Power Cords Snake Oil ??

Having been a long time audiophile living with countless high end compnents I have to wonder about the theory and practicality of high end power cords.

I have yet to hear the difference a power cord makes. Ive owned, synergistic, Shunyata, BMI and cardas. I in no way can detect any sonic signature or change. Give me a pair of interconnects and I imeadiately notice a difference somewhere in the sonic spectrum. Not the PC though. I have accomplished 4 blind tests with my friends. 3 out of the 4 they did not know their cord was replaced. All 4 were using a stock factory supplied cord. Each of the 4 tests were done on different components. Amp, CDP, Preamp & dac.

My electrical backround tells me that provided you supply the component with its required voltage bet 110vac or 220/240vac its happy. Now, change the incoming frequency from 60hz to say 53hz and watch how quickly your soundstage collapses.! This is often the case during the summer months when home air conditioners are in use and the utility company power output is taxed to the max. A really good power conditioner should however take care of the frequency fluctuations. But 110vac is still 110vac regardless of the conductor it passes through as long as its remains 110vac when it reaches the intended circuit. Does your 8k amp or preamp know the difference of the path the voltage took to reach it ? Many an audiophile will use a dedicated 20amp circut for their equipment.That is a good idea as voltage & frequency fluctuations will occur in the home circuit to to other loads on the main breaker panel but again, A power cord simply is the means of transporting the voltage from the wall to the component. IF there is a clean 110vac @ 60hz at the wall socket, no matter what the medium is to go from the socket to the component, it will still be 110vac @60hz.

Could somebody expand on this a bit more. I just dont understand it. ??
Somewhere in the archives you'll find a post that i made where i actually charted a difference in system frequency response when swapping AC cords on an SACD player. I'm not saying that this is the norm, but that some components are far more susceptible to changes in the AC feeding them than others are. The units that respond the most vividly to alterations in AC cords are the units that are the most under-designed. That is, so long as one is not altering the polarity of the AC. Some units have very specific polarity needs due to built-in filtering. Reversing the polarity negates the effects of the filtering. Sean
I hear the differences in PCs but nothing huge, just slight changes. I hae a friend who hears more than me with his system. I also have dedicated lines. I will eventually get around to trying one the conditioners to see if I can hear more of a difference with one. So I also think it depends on each system. With my B&W speakers I hear less of a difference than with the Talon speakers.

Happy Listening.
this is something im skeptical on, i have no experience with high end power cords. I can see the logic in a dedicated outlet, however there is one thing about the high end power cords that make me dubious.

with high end power cords, you are merely changing the quality on the last 3-6 feet of electrical path. So, it would make sence to me, that your power cord will only be as good as the electrical cable bringing the power to the outlet. So if the cable from the power box is crap, then spending a buttload of money on a power cord wont make a difference.

Its like crawling through 20 feet of crap and putting on a tuxedo on the end. The presentation is better, but yer still covered in crap


Like i said, i have no real experience with the high end power cords, but changing the quality of the last few feetof the electrical path seems like it wouldnt make a big difference.

Funny thing, is im sure i will be hooking one of those garden hoses up to my amplifier as soon as i get a good amp


wait a second, Ok, here we go. On the same train of thought, why have a cable at all? why not run the power from your powerbox directly to your amplifier? Wouldnt that be the ultimate power cord?
Slappy, You're right on track. Who knows what garbage is being fed from the breaker panel and there is little one can do to correct it anyway (within reason). As you said you'll probably hook one up just the same. I'm currently using a BMI whale and yeah...It looks cool snaking its way from the amp to the wall but I know damn well it aint doin a damn thing. In fact,I again installed the cheesy factor cord and no difference at all. My wife still believes that its using twice the electricity "well its quadruple the size" she says. Eh, I love her just the same.

Think about it. How can you possibly spend 2k on a power cord and not believe that it adds that magical mystical final tweak that your system needed. ??

Levinson, Cary, Sonic frontiers, Krell...blah blah blah. I hear no difference in presentation. Could the slight difference that bigkidz hears with speakers be due to the fact that the components involved are at the very least momentarily turned off then on again to interchange a different power cord ?

So, who among us knows anyone with cryo'd,silver plated,shielded, electrical wiring from their breaker panel to the wall socket. The only possible advantage to a big dollar cord might be the lower resistance to current flow it provides due to the larger conductor. In the end though...you still either have 110vac @ 60hz or you dont.

