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R we kidding ourselves about improvement the designated power cord brings to a system? There is thousands of miles of power lines from power plant to our apartment. What do we actually change if we replace the last meter?
What is a sane logical explanation here?
Follow Ups:
If you extend the house wiring from behind the walls to reach directly to the power connectors of your components, it would be the purest extraction of the available line power.Now if you insert a power cord into path, it may degrade or enhance the power signal. Perhaps a power cord can have some filtering properties that enhance the power, but it just seems to me that effects would be minimal and better achieved with outboard power conditioners.
Assume you have an ideal AC power conditioner or regenerator, with zero distortion and output impedance. It will have a standard AC receptacle for its outlet.The power cord that connects your equipment to the conditioner will act as an RF resonator, with a fundamental frequency around 25 MHz for a two-meter cord. The standard AC receptacle at the plug end and the IEC connector at the other end are likely to be impedance mis-matches for the characteristic impedance of the cord. The cord will have a high quality factor (Q) unless it contains special materials that absorb and dissipate RF energy.
Such cords will amplify RF noise at particular frequencies determined by the length of the cord and the signal propagation velocity on it. RF noise in this frequency range is damaging to the audio signal through the processes of mixing and detection in equipment and dirty contacts. Noise may be blocked by the conditioner, but picked up by local induction and/or generated by the connected equipment on the load side of the conditioner.
This is not to say that conditioners are not useful where the AC wiring carries substantial RF noise. However, they may not be the ultimate means of eliminating all noise.
Stock cords that receive UL listing are designed primarily to be safe, not to be low-Q participants in the RF behavior of an audio system.
Al:Resonance at one frequency... very high Q... right?
So... do we need to have RFI at this frequency PRESENT in order for it to be "well conducted" by the cable's resonance? Or is RFI typically "white noise like" in nature, that it's pretty much guaranteed that this resonance will be a problem?
Just wondering. I like your explanations though. Thorough, but "laymanized" enough for the rest of us.
Some RF energy needs to be present to initiate the resonance. The resultant resonant tones can be much larger than the initial input, depending on the Q. Think of an organ pipe: it sounds a strong tone with a modest white-noise input.The requirement for resonance is reflection at both ends of the cable for standing waves. These waves are at frequencies where the cable length (between reflecting ends) is an integer multiple of half the wavelength. The cable can support lots of harmonics (integers larger than 1) as well as the fundamental (integer 1). Some RF noise must be available to stimulate the harmonics, unless the cable itself has some intermodulation distortion.
The RF noise environment can be a mixture of white noise, strong tones at particular frequencies, and a scattering of tones from things like digital signal transitions. Every noise source is different, so it is somewhat of a puzzle to find the ones that most strongly affect your audio system, and the cords or cables that are most sensitive to them.
The issues surrounding power cord and cable sonic behavior share the basic property of RF resonance, but the same cable or cord model may behave differently in different systems, with different RF noise environments. The cord or cable may have adequate damping measures built in to it so that it has superior performance in many environments. However, if the environment were perfectly quiet, then the cable resonance and damping properties would not matter.
This means audiophiles can do simple things to improve their sound, by experimenting with non-audio equipment noise sources under their control. Even if the audio cables and cords are resonant objects, because they lack proper damping, reducing the noise environment reduces the ability of the cables and cords to generate the strong tones that affect the sound.
Look around for sources. Unfortunately, many appliances these days contain computers and switching power supplies. Both of these can be strong sources of RF noise. My worst source was a TiVo digital video computer, which thankfully died after some power surges. Its replacement is quieter, and I've taken measures to filter the noise it makes from the AC power wiring. I've also found that a combination microwave/convection oven is a bad noise source.
Unfortunately, not all noise sources are under domestic control. Even after all the local sources are filtered or removed, the external ones will still cause trouble. This is why cables and cords that are damped against RF resonance will provide further improvements.
Al:"This means audiophiles can do simple things to improve their sound, by experimenting with non-audio equipment noise sources under their control."
This I like. If there is a point where we can start measuring stuff to connect the theory to practice then we're in business.
I am afraid that even if I study transmission line theory and known ways of reducing both induced and conducted RFI, I will be no closer to understanding the how's and why's of a lot of AC cable products.
Then again too, not all audiophile AC products are created equal. I am doubting that resonance issues were taken into account with cables that appear to be nothing more than shielded Belden wire in a fancy sheath.
Much to read and learn about here...
Thanks for your reponse.
Careful laddie, you're likely to raise the ire of a naysayer or two that think outboard power conditioners are pure silliness!
Although everything but my amp sounds better through it. My amp is plugged directly into the wall. I think it's the Furman PST-8 digital.
Actually both of them! Neither very expensive, a Monster HTS 2000 MKII that I've had for a good while, even plugged my amplifiers into it... maybe did loose a little bass weight and quickness but sound from the mids on up was bit ragged when plugged directly to the wall.Recently got a used Chang Lightspeed 3200, so now the Chang plugs into the wall, the Monster plus into the Chang (i.e. piggyback), the amplifier plugs into the Chang, and otherwise everything else goes into the Monster. Nice improvement but I did a minor upgrade to my powercords at same time, just most recent model of the same ones I was using with pretty Furutech audio jewelry plugs. :)
No Guru, No Method, No Teacher
First, the "miles and miles" of power lines is a neat tidy FALLACY that gets used to turn off the brain from thinking.As some folks have pointed out, it can certainly be looked at the other way, that the power cord is the first M, not the last, and in like manner, that it is an extension of the power supply wiring.
But the fact of the matter is, as far as your home electronic equipment is concerned, the power line 'starts' at the transformer out on the pole outside your house. This is the local low impedance source of the 240/120V power that enters the home, and thus, is the real beginning of the AC power line circuit.
For more on power cords and AC power issues, see:
http://www.audioasylum.com/audio/cables/messages/82423.html
and all the previous posts it references.That is, if you really want something reasonable to think about.
Jon Risch
"the power line 'starts' at the transformer out on the pole outside your house. This is the local low impedance source of the 240/120V power that enters the home, and thus, is the real beginning of the AC power line circuit"Well, this is still arguable, but I think it's a darned fine point to start modelling...
If you dissect this circuit, from the secondary winding of this transformer, you get the following components involved:
-Secondary winding to O/H line connections (marrettes? crimp? terminals?)
-O/H line to Service Mast (wires twisted on steel guy wire)
-Service mast to wires in conduit (marrettes and tape)
-Wires in conduit to Panel Main Breaker
-Main breaker load side to vertical panel bus connection (bolted?)
-Panel vertical bus to branch circuit breaker line side connection (snap in?)
-Branch circuit breaker terminal to branch circuit conductor (solid wire in a compression screw terminal)
-Branch circuit conductor terminal to branch circuit wiring
-Branch circuit wiring to wall outlet terminals.Now... if series inductance is the "killer" of quality audio, I want to know what the series inductance of the O/H lines, wire in conduit, and branch circuit wiring is.
