How can power cords make a difference?

I am trying to understand why power cords can make a difference.

It makes sense to me that interconnects and speaker cables make a difference. They are dealing with a complex signal that contains numerous frequencies at various phases and amplitudes. Any change in these parameters should affect the sound.

A power cord is ideally dealing with only a single frequency. If the explanation is RF rejection, then an AC regeneration device like PS Audio’s should make these cords unnecessary. I suppose it could be the capacitance of these cables offering some power factor correction since the transformer is an inductive load.

The purpose of my post is not to start a war between the “I hear what I hear so it must be so” camp and the “you’re crazy and wasting your money,” advocates. I am looking for reasons. I am hoping that someone can offer some valid scientific explanations or point me toward sources of this information. Thanks.
I could give you lots of reasons for why they shouldn't make any difference.
It doesn't matter how many reasons you can list why they shouldn't make a difference. If there is only a single reason why they do, then they do and the reasons why they shouldn't are meaningless.

My wife shouldn't care which way I fold my underwear in the drawer, but she does.
Have you checked the PS Audio website ( I can't explain the physics behind it, but perhaps the guys who developed the Power Plant can.
Here's your answer, Bruce:
There a some very detailed "white papers" on AC power at the Vansevers website;
PS: At the Vansevers website the best place is to click on "Notes" on the left menu. One of the notes is: "Why do things that aren't suppose to have a sound, have one anyway?"
I don't know why they make a difference but I've found even realatively inexpensive i.e. $100.00 cords make an audible difference. Beleive the scientists or believe your ears, it's all the same in the end.
Nrchy, don't start that scientist crap again. I am sick and tired of reading the sos.
I don't know how many of you out there have read the Mike Van Evers explaination of why power cords make a difference but IMHO it makes no logical sense at all. Any other comments out there?
I had stock power cords on my amps.On certin tracks i would get bloated boomy bass.I changed the power cords to some homemade 14 gauge well insulated and shielded cable with high quality IEC and Wall plug.
Right offff the bat the bass came in and no more bloated and boomy bass.
I dont know the science but the sound is better.
Just read the white papers on the vansevers website. This guy could give the Brothers Grimm a real run for their money.

The powersnakes website makes the most sense, until it gets to the magic stardust part.
The powersnakes metaphor of a river current (that is, the AC) being calmed as it enters a large peaceful lake (a quality PC) is a really seductive "explanation" of why PCs make a difference. There are also some interesting scientific explanations from HMS, but I think they are only in German, and there is also a company--CIC (one of the Cs shoud be backward)--that includes a long white paper with all of their products.
So which one is a good power cord to buy for BK REF 7250.
Power cords make a difference. With a powercord, one on each piece of equipment... it is possible to turn the equipment on and (if you have paid your utility bills and figured out the complex series of operations to make the whole system work together) create a sort of noise. However without power cords, this is definitely NOT POSSIBLE. So... here is conclusive proof the power cords DO make a difference.
Elizabeth! You have solved a problem that has been plaguing me for months. The stereo in the bedroom would play during a lightning storm, but once the storm died down, the music stopped.