My next cord purchase will be the cheapest cord I can find that looks good. Unless of course one of you out there can convince me otherwise ;)
Honestly i think some of them are worth it alone for the presentation they show.

The fiancee and i are debating buying a new house or the one we are renting. If we buy a new house, ill be in a position to be able to do alot of nice electrical work for my system. Im gonna make sure i got real good cable from the box to the outlets. Maybe then i will be able to hear a difference?

Who knows. They definatly make yer gear look aot more burly though.

I think im gonna go read Sean's post he was talking about. im curious about this.

Hey sean,
you certainly do know yer stuff, no doubt about it. What are your opinions on the issue of the quality of cable from the power box to the outlet? Do you think that few feet of high end PC would still make a difference? I would really like to hear your insight on this, you manage to point out things that alot of people miss.

Has anyone ever heard of somone doing a direct connect from thier amp to the power box with no outlet? Wonder what effect that would do.

I know if i had a rig like say.. Brainwater, i'd be making damn sure my stuff was up to par all the way to the electrical plant.
Sean, I'd love to see the charts you're talking about. There has been a raging debate on TalkBass.com (a discussion forum for bass guitar) about power cords, and everyone is asking for measurable proof.

WOW! I read another thread on Power Cords, looks like they beat this issue to death.

The way i see it,

Group A Cannot hear any difference
Group B Hears a massive difference.

I wouldnt say group B is wrong, there are alot of audiophiles that i respect strongly stating that PC's make a difference
Same goes for group A.

Here is my reasoning why some people CAN and some people CANNOT hear a difference.

Group A has crappy cable in thier walls, so that it is basically matched with the stock cords. That extra 3 feet they plug into the wall doesent make a Difference.

Group B has real good cableing in thier walls, and probably shorter runs to the Power Box. They very well may hear a big difference, because the stock PC cord is not as good as thier electrical runs. When they upgrade to another PC, which is more of the calibur of thier electrical runs, it improves sound.

There. It is settled for once and all.

If you cannot hear a difference with a high end power cable, then fire yer contractor and hire somone to run some real good quality cable.

I read about 1/2 of that thread and there was alot of immaturity, alot of heated debate, and nobody mentioning the possibility of crappy electical runs installed in the house.

There. It is solved. you can all thank me later.

Im gonna look into electrical runs, and when i buy my house im gonna have it wired up with the best.

because damnit, when i buy that 200.00 power cable, I BETTER HEAR A DIFFERENCE OR MY FIANCEE WILL NEVER LET ME BUY ANOTHER COOL GARDEN HOSE AGAIN! :) :) :)

Peace! :)
Slappy, your comment about the last 3-6 feet is exactly what each of us has asked himself. Ditto with hardwiring your components. The thing is, I think, you have to think about it a little differently. The high-end PCs--some of them at any rate--don't simply provide better signal transfer for that last 3-6 feet, because--as you say--who cares? Rather, they DO SOMETHING to the power before it enters the component. What they do varies and is beyond me, but I think that's what's going on. Think of it not as an extension of the Romex in your wall but an enhancement or filter or whatever to the signal just before it gets to the component. I'm technically unqualified to give any sort of explanation, but this "theory" of how it works helps me make sense of the clear differences I hear with some cords. I wish it weren't so.
The power cables you are disscussing are basically the same; so why should you expect a difference? There is only one power cable that is truly different and commands the technology that astounds;but you won't go there because the answer sounds to radical. You chose to cling to the same old ideas and complain about the results.
The power cables you are discussing are basically the same; so why should you expect a difference? There is only one power cable that is truly different and commands the technology that astounds; but you won't go there because the answer sounds to radical. You chose to cling to the same old ideas and complain about the results.
There are different ways to use your "snake oil."

I have an AC cord designed to eliminate mechanical resonance between the wall outlet and power distributor. Then, the power distributor has a passive filter that clears up the emi/rfi. This combination cleans up a lot of junk fed into the home wiring.
I hear differences between PC's on most of my components, some more than others. Do I think these differences would be revealed in a blind test? Could be that they wouldn't: I personally am of the opinion that blind testing is a very good way to *obscure* fine sonic differences, not to reveal them. But I also believe that the placebo effect is quite real, and can be about equally confounding to sighted test results as is the deliberate confusion intoduced by the blind ABX methodology. Still, although I have to admit that some of the differences I've thought I've heard have been very subtle, elusive, or tough to repeat with consistency, others have seemed unmistakable and unchanging.

