Anybody up for a *friendly* discussion on Power Cords?

[Talos2000]

I am always interested in rational discussion on why Power Cords might affect the sound quality, and I have from time to time engaged in various such discussions on internet forums. Much to my frustration I find that Power Cords do make an audible contribution to the sound of my system. (And even though I'm into my 5th decade as an audiophile, why is it that I am still astounded by the prices charged for Power Cords?)

 

I hear a lot of arm-waving arguments for the contribution of Power Cords that are based on "it stands to reason that ...", but what I never hear is a rational discussion that says "I think Power Cords have an audible effect for reason X, and so if I design a Power Cord according to Design Rule Y, then it should sound better". I would like to follow such a discussion.

 

Unfortunately, these topics always attract the type of Internet Bully whose only contributions are effectively to say "Power Cords cannot possibly have an audible effect, so you if you claim to hear something then you are obviously an idiot". Which only serves to derail the discussion.

 

So please, don't post unless you have a constructive comment to make.

 

I will kick off the discussion with a couple of posts that raise a few questions on the subject that circulate in my mind.

 

[Talos2000]

I have heard this theory proposed on more than one occasion, but have actually seen arguments in both directions. There are those who say the job of an AC Power Cord is to filter all of the rubbish (HF to RF) out before it gets to the amplifier. Because "it stands to reason that" HF/RF noise can only degrade the performance of an audio component. There are expensive products on the market that are constructed this way. Then there is the argument that the job of the AC Power Cord is to allow the AC Power signal to pass as unhindered as possible en route to the audio component. Because "it stands to reason that" degrading the performance of the AC signal will degrade the performance of an audio component. Interestingly, I have built an experimental Power Cord using RF Power Transmission cable to test this theory, and it actually sounded pretty good!...

 

 

 

[Talos2000]

This is one of the most commonly propounded arguments. The AC signal goes all the way from a power generation plant someplace and ends up flowing into your audio component. Along the way it encounters transformers, meters, fuses, who knows what else ... and miles and miles of cable. So why should the last six feet of cable matter? No, the argument goes, this is the wrong way to look at it. It is not the last 6 feet, it is actually the first six feet of the link between your component and the power grid. "It stands to reason that is the most important 6 feet in the entire chain.

 

Why so? And if you hold to that view, how does it inform the design of a Power Cord?. Should we re-wire the mains in our houses, and if so, with what design of cabling?

 

[Talos2000]

Don't worry about the cable ... just attach a FuruTech plug. Its made with Carbon Fiber so it must be good. I can also have plugs with gold plated pins. Rhodium plated pins. Nickel plated pins. Cryo-treated pins that have been immersed in liquid Nitrogen for 24 hours.

 

Darned if they don't sound good too! But why? I can rationalize why the actual connectors can impact the sound quality in an interconnect, for example, where the actual signal is being transmitted through it. But on what basis should I expect the Mains Plug to affect the sound quality? And how does this inform the rest of the Power Cord design?...

 

[esldude]

Well it seems some power cords do matter. Never been comfortable with why. Some ideas for experiments. You think it is filtering? Well why not rig up one that sounds good (presumably good filtering) and parallel it with one that sounds bad (presumably poor filtering). Then see if the two combined sound like a good one, a bad one or in between. Of course filtering isn't a terribly complicated thing. Groups of boxes with the appropriate caps/coils etc should be able to do what you want. Connect generic power cord feeding a box with filtering components. Good sound for cheap, and tunable too. Yet some don't think this is the same.

 

Another idea is series connection. Make a box so you can have bad cord feeding good cord. Good cord should filter bad cord. Reverse, then it should sound different should it not? Are we filtering junk on the power line, then maybe a filter anywhere near the end works. In which case reversing series cords might sound the same either way.

 

Even then, seems hard to wrap my head around what is being done for some of the cords to cost more than a thousand dollars. I would like some explanation even if it is "we don't know, we tried a bunch of stuff and this works". Of course I then would like to know what they do that requires a cost at that high amount. It isn't materials and construction costs.

 

Just as an odd accident of what can go on. I had a Conrad Johnson Sonographe CD player way back when. I had a high pressure sodium outdoor light on the back of my house. A neighbor's kid shot it with a BB gun. Broke the outer cover, but left the core of it intact. No light output, but caused some odd noise on the line apparently. The CD player would play about 3 seconds, skip backward 2 seconds, then play 3 seconds and skip back. I had lost that light and turned my music rig on to find this. Thought it must be a power surge or something. Next day I saw what had happened to the light. Unplugged it and CD player is fine. Got to wondering, plugged it back in and it skipped backwards just like before. Tried it a few times and it definitely was that goofy light throwing some garbage on the line. I still have no idea how that could happen exactly that way whatsoever. But it did. Wish I had kept the light to plug in and show the effect to others as I have been called a liar about it by some well regarded audio people.

