A Study On Power Cables: Music From The Wall!

[DiminishingReturnsOfficer]

I would like to initiate an intelligent and informative discussion about the effect an aftermarket power cord can have in your system. If possible, I'd like to focus more or theories as to how and why these cables can improve the sound of a component. Although I will quote specific manufacturers' technical manuals, my intent is not to evaluate specific products. I'm interested in hearing from both sides: people who believe in aftermarket cables, and those who don't. What I'm really seeking is the reasoning behind your position. There are many gifted, highly intelligent audio engineers and hobbyists on this site. I'm hoping we can shed some light on what is one of the more enigmatic phenomenons in music reproduction.

From the beginning of my entry in this hobby, it was my intent to get the best possible sound for the least possible investment. My first experience with cable upgrades was going from a manufacturer provided set of interconnects to a pair of Monster IC's. I noticed a slight improvement in soundstage width, and clarity. Bass might have "tightened up" a bit as well. I went on to upgrade speaker cables which was about 4 times as expensive, and yeilded only minimal improvements. Around this time, I began to see the ads for aftermarket power cords. What a joke! I thought. I am an experienced electrician, so I'm familiar with many of the concepts behind power distribution and consumption. Other than stepping up the conductor size for a lower (although already insignificant) volage drop, what could an AC cord possibly do to improve (or even change) the sound of a stereo component? After all, before reaching your system, the power travels hundreds, perhaps thousands, of miles through a multitude of high voltage transmission lines, transformers, switchgear, and overcurrent devices. Once it reaches your dwelling, it goes through many feet of, relatively cheap, unshelided, in-house wiring with the associated twists, turns, nosie sources, staples, wire nuts, and terminates in a $.85 receptacle. How is 6' of cable at the very end of this chain going to improve anything?

I ran this by the in home dealer who sold me my speakers (and incidentally does not sell power cables), and he said he couldn't really explain "why" but could attest to the merits of power cables. He suggested things like cable geomertry acting as a filter, and improved vibration control. Then, he challenged my "chain is only as strong as its weakest link" assumption with what I feel is a noteworthy example: if you have a source, let's say a DAC, a preamp, and a power amp connected together with cheap interconnects; and you replace just one set of these cables, say the link from the source to the preamp, you will hear an improvement. Since the chain would be defined by it's weakest link and that link is still in place (preamp to power amp IC), so much for the Chain Link theory.

A reviewer, who I believe is also a member of CA, made the significant statement that a power cable represents the FIRST couple of feet relative to your audio component, not the LAST few feet. I'm not sure who to credit with the following quote, but its one that most of us are likely familiar with: (paraphrazed) "When you listen to music on your stereo, you are quite literally listening to the power from the wall." OK, now with the Chain Link theory laid to rest, the "first few" feet concept in place, and the idea that what comes out of your speakers IS what comes out of the wall, I was finally ready to consider that a power cord could effect audio performance.

What comes next is a revolutionary adjunct to these ideas: I was reading up on the subject online and came across the following article from Argentum Acoustics: http://argentumacoustics.com/multimedia/Argentum_Whitepaper.pdf "As signal energy is transferred to the speakers from the output transistors, it draws

down the storage capacitors in the exact amount of the outgoing signal energy. The

capacitor drawdown must be identical in amplitude and waveform to the energy

transferred to the speakers.

As this occurs the storage capacitors try to maintain full charge by drawing energy

(normally 12 or 24 volt DC) from the power supply rectifier(s)32 The rectifiers, in turn,

draw 12 volt AC (converted to DC) from the power transformer33, and the power

transformer draws current through the AC power cord from the wall, with, because

amplifiers are “zero sum” devices, the demand at the wall being identical in both

amplitude and waveform to the signal transferred to the speakers.

That is the case with every device in the system: The output signal of a device, no

matter what it may be, ultimately comes from the wall and must be identical in every

respect to the device’s output, and must travel through the power cord!