Anyway, one of the simplest explanations for why the last few feet ought to matter is the question of shielding. A theory goes that a large portion of the EMI radiation the incoming power is exposed to is actually generated by the system components themselves, therefore making shielding an issue between the wall and the gear. Since stock PC's are generally unshielded, if this supposition is true then it could help explain there being an audible difference. This theory might also be turned around: A stock, unshielded cord might be acting as a 'broadcast antenna', radiating 60-cycle noise that could interfere with nearby components.

In fact, a lot of the potential differences could be explained in basically similar terms - that is to say, that the aftermarket replacement cord is doing something competently that the stock cord did poorly. For instance, if the stock cord distorts the incoming power due to spurious internal strand resonances, this might have a detrimental effect just as it could in a speaker cable or interconnect. Or the stock cord might serve as somewhat of a 'bottleneck' during heavy demand (maybe being too light in guage), current-limiting or time-smearing the power required by an amplifier on transient program peaks.

Or, as Drubin alluded to, some aftermarket cords may be doing something active, like intentionally filtering high frequencies. Or as Sean says, the degree of difference might be directly correlated with a component's power supply quality (or lack thereof). But the bottom line is, if you look at a component's power supply as being in the signal path (which I do, since the output of any amplification device represents modulated wall power, and *not* the original input signal passed straight through), then it only makes sense that purer incoming wall power could result in a higher-fidelity output signal. So in an age when most audiophiles are in some way 'conditioning' their power after the wall socket before it hits their components, it additionally only makes sense that you would strive to preserve that powerline purity between the power conditioner and the gear.

The 'last 3 feet' argument-against also overlooks the real possibility that if you could somehow replace all the powerline wire going back to the breaker box, or to the utility pole - or even all the way back to the power-generation plant - with the same aftermarket PC cabling you use from the wall, then the sound would just get even that much better ; simply because you can't doesn't mean you won't be able to hear *some* (albeit less) potential improvement merely by upgrading the final cord (and particularly if *that* happens to be one of the 'weakest links' in the overall power-delivery chain).

But: I agree that the degree of difference made by aftermarket PC's is probably often oversold to some extent or another, and if you can't hear an improvement for yourself, then just consider yourself lucky (monetarily speaking) and continue to listen happily through your stock cords.

P.S. - It is interesting to note that the brand of amplifiers reputed to have some of the most sophisticated power supply engineering in the audio world, the Halcros, nevertheless are now sold outfitted with base-model Shunyata upgrade PC's as stock. Yes, this could just be clever cross-marketing, but it is highly doubtful that Halcro in any way needed to do this in order to help sell their premium-priced product. Given their 'slide-rule-driven' company image, I suspect they've sincerely determined that anything less would truly be insufficient to serve as their 'stock' cord, kind of a remarkable thing when you stop to consider that at these price levels, many if not most of their customers will be intent on immediately upgrading to ultra-premium cords anyway.
my 1st experience w/pc's was when a friend brought over a
mit pc w/the blk bx. We were listening to "strange fruit"
on a cassandra wilson cd. The cut opens with a "match striking" sort of in audio slow motion. With the stock cord
you could not readily identify the sound as a match but only
tell that there was some kind of little noise. The only component I had w/a iec connector for a pc was my vtl deluxe
preamp. We put the mit in, replayed the track, and realized
that the sound was a match striking. Of note is the following: NO I didnt immediately go buy an mit. I did order
some audioquest heavy guage speaker wire,solid core,unshielded from micheal percy, (he's always popping up
in these discussions isnt he?) and an iec plug and male ac
plug, and made a pc up. Guess what? I could hear the match
strike with this cord too about just as good for about $40.
worth of materials. Further, I later added very fast,soft recovery diodes to the high volt and heater circuits and these actually made the now famous "match strike" even more
audible and much smoother and more detailed. Bottom line,
wether its pc's or soft rec diodes anything that LOWERS THE
NOISE FLOOR is going to be helpful. Made a shielded pc for
my rebuilt dynaco mk III's and they just seemed a bit quieter. All this was about 5-6 yrs ago. Just now getting
back to thinking about pc's because I happened to build 2
mono amps w/removable cords. Also it has been my own and my
friend erics experience that rewiring pwr supply leads w/solid core silver wire also can lower noise flrs. Please
use appropriate guage and insulation.
I was pretty much a power cord agnostic until I had the opportunity to change five of them (to monoblock power amps, VPI SDS, PS Audio P300, Sony XA777ES) at once. Wow. Nothing subtle about the improvement. "Course I have no idea which cords did which, or whether any of it is measurable. But there's no going back.
Just as an aside, if you are still in posession of any of the power cords that you mentioned, I would be happy to give you a fair price for them.
This is one of the more ridiculous ideas in audio, but, to help our nation's economy, I won't discourage people from buying $2,000 magic wires.