I also want to know why a cheap and dirty 15A rated contact in a $5 circuit breaker that is "plugged in" to a $100 panelboard is okay but a receptacle on a branch circuit from this very panel needs to be an oyanide cryo'd high-pull-out-resistance audiophile grade receptacle costing $200?
WHY ALWAYS STOP AT THE WALL OUTLET IF CABLE IS MISSION CRITICAL?!?!
The only thing that I think needs further investigation are claims that special "audiophile grade AC cables" do indeed reduce "conductive RFI" or a cable resonance. (say 25MHz for arguments sake).
But before THIS question can be answered, I would need more proof that this resonance is going to a)result in more RFI being conducted or induced in the components PSU which b)can get PAST the filtering in the PSU and c)cause audible deleterious effects to the audio signal if they even get that far. And even then, I wonder why ONLY THE AC CORD IS A BIG BAD RESONATING THING and why house wiring and wiring back to the transformer is never addressed. I also wonder why the AC cord is thought of as a component, when in fact, the entire current loop from transformer to transformer should be examined, either as a model, or a bunch of "components" in series. How can only the last 6 FEET of cable be "not good enough"? What about the other 100 feet and three other wiring methods that are NOT even CLOSE to being as good as even a $5 serpentine service cord for RFI rejection and inductance? Not to mention the two breakers and how they connect to the panel bus...
It this because expense for lavish cables is okay but thought and effort is out of the question?? I suppose ANYBODY can upgrade AC cords - and do not need an electrician to do this...
(((I THINK SO!!)))
There is a huge difference between "miles and miles" and a hundred feet (or less). Miles and miles turns off the brain, it just can't matter, etc.Of course, you chose to still try to make out the "6 feet" as insiginficant, while all the other arguments and measurement info I posted in the reference material is still true.
Folks should read the cited posts and web pages, and see for thermselves what you have glossed over so casually.
Jon:Not really. I am moreso suggesting that if things like trapping RFI, keeping out EMI, and minimizing inductance is important (and let's say they all are for the sake of this post) then why is it the 6 foot cord that gets the most attention? Is it the worst cable method of all the ones in place? Or just the most convenient one to experiment with, as I suggested?
Keeping out EMI is a no-brainer. Even with proper grounding, why put 60Hz fields near signal sources?
RFI resonances *do* appear to have merit from an engineering standpoint (transmission line theory), but you said something in that article that caught my eye:
"Reduced levels of induced RFI and radiated EMI/hum fields would not hurt SOTA sound reproduction."
Okay, these guys (Sean and J. Neutron) are differentiating between induced and conducted RFI, and there are different bandwidths for those kinds of interference. But your statement makes me wonder. Do we do things in audio beacuse they won't hurt? Or because they actually help? I can do 1,000,000 things that don't hurt - but they're all FREE! I don't think doing things simply to be "on the safe side" is good engineering, and it opens the door for products that "might do something" that we all need to use - to be safe.
I've read soooooo much about cable theory in the past few days I truthfully need to give your article a much better read. (There is a lot there to process Jon). I just liked your concept of what constitutes a "sane model" for looking at this. I do plan to read and digest as many references as I can. The theory alone here is not for the faint of mathmatical heart!
But you must admit: building the "perfect cable" that rejects RFI is amazing. But putting it in the same circuit as wiring that could very well be an "RFI magnet" (and inductive nightmare) does not make sense to me.
And we all know of quite of few guys who put special wiring back to the panel (and even better quality breakers) when renovating or building custom audio rooms.
So? Are these guys on the right track? Or did they just need a better AC cord or two? A couple grand for two good AC cables compared to tearing into walls? I can see the attraction and empathize.
Cheers,
Presto
It is undoubtedly due to changing out an IEC connected power cord is a lot easier than ripping the wires out of your walls, and having a high priced electrician come in and put some other wiring in there.Ever try to work with a local electrician, and ask them to install some high performance wall wiring? Unless it looks just like Romex, they freak out and won't do it.
Going from typical Romex to a shielded heavy duty wiring run is not a trivial expence, especially if you literally have to rip out the walls to do it. Unfortunately, the major expense comes in from repairing/replacing the walls!
Of course, it would make a lot of sense to have superior wiring put in place from the transformer, to the breaker panel and so on. But there are limits to what the average consumer can do and afford.
In most cases, even replacing the breaker panel is a major pain in the behind and wallet, in some locations, unless the panel burned up and is no longer functional, you literally CAN NOT replace it, it is against some local ordinance.
Then of course, there are people in rented houses, apartments, condos, etc.
So dealing with the line cord is indeed the easiest way to try to control the AC power situation. Note that the power cord is the closest thing to the audio components in most cases, while the wall wiring is spaced well away from all the components and cables.
Note that I do not advocate spending $2000 plus on an AC power cord, hence my DIY recipes and recommendations (I believe that I almost single-handedly made the Volex/Belden pre-moulded power cords as an aftermarket replacement, a popular alternative).
Also see:
http://www.audioasylum.com/audio/cables/messages/123367.html
and my two replies, especially the last at:
http://www.audioasylum.com/audio/cables/messages/123437.htmlYou might find those posts interesting.
nt
Interesting John. Just a question: Are you saying then that in general the improvement of going to a premium power cord for Class A devices is negligible (ignoring sheilding for a moment)?
Even in terms of JUST current delivery, not negligible, just a lot less than for Class AB power amps.Note that the crappy connections of the pre-moled cords are still there,the overall resistance of a given pre-moulded cord is still much higher than the high performance cord that is hand wired, etc. Then throw in the shielding, any EMI/RFI filtering, etc.
Audio equipment is designed to run on 50 or 60 Hz AC power. Unfortunately, the good intentions of the equipment designer do not in themselves make the equipment totally insensitive to electrical noise of other frequencies on the power wiring.If nothing but 50 or 60 Hz AC was present in your power distribution wiring, then this would not matter. If roads were perfectly smooth, cars would not need springs or dampers ("shock absorbers" in the USA). The two situations are about as equally likely.
Power cords act as filters for the electrical noise, whether the cord designer was aware or not. Some of the fancy ones are designed to avoid making the noise problem worse. There is much more involved in this than simply shielding or not shielding.
They've been very insightfull. The opinions are- obviously- split on this matter.I dont agree w the first meter theory, because I think the speakers are the ones that actually transform the electric power to music.
Alternativelly, we can describe the stream od signal going from the source to the speakers, but then again this signal is electrical.IMHO, untill it enters the transformer of the amp it is exact the same AC power stream as in the wall, isn't it?
I don't argue someone might hear audible difference... it is then in the "mystical area" as are most other things connected with the passion of hifi anyway...and that we all like to explore.
But if that audible difference is basically reduction of noise, then aren't the cords some kind of filters? They do to electrical stream what tone controls do to the musical output, kind of? They purify the AC stream that gets transformed to DC stream afterwards anyway... and then the lamps come in and flood everything with noise...
