There is no conceivable way that a power cord can affect the sound of your amp. All it has to do is be big enough to handle the power. If someone disagrees with this ask them for a scientific explanation.
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leaf - I will leave chastened and humbled if you will merely grace me and any other interested reader with your understanding of effect of power cords on the fidelity of amplifiers. I am particularly interested in hearing you explain the theory and principles which cause this phenomenon. No hand waving, please. Give me real analysis.
I also own the LS25. I have had excellent results with the NBS (Monitor IV or Mine/Serpent II) and the Powersnakes Sidewinder, which are all affordable and "juices" up the performance of the LS25. However, The most significant tweak for the LS25 would be to replace the stock 6922 with NOS 6922 such as the 6H23 from Upscale Audio.) These tube make the LS25 sound like a much more robust and dynamic preap with
Stevemj: I suppose the world is still flat, because you have not traveled around it.
Listen guys, you are just not thinking. The power cord, as far as the amp is concerned, is part of the house wiring. The house wiring is connected to the pole pig. From there it goes to the substation. From there it may go to directly to a dam or gas turbine. There is lots and lots of ordinary wire between you and where the power is generated. Hundreds of miles. So, even if your fancy 6 or 8 ft wire were better, which it isn't, what good would 8 ft of special wire out of several hundred miles do? Nobody here has the foggiest idea how fancy line cord can make an improvement. Nobody is going to provide any evidence at all for why expensive line cord improves performance. And the reason is that there is no possible way for line cord to do anything except lighten your pocket books and send the marketing people who cook this kind of sucker product home laughing.
What you should learn from the fact that one cord sound diffrent to you than another is not that there is difference in line cords.
Stevemj - the power cords can have an effect in two ways that I can think of.
1. They act as filters for noise. Anything other than 60Hz is filtered and doesn't make its way into or out of the system
2. They control the radiated fields around the cord so that there is less interference and pickup with nearby cords and devices.
True that the cord is just part of the many miles of power line. But then, so is the power supply in your amp.
Jaykapur - They do not and cannot act as filters. They can be shielded, this is true. However, you have shielding on you phono cables and the amount of radiation from line cords is nothing compared to the power amp's transformer. The whole house is filled with radiating wire and it's not a problem. This cord stuff is, honesty, a scam.
I don't know whether I should step in this or not. The topic has been debated into the ground and if you want to start another topic Stevemj to debate it some more... you should. But.. Rwd asked for suggestions about cords which means that most likely, he has decided that power cords do make a difference. My suggestion to anyone, is to get several cords with a return policy on all of them. That way you can compare for yourself and if you feel they don't offer anything but marketing hype... simply return them.
AC Power Cord Effects
So, how in the world can a power cord make any difference, if it is properly rated for the current draw, and is UL listed?
Like many questions about audio systems, this one seems very logical and reasonable. Just use Ohm's Law to calculate the current draw, and viola, we have the voltage drop, and we have the cold hard facts, Yes?
Like many overly simplistic answers, this one does not take into account all the facts. Let's look at a hypothetical power amp to start. Lets say it is a moderately high power design, and is rated to draw about 8 amps from the wall at full rated power. That's about 960 watts from the wall. We won't even get into side issues of switching power supplies, which play total havoc with the simple Ohm's Law approach, we will stick to linear power supplies.
So if the AC cord is UL listed for 10 amps, it is likely an 18 gauge cord. Many 18 gauge power cords are rated for 10 amps of current. How is this rating determined? By how hot the cord gets while carrying the rated current, NOT how much voltage drop there is.
In our hypothetical amplifier, the RMS voltage drop in the 6 foot cord would be approx. 1/3 of a volt according to Ohm's Law. This does not take into account the wall outlet contact, or the IEC connectors if present, nor does it take into account any other factors, just the resistance of the 18 gauge wires in the AC cord.
On the face of it, this seems quite harmless. How could a third of a volt make any difference? Well, because the voltage drop is NOT 1/3 of a volt! Has Ohm's Law been repealed? Are engineers all insane?