Now that it is plugged into POWERCORDS, it plays most all the time. That is, until lightning comes again, then the sparks fly and it falls silent again. What is with this system?
OOPS I see my sense of humor was NOT found to create gales of laughter...
Its a very tough room...
Funny story I am progressing through right now. A friend of mine(a guitar player) is recording a CD with his band. I expect it to be big. Don't be surprised if this band bursts on the scene big time. I asked him if he could try out a power cord with his Mesa Boogie, so the CD could sound its best. I gave it to him a little over a week before the recording session. He called the next day to say that the cord made an improvement in his sound. Not night and day, but meaningful. Subtle. He recorded, and all went well. He then reinserted his stock cord. After a day or two, he just wasn't happy with his sound. Was it this, that, or the other thing? Was it the mood? Was it him? He couldn't figure it out. Then, he reinserted the cord I gave him. Everything instantly snapped back into the way it should be. It was the cord! A little later, a recording engineer commented on his sound. He asked about the equipment, and looked it over. Nothing seemed any different than anything else he's ever come across. He asked if the amp was hot rodded or whatever. He commented that he couldn't believe the sound coming out of his amp. My friend then told him about the cord. My friend then returned the cord to me, and I gave him another to try. His remarks to me were that he cannot live without a good power cord. He no longer sees the difference as subtle. His impressions are now concrete. Now he NEEDS a power cord. Are we going to start a revolution in pro audio???
Trelja: I have the HT IEC adapter on it's way for my Pioneer CD burner. I will try upgrading the power cord for the analog to digital copies that I will be making. Upgraded PC's have worked on everything so far with the exception of my tube amp (which seems to be impartial) and we'll see if it improves the quality of the copies. I will also check to see if it makes a difference on digital to digital copies as well.
All a power cord has to do is deliver AC energy to the audio or any other kind of device's power supply. The more current the device needs, the larger the conductors in the cord should be. Thus a 120VAC power amp might benefit from a 14 or 12 gauge cable, while a CD player would typically only need an 18 gauge cable. There is no audio signal going through the power cord, and the supply itself isolates--or it damn well should, if any sort of competent person designed it--the audio circuitry from the AC and the power cord. Fortunately, cables are a commodity item, so there are inexpensive ones for those who want performance at a low price, and there are expensive ones for those who want performance at a high price.
70242.241. So are you inferring that the stock power cord on my new Sony 9000 ES, which was an 18 gauge, is sufficient enough that replacing it with a high quality power cord ( 12 gauge?) from Purist Audio will not affect the performance?
Albert - There is literally no conceivable reason why your Sony DVD player should benefit from a 12 gauge line cord. If your Purist cord does improve the sound it is because of some phenomenon outside the known laws of science. It is very similar to someone claiming that their car runs better when the gas is pumped thru certain brands of pump nozzels.
CHAH I smell Rhubarb cooken'
Look whos telling who what. Stevemj, when you have half the knowledge not to mention the equipment of Albertporter maybe someone will listen to you. Please tell me, are you saying Albertporter is hearing something that isnt there? Were you there? Is he lying to us? Your gas pump analogy is pathetic. So are your posts.
Stevenmj, I think a more accurate analogy would be to say that my car ran better because the fuel line size was increased, and therefore provided less resistance and lag time in supplying the energy source to the engine under high demand.

Your analogy (at best) would only represents the amount of time required to fill the fuel tank. And of course, this has no affect on final performance, unless there was an engine that used energy faster than it could be pumped in.
Not to take sides here, but its worth mentioning that current is drawn, not forced as the gasoline hose analogy would imply. All that is required is a cable with sufficiently low resistance that is able to provide the current when demanded. If 18 gauge doesn't adequately fit this bill, then a larger cable will likely be a benefit. However, the amount of current demanded by a DVD player is relatively small, and a 6 foot run of either 18 or 12 gauge copper wire should have very low resistance, so its likely that any differences you hear are probably due some factor other than the ability to carry current. I know that there are many theories about producing high quality power cables, and its possible that something is coming into play other than the absolute size of the wire.

You may well be right, Ken, that there is something at work other than the guage of the wire. I don't really know, and I don't really care. The fact remains that there are a number of people in this forum (myself included) who, through direct experience can hear differences in various power cords with various pieces of equipment. Most of these people do not seem to be delusional based on their writing styles. The key phrase here is "direct experience", something which both Stevemj and the 702 man have none of. Until they get back to us with the results of some meaningful experimentation, it really is pretty meaningless to debate with them, don't you think? What cords have you listened to with what equipment Stevemj and 702?
Hey Albert, I'll talk about my own engine thank-you. I had to quit driving once the consumption exceeded the intake, now I'm trying power cords, same damn problem.
Trelja, if your buddy can get some stuio time to try something, I was thinking that recording a test disk of three power cords would be interesting. This would be better than the "double blind" in that first we wouldn't know wich or if a cord was switched and all the equipment would be exactly the same. I'd love to hear the results of such a test. I'm sure it wouldn't meet mr. 702's "high" standards but it would meet mine. If 702 really wanted it sounds like he has the same ability, but I'm sure he doesn't know wich cords to try, so I think your a better canadate. J.D.
Albert -

You're being somewhat inconsistant in that you talk about reduced "lag time" from so-called better cords, while complaining about stevemj's analogy only filling the tank faster. But you're exactly right when you say that this should have no effect on final performance.

RFI, that's another story. And one that's ended with a few bucks worth of ferrites.

