EWA: Alan Elsdon / Colin Wonfor discuss their MC-V power cord

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Colin Wonfor

Editorial note: Written by Alan Elsdon and Re-engineered by Colin Wonfor (above)

Q: Looking at the EWA power cord – your MC-V - it doesn’t look anything special. But knowing you, there’s clever engineering that’s gone into it and so a few questions if I may.

Let’s start by looking at the topic through the eyes of a novice, or perhaps a skeptic or even yes ….. a cynic. I’m none of these but some of our readers are. So your answer should please be constructed with them in mind. Here’s a typical observation …. “Power cords surely can’t make a difference. It’s daft.. n kilometers from a power station and you’re telling me that a glorified kettle lead of a 1.5m and an idiotic price and a bling IEC plug can make the sound better. Pull the other one, son”.

A: The problem with mains power delivery is the same as signal transfer from point A to B. The better you can transfer power / signal then the better the sound should be coming out of the speakers. At the same time you have to stop this transfer being affected by external events AND stop the transfer itself from affecting other equipment.

Basically the ring-main in your house is relatively low impedance (mostly capacitance), this is feeding into a higher-impedance load via the mains cable which can act as an aerial receiving and transmitting noise.

 

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Q: Hmm, okay and thanks. So now, back to our reality. So for the rest of us, power cords do make a difference. That said, does the audiophile world really need yet another power cord and if so, why?

A: Not really - all we need is the perfect means to transfer power from the mains to all devices without any waste of power any interference - simple. Since this does not yet exist then we will keep seeing people trying to resolve all the issues surrounding power delivery.

Q: In a nutshell, what’s your take on an age-old design; what makes the EWA one so special?

A: In a nutshell - we are not saying! We will publish all the measurements showing why the cable sounds the way it does - but as to how this is done will not be published as we want to stay in business having spent time and money researching the various functional areas of power-cables!

Q: Let’s start at the wall end. You’re using a standard MK 13 amp mains plug. I guess there’s not much in the way of alternatives available to designers ….. unless of course they decide to have a molded plug. What are the sonic advantages – if any - to having molded plug?

A: I cannot think of any SONIC advantages of a moulded plug - there are some safety advantages - it stops users fiddling with the plugs and possibly killing themselves. It’s a legal requirement that the manufacturers / distributors fit the correct plug to any domestic device; using a moulded plug satisfies this requirement. It should be noted that a mains cord by itself does not constitute a domestic device hence you can get all the parts and make your own cords.

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Q: The pins are silver-plated and presumably you’ve done this give a better quality or consistency of contact, or perhaps both. However, way back you pioneered the use of gold-plating on plug pins and so – inevitably – what made you switch to silver?

A: It’s all to do with the migration of dissimilar metals; for instance there is a chemical reaction when you put a brass pin into a copper socket, the resulting corrosion is not as conductive as the original metals, hence power losses. If it’s Gold to Gold then there is no corrosion; with Gold to Copper there is a reaction and over time the gold migrates into the copper revealing the pins base metal (brass or nickel).

Silver would have this problem but it oxidises at a quicker rate than the silver to copper migration and since Silver Oxide cannot migrate but does conducts as well as silver the problem does not arise. For the best results, both plugs and sockets should be of the same material.

Q: Fuses, Colin – fuses! Are you using anything special inside your mains plug and if so, why?

A: Silver plated caps on the fuses - see previous answer.

Q: Thanks. Now then, most if not all equipment has internal fuses. Why does the cord need a fuse; is it to protect the cord from overload?

A: It’s a legal requirement! We also fit internal fuses on all our electronic products as a fail-safe.

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Q: Do fuses really influence the sound? And if so is it only designers that can hear this and even then are they sometimes self-deluded – or always self-deluded – or what?

A: Yes. With a steady-state current demand the fuses impedance will not alter, however with a dynamic demand the fuses’ impedance changes causing a reduction in the power availability.

Q: Okay …. so might a system sound better – even assuming one could do this these days, using the old 15amp wall socket with a fuseless old 15amp round-pin plug on your power cord. Theoretical of course but I’m inquisitive.

A: BS 546 plugs and sockets are still available and allowed, most especially the 2 amp plugs and sockets used in lighting circuits. However the 5 and 15 amp un-fused plugs can only be used on Radial circuits fitted with a circuit breaker 16 amps or less.

Q: Is the audiophile fuse market a bit of a con?

A: We can hardly say 'Yes' since we are using silver plated fuses in our current mains cable and intend to use gold plated in some of our future products. I would refer the gentleman to our previous answers.

Q: Are you in a position to produce specialist fuses or it one hassle too far?

A: Not really - and anyway, they are already fitted in the plugs we currently source.

Q: If microphony is such a big issue then why is it that fuses aren’t packed with something like sand or perhaps powdered glass because presumably this would reduce microphony? Before answering this though I have to tell you that personally speaking I’m sceptical about microphony in fuses because apart from anything else mains plugs are usually solidly connected to the high mass of a brick wall. That said, I’m open to demonstrations proving the differences.

A: Microphony - in general - is not a problem in the plugs.