No, just an overly simplified analysis that failed to take into account ALL the factors. So what could possibly make that much difference. Well, for one, it would help to know that linear power supplies refresh their DC reservior from the AC line in bursts of current, current peaks that are in time with the peaks of the AC line. That is when the filter capacitors are refilled, when the AC line voltage its it's peak value, and the output from the secondary reaches a level above that which the PS capacitors have been drained to. Instead of a nice steady drain of 8 amps, we have current peaks that
last only for a brief moment, and the 8 amps is an RMS amount.
What this means is that because the current is being drawn only for a fraction of the AC voltage cycle, or for about 1 thousandth of a second (one half cycle lasts for 0.0083 seconds). The peak currents can easily reach ten times the RMS value. What is the voltage drop for 80 amps? At this point, the resistance of the AC plug contacts, and even the bond inside the cord between the plugs and the internal wires become a significant factor. It is not hard for the voltage drop to reach 5 volts or more. The AC line peaks never reach the full value, because the line cord has lost some of it.
Power amps depend on receiving the full measure of AC line for their full rated power, so such a drop will reduce the actual output power in a seemingly disproportionate amount. A 200 W amp may be reduced to 170 watts before clipping.
The above (still simplified) analysis assumes a steady signal, and a steady current draw. Musaical dynamics make it a much less consistent thing, and the dynamic demands will cause dynamic perturbations.
This is not the only effect on the power amp. These current peaks can easily cause AC line distortion, and the heavy current draw can generate harmonics on the line, the hash from the rectifier diodes can increase, a whole series of events occurs that are not immediately obvious just by thinking of the amp as a simple resistor and using Ohm's law.
Most house wiring is either 12 gauge or 14 gauge, while many OEM cords are 18 or at best, 16 gauge. Most OEM cords do not have shielding or any provision for reducing radiated EM fields, do not have premium AC outlet plugs or premium IEC plugs for better electrical contact at these junctions.
So what happens with a bigger power cord? Replace that 18 gauge cord with a 14 gauge cord, and the voltage drop will go down by a factor of about 2 and a half.
Include shielding in that cord, and the possiblity of radiated EMI/RFI goes down compared to an unshielded cord.
Shielding and radiated EM fields might not seem relevant since the house wiring has neither advantage. However, the house wiring is not laying right next to the other component's AC line cords, or right next to the line level or speaker interconnects. Reduced levels of induced RFI and radiated EMI/hum fields would not hurt SOTA sound reproduction.
Since the AC power cord is usually laying right in there with all the other AC cords, and probably the speaker cables, and the interconnects (some people even bundle them all together for neatness, OUCH!), it is quite possible that a premium AC cord will help reduce interference in the system, and raise the amount of power available before clipping,
and smooth any AC line distortions, etc.
This is all without even going into secondary effects, or other more esoteric aspects. Just a more nearly correct way of applying Ohm's Law to the real situation. Add in ferrite filters, built-in filter components, shielding effects, and the esoteric aspects, and it should be obvious that AC cords are not at all simple, nor are they a no-brainer.
There is the issue of resonant situations. Certain power cords and power supply transformer primaries might tend to resonate at RF or high frequencies. This resonance might make RFI/EMI problems worse, changing to a different cord will change the resonant frequency, and change the RFI/EMI effects.
The plugs are not a trivial issue either, and may be more responsible for sonic improvements than the other factors.
Hubbel and other premium plugs and sockets will increase contact area and pressure, reducing contact resistance and other contact related problems. It has been claimed that poor AC plug contact can cause micro-arcing, with it's attendant hash being injected directly into the audio component.
It is not as simple as just simple wire resistance. The connection at each end of the cord adds resistance, the wall outlet socket adds resistance, etc.
For the raw wire, round trip:
12 gauge, approx. 6 feet = 0.0206 ohms
14 gauge, approx. 6 feet = 0.0328 ohms
standard AC power cord
18 gauge, approx. 6 feet = 0.0830 ohms
Measuring real AC power cords, I get around 0.128 ohms for an IEC 18 gauge power cord, and about 0.022 ohms for a 12 gauge IEC cord, not including the AC wall socket connection.