However, the suggestion that the power line frequency changes from 60 Hz is completely wrong, and if it were it would have no effect on the DC voltage generated from it. The power transformer might get warmer. No power cord could have any effect on frequency. Power companies maintain tight tolerances not only on on frequency, but also phase, even when the voltage sags due to problems. This is necessary so that different generating facilities can be tied together in a grid, and because many kinds of electrical equipment (eg: clocks) rely on the frequency for a time reference. Actually, once a day, usually around midnight, the power companies go through a brief procedure where the frequency is very slightly modified for a short time as necessary to have the exact number of cycles in one day (5,184,000). If they didn't do this electric clocks would gradually loose or gain time.
The only thing that matters is what YOU hear.
If you try one and notice a difference with high-end power cords, then you might want to buy some. In my system different cables make a difference- some for the better, some not.

This notion that people can't hear the differences rendered when changing cables has always puzzled me. I can clearly hear differences when swapping interconnects, and often power cables as well. Am I a "Golden Ear"? No. I'm just very familiar with my particular system. That intimate knowledge, I believe, is the key to hearing any improvement or degradation in sound quality when experimenting with cables.
Sync to grid that is, Eldart!
If you don't think they matter, than don't buy one.

My Dad likes his Bose headphones. He thinks they are top of the line. I won't waste my time telling him otherwise.

He also thinks a Honda Accord EX is a technologically superior car over an Accord LX; when in fact all Accords are exactly the same; the EX just has more gadgets on it.
You are correct the power cord does not change the 60 HZ frequency. However, the PC has its own resonance frequency and the conflict between the two creates a harmonic structure that is passed into the system producing distortion.
I can share my experience, but I can't verify anything with measurements.

I was a longtime subcriber to Stereophile till about ten years ago. I did not cancel because of the number of ultra-highend reviews, but because of all the discussion about powercords. I just could not buy into the theory that they could make such a big difference, and besides I was happy with my system.

About five or six years later I got a card from someone saying I could resubscribe for about $10.00 a year, and I thought, what the heck...

They were still talking about powercords!!! I decided to take a chance and see if there was anything to all this hype. I went down to the local audio emporium and snake oil dealer and bought one Transparent Audio powercord. It cost about $120 which I did not consider to be too outrageous.

I did not know what to expect in my system with the new cord so I didn't really have any expectations. From the time I plugged it into my amp I heard a very noticeable difference. The mid to low bass was much more pronounced and the soundstage seemed to come from a more quiet background. I was so surprised that the next time I got paid I ran back to the snake oil dealer and bought another powercord. I used this one on my pre-amp and heard more of the same thing as I did with the first cord.

Since then I have replaced all of my PCs with DIY versions of the old Chris VenHaus PCs with great satisfaction.

I certainly am not suggesting that anyone who did not experience the same thing as I, is wrong in their conclusion. I just want to point out that I was extremely skeptical about the virtues of aftermarket PCs, but based on experience have become a believer.
I am of the "for those that can hear, buy.. For those that cannot hear, save your money.
Who cares if somebody ELSE thinks they hear a difference?
I tried some auction Zucable "Birth" powercords and heard a definite difference. So?
YOU are not required to run out and buy some new powercords!!!
For the folks thinking about trying some.. buy 'em used on A'goN and if they suck, sell 'em to some other 'sucker'

I'll qualify my post, as I am a former consumer, reviewer and now marketing and sales person for a company that manufacturers, among other things, power cords.

From within the audio/video trade industry and in professional audio, the "power cords are snake oil" issue is entirely moot. For any that have experiemented, ALL that I know, have purchased and continue to use and endorse some type of specialty power cords, whether in film studios, mastering labs, recording studios, trade-show or electronics design systems.

These professionals didn't purchase aftermarket power cords on a whim or because of a "buzz" or a media review. They purchased them after thorough testing within controlled environments, and within electronics systems that are among the most highly calibrated systems in the world.

Of course, consumers will have varying experiences because of the wide range of systems and contexts power cords are applied in. Forget power cords for a moment, as there are still some that believe most SS amps sound the same and that CD replay stops improving at the $1000 price point. These threads also pop up on the talk boards from time to time and they are equally, er, profound. There are different points of experience across the spectrum, and arguing individual experiences on-line is an extremely complex and non-productive pursuit-- imo.