 

Also, might be a good test to see if power cords could filter this out. Alas I have no idea how that could be recreated.

 

[goldsdad]

"I had a high pressure sodium outdoor light on the back of my house."

 

Has anybody investigated the electrical disturbance to hi-fi when their basement ...errrr I mean their neighbour's basement... is rigged up as a grass plantation?

 

 

[cjf]

LOL

 

[AudioDoctor]

are that when you, I mean your neighbor, uses some of the plant growth for its intended purpose the music gets really groovy and like, deep man...

 

[wgscott]

I have the functional equivalent, or worse: a 100 gallon reef tank on the same circuit as my system at work. This has two 95 W [sic] compact fluorescents and two 150W 20,000K double-ended metal halides with ballast, and a whole bunch of pumps, including one huge one.

 

Turning the lights and/or pumps off makes absolutely no difference at all.

 

[cjf]

Hello,

 

I believe that a properly implemented power cord can bring excellent results in the way your system sounds. Just like others, I have a few theories of my own that have crossed my mind while in a drunken/hazy stupor as I sit and listen to my music library.

 

One theory of mine is that some of these higher end power cords help to act as a capacitor which keeps the cable saturated with electricity to always meet the demands. The larger (ie..heavier gauge) wire can store additional sums of energy that the smaller gauge wires can't. I imagine that the type of metal and insulation used also play a roll in how much energy is stored.

 

Part two of my theory also includes the idea that when a component like a Preamp or DAC is in use there are times when it will PULL or want more JUICE for a given operation. I think that by having more energy available thru the use of capacitance, which also helps to place this stored energy in closer proximity to the component it will shorten the amount of wait time required to re-energize the cable so it can instantly meet the demand. The end result is a more enjoyable listening session.

 

[wwh]

It seems reasonable that good quality plugs and receptacles are beneficial, along with heavy-gauge cable, by reducing points of resistance in the electrical supply (especially for power amps).

 

One thing I've wondered, though -- especially in light of the high prices some of these cables command -- is why not hard-wire the components using standard residential or commercial electrical cabling (solid 12 gauge THHN in flexible conduit, for example)?

 

I suppose an obvious problem is that audio components can't accept such a connection. And maybe you wouldn't want your components to be non-unpluggable. But perhaps not outside the realm of possibility if you're willing to void the warranty and maybe do a little drilling and soldering...

 

- Bill

 

 

[esldude]

Well, not to rain on your idea, but well okay I guess I must. Capacitance isn't too much of a mystery. You can measure how much a cable has, and it isn't that much. If that were the answer, well, just add a capacitor to your cable no big deal. So whatever might effect sonics is more than just capacitance supplying more power.

 

 

 

[barito7]

Good post, I was just wondering whether your equipment is more a factor here. My question is:

 

If you have mid-fi gear do you really think that investing in power chord will make a discernible difference?

 

Cheers

 

[cjf]

Well then I guess the next question is what the capacitance difference is between high end cable A and budget cable B. I don't know that there necessarily needs to be a Big difference, but a difference in favor of the larger cable storing more energy.

 

Were not talking joules of additional energy storage here obviously. If it's widely accepted that folks can here the difference in jitter measurements over an SPDIF interface which is on an even smaller scale then why would this theory sound so far out in left field?

 

[Talos2000]

I think your suggestion is that more cable capacitance = better sound, whereas for jitter the theory is that less jitter sounds better. So while it becomes a technical challenge to reduce jitter, it is a relatively trivial practical exercise to increase the capacitance of a cable.

 

You are suggesting that energy stored in the cable itself has an audible effect on the sound quality. As others have pointed out the actual energy stored in the cable is practically negligible. However, if you are talking about the Power Cord as a total entity, you can quite easily add energy storage in the form of additional capacitance as discrete components at either or both ends of the cable, or even at various points along the cable. In engineering-speak this approach can modify the effective source impedance of the power source, but is likely to do so to different degrees at different frequencies.

 

So, if you propose that a valid design approach is to modify the compliance of the mains power source, the question becomes, by how much and over what range of frequencies? Does this inform the practical design of a better Power Cord? Me, I'm not convinced - yet.