Why is the 18 gauge resistance so much higher than just the wire resistance? Ever tear one of those cheap cords apart? Poorly crimped or barely soldered connections are responsible for the bulk of the extra resistance.
Preamps and CD players all have their special requirements: CD players require shielding to help keep the digital hash that back-feeds from the circuitry out of the rest of the equipment, preamps need a nice steady voltage for minimum noise, and freedom from RFI, etc.
Fancy AC power cord geometries might also reduce the inductance of the 6-8 feet of line cord, raising the available voltages. but this would be limited to the ratio between the length of the power cord vs. the wall run. Such geometries often reduce the radiated energy, and aid shielding of the cord.
Some power cords might have a built-in filtering action, like the water jacketed ones, that have the conductors and insulation surrounded by a conductive fluid. This fluid might short out and reduce/damp any EM fields the cord would conduct to the component besides the 60 Hz AC power signal.
It also helps to keep in mind that we are not supplying a Sears rack system, that any system which aspires toward the SOTA is going to be more sensitive to minute effects and minute improvements. How much does a big fat shielded power cord help things? Probably about as much as upgrading from an OEM interconnect or zip cord speaker cable to
some decent aftermarket cables, some systems are more sensitive to AC cords, some are less sensitive to cords.
As always, the bottom line is: you have to listen for yourself, and see if their is any benefit for you, on your system, with your listening habits.
Do AC cords have the potential to influence high end sound? Yes. Does anyone who believes this also believe that high end cord costs are justified? No.
In my DIY AC Cord note, I recommend an $11 shielded heavy duty Belden (now Volex) cord, not a thousand dollar high end cord.
See my DIY AC cord note at:
Some of the cord/cable manufacturers get carried away with using only the very finest materials and assembly techniques, carrying over the technology and costs from their high end audio interconnects and speaker cables.
Is this necessary? I don't know, I will not discount it out of hand. Does it make the cords cost a lot? Yes.
Does this make them dishonest or imply that they are deliberately trying bilk the customer? Not at all.
And how about a little from John Curl
If you are not an engineer or a physicist, it is almost impossible to seriously attempt to explain why a power cord should work. Most power supplies are designed by engineers who don't believe that AC cords should make any difference. For example, I use a $2000+ Stax Lambda Signature headphone system to test power cables. Why? Because that's where they are the most apparent, along with other input tweaks. Apparently the Stax power supply 'leaks' stuff in from the AC power line.
The precise flow of electricity is not well understood by ANYBODY! If you doubt this then get a copy of 'Electric Properties of Materials' Hummel, Springer-Verlag. This is a book for upper division engineers. If you can read a single page and understand it well, you are far ahead of the pack. The simple explanations of electricity flow used by technicans and even most engineers is not enough in this case.
You can check out the entire discussion at:
Kevperro,thanks for the very informative post on the possible benifits of powercords. I have three of them myself and find that they do indeed change the sonics on gear.The bigger gain in sonics in my gear came as a result of dedicated 10 ga lines to my new hubble outlets and 20 amp breakers that i installed.This lowered the noise floor which in turn made my systym sound more dynamic and detailed.
Kevperro - Some of what you say is true. A larger gauge line cord will reduce the voltage drop and thereby increase the maximum RMS power of an amplifier. On the other hand a larger line cord because of its lower resistance will have a higher rate of change of current vs. time. Faster rate of change means more EMI. (If there is anyone out there who knows anything about electricity, well, my appologies)
Now, for the really misleading aspect of your post. You failed to mention that an amplifier playing music at full tilt (occasional clipping) is delivering 5 to 10 times less that its rated power. This trashes all your calculations by 5 to 10 times. Since max power is a function of the square of the voltage, a power lost calulation would be off by 25 to 100 times.
I have no idea whether you were simply unaware the average to peak power requirements of music or if you were being deliberately inaccurate. I do suggest that before you invoke the possible effects of the great unknown that you first come to grips with the simple stuff.
Stevemj: The post is not mine. I should have referenced it better at the start. At the end you will see the signature of Jon Risch. I was only offering it, and the link attached, as a source for a more technical debate on the topic. John Curl was also a part of the conversation and I think that his reputation in the field of Audio is well established.