Because power cords are largely available for personal testing with no cash outlay for anyone that wants to listen for themselves, that would seem the logical course for the curious. On-line argument is for those who will hold their untested beliefs and theory above all evidence and explanation, measurements, graphs etc. For them, the argument IS the point and the hobby, not what may or may not be true. If truth were the target, then these raging debates would be a lot more collegial and less polarized or pointed.

The technical reasons power cords can improve the sound or visual displays from systems of electronics have been explicated here and on AA countless times. 5 minutes spent serching will illuminate many legitimate reasons why power cords or conditioners have the capability to affect sound. I include conditioners because they often incorporate similar design impetus and material constituents as power cords. The big difference in many cases is that they are a "box" and specialty power cords are not. Capacitors and inductors can be put into power cords, and there are some companies that use these. Obviously, these products now have reactive elements in them that at the very least will have a strong and empirically well grounded "chance" to effect a noticeable change in the performance of the applied device.

The most obvious element in this non-issue is that by far the vast majority of consumers who have tried a decent variety of power cords know that some make a noticeable, repeatable difference in performance. For example, they know that a power cord using silver, or ribbon conductors will often "sound" very different from one that uses solid core or stranded copper.

The VAST majority of those that rail against the possibility of a power cord effecting a positive difference are those with NO experiential evidence to back up the claims they make. Jetmek above is the first person I've seen who rattled off some names of power cords and claimed to hear no difference, although there wasn't any specific context offered to butress his stated experience.

In this industry, I know from personal experience that the priciples of many electronics and speaker companies have experimented with a variety of power cords--extensively, and have chosen to use them in their reference, development and trade show systems. Why would any electronics company want anyone to think that their electronics could be improved by a power cord? Because they no them to work. These are all companies who arguably, make some of the most recognized and better designed electronics in our industry.

Audio Research
Balanced Audio Technology
Jeff Rowland Design
Pass Labs
ART Audio
SIM Audio
Edge Electronics
Musical Fidelity(US)
Wilson Audio

There are many, many others, but this short list will suffice to make the point.

What about pro-audio? The empiricists? Mastering engineers? Recording engineers, Record producers, recording studios, film studios? What motivates these people are results.

All of the following well know pro's and studios have chosen to use aftermarket power cords in their systems after extensive testing revealed obvious performance improvements, and repeatable results.

Sont Music (Mastering systems--Japan)
Philips (US Crest National Film studio and SACD production plant)
Memory Tech ($100 mil. Japanese CD/SACD corp)
Astoria Studio (Dave Gilmour's studio UK)
Doug Sax (Mastering engineer)
James Guthrie (Mastering engineer)
Rick Rubin (Record producer)

There are many more, but these electronics manufacturers, studios and engineers are invested solely in the bottom-line of achieving enhanced performance. They develop their testing and recording systems with products that let them hear/see what is going on within the recording, or the electronics/speaker design.

Aftermarket power cords will not work in all systems or for all people as contexts and individual differences vary so widely. That is why most companies and dealers offer trials so each person can determine the efficacy and value of a a specific PC design for themselves.

I see two hobbies evlolving on-line. One is the enthusiast high-end hobby where shared experience is the point of the thread. The other is the endless debate and argument hobby. I suggest leaving argument to the "pro's", and finding ones own experience to share with others.


Sugarbrie, Whats the point of your comment. Im simply asking(wondering) what contribution the pc gives the system and inquiring as to what different peoples real world experiences are and possibly somebody with some measurements to share. I still remain firm(IMHO) that the pc does little if anything to improve. Im buying them cause they look cool.In the mean time I'll still be searching for a pc that may offer a sonic improvement.

There is still 30 or so feet of garbage before my equipment sees the power. The average hi end pc is nothing more than a well made conductor. Some are shielded to ground, but that ground these cords are shielded to is chock full of noise. Its the same ground that the 59 cent outlet socket uses. Now of course there are actively shielded cords. That configuration I'd be willing to try and would not be surprised if it made a difference.

I enjoy reading the different approaches and ideas.
Elizabeth, You're missing the point as well. While I say I cant detect any sonic improvement or difference, I have a BMI pc hooked up right now!

The question is: Is there theoretical evidence that supports the pc. Why should anyone hear a difference ?

