 

The Ohno Continuous Cast (OCC) process claims to reduce the number of crystal boundaries in the copper. So the electrons flow in a much more coherent manner through the conductors. Another approach is use multifilament conductors each insulated from the other. Proper screening of the conductors also has a role to play. 

I only base these observations on what I hear. My Rega Aria phonostage sounds amazing with OCC conductors. The nDAC is vastly better with more than one FEP insulated conductor carrying live, neutral and earth. It's not even that it's better than a box upgrade - a good power cord frees up the box to perform at its best even if the box is only a Power Supply. So I now get the musicality that seemed restricted to late night listening on demand. I will order my own cords soon.

I don't know the spec of PLs. They are a great improvement, but maybe not the ultimate or even best VFM.

If you read this Wikipedia article https://en.m.wikipedia.org/wiki/Inductor you will find out more about AC current flow. A large monofilament cable will not achieve a uniform current flow through its cross section because of the laws of electromagnetism. 'Skin Effect' means that the electrons are forced towards the surface and away from the centre. Other problems are the Oxygen content and the crystalline structure of the copper creating unequal paths for the electrons.

In a Hifi system the time dependent energy output to the speakers must reflect the music being played. This energy comes from the mains and despite the power supply designers doing all they can to smooth out the demands there will always be a small time lag so the energy transfer through the mains cable will always be a smoothed out version of the music. When the Hifi cannot get all the electrons it needs from the PS the music will not be faithfully reproduced. Voltage regulation helps but in the end it's a demand and supply issue.

The Ohno Continuous Cast (OCC) process claims to reduce the number of crystal boundaries in the copper. So the electrons flow in a much more coherent manner through the conductors. Another approach is use multifilament conductors each insulated from the other. Proper screening of the conductors also has a role to play.

I only base these observations on what I hear. My Rega Aria phonostage sounds amazing with OCC conductors. The nDAC is vastly better with more than one FEP insulated conductor carrying live, neutral and earth. It's not even that it's better than a box upgrade - a good power cord frees up the box to perform at its best even if the box is only a Power Supply. So I now get the musicality that seemed restricted to late night listening on demand. I will order my own cords soon.

I don't know the spec of PLs. They are a great improvement, but maybe not the ultimate or even best VFM.

Fascinating subject, mains. My favorite area of fiddling and tweaking.

You do need to know what you're doing but what makes itso much fun is that trying & testing things usually doesn't cost an arm and a leg. But the possible gains (and losses) are huge and very fundamental.

As I've recently moved to a new house I'm currently in the lenghty process of testing/auditioning various 10M / 30ft runs of cable to go between the consumer unit and the mains block for my system do decide which cable I will use for a dedicated spur. The cable of choice will go into the in-wall tubing I had installed during the rebuilding of the house.

Solid core, stranded, shielded, non schielded, different diameters & manufacturers. I've narrowed it down to 6 cables. Each cable takes at least a week of playing time to break in and  show it's sonic signature. So it does take some time. 

Over the years it's the 3rd time I'm doing this (after moving house) and every time it's jawdropping how big the impact of the mains cable(s) is on the overall SQ and performance of a system. Much, much bigger and more fundamental than the average component upgrade.

There is no one-size-fits-all best cable. As with components and all other cables it's a matter of personal preference, system, acoustics of the room etc. It's certainly not a matter of resistance alone and bigger/fatter conductors are not always better. If it was only that simple!

It's fascinating to swap cables, press play with the same piece of music on the same volume and hear what happens. I've had non audiophile friends getting almost irritated with me as they thought I was fooling them and did some other 'trick' because swapping a mains cable can't make that much of a difference.

Fascinating stuff!!

Richard

Add to the above; wall outlets, mains block sockets & wiring, power connectors, receptacles, plating of the connectors (nickel, gold, rhodium etc.) all play their own song in the chain.

Richard

If you google "ohno continuous cast copper wire crystalline boundaries" you will find interesting articles. Whilst a new spur might prove very expensive in OCC, it does seem from observation that a power cords can have the effect of organising the electron flow into a power supply. Copper crystal structure did seem to explain why cheap heavy cable was not such a good idea.

In my younger days I was an experimental physicist. Hence I have always want to understand what is going on. My last post was an attempt to demystify mains and power cords in layman's language. Wikipedia is full of so much useful knowledge.

In another post I tried to demystify racks (reduction of vibration) as reducing movement of current carrying wires and hence induced currents. The Wiki article covered Maxwell's laws.

Thanks for your interesting feedback. Incidentally, the recommendation to use CY cable came from an audiophile electrical contractor. 

Phil

I looked into the subject a few years ago when I was fiddling with my mains. First I used 6mm2 cy cable as advised, but later changed it to 10mm2 and the difference was huge. I thoroughly cleaned/changed the whole chain from the incoming outside supply piece by piece to my powerlines. This involved an uncut cable from the meter to the consumer box. Tricky to do, but possible. The Prysmian 10mm2 cable I use is 7 strands per core. I researched the net to find less strands using ofc, but couldn't find anything. I only have a 5m run from my cu to my sockets and it's easily accessible, so I can/could try anything anytime. I always thought a more multi-stranded cable was not the way to go, so ultimately wanted 10mm2 single strand ofc (or at least less than 7). Unfortunately I don't think this exists, probably because it would become too stiff and ultimately fail due to stress fracture.