Just wanted to thank everyody...
The truth is out there...
Do not think of it as thousands and thousands of miles.Think of it as: why the hell would any sane person design a high gain system that RELIES on the ground potential of the power input cord as the input reference. WHYYY?
As a result of that sillyness, we have gound loop hum as the worst case.
Do you believe that if you can reduce the hum, that the loop is not there???
Coupling to the ground loop is proportional to frequency..and the power amp haversines are a big source of higher harmonics.
If you really want a technical explanation, take it to props or diyaudio...there I can post pics..
It's amazing how an audiophile will trust an electrical engineer to design all the circuits inside the case of a component, and pay a lot of money for that component, even though the same engineer has visibly demonstrated his "limited skills" by attaching an "inferior" power cord to that component case! One can only wonder how bad the circuits are INSIDE the case!The good news is the power cord is only in use for a very small fraction of each second and does nothing except collect dust the rest of the time.
The audiophile obsession (and spending) on wires makes no sense when the room and speakers are by far the weakest "components".
Many audiophiles spend little or no money on improving room acoustics.
It is possible for an audiophile to need extra/better RFI shielding for his wires in unusual situations.
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rw
While I am not supporting power cords Richard there are many engineers making very high grade amplifiers who do in fact use much higher grade power cords because they think it matters over say the $100.00 Pioneer amp sold at the supermarket. Perhaps the guys at pioneer also use a better power cord with their elite products (in fact they do - so it may be that some are simply cutting the corner on the power cord because it meets the safety standard even if not a sonic one.This is merely to be devil's advocate but the power cord on a Bryston is a lot better than cheap stuff - and Bryston is not a power cord supporter - their idea of minimally acceptable though is significantly higher than the cheap stuff at wal-mart.
Thus all the engineers using anything beyond bargain basement wie must think it matters -- at least to a small degree. And unfortunately once you have them ALL going the small degree then it opens up to spend $40,000.00 on a power cord which may who know offer a very small degee of the small degree.
Too funny!
A favorable review from a magazine, friend, or salesman, that led to the audition of that component could bias what was "heard" if the component's brand/model was not hidden during the audition.A person who really wanted to trust his own ears would NOT want to know the brand/model of component he is auditioning because those facts are not necessary to judge the sound quality.
This is just common sense applied to prevent what you know (or think you know) about a component from biasing a purchase decision that you really want to be based on sound quality.
Maybe YOU need to know the brand and model of component in use to determine how it sounds.
I don't.
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Richard BassNut Greene
Subjective Audiophile 2007
How to explain audiophiles--scads of 'em!--who read the good review and end up not liking the unit or, even worse, preferring the sound of a cheaper one with a less impressive faceplate?
Power cord audibility is strictly overactive audiophile imaginations.The power cord is not part of the DC music circuit within a component, except for very brief AC power inputs.
Power cords have no effect on room acoustics.
They are equivalent to Clever Clocks, except in a rare instance of unusual RFI that COULD be affected by a power cord.
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Richard BassNut Greene
Subjective Audiophile 2007
. . . the way you bob and weave while avoiding answering the question. ;-)I'll bet your wife loves you for it.
Meanwhile, I manage to overcome my imagination on a regular basis and evaluate components, drivers, and parts by how they sound. The results often surprise me. Apparently they'd surprise you, too!
If my aural judgment were that succeptible to "imagination" I'd have a lot of trouble doing the work I do. In fact, I'd be unemployable.
Power cords have no effect on the DC music cicuits, or on room acoustics.
Differences" are entirely in your imagination.
An active imagination has nothing to do with "evaluation".
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Audiophiles are perfectly capable of making judgments about the sound of things without regard to the bias they may or may not incur from positive reviews, manufacturers' reputations, internet postings, the thickness of the faceplates, or the price tags. That audiophiles routinely overcome such biases to the extent that they often prefer less "impressive" products. And that audiophiles sometimes hear no difference at all.Except for power cords.
Real audiophiles always claim to hear a difference.If they don't, they will be called Tin Ears and told they have a Mid-Fi stereo. You could look it up.
It's not possible to know something about a product and then be completely neutral during an audition.
Maybe a Vulcan from Star Trek could do that, but not humans.
The fact that you are auditioning a component already suggests you walked in with a positive opinion about it.
Just asking a salesman to hear a specific component is a statement about yourself as an audiophile, and that statement means you want the component to sound good.
But the opinion you have AFTER the audition may have absolutely very little to do with the positive opinion you came in with.
That's because so many auditions are not done at home -- the room and every other component will be different when listening in a store, or at a friend's house.
Therefore any opinion about a component auditioned outside of your home ... is almost meaningless.
True if the component was a speaker, the mid-range and treble output in a store would be similar to what would be heard at home.
But the bass would be quite different in a different room.
Any audition of an AC cord is meaningless because AC cords have no effect on the amplitude response and timing of the sound waves we hear.
They could only affect hum and RFI ... if those problems had been audible (rare).
Auditioning an A/C cable in an audio store is the silliest thing I've ever heard about audio.
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Richard BassNut Greene
Subjective Audiophile 2007
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nt
Except for components borrowed for a trial at home, which may be for only a day or two, audio components are often judged in different rooms and used with different components than they would be in their final destination: The audio system in YOUR home.And there would different AC lines in different locations.
The usual audition methodology, which usually includes comparing components playing at different volumes, along with the possibility of imagining differences because the listener expects to hear certain things with the brand/model in use ... leads to a high probability of a listener claiming to hear 'differences'.
In fact, the typical methodology for auditioning components almost guarantees "hearing differences" even if the same component is used!
Component A heard at a store, or heard at a friend's home, is VERY likely to sound different than the same Component A heard in your own room ... simply because the rooms and associated components are different. The SPL's are likely to be different too, not to mention the AC lines.
If an audiophile wants to audition ONLY the sound quality of a component without "expectations bias', then the component must be auditioned long-term, at home, with the brand name hidden.
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Richard BassNut Greene
Subjective Audiophile 2007
"If an audiophile wants to audition ONLY the sound quality of a component without "expectations bias', then the component must be auditioned long-term, at home, with the brand name hidden."But why stop there? I mean surely if the audiophile were aware that some new component was installed this in and of itself could involve expectation bias that might well affect subjective evaluation.
Don't you think it would be better if the retailer snuck into the prospect's dwelling and secretly swapped components. Then the dealer could monitor the audiophile's internet posting to see if he/she were adopting a more favorable attitude, i.e. expressing more joy from the listening experience. If this were detected the dealer could then send out an invoice. However if no change were detected, or worst, the audiophile now seemed less pleased, the dealer could sneak in again to install some other component.
What do you think Mr. Nut, sensible ain't it?
ROTFLMFAO
(no standards = "I know what I hear and could never be wrong")
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Richard BassNut Greene
Subjective Audiophile 2007
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No Guru, No Method, No Teacher
I do have to admit that when you follow my advice to only post (nt) posts, it saves me a lot of time. Not that I ever got past the second sentence of your message before falling down from laughing so hard from your usual lame character attack.