At the end of the day its the music that matters. It's just a topic to ponder and maybe people can learn from it.
The effect of a power cord depends entirely on the power supply design in your components. For instance, before modding my amp and DAC, they both improved significantly with low-inductance power cords. After modding I can use a wall-wart ppower supply on the DAC and a cheapo cord on the amp - makes no difference. This is because these components are no longer demanding high-frequency transient currents from the cord/AC supply.
Nrchy, I (and I'm sure many others) had an experience similar to yours. Several years ago, I bought an amp (which shall remain nameless for this discussion) used from a local guy. I auditioned it at his house and was satisfied, but when I got it home I wasn't quite as happy after the first couple of weeks or so. I called him about it to see if he had any suggestions, and he told me that when I had auditioned it, he had been using an aftermarket PC (also to go nameless here) which he found indispensable for getting best sound from this particular amp. He wanted about 1/3 of the price I had paid for the amp for the PC (neither was very expensive), but was willing to let me take it home for an audition first before buying. Back then, I had no experience with aftermarket PC's (not to mention a much less revealing setup than I do today), and though I had read some positive opinions about them, I was quite skeptical about the whole concept, for the usual reasons (read: I had no actual listening experience with PC's). So I got this cord back home, and damned if he wasn't 100% correct ; going back to the stock cord seemed to make the amp only half as good as it could be. So I bought the cord and used that amp for the next two or so years, and to this day that was still the biggest difference I've heard in my system concerning power cords (of course, I also had no power conditioner back then as I have had since).*

Eldartford: I'm glad you corrected the post regarding line frequency variations - this is what I thought, but I also thought it better to let someone technically qualified question the assertion. But about your "one of the more ridiculous ideas in audio": I'll grant you that on the $2,000 figure (no cable of mine remotely approaches that price level, though I'm content to let the market figure this stuff out, and understand that a premium cord could be better in absolute terms than the ones I'm using). But if what you meant was merely the cord idea itself, at any price level, I've got to ask you: Have you ever comprehensively auditioned one at home?

*[As a footnote to that experience, a dealer I had bought from in the past, and who's electronics brand lineup included the manufacturer of that amp of mine, immediately poo-pooed the entire possibility out-of-hand when I told him about my test results, based solely on 'principle' from what I could tell. I never returned to his shop again - not because I was insulted, but because I decided he must either be closed-minded or just couldn't hear. I sympathized with him, and understood where he was coming from, but for a guy in his business I couldn't trust his judgement anymore.]
Audioengr, have you done a control experiment where you take your amp and dac to a city environment with really dirty power, fluctuating voltage, and rfi. Does the power cord independence hold for these conditions? Your result sounds like a very good first step in separating out the elements of the power cleanup issue.
Samuel (Grant), thanks for one of the most well-written posts. Your points about power cords are actually less important than your point about people having different hobbies: some of us are into audio, while others are into Internet arguments.
What amazes me is how heated these power cord discussions are.

Want to see a fight on A'gon? Ask about power cords and thier validity.

As for now, im with Jetmek, i think they look burly as hell and i like the way it looks. I will probably buy them for appearance reasons alone.

Who knows, maybe i will hear a big difference. :)
For what it's worth, my experience is that, yes, an upgraded power cable offers performance advantages over the stock cord. Better constructed connectors, quality wire, a tighter design factor; I guess all these things do make sense. I do have my doubts, however, about any PC over, say, $200.
Audioengr: Glad to see that we are on the same page i.e. my previous comments about deficient design of the gear ( specifically the power supply ) making them more responsive to power cord changes. If you want to take your designs / upgrades to a new level, try installing a Zobel network into the power supply. This will attenuate the ringing that the transformer itself generates. This will make each unit more universally consistent in performance, which in turn would also deal with Flex's question that he posed to you. If using such an approach, you'll find that proper AC polarity is critical.

Corona: While you've never been one to give away any of your design concepts, i'd really love to pick your brain / compare notes. Too bad doing so will cost me hundreds of dollars i.e. having to buy one of your products and reverse engineer it : )

Slappy: I think that people look at AC cords in the wrong manner, much as i used to a few years back. Rather than thinking of them as an extension of the wall outlet, think of them as an extension of the unit's power supply. Since one can design different aspects of filtering and / or reduce the susceptability to picking up / re-radiating noise on the line or noise generated within the equipment itself, what stops one from doing the same with a power cord ? After all, filters are comprised of inductance, capacitance and resistance and all of these electrical characteristics can easily be manipulated in a power cord.