Seen in this light it is more obvious that AC power cords are fully as important as any

other cable because ultimately they must carry the same signal!" This really blew my mind and I'm still kinda reeling from it. I'm not sure that I agree 100% with this notion that a power cable carries the exact same music signal that your speakers transduce into sound waves; which is why I decided to introduce the concept in this forum. I was hoping to entice the scrutiny of our scintific minds who would be able to place it in proper perspective.

My own (albeit limited) knowledge, as an electrician and hobbiest, suggests that Argentum's model may be somewhat flawed. If their theory is correct, you could take an wattmeter that's sophisticated enough to read instantaneous (not average) power and compare that to an Ociliscope reading of the analog waveform from the source and they would be identical. That just doesn't seem right to me. For one thing, the AC is delivered at 60Hz., and converted to DC. Even if all the frequencies in the amp's output could be represented as multiples of 60Hz., how does the line (supply) side of the ciruit respond to the frequency information? I thought that the transistors or tubes that modulate the amp's output drew their current from a bank of capacitors that was charged by a separate set of rectifiers. How are frequencies, other than 60Hz., important to the power supply rectifiers? Wouldn't they just be looking to bring the overall charge of the capacitor bank back up to a certain level? I've looked at non-linear loads on O-scopes and weveform monitors and they've never looked anything like an analog signal! Of course, these were VFD's and not stereo amps...

Assuming that aftermarket power cord designers are actually trying to accomplish more than merely liberating unwitting consumers of disposable income, perhaps there is something more to the Argentum Acoustics' model than I realize. In researching power cables, I naturally came across the PS Audio website. They were discussing something very similar in their white papers. Although they never directly stated that the power consumed by an audio component is identical to it's analog waveform, they go to great lengths to describe how they engineer their conductors to benefit the various frequency ranges: "Breaking the variables into separate groups was the first step in our design. Our experience has shown us that we can achieve a remarkably balanced and seamless power delivery system by breaking the conductor geometry into three groups:

Bass

Midrange

Treble."

They go on to discuss how different ratios of cross sectional area to surface area effect the midrange and treble. Their Perfect Wave range of power cables all feature rectangular bars of copper in conjunction with various round conductors. I came across this info. long before the Argentum pdf., and tried to understand how any frequency other than 60Hz. was relevant to a power cable. The conclusion I arrived at was that they were trying to manipulate conductor geometry to enhance the sound of various frequencies, but they were not suggesting that those frequencies were actually travelling on the conductors. The literature does not say for sure either way, but based on the AA whitepaper, this may well be exactly what they are trying to do. What would be the point of manipulating the skin effect of frequencies that would never be present on the conductor?

 

 

 

[goldenpiggy]

I think when some people spend big bucks for audio equipment, emotions often take precedence over EE101 when it comes to accessories like power cords.

 

It's important to understand how the power supply works, and you've addressed that for linear. For switchers, it becomes even less of an issue.

 

Everything I have learned and experienced as an electrical engineer and sound engineer tells me that big bucks power cords are one of those diminishing return items (sorry for the choice words.) For AC cords, I only care about the four things: make sure the gauge is sufficient for the current the amp or whatever equipment will draw, that it is shielded, that it's flexible (so it should be stranded), and that it's short.

 

The wire gauge is pretty obvious. Shielded cords are not so obvious, and for most well-designed power supplies, IMO probably not necessary. But here I prefer to err on the side of caution as shielded cords (the computer/medical/test equipment variety, not audiophile) aren't much money. From being in the lab at work and doing live sound where there's a lot of noise and RF in the venue, it doesn't hurt to use shielded power cords. I would even go as far as putting ferrite beads around each end for further noise suppression, but no further.

 

Flexible cord is better for me as solid copper wire is easier to damaged if you connect/disconnect or rearrange often (you know it from handling coax). Keeping the cord short is for neatness, reduce the chance of it being an antenna, and attenuation (although you'd really have to have very high current draw, super long cords, small gauge, and power supply that's not so tolerant of AC mains variation for attenuation to become an issue in nearly all modern audio equipment.)

 

So from the technical perspective, I don't waste money on high end power cords. Just use shielded, higher-gauge (14/3, 16/3) cords is good enough for me. If you want to hear the difference, something like an AC regenerator is the way to go.