 

[Talos2000]

I did that back in the eighties. It was my first OMG experience in the field of power cords. I used the same cabling as was used in the house's wiring, soldered directly to the transformer terminals on my Naim 250. Unfortunately the practical aspects are self-evident - most particular as they apply to your insurance in the event that you burn your house down.

 

Of course, it is totally possible to hard-wire only the component end of the cable, as is normal for most very low-end equipment. Hmmm ... could that be what makes it sound low-end???...

 

[Talos2000]

Bang on.

 

Every proposed design theory for a power cord should be obliged to at least submit itself to the 'series connection' thought experiment.

 

Do you know if anyone has ever actually tried to conduct such a test as a real experiment?

 

[Trev or Trevor]

I found this article interesting. Shunyata claims the two most

important factors are to deliver current and reduce noise caused

by your own equipment connected to the same circuit.

 

http://www.shunyata.com/Content/ac_overview.html

 

I don't own any of their products, but I've heard good things

about them.

 

 

[Talos2000]

Over the years I have put together various home-brewed power cords, purely out of interest. Most of them sound no better than my 'reference' Belden cords. Some of them are quite spectacular, if physically unwieldy. Just buying parts to tinker with can be an expensive proposition.

 

In my day job I am CTO of a laser company, so I have at least some base-line credibility from which to comment on cost. And I can see where the selling price of a high-end cable comes from. Your basic rule of thumb for consumer electronics is that it costs less a tenth of what you pay for a product to buy the parts to make it with. Assuming your objective is to make a profit.

 

But from a perceived value perspective, cables are traditionally a hard sell. I recently bought a Blu-Ray player for my condo. The store wanted to sell me an HDMI cable to go with it that cost the same price as the blu-ray player! Should I complain that $80 is waaayyy too much for a cable, or shake my head in amazement that I can buy a blu-ray player for $80?

 

[Talos2000]

That is a very nice article by Shunyata that you dug up for us.

 

Personally, I found it very interesting. My most successful (if only from a sound-quality perspective) power cord experiment to date comprises two lengths of double-shielded RF Power Cable - half-inch in diameter and semi-rigid (all but inflexible) - with the cores connected live-to-live and neutral-to-neutral, and the shields, paralleled with a copper ground line, connected ground-to-ground. Oyaide rhodium-plated cryo-treated hardware completes the package. The idea was to minimize the source compliance at all frequencies up to as high as I could get, recognizing that the design is such as to let the maximum possible amount of RF flow from the mains into the component. Shunyata's article suggests a basis for why this approach is actually desirable. And possibly why, much to my surprise, I found it works rather well.

 

 

[esldude]

"Well then I guess the next question is what the capacitance difference is between high end cable A and budget cable B. I don't know that there necessarily needs to be a Big difference, but a difference in favor of the larger cable storing more energy."

 

Well, I just measured two high end power cables. Both are a few years old. Both 6 feet long, and the same brand. One measured about 350 picofarads and the other about 340 picofarads. A bit lower than I expected. For comparison I measured two generic 6 foot cables like you might use on a computer or similar equipment. One with a shield measured 390 picofarads and the other without measured around 300 picofarads. For the most part power cable capacitance is so many picofarads per foot. So the longer the cable the more capacitance. If it were merely more capacitance, then just get a longer cable. Plus the levels of capacitance are just too low to much matter at 60 hz. There is always wondering about higher frequency noise etc. But it isn't just capacitance.

 

[esldude]

I don't know of anyone doing the series experiment. If you were to make up one of your homebrew cables with an appropriate connection on both ends then it would become simple to do. Of course we are all doing it in a sense whenever we plug something in. We are series connected to everything in our house and back to the transformer.

 

As to the $80 HDMI cable, well www.monoprice.com will sell you one that won't exceed $10 while having gold plated connectors of good quality. I think this is most definitely a case of that $80 cable being a rip off. Chances are it was made no better than the $10 (including shipping) monoprice cable. So there should be no difference in parts cost.

 

I knew the rule of thumb is 10x parts cost. Even then I usually fail to see $100 parts cost in $1000 cables. And cable makers get them cheaper than we can buy one off's for making stuff at home of course.

 

[Dj]

This article sounds interesting:

 

http://www.audioholics.com/education/cables/power-cables

 

[barito7]

Link is bad.

 

[Dj]

Check you browser setting! Link is working perfect. Just copy it and put in the address bar of your browser.