Once you understand this concept, you'll realize that it does not matter how far or long the AC has to travel to get to your outlet or how dirty that AC is. What does matter is what a filter is trying to accomplish, how effective that filter is in achieving those goals, where it is placed within the circuit and if there are any noticeable drawbacks to such an approach.

As far as most commercial designs / designers go, they only look at a very small portion of what an AC cord should and shouldn't do. As such, they typically only look at the "good things" that they want to see and forget about what the side effects are to the approach that they used to achieve those goals.

A perfect example of this is "shielding" While shielding is beneficial in ALL cases, the way that most designers impliment shielding is typically loaded with drawbacks. This creates other problems all their own. Having said that, the drawbacks of poorly implimented shielding may not be as noticeable with some specific types of equipment as it is with others. Sharp audiophiles with resolving systems have noticed this using nothing more than their ears, but test equipment can / will / does verify what and why they were able to discern the suitability of some cords over others with specific pieces of gear. Obviously, there are different methods and materials used for shielding purposes, so take these comments with a grain of salt and an open mind.

JD: I don't remember what specific thread it was in, but it might have had something to do with a Philips SACD 1000. That was the player that i did the testing with. I explain how / why i did that specific testing in that thread. As mentioned in that thread, the really "weird" thing was that the only difference between the two cords used / measured was in how the cable was grounded. While the SACD 1000 has NO ground at the IEC jack on its' own chassis, altering the ground on the AC cord itself changed the impedance of the cord enough to effect the units performance into the system as a whole.

As far as amplifiers designed for musical instruments go, most of them are SO poor that changing power cords might / might not make a difference at all. This is especially true of bass guitar equipment, as the speakers / cabinets that they are using are HORRIBLE to say the least. If you doubt this, you should try feeding a frequency sweep into a bass amp & cabinet and see what you get. The open "E" will be so low in output compared to the other strings that you don't experience the impact or extension that an electric bass is capable of.

Suffice it to say that most all commercially available bass and PA cabinets are utter crap. Once again though, cheap and sloppy vented cabinets dominate the market and sound quality / performance has taken a back seat to efficiency / reduced production costs. I could go off on a tangent about this subject alone, but i won't. If you want further info about this, email me directly. Sean

PS... About 15 - 20 years ago, i used to run a limited edition neck through body Ibanez Musician 944 with active Bartolini's into a Crate preamp electronically crossed into an SAE 2600 ( 600+ wpc ) feeding eight 18's and eight 10's. Yes, i could shake the foundation of the Earth. No, i haven't touched it in a long time as i went into doing sound rather than playing.
Hey Sean: While you were doing that, my '60's hollow-bodied Vox 'Bill Wyman' bass was running through an equally old flip-top Ampeg Porta-Flex with one 15", and I'm guessing about 40 all-tube watts. No, I couldn't shake any foundations, but it *did* look really cool the way the clear lucite "Ampeg" logo plaque got lit up edgewise from below when the power was switched on...

“Hundreds of dollars” to reverse engineer our product? Try thousands of dollars. There are about 45 custom parts that are made by hand and constructed of real exotica. The materials took over a year to source and the few companies that make them have a minimum order would not believe.
Yes it would be fun to compare notes, but you know the problems with that.
The design concepts we are using are really “off the map”. However; since the recent advent of “String Theory” as the dominant position in physics what we are doing does not seem so “out there” any more.
What is the story on the "Corona Power Cord"?
Flex wrote:
"Audioengr, have you done a control experiment where you take your amp and dac to a city environment with really dirty power, fluctuating voltage, and rfi. Does the power cord independence hold for these conditions?"

I recently lived in Portland, OR, where the voltage does fluctuate, but it is nearly always on the high side. This is where I did this testing.

RFI has nothing to do with power delivery. The impedances are too low. It has to do with ground-loops that form loop-antennas at the resonant frequency of the RF.

High-frequency spikes on the power can cause problems, but generally these are filtered-out by the transformer banswidth.

Folks attribute all types of noise to RF and HF noise on the power. The reality is that these are often due to ground-loops and other sources.
Sean - I will try the zoebel experiment. What values do you recommend?
Corona is a Mexican beer...
You mean TOO MUCH Mexican beer!
Corona: I wasn't trying to insult you or "lowball" the value of your product. The figure that i arrived at was based on having to purchase one of your products, not the amount of R&D and custom fabrication that went into it.