The problem that I see is that you are not interested in a technical debate of the ideas. If you where, you would find a group of people who have technical backgrounds. If you are looking for a technical explanation why do you argue with what is obviously, people without a physics/engineering background?
The question I have, is what are your intentions? If your interest is helping people, I would recommend that you take it easy on the rhetoric. If your intentions are to inflame hateful debate...just keep up what you are doing. You don't endear people towards your opinions when you come at them from the standpoint of being superior to them.
Well stevemj i have tried power cords stock to transparent super power cord and u can hear a difference. this is on expensive equipment. seems that what ever u do in high end audio it affects the sound, ie@ audio point, racks,sorbane feet, mipingo dots, tube dampers, red rollers , audioquest rf stoppers the list is endless.
So the question is when a manufacturer is testing his prototype amp does he use all these accessories , probably not. So if someone want to spend money for accessories then so be it.I bought power cords not really necessary but they did seem to improve the sound what ever that is?
This whole game of high end sound is so arbitrary because there is no right or wrong, if u like the sound that is what is most important.
If one is not careful the will get caught in the high end spiral of buying and selling my advice to anyone is buy from mainstream manufactures whether elctronics or cables.mixing and matching is for reviewers not consumers
Ontario - This is the proof that much psychology is involved......."seems that what ever u do in high end audio it affects the sound, ie@ audio point, racks,sorbane feet, mipingo dots, tube dampers, red rollers , audioquest rf stoppers the list is endless."...... Try listening with the car in the garage and the car out of the garage, you may hear a difference.
Kevperro - You have a point. After having been called a whore a pimp and accused of jerking off while writing my posts, I haven't much concern for the sensibilities of of folks here. I should because most here are not like that.
At first I was naive and thought that common sense would have some effect. However, the experience of thinking that you have heard some change even tho there is no scientific reason for it is so attractive to many that reason can't compete.
I have asked a few of my most knowlegable engineering friends to contribute, but the stuff discussed here is so wildly farfetched that they won't touch it.
Anyway, I was hoping that some who read but don't post might be saved some money. And, having been a partner in a company that manufactured highend gear myself, I find that I resent the manufactures who are making money selling and promoting these hoaxes.
You realize that manufactures who know better can't say anything because they will lose the business of the people who think that "everything makes a difference". I came here to buy some B&W speakers. I've done that so probably won't be around much anymore.
You shouldn't leave because your opinion is unpopular. You should know better than to troll on this type of topic. Many..many people have spent big dollars on cables etc... Assuming that they are all just imagining the improvements brought about by cables is a rather insulting suggestion. I would ignore your friends advice and try yourself. This mind game you are having over whether you can tell or not isn't even an issue. If I can not tell a significant difference between cable I don't care, but sometimes, you have to be deaf not to hear the differences. If the differences I hear in cables is just my imagination... then I'm having a serious acid flashback.
I have never met Stevemj. I keep reading the same posts over and over, with only a few words changed
here and there, on my computer. I have come to the inevitable conclusion that since I have seen no proof with my own eyes that Stevemj is actually a human and not a computer generated series of ones and zeros, there is, in fact, no Stevemj. Since I have not seen him, he does not exist. Works for me. Seems to work for him too. As for the humans on the site, can we get on with our favorite hobby now and have some fun?
Steve, I don't have phono section, sorry. I can't reverse the balanced set of Transparent. In the not so distant past I accidently hooked up a set backwards ( network at source ) and it didn't sound right. Listened for an hour before finding what the heck was going on. I thought it was just cable that needed to be broken in until I investigated. Maybe it was because of the whole network thing that it was so obvious? Haven't tried it on non-networked cables. Steve, I think it might benefit you to at least list what components you like? own? feel do make a difference? It is hard to make a point if no one knows what your preferences are when it comes to audio.
You should work for the State Department, so diplomatic.
Obviously, stevemj has an "axe to grind" and is not interested in any opinion but his own. It is to his detrement that he is so closed minded about an issue that can be easily resolved by simply listening to diferent cables in his system. Does he have a stereo system?