 

Incidentally, both my Accuphase preamp and amp ship with "special" power cords that cost $100+ to buy separately. As far as I can tell, no difference in sound quality compared to the run-of-the-mill shielded computer cords that I use. The Accuphase cords are of course very nicely made, large gauge with gold contacts. I presume it is also shielded but doesn't say.

 

In conclusion, instead of spending big bucks on esoteric power cords, spend it on the interconnects where you could hear the difference on a high resolution system, or better yet, spend it on a good beer or dinner.

 

Cheers,

JR

 

[wgb113]

Chalk me up to the non-believer camp. I'm no EE but I do work in the wire & cable industry and had a brief stint in the hifi industry as well.

 

My time on the retail side of the hifi industry enlightened me immediately to insane markups that exist on most gear but hey it's what the market will bear!

 

Now, I deal with all of the major manufacturers of wire & cable in the U.S. (many of them global companies). Many of them are contracted by the audiophile cable companies to produce their products. Many of those products are "off the shelf" designs with tweaks to make them aesthetically more attractive and nothing else. Some do submit their own constructions but in discussions with EEs at the manufacturers they claim it's a lot of snake oil.

 

This shot down all hopes I had that the aftermarket interconnects and speaker cables I had spent the obligatory 10% of system on were making any real difference at all. This even after I knew what the markups were from being in the hifi industry.

 

Basically they all agree that you should use a well designed (not the same as over-engineered) cable for your purpose that is of the correct length. They tend to only believe in performance improvements that can be measured and have a good laugh when the plant fires up the "directional arrow" print legend.

 

So now I just buy a well made cable that is of the correct length (most that are packaged with equipment are not the right length I've found).

 

I'm also of the belief that the point of diminishing returns hits fast with cables. IMO it's money much better spent on more music or treating the room.

 

That said, I do "get" the idea of cables as an accessory in this luxury hobby. I understand why owners of Magico Q5's don't have them connected to their amplifier via 12awg zipcord. I just have a quiet chuckle when I hear some of the inflated claims as to how much of an improvement some say their cables make. To each their own!

 

Bill

 

 

[wgscott]

 

 

 

 

[wgb113]

I love it!

 

[DiminishingReturnsOfficer]

@ wgb113; I was going to save this for another thread, but since you brought it up, what do you all think about cable directionality? The idea here is that a piece of wire will favor a signal travelling one direction over the other. Allow me to point out that many well made single ended interconnects are marked with directional arrows, heat shrink, or some means of identifying the direction the signal is supposed to travel through the cable. This is because its a shielded cable with the sheild attached to the RCA plug on just one side (to prevent ground loops). This is not what I'm talking about. I'd like to know if anyone knows just cause that a wire will favor a signal travelling in one direction opposed to the other. This would indicate that the wire is acting as a diode and that would be disasterous for any alternating signal or power link. The only proponents of this that I've encountered are also in the business of selling directional cables. For example, PS Audio, claims that PCOCC will sound better if listened to in the same direction that it comes out of Professor Ohno's OCC machine. They listen to every spool that shows up in their warehouse and claim that its not a subtle difference and only take 2 hearings to verify. I've also heard proponents of wire directionality postulate that it has something to do with crystal boundaries. They say that its narrow minded to assume that an actual electron can only travel in just one direction, and that the overall migration of electrons is influenced by metallic structures within the wire. I don't recall how they explain what happens when the signal reverses; or if they have an explaination. If such an explaination exists, I would very much like to hear it!

 

[MetalNuts]

I have used many power cables all over the year though rarely exceeds $1,200 each.

 

I do hear the difference between the cables and sometime it is very obvious. Nevertheless, I agree it is not worthwhile to invest heavily on the power cables and it is much sensible to spare the money on the A/C generator to improve the overall quality of the electricity which is more fundamental to the whole system of equipment.

 

Of course, if one has unlimited resources, using different power cables to tune the sound of the system isn't a bad option.

 

 

 

[wgscott]

First I have ever heard of it. The invocation of crystal boundaries I can safely tell you (as a professional crystallographer) is nonsense. My guess is the rest of it is no better, but I would have to take a look at this.