Brulee, HDM -

If folks feel that aftermarket power cords improve the sound, OK! However, the ability of the senses to be mislead is legendary and I'd bet big bucks that's what is happening for most people who honestly feel that the PC makes a difference, other than instances of too-small cords or RFI issues. In the end, though, all that really matters is your enjoyment of the sound.

The people I have an issue with are the rip-off artists (either ignorant, just plain greedy or both) putting these kilobuck wastes on the market in the first place.

Listen Albert, The differences in power cords and ICs that you ,I and others hear, are also quite audible to non- audiophiles as well. I have done the trials on many people in my sound room. I am sure Steve and 702 would hear alot of what the rest of us hear too. The simple fact is that these people don't hear the changes, because they don't want to hear them!! No amount of dialouge is going to change their philosophy. If I put these guys in a room with, say ,Radio Shack ,MIT, Siltech and Magnan cables and changed them in that order, with the same music and amplitude level, and they told me NO DIFFERENCE, then I would have to say they were flat out lying...these are not subtle changes. You dont need golden ears to hear these differences, you just have to be honest with yourself.
If they were to say, "We hear the changes, but will not support the obscene prices and therefor condemn the entire wire and cable scene as plain robbery", then that would be a more honest post.
In the end I think the driving force here is the thrill of conflict with you guys (and gals). This will continue to be a weekly battle with no results. I must admit it does draw alot of interest, but forget about the truth ,it won't happen........Frank
Albert - Since I don't know all the laws of science, it's more than a little presumptious of me to claim that an effect must be outside all known laws. So, sticking to the few laws I do know I checked the resistance and voltage drop of 18 vs. 12 gauge line cord. I know claims are made that there are other effects of some kind that are more important. Anyway, I thought you might find these numbers interesting as they help keep things in perspective.

Assuming that your DVD draws about 10 watts, a 6 ft 12 gauge cord will drop .0016 volts while the stock 18 gauge cord will drop .006 volts. Now, it is typical for your utility voltage to vary 10 volts during different times of the day. Also, good gear is design to handle two or three times that amount without any problems. So, the voltage stability provided by the larger line cord is somewhere around 1 to 2 thousand times smaller than the normal variations of the utility's voltage.

I picked my analogy of the pump nozzle effecting the performance of the car because it is similar. Electricity is pumped to your power supply where it is transformed, rectified and stored for (by electrical time standards) later use. Much like the gas from the service station pump doesn't flow into the engine, the electricity from the line cord doesn't flow into the digital/audio circuitry.

It is this tremendous isolation between what is happening at the line cord (330 peak to peak volts) and what is happening at the circuitry level (low nearly perfectly regulated dc voltages) that make it incomprhensible that the minute contributions of exotic lines are significant.
Hey Albert, have you found it odd that "the" guy who claims no possible change can take place from a power cord should have limited scientific knowledge? I must have missed something, but I was sure "he" had the answers.
Also wondering how power is "pumped", oh well guess I'll believe you in that you speak with a basis of knowledge.
All the anti-expensive cord people overlook the one fact that makes these expensive cords sound different. First they start with the false assumption that current demand by the component is somehow constant? They argue that the original factory cord will deliver sufficient current for the component to operate as designed. That is the only thing they are right about. The sonic difference comes in the PC's ability to perform during extreme dynamic changes in the music. When the music changes, the current demand by the component changes. If you choke the power supply in any way or open it up, these changes will be audible by the average person. The music is not static. Test tones are static.
Gumby -

Could you be so kind as to identify whoever stated that current demand is constant - I've never seen anyone say anything like that, and it would be a ridiculous statement in any case.

But strangely, while you agree (correctly) that the original cord delivers sufficient current you seem to imply that it also "chokes the power supply". This seems inconsistant, to say the very least. Could you point out some specific components that cannot draw adequate current through the orignal cord? I'm most eager to find out which vendors won't spend the few dollars on a cord of sufficient guage.

By the way, how many people can identify different cords in a well-designed objective test (barring too-small cords or RFI issues)? In the past few days on, a gentleman who generally falls in the so-called "subjectivist" camp scrapped an article on PCs because he could find no difference.