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Richard BassNut Greene
Subjective Audiophile 2007
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No Guru, No Method, No Teacher
that next time I try different caps or opamps in one of my DIY projects I'm going to have to tape over the brand names?When I try out new drivers in my speakers, will I have to have someone else install them?
If I had to evaluate everything I use in my stuff with a DBT, I'd still be on my first crystal radio from 45 years ago.
Fact is, when I evaluate such things--and components, too!--sometimes I prefer the cheaper unit over the hoity-toity brand, sometimes the opposite, and sometimes I hear no difference at all ! The horror!
Me neither. I just want good sound. I don't care what others think of a brand. I may read what they say but that's it. I need to try things for myself.
d
I blame Irritable Male Syndrome.
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Richard BassNut Greene
Subjective Audiophile 2007
c
Or to be more specific, a mood worse than usual!Since we are talking about AC cables, which have no proven effect on sound quality, the only two variables are whether you are in your usual bad mood, or in a really bad mood, during the audition day ... AND whether or not the brand name affects your bad mood that day.
If you are in a bad mood even worse than usual, and don't happen to like the sound of the brand/model name: "Irving Lipshitz Clever Cable", not that there's anything wrong with that, then what chance is there of you liking "the sound of" the "Irving Lipshitz Clever Cable"?
I'd say almost none.
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Richard BassNut Greene
Subjective Audiophile 2007
...were a cable named Stanley Lipshitz, would *you* listen, at last?clark
Funny to me and many others.Maybe unpleasant sounding to you.
And how would you know someone named Irving Lipshitz is Jewish?
Are you stereotyping?
Do you just assume a person's religion based on their name?
Based on my name, am I Jewish?If you have a few funny names that don't sound Jewish to you, then please provide them and I'll use them next time I disagree with you in my post.
Clark Johnsen is not a funny name.
Richard Greene is not a funny name.
Irving Lipshitz is a funny name ...
... unless your name is Lipshitz!
> If you are in a bad mood even worse than usual, and don't happen to like the sound of the brand/model name: <I'm going to assume you meant... "and don't happen to like the *look* of the brand/model name..."
Interesting conclusion. How did you arrive at it? It appears you speculated the conclusion - a cable is liked or disliked because of our mood and its appearance - based on an unproven and thereby faulty premise - that it can't be because of sound since cables have no sound.
Why not just say that if we eat peanut butter on one day, we'll like the cable and if we eat jelly, we won't? :)
At any rate, I do not like the appearance of my interconnects and speaker cables. There have been numerous products that I have loved that did not look like anything one would brag about. It's not looks. And if it's mood, then during auditions for my own personal gear, I must be in the same mood several days in a row.
Nice try but it's not an answer. See markrohr's response above.
...no evidence even! Yet behold him demanding same from others.Will he ever take a step back and look at the spectacle?
The "Bias" thing simply doesn't hold. There have been numerous pieces of gear that some reviewer has extolled the virtues of that I thought was not right for my system. There have also been pieces that were met with less than enthusiasm in the audio press that I've loved and purchased. Granted, we've all probably been caught up in the hype of something but no one has ever shown to my satisfaction that the bias argument holds any water. Quite the opposite, in fact -it falls on its face via empirical evidence.
xc
You do have more ranting experience than most.And how do you find the time to read this post, given how busy you are with your 20,228 posts?
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Richard BassNut Greene
Subjective Audiophile 2007
as
Any theories on why it only comes up occasionally with respect to audio gear, even without DBT's?
Then again I had the "pedantic one-liner" filter on...Lemme try again... :o)
Cheers,
Presto
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No Guru, No Method, No Teacher
Which is why I neglected to include a brand name on the wire I sent ya..(actually, it never occurred to me to stamp the stuff..:-( )Did you receive the package of wire? I made the assumption that "ribbon wire" as a descriptor would satisfy customs..and you haven't answered my e-mail query..
Now the beginning of a likely even longer delay. Patience!
No Guru, No Method, No Teacher
Sheesh, that took forever. What happened, did customs rip the box open or sumptin?? Perhaps a sticker from australia or hawaii?Cool.
Be careful when separating the ribbons, I do not know if the tape I used is prone to rip. I hope there is not too much difficulty pulling the tape off the wire where the lugs will be soldered.
What am I, chopped liver?
If the wire ever gets to bjh, he'll still have to have terminations soldered to them, like lugs..I recommended he not go crazy with the lugs, just a good joint. That way, if he doesn't care for them for whatever reason, he could ship em out to somebody else for a try.
I leave that up to him..
The cost to him is a post detailing what he did, and his impression of the wire. If he does so, and doesn't want them, I requested he pass them on..and I'll eat the cost of manufacture...40 cents per meter..
Yeah, I'd like to check 'em out. What did you send bjh? Lengths etc.
I sent you a pic. It was 12 foot give or take, of a four ribbon construct. bjh will cut to size.. a valhalla clone, albeit slightly wimpy in the resistance aspect as a main, better as a biwire top.. I am considering doubling or tripling the copper to get to valhalla levels of "quoted" resistance..I say quoted, as I've never measured them for a check of the vendor's claim.Cheers, John
I cannot speak for others here, power cords do sound different. The mucho miles to the power station notwithstanding.And the right power cord will enhance the enjoyment of an audio system.
Thank you for permitting me to hold my own opinions. Very generous of you!
Try it yourself and see. I am not kidding myself. I too was suprised. Remember the units take the AC and then change it to DC....but a good power cord still makes a big difference. Technical explinations don't mean anything to me when it comes to things like this. The only thing that matters is does it sound better. They do.
> > .
There would be no windbags without air!
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There is thousands of miles of power lines from power plant to our apartment.Is thousands?
The PC is the first meter. More importantly, it is nearby the villains the cords are trying to combat - RFI sources like CDPs, digital cable boxes, computers, wireless phones, routers, etc. all found within your house - not at the sub station.
I guess you've never used a water filter before.
A water filter . . . . in my sound system? actually no!
The part about the water filter sums things up quite nicely. Regardless of the length or quality of the path taken, the majority of contamination accrued along the way can be removed prior to end use.I've learned to look at the power cord as an extension of the power supply rather than an extension of the AC outlet. When one looks at it this way i.e. as part of a tuned network rather than just basic cabling, it tends to make more sense. Nobody would doubt that altering the tuning / bandwidth of the power supply could make a difference, would they? As previously mentioned though, some power supply designs are already quite advanced, negating many of the "benefits" that one might achieve using various power cords on lesser designs. Sean
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z
"Regardless of the length or quality of the path taken, the majority of contamination accrued along the way can be removed prior to end use."Not with a shielded cable in a fancy sheath it can't.