Q: Before leaving this contentious issue, is there any audible merit in applying contact cleaner between fuse and the fuse holder terminals?

A: In the same way that gold / silver are used to create a better transfer from socket to plug (and vice versa) then we need to ensure that this is not affected by age. Leaving aside any environmental issues (smokers, pets etc.) then Gold (provided it’s plated correctly) should not present any problems,

Silver will oxidise but the oxide is just as good a conductor as Silver, it just looks awful.

This is not an area we have investigated so we cannot comment on the chemical makeup of the various products available to remove unwanted deposits on metal surfaces nor those that claim to keep surfaces free from harmful residues. However anything that contains flammable material could be dangerous.

Q: Ah yes one more question on the topic ….. do you think fuses age and if so does it make sense to change them a regular intervals?

A: Of course fuses age - at switch on they have large currents flowing through them and like all other electronic devices over time they will be affected. As the fuses heat up, expand and cool oxides form on the internal fuse wire eventually causing fatigue. How often they should be replaced is moot, it depends on load, on average it’s about 3000 - 5000 hours.

Q: Turning to the IEC plug, it seems very fashionable to have gigantic plugs that certainly look ‘the business’ but don’t necessarily add anything to the sound. Or do they? Anyway …. it may well add to the sense of confidence in the user. In contrast you using something which – frankly - looks pretty average. But it isn’t, is it?

A: The size of IEC plugs is, for the most part, irrelevant, I say for the most part. However there are a few factors to take into account, firstly the size of the mains cable itself and the method of ensuring a good contact between the cable and the pins.

Some of the large cables (e.g. Belden 19364 which I have used extensively over the years) is not easy to fit in most UK and IEC plugs. Once you have stripped your cable there is the problem of attaching the cable to each pin in a secure manner, and some plugs make this easier than others. The easier it is to fit the cable then the better the installation should be and, therefore, the safer it should be.

Q: You had pretty good reasons are picking this particular brand. I've seen it used elsewhere on fine sounding power cords and so you’re not alone. Is it something to do with the quality of the contacts between the wire and the IEC terminals?

A: The brands of UK mains plug and IEC socket that are used for the first mains cable obviously are not only chosen for performance but also for cost. The MK ToughPlug is extensively used in Hifi and could be thought of as a standard - and of course a lot of people will be familiar it. In looking at IEC plugs there were quite a few available, the one we chose can take large cables and has very solid pins which form a very good contact with IEC inlet sockets.

Q: Thanks Colin. Now of course all this may for the casual reader seem tedious but I assure you that there is a section of the market who are insatiably curious about the design motivations that drive designers to produce ever better products. Are you still okay with this?

A: I am a typical Engineer, I like to know how things work and how they can be improved including all the things I design. There are always new things to learn and keep the mind working.

Q: Great. So now we turn to the overall look and feel of the cable. It doesn’t seem particularly substantial but is clearly well built. Given the fashion for power cords thicker that the thumb of an adult gorilla, yours looks thin. Highly flexible though. There are, I guess, from your perspective sensible design reasons for this. If so then please explain to our readers, or at least give them an insight into the special qualities of the internal construction and sheathing.

A: This is not easy to answer (almost impossible) without giving away trade secrets. The whole range of our cable products is designed to fulfil the following criteria:-

a). Signal / Power transmission must be as efficient as possible, i.e. losses to be as low as we can make it for the price.

b). External influences affecting the cables are to be minimised.

c). The cables are to have little impact on external devices.

From an initial concept of what I want the cables to do (and the requirements differ from mains to interconnects to speaker) I look at how best to achieve this in a way that has, for the most part, not been done before.

In order to do this I look at the wires that can be used, the construction of the wire, the dielectric around the wires and the sheathing. When making prototype / proof of concept cables I then measure the various parameters and adjust the materials/construction to better approach the specific requirements.

The measurements obtained from our testing will be released to show how the cable performs and thus allow the potential customer to determine whether it is suitable for their installation.

Q: Are you a believer in microphony influences on power cords and if so, what have you done in your design to address this?

A: Yes, microphony occurs in all cables; in a mains cable when there is an external force (sound waves) acting on the magnetic field produced by current flowing in the conductors then modulation of the current occurs producing unwanted signal. Under power the magnetic fields are always produced, therefore mechanical damping (of one form or another) is needed within the cable to reduce this effect.

Q: Okay. Err …. we’ve pretty much covered all that can reasonably be said – for now - about power cords without getting into commercially sensitive areas. So the next questions really apply to power cords in different applications. To start with - and I do realise that you’re not a valve amp designer - do the beneficial effects of your power cord design change depending on whether you’re using a tube design or solid state and – if so - why?

A: Different electronic components have different load requirements and current demands - it is not necessarily a function of Solid State or Valve  ..... it's purely how the electronic component demands power.

Q: Do the different voltage and/or current demand characteristics between a pre-amplifier and a power amplifier influence how the power cord ‘behaves’?

A: I refer the honourable gentleman to the previous answer.

Q: Price and availability?

A: 230v versions available now at £265 including vat.

We do not sell direct to the public

Well Colin; that’s it. All done and thank you.

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