 

It is certainly easy enough to test.

 

[The Computer Audiophile]

Power cables with directionality? Don't they usually have one end that can plug into the wall and the opposite end that has to plug into the component?

 

I have other cables with directionality but those cables can be connected either way with single ended RCA terminations.

 

 

 

[AudioDoctor]

with an arrow on them, pointing the proper way so nobody gets confused.

 

That arrow lowers the noise floor, creating deeper black backgrounds from which the music erupts like a volcano in Iceland...

 

Because, lets be honest here, what use is a power cable if it isn't properly plugged in?

 

[CoolMilo]

Last year I read an article in a Hi-Fi publication about Shunyata power products. The article left a lasting impression and so I decided to audition several power cables when they went on sale during the last holiday season. There was a significant and immediate improvement to the sound quality, especially the soundstage, as the result of replacing my cheap OEM power cables with $99 (retail) Shunyata Venum 3 power cables.The music came alive!!! They also improved the low end (slightly) with a set of HD 800's that I used to own. The improvement was noticable and repeatable after switching back to the cheapo cables.

 

Perhaps any decent shielded cable will yield the same result when compared to the OEM cables shipped with most components.

 

 

 

[barrows]

First, power cables do sound different, anyone with a good system, and reasonable hearing can find this out very easily through LISTENING!

 

Second, directionality, this is applicable to all cables (with the exception of DC umbilicals): both the AC power cables and the signal path cables are carrying AC, this is alternating current folks, so there is equal wave propogation in both directions-to suggest that a cable would be directional as far as its ability to carry the signal is nonsense, but: some cables are sheilded, with the sheild only terminated at one end-thees cables are directional, as the sheild is designed to drain towards the source end. So if you have cables with sheilds terminated at only one end, they are directional, but only in relation to the sheild.

 

Stranded wiring in a power cable can increase noise: electrons jump from strand to strand, and crossing the boundries micro arcing occurs, this causes noise. Better cables often use litz wire (strands which are individually insulated to mitigate this effect), or many smaller diameter solid cores.

 

Sheilds: while sheilds may be good idea in some systems, they also have drawbacks. Sheilds can increase resonances, as RF can transmit from the inner cabling, hit the sheild, and bouce back to the cabling. Imagine this happening billions of times, and one can see how this would cause noise. Abetter approach could be a carbon fiber sheild, as carbon fiber has a more damping effect. Another way to deal with this is to carefully space the sheild away from the conductors, but I am not convinced that this approach actually works.

 

Geometry: cables can be twisted and laid in ways that naturally resist RF pick up, doing this right may allow one to avoid the problems sometimes caused by sheilds.

 

Resonances: you have got at the very least, 60/50 Hz signals running the cables (ignoring the very real possibility of the power supply modulating the incoming AC, as mentioned by the OP) harmonics of these frequencies will be present as well-these harmonics are noise and hence a good AC cable will be critically damped to avoid an excess of these resonances.

 

Dialectric effects: some of the signal is absorbed into the dialectric, and then released. This will cause phase problems, and will result in noise in power supplies.

 

All of the above are real, physical effects, which should be addressed in power cable design. There are more esoteric concerns as well.

 

Yes, the power cable is the first thing a component "sees" and as such it is important. Of course, I would suggest the AC outlet should be addressed as well. And if one can use better wiring from the outlet to the junction/breaker box, great. I do not think your power company will let you upgrade the wiring from the transformer to the home, so...

 

[wgb113]

I've never seen them on power cables but I can tell you that most of the ones you see on interconnects and speaker cables are just part of the print legend on the jacket and absolutely nothing more. The rest is just marketing BS.

 

Again, to each their own. After seeing and hearing what I have I'm comfortable not spending much money on cables as a "component" of my system. Others that feel they hear an improvement...great!

 

Bill

 

[AudioCynic]

First " power cables do sound different, anyone with a good system, and reasonable hearing can find this out very easily through LISTENING"

 

No one can tell the difference without first being told and being convinced that they make a difference. There's no measurable difference in the sound being produced.