Having said that, sometimes just looking at a product and seeing the way that it is designed and the parts used can be a very worthwhile venture. Obviously, duplicating or improving any design takes identical or better parts with the know how to do such. Much of what i've learned has been done by using such an approach and then following through on those ideas where others seemed to stop short. It always amazes me how someone can come up with a very good circuit yet overlook some very simple yet advantageous changes they could have made, in effect, making the product / circuit even better for sometimes even less money.

While i have no first hand experience with your product or design, it sounds as if it would not be easy to duplicate due to all of the custom manufacturing involved. Then again, how hard can it be to design & build a power cord ??? : )

Audioengr: You are going to have to play with values and placement. Try either a 470 / 560 / 680 ohm with a .1 cap to start off with and go from there. This works best on center-tapped designs but is also applicable to "unbalanced" AC too. Sean
Psychic: I think that "Corona" takes his name from the electrical term i.e. a high voltage discharge, not the yellow water & chemicals that someone is trying to pass off as "beer". As far as "beer" made in Mexico goes, Bohemia is far superior to Corona : )

Z: I've recently had the urge to pick up my bass and start playing again. With the holidays coming up, maybe i'll get the time to do so. I sold all of my PA gear and three of my bass cabinets, but i've still got the guitar, the preamp, power amp and two 18's and two 10's. As rusty as i am though, i probably couldn't even play a steady open "E" let alone "Five Bar Blues" : ) Sean
Umm...shouldn't that be a twelve-bar blues? Yours sound about seven bars short of a blues... ;^)
Z: THAT should tell you something right there. It's been a LONG time : ) Sean
Must be all those years of listening to nothing but goth and speed-metal... ;^)

I recommend NRBQ's song "12 Bar Blues" (from Grooves In Orbit) as an antidote. Terry, Joey, Tommy, and Big Al will step you right through it...just like riding a bicycle, it'll all come back to you in a rush. :-)
No problem, I took your interest as a compliment. What makes copying difficult, on most of the models, the internal structure is bonded together any attempt to disassemble will lead to disaster unless you have sourced the replacement materials. If you would like to see a picture of these wonders: click Browse then Cables [power] scroll to Dealer Demos and click PreThrilla and Ampthrilla, the Prothrilla and Supremium are not yet posted.
Any of you Audiogoners that not yet investigated “String Theory” check it out on the “net”; its implementation is what’s going to divide the past from the future.
Corona: Are you implying that your product achieves 'unification' on the sub-atomic, electro-magnetic, and gravitational planes, while operating in 12 looped dimensions so tightly packed into the fabric of space-time that their existence may never be directly revealed to us? (Answer: If the theory's true, than yes - same as for you and me and everything else. But that's the beauty of a marketing plan that invokes untestable hypotheses - you can never disprove it.)
I didn’t say that you did; according to E. Whitten it’s 11 dimensions.
So what does “String Theory” have to do with my audio system; is that your question? Here is a list of conventional electrical engineering precepts which are employed in almost all cable designs to the detriment of all audio systems. The following would not be supported by String Theory.
1. Building a cable without any consideration of the field that surrounds the conductor.
2. Designing a power cable as an isolated entity as if is has no bearing on the performance of the speaker,amp,etc
3. Claiming that electrical and mechanical resonances are mutually exclusive phenomena.
4. Claiming inductance, capacitance, resistance are the central issues in all cable design.
What String Theory is asserting: all revolves around resonance. This has been our position for the past decade.
Why not have forum sub-categories under "CABLES" (IC or PC.)

Forum>Cables>for those who "do" hear a difference
Forum>Cables>for those who "don't" hear a difference

I now belong to the former after being a rabid member of the latter for many years.
I have had electrical engineers, physicists, mathematicians, and palm-readers explain to me the laws and characteristics of an electrical current...I've also visited my doctor for an ear exam. My conclusion is that my ears are right and the theories, although not wrong according to present level scientific knowledge, will eventually be deciphered correctly when more facts are available through experimentation.

I don't own megabuck PCs. All of mine were purchased from Signal Cable. Incredibly well made and the first PC that let me hear the difference between regular equipment cables and after market ones. Although I have auditioned quite a few much-more-expensive cables, the small differences in sound–for me–didn't warrant the expense.

We can go on beating this dead horse until even the flies will refuse to land on it! (However, it was my reading of a few of these combatitive threads that lead me to give other power cables a listen.) So, maybe this carcass still has some meat to pound on.
I strong agree wtih "all revolves around resonance." and that is exactly how I design my cables. Indeed it is the right way and the only way. You just let the secret out.
So lets take one of Corona's cords and check it out on Audioengr's modified amp and dac. If no audible change, what happens in string theory?