Gumby, I would be willing to bet that in a better piece of equipment the power cord never sees the severe changes that you talk about. I do agree that the AC side of the supply does see changes in current demand but if there is sufficient filter capacity just after the rectifiers the greatest demand for power should only be when the amp is powered up. This is true simply because an uncharged capacitor looks electrically like a very low resistance.
Once the caps are charged, the demands of the amp are borne by the filter caps which in turn is charged by the rectified AC from your transformer and power cord. I think that a well designed power supply with a hefty set of caps renders the expensive cords impotent. I do however hear differences with different interconnects and speaker cables.
Stevemj and 702. Until you actually plug a cable into a player like mine and have valid comments about such, I am going to do my best to ignore you. We have beat this topic to death in one way or another on multiple posts. We have literally devoted thousands of words to this and have arrived at exactly where we began.

You and 702 come here to fight, I come to learn about music. There are always people like you who know so much that they have their mind made up before they even begin. You definitely fall into that category. You will eventually learn that there are reasons that cables perform differently, and there may even be a scientific explanation for it (someday).

Until then, I am content with the high performance music that real life experience and long term listening has provided. You will remain content, fighting over theory and numbers. I got the better end of the deal. Your system, based on what you post here, sounds terrible. That should be punishment enough for you, it certainly would be an unacceptable experience for me.
Albert, Brulee, Hdm, and others- We've all gone round and round with these individuals who continue to hold to the rationale that would justify their not obtaining/purchasing "expensive power cords". They continue to refuse to participate in the wonderful world of self experience. Regrettably, they are the only losers (musically speaking of course) with this attitude. The rest of us few will continue to obtain greater levels of enjoyment from our audio systems because we are willing to try and experience for ourselves. I wish them well in their smaller world, where troubling ideas and thoughts are vanquished with the wave of a textbook (I'll bet written from someone else's experience?). It must be comforting to live in a world where ALL is known and so thoroughly understood. I for one will enjoy the company of the few souls who wish to travel the road less often taken. Just one man's opinion.
Power cords make a difference, because they are in series with the AC current that supplies the audio equipment's power supply, with AC electricity.
Many times the power cord has made no difference in my system. If I were somehow brainwashed into believing in the placebo, I would think I heard the difference all the time. But I don't. In my system, the differences are most apparent on my preamp and TV. I've tried different cords on everything else and they don't make too much of a difference.

The difference between stock cords and expensive cords is the difference between the system "working" and being more "musically involving, emotionally involving, live, present, soundstage, etc." .

Your system will "work" with the stock cord. But, the music enjoyment will be choked off in my experience.

Anyone who has ever heard and appreciated the difference that good PC's make will never go back to stock cords.
Jay, I always wash my brain with Kontak, and chase it with bleach. It helps me hear power cord differences better. Don't knock this tweak til you try it. It also helps clear up some of my other brain problems.
I WAS a non-'enthusiast' of "special" vs "ordinary" power cords until I decided to actually TRY one. So I bid on and won a ZuCable power cord. I put it on my amp and WHAM! no bass??? Much better upper register, clearer and smoother treble, but the bass all but disappeared. So I took it off the amp and put it on the preamp, same thing but less problems with the bass. Eventually I cut the cord by 2/3 and 1/3 making two cords and put the long part back on the amp, but straight into the wall (not via conditioner) and the preamp via the conditioner, after a hundred hours or so of break in... the cables started workin' right. My SACD is via 3 conditioners in line with another 6' ZuCable now. After break-in the power cables bass was restored... And now I can say the non-Zu power is like a "wooley rinocerous" trampling around in my listening room. Where th Zucable is taunt, and way-more correct and true to the music. The treble remains cleaner and smoother. So a non-believer became a believer after trying one out. My story. The END.
Same here Elizabeth. A realist by nature (some might even say pessimist but I don't think the affliction is quit that advanced) I tried a "designer" cord on a whim. Fully expected to notice no difference. On the source (DAC or transport), where others claim the most benefit, there was no appreciable effect. Putting it on the preamp was another story. The sound was more "musical" and lively. On the amp the difference was VERY noticeable. Here it brought a considerable increase in the heft of the low end and at the same time the overall sound was less strained.

Bought another cord to put on the preamp. Ah, the best of both worlds. Eventually my anal retentive nature caught up and now everything has an upgraded cord. The source didn't really *need* it, but what the heck!