I can't resist -- this debate is so out of control... At one point in my life when I thought B&W speakers were awesome, I also could not hear the difference in power cords. (I am not saying that B&W are not fine speakers -- I have found that there are others that are much more suited to my listening tastes) Now that things have advanced significantly in my stereo, power cords do make a significant difference, some more than others, and the cord / equipment match is extremely important. I have a friend that is a professional sound engineer that brought his spectrum analysis equipment to my home, and this equipment could detect signal rise and fall timing and 1 db peak level differences when the amp was equipped with a very high end power cord. Is the cord worth 3K??? Are some exotic cars worth $300,000K -- its only paint, metal and leather... Let your wallet, ears and seat of your pants decide... I know which cord is in my system...
Gmorris, Thanks, I try to look at things from both sides if possible. But sometimes will still snap off a reply that I might shouldn't have in the moment of anger. I think it would help to know what he is listening on. If I had been here back in my Yamaha reciever/ cd player days preaching that cables didn't matter.... well then you would know why. Not that it was a bad system, just mid-fi though and tweaks or cableing didn't matter so much on it.
Rather than get catchup in other cable/cord war, I'll jyst offer my personal recommendation of the fine Shunyata pc's and also that AR found their KinG Cobra to mate best with the after-market cords sampled. I would also suggest you look into the equally fine BMI cords. If our resident skepic
will not believe the testimonials given why would he believe our crediable data? MikE
Sure I do Steve, but just barely. I don't see how that matters though. Do I need to know how the combustion engine works to choose the car I like? I don't think I will ever know the theory that you do and I am sure you worked really hard getting there. But I can't ignore what I hear no more than you can not ignore the numbers. So why don't we get to gear that you do like? You would be more likely to win over someone if they at least agreed with you on some other aspect of audio.
No money - Audio is AC. Your interconect cables carry only AC. If there is anything but AC on your cables then something is defective. Now, in order to cary AC your cables have to do just as good a job when electrons go from the cd player to the preamp as when the electrons go from the preamp to the cd player. If the electrons are treated differently by the cable based on which direction they are going, it would make a terrible mess of the signal. So, if you have ever heard a difference based on which direction your cables arrows were pointing, you can be certain it was your imagination.
onterio - I'm not claiming to be an expert on much. I know there are many here who know much more than I about many aspects of audio. I have only commenting on simple things - line cords, arrows on IC's, outlets, cable conditioners. Items that cause the engineers that design the gear everyone uses to break out in howls of laughter.
Steve, the issue is done. I know what I hear and I know I like it. Case closed. Apparantly you just want a debate. I have an idea...... Lets debate SOMETHING ELSE. Maybe some other gear you like? Even if you don't have any gear just make it up. The folks that also have that brand of equipment will at least agree with you there and maybe you can win them over to the dark side then? I thought you knew all about this psychology thing?
No money - With only the tiniest bit of knowledge about electricity you could understand the impossibility of what you have claimed. This would make you a smarter listener.
I think many here prefer ignorance so they can maintain the egotistical believe that they can hear things that baffle the best scientific and engineering minds of our age.
It is not simply AC vs DC and Ohm's law as you are suggesting. The energy transport from source to sink is vey complex. There are no exact models.
I think that you have added to the old adage: " a little knowledge can sometimes be dangerous."
What is your qualification in terms of your technical background?
I use to be a "techno freak" until I realized that measurements cannot predict exactly how a component will sound/perform in a system.
Why don't you experiment with different cables in your system, instead of "shooting in the breeze."
Stevemj: Thanks for the common sense approach. A further deficiency of Jon Risch's "explanation" that Kevperro posted is that Risch assumes that the conduction angle in the primary of a power amp's peak-rectification power supply will remain the same at heavy current demand as at light current demand, and thus he divides the RMS current demand by the conduction angle to come up with an absurdly high peak current figure. In reality, the conduction angle increases as the current demand rises, and thus the peak current rises to only about 50% to 100% above the RMS level. That still points to the need for good power conductors to minimize power loss, but they can be had for a fraction of what the boutique power cords sell for. Power cords that sell for $50, $100, $500 or whatever serve the ego and not the audio.