P.S. Electrical cable doesn't cause a room dependant preference, it produces a cleaner, less polluted signal, which is in turn processed easier by your brain.    

Thank you Count.d.

It seems this whole area has no simple answers. The Prysmian 10mm2 is £75 approx for 10m. I guess it is a good quality. Your run is short and you have improved the whole chain from the meter. 

For me power cords are making a big difference, the Isotek Optimum on the Rega Aria Phono stage in particular. The Rega interconnects at £100 are a massive saving when the power cord does so much to improve SQ. Rega use the same cable on their arms so one can't avoid it, and there seems no reason to with a good power cord etc.

Filipe posted:

It seems this whole area has no simple answers. The Prysmian 10mm2 is £75 approx for 10m.

Shop around, I've just bought 10m from Screwfix for £36.69

which would be a better cable: Prysmian 6242YH Twin & Earth Cable 10mm2 or PRYSMIAN LV ARMOURED 6943X 3-CORE CABLE 10MM²  ???

CY cable is know here in the Netherlands as Lapp cable. Prysmian is sold here as Draka cable. Same cables, different commercial labels. 

Funny... a few years ago the most mentioned cables on this forum were 10mm2 and they still are it seems. I tried both the Lapp (aka CY) and Draka (aka Prysmian) extensively in my previous house with disappointing results. 

Durng all the testing/auditioning I've done throughout the years - including right now - I've never been able to get satisfying results with any mains cable with a cross section above 4 mm2. Regardless the make or type (solid, stranded etc.). To my ears 'fat' mains cables kill speed and PRAT, shielded an unshielded alike although I clearly prefer shielded. 

During my current auditioning I listen blind as my wife switches cables (simply pull one plug out in insert another at both ends) . The remaining 3 'contenders' are living behind the curtains so I can't see what I'm listening to. Very interesting. My preference so far is consistant every time. The thinnest of the lot, a modest 14 AWG / 2.1mm2 shielded cable beats the others easily in musicality, speed, energy, harmonic richness and imaging. 

I love this weird science! 

[@mention:1566878603896049]   Yes they do have a room dependant preference as they all sound different. Just like all other cables in a system do. Some cables give more bass than others and in a room with a darker bass prone sound such a cable is probably not the best option. 

BTW, in the Netherlands we have Shuko plugs without any nasty fuses in them. 

KTMax posted:

Durng all the testing/auditioning I've done throughout the years - including right now - I've never been able to get satisfying results with any mains cable with a cross section above 4 mm2. Regardless the make or type (solid, stranded etc.). To my ears 'fat' mains cables kill speed and PRAT, shielded an unshielded alike although I clearly prefer shielded. 

During my current auditioning I listen blind as my wife switches cables (simply pull one plug out in insert another at both ends) . The remaining 3 'contenders' are living behind the curtains so I can't see what I'm listening to. Very interesting. My preference so far is consistant every time. The thinnest of the lot, a modest 14 AWG / 2.1mm2 shielded cable beats the others easily in musicality, speed, energy, harmonic richness and imaging. 

I love this weird science! 

KTMax

Interesting! My main system uses 4mm shielded CY. Maybe I should ask the electrician to use the same again rather than 6mm on Thursday when he does the upstairs radial?

I will post more later, but I found some US university lectures notes calculating the electron speed in a 50-60 Hz mains conductor. Surprisingly it is only 1/30 cm per second in 3mm cable running at 20 amps Why it it so slow? Because the 'free' electron density is so high.

On skin depth, where current density decreases exponentially, one has to realise that at 60 Hz the delta (scale) factor is 8.5 mm but at 10kHz it is .66mm. Bear in mind that the current represents the energy flow and it has components representing the frequency of the sound even if the power supply is doing some smoothing. A better power supply will to some extent compensate.

So the electrons should not be thought of as all travelling at the same speed and with uniform current density through the conductor.

Designing good interconnects and speaker cable is more complex than just skin effect though. Shielding for instance creates capacitative effects, but by having enough separation between the conductors and the shield it can be significantly reduced. If cable dressing can't keep the power cords away from the ICs then shielding is a benefit. I use water pipe insulation to keep things separated as it is mostly air.

Filipe,

Maybe you should focus less on the numbers & theory and just listen to various options. Your ears are able to detect a lot more than current knowledge and formulas can proof and explain. As is the case with many aspects regarding (high end) audio.

Blind auditioning is a real eye opener (ha ha) 'cos it doesn't allow prejudice and your eyes to listen for you. Based on the sound quality, drive, weight, energy and refinement I was 100 % sure I picked the fattest, butchiest and most expensive cable among the ones I was comparing (a Furutech). Completely the opposite turned out to be the case. 

If you're using shielded cables a very interesting experiment that always works amazingly good for me is to connect the shielding the other way around. Common practice is to connect the shielding to earth at the originating side (ie the power outlet/socket). Connecting the shielding to earth at the receiving end (ie mains block or component side) sounds crearly better. No idea why, no formula or theory to 'prove' it that I know of but it does...