Cables can prevent noise from getting in, but if you are buying a cable that is being sold as a noise filter, I have a perpertual motion machine I want to sell you. The only way to "filter" noise is to do just that - use a filter. It's much easier to clean up DC that it is to clean up AC anyways, and people that design audio circuits typically know this. Claims that "it must be the lowered RFI" that makes this alleged difference are interesting. It's always amazing with controversial tweaks that everything above the audiophiles threshold of audibility is BELOW the sensitivity of the finest electronic instruments on the planet. Only in audio does human perception trump higly sensitive instrumentation.
If companies like Lynx can make pristine sounding PCI cards containing analog output sections using a computers PCI bus power (the noisiest power on the planet), then there is nothing a competent circuit designer can't do with 120VAC.
This "ignore the engineers - we know what we hear" mentality is where the discussion should really end, not begin.
I for one believe if you can't measure any improvement in power quality as a result of that cable, the only possible benefit could be lower series resistance... if the IEC cord was the limiting factor in the first place. It's usually the branch circuit wiring that causes most of the voltage drop when large amps are re-charging suppply caps. Good amps will have enough supply capacitance to have minimal voltage drop on the DC supply rails.
Unless you're playing Beyonce at 120db with dual 18" subs.
In which case you're more of a DJ than an audiophile anyway - precluding the need for $2000 cables.
RF is very sensitive to impedance. By manipulating specific electrical characteristics to purposely alter impedance in a controlled manner, the susceptability to picking up external RFI and / or conducting existing RFI already on the line can be drastically reduced and / or negated. The same can be said about EM fields to varying extents.As to believing that shielding is a cure all to RFI, i am not of that school. In fact, i know that shielding can create as many ( if not more ) problems IF improperly applied. If you've read any of the hundreds and thousands of posts that i've made either here or on Audiogon, you would be well familiar with this fact. Most all commercially available products that i'm aware of apply shielding in what "I" consider to be a less than optimum manner. I'm sure that there are some products out there that don't fall into this generalization on my part, but i'm simply not aware of them at this point in time.
As to "measuring" the differences in performance when changing cabling, i've done that more than a few times. Not only in the amplitude and bandwidth of distortion characteristics, but also by taking in-room frequency response measurements. I can do this with good and repeatable accuracy due to having the necessary test equipment ( HP distortion analyzers, HP spectrum analyzers, HP tracking generators, Tek scopes, etc... ). I've discussed this in the same hundreds and thousands of posts that i've made both here and on Audiogon.
Obviously, i'm not of the audiophile persuasion that thinks that one can wave a magic wand or sprinkle fairy dust and hear a difference. I know that much of what we hear can easily be measured. Having said that, i also know that much of what we hear is not easily interpreted by standard test procedures. As such, this gives us further reason to expand our knowledge and the test methodology used. Hopefully, we will continue to do so until we can not only measure and quantify such things, but also understand and explain them in both reasonable and logical terms.
At one point in time, the greatest, most learned minds in the world thought the world was flat. Many of these same folks would have also sworn that the Earth was the center of the universe. As such, they were promoting certain ideologies that were less than fully understood, even though they were accepted as fact. In the long run, those very learned and great minds ended up being a stumbling block to further knowledge and exploration. In effect, they were part of a problem that they helped create, not part of the problem that they helped resolve by working towards a solution.
Those that found the solution were those that ignored conventional wisdom. They took it upon themselves to learn and experiment on their own. That's how i got to where i am today, as i too was once a "cable naysayer". That is, until i actually tried, tested, heard and later measured the differences.
All of this does not make me smarter than anyone else, but it does change my level of understanding and therefore provide a different perspective. As i've said many times before, i know what i do because someone else took the time to help me explore and understand what was already common knowledge to them.
With all of that in mind, your ears & brain are more sensitive than you think. If you do some testing, you'll find that proper testing and interpretation of the results will, most of the time, verify what your ears & brain have already told you. That is, if you're a skilled listener and have the technical background to properly interpret the results.
Most people aren't skilled listeners, even though they might qualify as "dedicated audiophiles" or "avid music enthusiasts". Most people also don't have the technical background to properly interpret test results, so they resort to trusting their ears and picking what they like most or seems to work best in their system. Since everyone hears slightly differently, and has slightly different personal preferences, there's no wonder that it is hard to reach a general consensus in this area. That doesn't mean that we can't hope to achieve such results though, through further testing, experience and education. Even with all of that, removing personal bias from the equation would be a tough task to conquer. Sean
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"RF is very sensitive to impedance."I have to assume you mean radio frequency currents driven by radio frequency induced voltages (since the only thing that is 'sensitive' to impedance is current).
"By manipulating specific electrical characteristics to purposely alter impedance in a controlled manner, the susceptability to picking up external RFI and / or conducting existing RFI already on the line can be drastically reduced and / or negated."
Excellent. Now explain how and we're done here. A mathmatically model is usually best for explaining this electrical stuff.
"The same can be said about EM fields to varying extents."
That's funny because "EMI" and "RFI" are the same thing. What causes RFI? Is it not an EM field resulting in induced voltage (transformer action) in cables that drives a current commonly referred to as noise? Does not an induced "noisy" voltage drive a "noisy" current?
Again, we're seeing much "this is how it works" with no mathmatical models behind it. Your "explanations" are more thesis statements than explanations - they offer no explanation at all, they merely state a theory.
Proof may be in the pudding with listening tests. But not in engineering. Proof is in the math. Feel free to post some of the many measurements you have taken to demonstrate your claim in the bold typeface above, if you feel that would help demostrate your theory.
In fact, until you step up to the plate and define WHICH electrical characteristics you are manipulating, how you are manipulating them, and how this directly (or indirectly) affects RFI conductivity, there is nothing to prove or disprove here because nothing has really been said.
Since you claim to have a high level of understanding of both electronics and math, start juggling various levels of inductance and capacitance around while looking at bandwidth, conductivity and power transfer. In order to achieve desirable levels of specific electrical attributes, one may have to play with certain conductor geometries, possibly even multiple different geometries in the same cabling.Since your so well versed in electronics, you'll know that multiple complex impedances can be summed up according Thevenin's Theory. As such, a multiple geometry cable such as described above would provide us with a nominal impedance. With that in mind, the impedance at any given point might be quite varied as frequency is altered due to the distributed impedances along the length of the line. In effect, one could build "traps" into a PC should they desire to do so. How effective these "traps" are would depend on how involved or complex the cable builder wanted to get.
Amongst the various geometries, one might also find varying levels of sensitivity to both radiating and receiving RF and EM fields. The key here is to find geometries that achieve the desired results within a given frequency range while rejecting or lowering the ability to transfer signals outside of that bandwidth.
As a side note, RF & EM fields are typically considered to be two different things when discussing audio. As a general rule, EM fields typically pertain to low frequency fields surrounding transformers and power cabling, etc... RF is typically considered to be high frequency energy generated by some type of transmitting device.