 

"electrons jump from strand to strand, and crossing the boundries micro arcing" You really believe that this is capable of causing noise? Quantify it? Give us the amplitude and frequency distribution of this noise. Point to genuine research that has studied this, not marketing nonsense "white papers" from snake oil vendors.

 

I'm too busy to address the rest of the unsupported noise that you've presented as information, but I will tell you that if you go told those stories to a group of radio astronomers, people who are experts in working with the most exquistly sensitive equipment capable of dececting the faintest signals from the edge of the universe, you'd be laughed out of the room.

 

 

[sandyk]

Ut does sound a little illogical that the use of an upmarket mains cable for the last 2 metres can make a difference after being preceeded by many KMs of unscreened copper , whether on poles or underground.I don't doubt that many people can hear differences with different types of mains cables, especially screened types, but have they first tried laying all mains cables flat on the floor, and spaced all signal cables well above the mains cables at all times, then ensured that all equipment mains leads pass the signal cables at 90 degrees ?

Alex

 

[4est]

"I do not think your power company will let you upgrade the wiring from the transformer to the home, so..."

 

I did just that about 7 years back. In updating my service panel and putting it underground, I had the sparky install over sized COPPER to replace the aluminum that was there. We had to do all of the work, but they did the final hook up.

 

[wgscott]

Replacing aluminum with copper is a sound decision, whether or not you ever listen to any sound.

 

[Russ]

When the wire was replaced, did you hear a difference?

 

[barrows]

Once again you've proven that you are deaf, or that you do not bother to listen. And, if you do not trust what you hear, then you might as well not bother to listen to music either.

BTW: I do not spend big bucks on power cabling, I make my own, which address the points I made, and sound quite good for a fraction of the price of similar commercial products.

All of the factors I described are well understood, and addressed in cable designs in many fields besides audio.

 

SandyK: do you think the wiring beyond the transformer servicing one's home should matter significantly: considering the higher voltage of the transmission, and that the transformer probably removes a lot of noise, I tend to consider the transformer the beginning of the AC delivery. The AC can get from the transformer to the home pretty clean as well, being balanced AC on that path. Quality, and age of the transformer does seem to matter, and the distance of the transformer from your home, and how many homes you share that transformer with. A few years back, while working at PS Audio, I had a customer who complained to the utility company about poor AC line performance (voltage instability, and high distortion levels), and he got lucky-the utility company put a new transformer in to service his home alone. He reported much improved audio performance; of course, his AC was pretty "broken" to begin with...

 

[DiminishingReturnsOfficer]

@ Barrows; I'm sure you can fight your own battles, but it seemed to me like the "Audio Cynic" was unfairly critical of your first post. You were actually one of the individuals who I was hoping to hear from when I wrote this thread, so please don't think that your input went unnoticed. The Cynic also levied some criticisms of my methodology in using information from whitepapers and manufacturer web sites. There doesn't seem to be much in the way of empirical research on the subject available online. Google "cable directionality" and tell me what scientific journals come up. Since this is just a post in an online audio forum, I didn't see the need to go beyond general avenues of information. Several people have written in saying that they were influenced, in one way or the other, by manufacturer or reviewers' claims. My intent was to present some of the more outlandish sounding claims, and allow our readers to place them under scrutiny.

Our founder, Chris, was good to point out that power cables "have one end that can plug into the wall and the opposite end that has to plug into the component". This is true if you buy prefab. cables, I build my own. Recently, I had just finished terminating the male end of a cord when I recognized that the directional arrows pointed in the opposite direction. I landed the shield at the plug (source) end, and had already applied heat shrink, so changing it wasn't just a simple matter of loosing 3 screws. I decided that directionality couldn't possibly matter in an A/C application especially since I'm running balanced (symmetrical) A/C.

Barrows mentioned that there is a possibility that a component's power supply could modulate the incoming A/C. This is primarily what I wanted to discuss. I've spoken with Josh at Sonicweld about a similar issue where he confirmed that a digital signal will modulate the computer's PSU; thus contributing to the overall noise level. This is a very interesting topic, at least to me. If this is happening in a digital component with a switch mode power supply, I would think that it would be quite significant in an analog component with a linear PS.