Ultimately it paid off that even as a doubting Thomas I was willing to try something new. If only that attitude could be bottled...
Albert - This isn't personal. I like talking about hifi related things. I don't get upset if someone says that their line cord makes a huge difference. I find it interesting. I don't judge people by whether they use expensive line cords or not. I have friends with whom I disagree about important things. Like you, I am just expressing my opinion. I don't like fighting and I take care not to write anything that sounds personal. I state an opinion and try to back it up with some information. I thought you might find the line cord voltage numbers interesting. It wasn't written with the intent to agravating you or with the expectation that you were going to read it and cry out "MY GOD, how could I have been so wrong!?"... And, I'm sure that if I had a chance to hear your system I would agree that it sounded damn good.
Dear All,
I've certainly read a number of interesting theories on why PCs make a difference. RF/EMI rejection, bigger guage "pipe" to supply electrical power, bandpass filter effects, various sound differences between metal types and purity, mechnical vibrational effects, soldering techniques, noise cancellation techniques and the dielectric content to name a few. Here's a thought. I've read about but never experienced the PS Audio PowerPlants. I've read that changing the output frequency can effect the sound. Sometimes better, sometimes worse. Perhaps the PC is merely removing certain frequencies from the incoming power or modifying the wavelength (or waveform) slightly.
I know that adding Uninteruptable Power Supplies (UPS) to complex laboratory medical equipment makes them run better. Repair costs go down, system failures go down, mechanical irregularities go away and precision improves. D/A and A/D convertors certainly work more consistently. There are power supplies inside the equipment that should protect and clean up the power. I've noted times when the power monitors showed no spikes or brown-outs but the UPS aided equipment ran better. So what's up? Personally, I don't know (I was a chemist not an EE). I can usually hear differences between PCs. Sometimes I like them, sometimes I don't. Hey, enjoy the music. It's not worth fighting over.
this is good:
I'm going to take a whack at this and would first like to establish my credentials. My experience with the scientific aspect of electronics is limited to the DYNA ST-40 amp I built back in the 70's. When I was done and put the cover on the box, I was struck by the little yellow label that said, "caution, no user serviceable parts inside". Truer for me than, I suspect, for many kit builders.
However, I do know a few things about science and the philosophy of science. One of those is that there is something called "electron theory". No one, not any of us or any Nobel Laureate KNOWS what electrons do or if they even exist as the theory supposes. It is just that, a theory.
I regard audio equipment designers, for that reason, as wizards in the true sense. They manipulate forces beyond their understanding to perform miraculous feats. Stevemj and 70242, on the other hand, are like the 14th generation of high priests who keep the scrolls that they can't read but you'd better not look directly into the eyes of the idol or you'll be struck down.
Way back when, kids rolled paper into a cone, stuck a needle through the narrow end and held the needle to one of dad's 78's while it rotated on the Webcor. Sound ensued. How much difference is there between that and a Goldmund Reference? Only one of degree. One has a suspension based on theory, the cone doesn't. One has amplification of the vibrations based on theory, the cone doesn't. The child with the cone doesn't know why there is sound, but empirically, there is. The modern turntable designer likewise doesn't know, although he'll probably tell you he does. His work is the result of empirical observation and a "belief system" grounded in a theory, not in fact. We laugh at the notion of an 18th century Dutch scientist who believed a little person he called a "homonculous" bent the light through a prism. Everyone knows that Newton "proved" that the light was bent due to the refractive nature of the glass' shape. Yet, we don't know why that particular shape bends the light, only that it does.
Electromagnetic theory "supposes" invisible, "sub-atomic" particles that have cause and effect. We can only observe the gross consequences of the theory. Where a finer understanding is desired, such as what is going on inside a power cord or a transformer, with impossibly tiny amounts of a theoretical concept called "current", we rely once again on empiricism, not objective truth.
Ohm's Law is not a law. It is a mathematical formula that allows "theorists" to predict the behavior of current, which, once again, is part of a theoretical model. Heisenberg's "Uncertainty Principle", while elegant and brilliant, is more of an apology for the inability to observe energy than an attempt to explain it.
When the so-called "objectivists" deride the notion of our tweaks, condescending to admit that perhaps any audible differences stem from something "outside of the LAWS of science, as we know them", that is the worst sort of hypocrisy and a telltale that they have no understanding of the true Science that lies at the foundation of rational thought.They are simply acolytes who guard a temple of their own creation to defend themselves against forces they do not understand.