In case you weren't aware of it, there are vast differences in the range / field intensity that these two different frequency ranges are typically radiated. On top of that, some forms of "shielding" can work reasonably well over a given bandwidth but are almost useless in another frequency range. Trying to deal with both EMI and RFI as being one in the same, which many "engineers" and home-brewer's do, may result in designs and products that are anything but optimally designed. It is this single minded simpleton's approach that introduces many of the other side effects that some audiophiles find particularly objectionable.
For the record, varying the impedance of a circuit most assuredly alters BOTH the current and voltage. You can't change the voltage or the current without altering the other. The only way to alter either voltage or current, with one directly effecting the other, is to alter the impedance of the circuit.
I'm not about to put you through school though, especially since you already have all of the answers and know everything that there is to know about the subject at hand.
"...start juggling various levels of inductance and capacitance around while looking at bandwidth, conductivity and power transfer."Conductivity does not change with frequency as it is a function of static resistivity , conductor cross sectional area, and length of the conductor. Perhaps you meant conductance . Or maybe admittance .
"In order to achieve desirable levels of specific electrical attributes, one may have to play with certain conductor geometries, possibly even multiple different geometries in the same cabling."
Define: "desirable levels of specific electrical attributes" (Or perhaps just name the electrical attributes, and explain what a "desireable level" for each would be.)
So basically, if I am to understand your very detailed approach to AC cable design, if one "juggles" RLC values and "plays" with multiple geometries, he can lower "excessively high" series inductance from somewhere in the order of a few pH/ft to ?????? (some unmeasureable value?) and create traps to block "certain" radio frequencies by some "desireable" amount.
WOW! So far we're doing a whole lot of juggling and playing, but you're still nowhere near a definitive explanation.
Perhaps cite some known phenomena or electrical principles (so far you've mentioned Thevenin where good old Ohm's law would have sufficed - you don't need a Thevenin equivalent circuit to add parallel complex impedances or at least you didn't when I went to school back in '93). Maybe put forth some measured data or name some specific geometries or talk about which geometry is GOOD for lowering inductance. Maybe mention ONE SINGLE ORDER OF MAGNITUDE for just a few "electrical attributes" instead of repeating the word "desireable" all the time. Maybe tell us *why* a stock cords inductance is unacceptably high for most audio circuits.
If juggling and playing is the best you can describe the mathmatics and methodology for implementing RFI suppression in AC cable design, then maybe you could have your "guru" post here. I am afraid your version of his story is far to watered down to be of any value.
Oh, and "for the record", if you want to put me through some schooling, be my guest. I'll take your money. So long as the courses are being taught by actual professors and mathmeticians.
First of all...Sean: "On top of that, i'm not going to hand anyone a bone when i normally get paid for the research that goes into my design / consultation work ( which is non-audio based )"
He he he... that was pretty obvious. Don't worry - you didn't give any trade secrets or methodologies away in your explanation!! :o)
Second of all... (both of you's guys)Q: If we are stuck with a certain source impedance (looking back from the wall plug) we get an X/R ratio that is pretty much set (unless we tear the Romex out of the walls - which has the worst possible geometry for inductance). This being said, how is having 6 feet of cable with a minimized series inductance (referring to the low frequency model of a cable here) going to make a difference in the source impedance seen by component's power supply? How can we "pretend" the source is a perfect source when it's connected in series and far from perfect? Sean: are you for replacing the Romex? I know you don't like it. (I think if I was finally CONVINCED that I need a $2000 AC cord for my sources and amps I would have a hard time justifying connecting them to a branch circuit with 40+ feet of #14 Romex!)
Third of all....(again, fire at will...)
Q: Let's say we are looking at an AC cord that is connected to a power supply that has both line-line and line-ground coupling capacitors in the microfarad range to deal with the RFI in the sub 30Mhz range (ballpark for RFI that is conducted and not induced), then how does manipulating cable capacitance in the PICO farads make any difference? Are not the capacitances of the cable also from L-L and L-G, putting them (effectively) in parallel with the caps in the power supply filters, thus making the capacitances of the filters and the cable additive? If so, then how is adding a few picofarads to a few microfarads of filtering going to change RFI conductivity for the "conducting" portion of the bandwidth?
Oh - Sean is allowed to leave blanks in his answers, but he must use the correct number of underscores to represent the correct number of characters in each word, and must allow us to "buy a vowel" at current market prices. When a word is guessed correctly, he must then procure the services of an aging but still really hot woman to flip the letters around.
Fourth of all:
Q: RFI is everywhere. Good thing we can't hear it - we'd go crazy. Let's say we can objectively reduce, minimize or even eliminate RFI. From either (or both) or you: are there some components that will benefit more than others (inherently) from reduced RFI? When does "reducing RFI" become an audiophile feel-good psycho-somatic pipe dream? If amp and source designers are getting their gear to spec and sounding really good, why would they investigate better AC cords and make them "part of the power supply?" If they can reduce RFI with power supply filtering and do it well, maybe they figure the cable's contribution to reducing RFI is too small to be worth the bother and expense? Or are these guys really that bad that they filter to meet FCC requirements and call it a day?
Questions are just brain-teasers to provoke thought and discussion...
Cheers,
PrestoAnd thanks for chiming in J Neutron. I was thinking when I was circling around this topic with what little theory I know on the subject... "I bet Neutron knows something about this!"
Nothing in what I have said related to the transfer of any bad stuff through the cord from the wall outlet.Everything I speak of is related to the amplifier ground reference being bounced about by magnetic flux changes.
The inductance of a line cord comes into play in my discussion simply because the higher the cord inductance, the better the cable is able to create an external magnetic field. THAT is what is picked up by the ground loop, and mucks up the amplifier's ground reference.
Historically speaking, tying (either hard or soft) the amplifier input ground to a wall socket safety ground is a huge no no. I've experienced this problem and solved it more times than I care to count..
Oh, and romex in wall? If you want to create a dipole 60 hz magnetic field, how better than with parallel wires? This guarantees flux entrapment.
I'm not about to tell you inch by inch of what works, what doesn't work and why. This was all something that i had to learn on my own AFTER many lengthy debates coming from a "cable naysayer" point of view. Some here will remember these debates, as they were "schooling" me based on their own personal experiences and audible observations.The education that i picked up along the way has been quite valuable. That education, along with the test results that i obtained, helped to confirm the aural observations that i had made with my own two ears using very differently designed gear. I could only wish that you might have a similar experience and awakening. Without actually doing something and trying things out for yourself, there's little hope in convincing a follower of theory / desk jockey. Not everything goes according to theory in the real world, simply because the real world is far more complex with tons of unknown variables present at any given time. Sean
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-I have custom braided AC cords (just for fun). I got about 1 whole twist per inch into that 12gauge wire!! (I want to experiment with multiple twisted pairs next, or maybe some concentric geometry stuff. Or maybe BOTH as you suggested! Bwah ha ha ha ha!!-I have custom UTP unbalanced interconnects using various kinds of wire - PVC insulation, FEP Teflon, Kynar, with small gauge / mega-twist construction. No shielding at all. Just UTP. Work great.