Also, Barrows mentioned that he worked for PS Audio. They are one of the outspoken proponents of wire directionality; claiming that they listen to every spool of wire that enters their warehouse to ensure that proper directionality is maintained. I wonder if you have ever been a part of these listening tests?

 

[wgscott]

If the shielding is grounded at one end but not the other, then I guess the cable has directionality in the trivial sense. But I took the suggestion to mean that what macroscopically appears as a symmetric piece of metal wire has, on the level of electrical transmission, an asymmetry. That hypothesis is demonstrably false.

 

[DiminishingReturnsOfficer]

@wsgott;

I can't speak for anyone else, but what I was suggesting is that there is a preferred direction for a signal (or power) to travel through a wire. Mind you that I'm not making the claim on my own, I'm just presenting what has already been suggested for our readers to evaluate. The claim doesn't readily lend itself to the scientific method because they aren't saying that the wire acts as a diode (opposing current in one direction and not the other). This would be easy enough to measure. What they're saying, or more specifically; what PS Audio is saying, is that the wire will SOUND BETTER when installed in one direction. This is a subjective matter, but they claim that its replicable and falsifiable.

 

[wgscott]

The claim doesn't readily lend itself to the scientific method ... but they claim that its replicable and falsifiable.

 

That is exactly what the "scientific method" is all about.

 

If PS Audio genuinely believes this, that is a compelling reason to never ever buy anything they make.

 

[57gold]

I'm a cynical skeptic...especially when it comes to spending $s.

 

That being said, tried a Synergistic Master Coupler (BS name for sure) years ago, if I didn't like it, I got my $s back. Attached it to my SS amp and got deeper bass, more 3D and smoother, detailed highs...I heard it, my teenage son heard it.

 

(As a side story, hooked up the SR MC to an Alessandro guitar amp, all tubes and George, the designer used some audiophile parts in his stuff like Audio Notes caps, silver signal wire...even bigger impact. Called George, he said "it's impossible, we send out heavy gauge PC with each unit and they are more than enough to run amp." Said "Do I sound like a nut job? I'm a business guy who loves music and I'm sharing what I'm hearing." George borrowed a SR MC from a local audio shop. He now offers his own cable line, instrument, speaker and power cables which I believe are manufactured by AQ.)

 

Still have a SR cable on McCormack DNA 500, this one has powered shielding, and a Virtual Dynamics cable feeding the Wadia 861i. Steve at Great Northern, the Wadia experts, suggested trying one and it somehow lifts the performance of the Wadia versus others tried like Shunyata, Kimber...the VD has some elaborate damping and powerful magnets incorporated in the heavy duty plug ends. I have no idea WTF all this crap does...other than make the music more real, impactful, lifelike and swinging.

 

Sounds like we have a bunch of George's who haven't tried a SR or Shunyata PC...not subtle. Get a loaner from a dealer or the cable company, hook up to your amp...might be surprised.

 

Unless you are hard of hearing or, you are like my "audiophile" buddy, who doesn't actually listen to music, just his system and recordings. He spent big $s regularly on his system...his Spectral amp was wired out of phase and he couldn't hear it...$100K system sounded like crap, especially with his vacuous audiophile recordings of non-music. No ears, less soul. Decent guy, needed a new hobby like golf.

 

[sandyk]

Barrows

Yes , I agree that having a new transformer located nearby can ensure cleaner power, however I have only lived at one place where the transformer was close by.

I have found what appears to be more important is the quality of the main earth.I know how difficult it is to get a very low resistance main earth from experience in Telephone Exchange maintenance, where even the sophisticated earthing sytems of the Telephone exchanges themselves can cause problems in some terrains.

Even some new larger PABX installations had on occasions difficulties meeting the absolute maximum reading allowed of 30 ohms at some locations.This reading was measured from the Telephone Exchange itself.

There were several reports that a previously unacceptable reading improved after the installer had a liquid lunch. (grin.)