-I also have MIL Spec teflon insulated and jacketed silver plated OFC cable for my balanced to unbalanced 6-channel conversion cable/snake for using 3-way stereo digital or analog active crossovers with unbalanced gear. Very pretty.
-I made a digital cable out of 75ohm CATV cable with a nice copper braid (the foil and foil drain wire stuff doesn't solder worth a lick). Added nice nylon braiding and blue heat shrink for added psychoacoustic benefit. Did not use transmission line theory to come up with the length - which I chose to be 3.128954348 feet. SNIP!! Cable is RCA to XLR, pins 1-3 tied, conversion cable for 2-wire SPDIF to 3-wire XLR AES/EBU/SPDIF input. (Works nice with Behringer AES/EBU/SPDIF input)
-I have a nice pair of Allen Wright's braided 2+1 conductor "three-nine" solid silver 'fine-wire' interconnects using teflon tubing (and some air!) as a dielectric (similar geometry Kimber braided stuff in theory).
-I have custom speaker cables, some are from Allen Wright's super-cables cook book (similar to interconnect design) and some CAT V jobbies I whipped up using 3 parallel twisted pairs, re-twisted and re-wrapped in their original skin and sealed up with black expanding nylon brade. Used banana jacks for amp end and Neutrik Speak-On cord ends and sockets for the speakers. Pairs were separated and color matched in true "audio obessive" manner. In the end, I only used the blue and white ones.
C'mon Sean. Does this sound like the work of a desk-jockey propeller head engineer?? No way man. This is shoot-from-the-hip DIY madman stuff done by a technologist caught in the chasm between theory and practive man!
Do these crazy DIY products make a difference? I can't honestly say. Sometimes I believe it does and other times I think lamp cord and $10 interconnects and IEC cords sound just as good. One thing that scares me... if I didn't engineer these products and they sound good it means that either:
a) the basic topologies are of sound design
b) the topoligies used are crap and I just can't hear it
c) the topoligies really don't matter as much as once thoughtWhich is it?? And for which cables?
Ah... but there is the RUB!
Sounds like you've been busy building and trying various cabling. Kudo's to you and thanks for sharing that. You originally came across as a "cable naysayer" that simply wanted to crunch numbers with no concerns for actual real world component interaction.I started out doing much the same, then i let the science that i knew and understood start working for me. Optimal or near optimal cable designs aren't that hard to figure out when you make a list of the pertinent criteria and analyze it. Then you have to come up with a design that meets all of that criteria as best possible with the least amount of compromises and / or the best that one can do within a given price range. In most cases, phenomenally good cabling can be made for pretty reasonable prices without bending over backwards or resorting to highly exotic materials.
It has been my experience that most people buy poorly designed gear or gear that isn't well suited to work within the same system and then try to band-aid the less than stellar results via cable changes. While this is completely backwards in my way of thinking, it is my opinion that this method of system assembly is what has fueled the high end cable market since the beginning.
Most people end up using cabling as an impedance transformer, hence the inconsistent results from system to system and component to component. When you try to get them to understand what is taking place and how best to deal with it, most folks will typically shrug their shoulders and carry on as if nothing had happened. They are content to waste their money and ignore common sense, even though much of "high end cabling" doesn't really seem very logical when you first get involved.
When it all comes down to it, it is all about impedance and frequency. Nothing more, nothing less. Think about that and how it pertains to the various designs that you've already built and are thinking about building. Sean
>PS... Ohm's law is not a substitute for Thevenin's theory or vice-versa. They are quite different even though they work along similar lines.
"You originally came across as a "cable naysayer" that simply wanted to crunch numbers with no concerns for actual real world component interaction."I don't really want to KNOW how I come across most times! :o)
"It has been my experience that most people buy poorly designed gear or gear that isn't well suited to work within the same system and then try to band-aid the less than stellar results via cable changes."
HA HA HA! You sounded like me there. That was priceless. Using "cable equalisers" to fix problems cables can't really fix? Yeah - sometimes this happens I think.
"Most people end up using cabling as an impedance transformer, hence the inconsistent results from system to system and component to component."
Sucks when you try and mate two otherwise exceptional components with an impedance mis-match. But, some folks don't know when to say when. I tend to avoid gear with atypical impedances because I try SOOOOO many iterations of gear, I like maximum flexibility.
"PS... Ohm's law is not a substitute for Thevenin's theory or vice-versa. They are quite different even though they work along similar lines."
Oh, this I know. In fact you don't need either to add two complex impedances. You just need to know soh-cah-toa or how to draw a triangle! :) (I'm an electrical designer)
In any case, your posts (and Neutrons, and Al's and Jon Risch's) has inspired me to learn more about t-line theory, propagation velocity and delays, RFI transmission concepts (induction versus conduction), cable resonance, traps, filters, shielding for different noise spectra.
What I really want to study is what makes an "end" (reflection point) an end, and what happens when you connect two cables (or wiring methods) in series with different resonances.
This is all Johnny Neutron territory. Real propeller head stuff. :o)
Thanks for being nice even after I was a dick.
presto: ""
Conductivity does not change with frequency as it is a function of static resistivity, conductor cross sectional area, and length of the conductor.""It doesn't? Crap, there goes my edjumakation. If y'all's gonna get all technical, conductivity is consistent as long as you stay below the terahertz range. Course, he didn't state that conductivity changes, he referred to it as a parameter as well as bandwidth.
presto: ""
"excessively high" series inductance from somewhere in the order of a few pH/ft to ?????? ""If ya's gonna lambast someone, please use numbers that are realistic. pH per foot??? Try pH per mil... A single parallel wire pair can only go down to about 150 nH per foot, and that is with zero insulation thickness.
presto: ""
WOW! So far we're doing a whole lot of juggling and playing, but you're still nowhere near a definitive explanation.""Here, I must concur. There is a lot of verbage, but absolutely no meat upon which to define a model from which a solution can be had.
presto: ""
Maybe mention ONE SINGLE ORDER OF MAGNITUDE for just a few "electrical attributes" instead of repeating the word "desireable" all the time.""Cord inductance, 180 nH per foot..cord capacitance defined by dielectric and insulation thickness..LC = 1034 EDC, assume an EDC of 10..
C = 10K/L...C = 55 pF per foot. Characteristic impedance of 57 ohms..(seems low, but I assumed EDC was 10, this implies high capacitance.)Ground loop coupling, waaaay dependent on geometry, power cord pitch..ground loop current dependent on loop resistance, amp internal coupling, dependent on how crappy the internal wiring is..star grounds suck.
presto: ""
Maybe tell us *why* a stock cords inductance is unacceptably high for most audio circuits.""Inductance is the measure of how much magnetic field is created by the current within the wire. Non constrained systems typical of parallel wire cords, spash the magnetic field outward in a dipole configuration. The more the cord inductance, the more field. One half of this field (in the upper limit) will pass between the source cord and the power amp cord. "Upper limit" includes the cancellation of the helix field, and the flux that passes outside the loop, this is not part of mutual coupling to the loop.
Given the lack of geometric control afforded any audiophile, it is not possible to come up with specific equational solutions to faraday's law of induction as it applies to the ground loop, other than to state that the coupling is proportional to frequency. Nor is it possible to generically apply Amperes law to the power cord, as pitch, spacing, and integrated total flux within the plane of the loop cannot be adequately predicted. Nonetheless, the flux will be consistent with the haversine currents drawn by the power amp supply.
It is possible to describe how to minimize the power loop effects, but numbers without controlled geometry...you ask for that which is not obtainable in uncontrolled circumstances.
Oh, btw..I would differentiate between RFI and EMI as follows:
EMI is local, and is concerned with the trapping of flux through a loop, such as the ground loop. Typical of 60 hz, as well as the low spectra for transient events like motor starts and stops. RFI I consider as a planar wavefront from a source which is not local. How either enter a system may not be clear cut..
Cheers, John
While the nominal impedance of the cable that you mentioned is pretty reasonable, the capacitance per foot is too low / inductance per foot is too high. Juggling these figures further in the direction that i have mentioned would provide not only a lower nominal impedance, but also greater rejection to RFI and EMI. Having said that, the cable that you described would be a good starting point and should provide benefits as compared to a generic power cord.I'm glad that you made the comment that you did about star grounding being far less than adequate, as i've publicly battled with several different manufactuers about this very subject. Several of them post here and manufacture products that are highly respected on this and other audio forums.
We are also basically on the same page as to the differences between RFI and EMI, although RFI may be considered "local" if within very close proximity to a transmitter. In such cases, one might be experiencing "front end overload" due to the concentrated EM field. This can occur by itself or in addition to AC based noise due to RFI entering the "long wire antenna" feeding the mains.
Obviously, there are a lot of various factors to consider in most every aspect of this discussion, hence my reluctance to present anything as being "concrete". On top of that, i'm not going to hand anyone a bone when i normally get paid for the research that goes into my design / consultation work ( which is non-audio based ). Sean
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sean: ""
While the nominal impedance of the cable that you mentioned is pretty reasonable, the capacitance per foot is too low / inductance per foot is too high. ""Inductance too high?? What kind of parallel wire are you talking about that is below that?? Remember, we're talking about a cord that must withstand 6 kv transients , so the insulation is certainly not very thin.
Did you mean the other direction??
And I was being generous with EDC, real values would bring capacitance down. Do not forget, that was not a measured value, but a generic one with the equation to calc the capacitance ...(hey, he was pingin for equations, so I did..:-)
RFI...I condider any energy transfer which satisfies energy balance and therefore, the wave equation, as being "planar".. (did ya know that transmission in any media or cable at it's propagation velocity requires the e and m field energies be equal ?...tidbit..)
Any field which does not satisfy energy balance, I consider EMI .
Star: You are the first person I am aware of that hates star ground techniques. It is an excellent technique when high impedance circuits are involved (aka tubers). , but sucks big time for low impedance ones (aka zistors, ala power stages, and when big loop areas or rich magfield areas... ).I wuz not aware you made a livin doing this stuff..I'll send ya my bill...(note, I made it easy for you, I highlighted the billable items in red for you..:-)
Cheers, John
ps..I crack myself up sometimes..It's a shame that while others do indeed laugh, I don't think it's with me...:-)
You offered estimated figures, providing numbers to crunch. I've measured real world products that are beyond the figures quoted. Whether or not they'll withstand a 6KV blast, i sincerely doubt it. Then again, i sincerely doubt that the majority of generic 18 or 16 gauge power cords made in China will hold up too well to that test either. I havent tested such things, nor am i aware of the specifics of the test methodology used, so i'm strictly guesstimating here.As you noted, star grounds suck for most everything BUT high impedance circuitry. In the grander scheme of things, that means that star grounds suck for the mass majority of modern electronic circuitry. This makes them a valid design approach for a rather limited number of applications. Too bad all of these "high tech, high end" audio manufacturers don't know this. Too bad the "high tech, high end" audio magazines haven't taught the end user this. Then again, when engineers with a handful of degrees can't / don't understand this, i guess it would be hard to get the average citizen to grasp such a concept.
As to making my living, i work strictly with RF, not AF. Most of my time is spent fixing / re-designing / modifying products designed by degreed engineers. It doesn't pay as much as i'd like, but i usually enjoy my work. Until the economy took a dump, that was reward enough in itself.
From what i can gather, i think that you may be in a similar situation, hence our having similar outlooks in many cases. THAT is why i can laugh along with you. The fact that you bring logic to what is many times an emotionally based exchange also makes it easy to enjoy your posts. At least, most of the time : ) Sean
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Sean: ""
You offered estimated figures, providing numbers to crunch. I've measured real world products that are beyond the figures quoted. Whether or not they'll withstand a 6KV blast, i sincerely doubt it. Then again, i sincerely doubt that the majority of generic 18 or 16 gauge power cords made in China will hold up too well to that test either. I havent tested such things, nor am i aware of the specifics of the test methodology used, so i'm strictly guesstimating here."'
The figures were estimated just to afford sometin to talk on. Don't take them seriously. It is possible a cable has those exact values, and I could easily construct one, but above and below are certainly viable. Higher inductance just means farther apart.The 6Kv is actually the accepted flashover voltage that is supported by the 120 volt outlets in the USA. 6kV is considered the highest transient that can therefore get to a piece of equipment that is plugged into line. Back at the circuit breaker panel, that number is 15 Kv.
For my purposes, I would just go with a 5Kv DC Hi-pot test, limit of 5 microamp leakage for 30 seconds or so. (Note, this is not a recommendation for safety testing of any equipment, just a "druthers" of mine. For true safety test regimes, gotta go with the national specs..
SEan: ""
The fact that you bring logic to...""Hey, gotta bring sumptin in..if I can't bring in intelligence, at least logic will do...:-)
*
Music making the painting, recording it the photograph
It should be very easy to measure a speakers performance data as J.A. does in Stereophile and switch power cords and measure again. Then gain, think of the money you can make by selling power cords with multicolored tex flex jackets.
Theprieb
All gear does not respond the same to various power cord designs. In most cases, the more that a power cord of suitable gauge changes the performance of a component, the poorer the design of the component itself. Either that, or the existing power cord was of poorer design than the manufacturer thought would be necessary. Since most products are built to a price point, the use of generic power cords is quite common. These power cords aren't really up to the task at hand, especially since the AC lines are so heavily polluted in highly populated areas. Sean
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"These power cords aren't really up to the task at hand, especially since the AC lines are so heavily polluted in highly populated areas."AC cords can filter line noise that is not from an external RFI source?
Good work laddy! Show me a schematic.
(P.S. - I read your "explanation" of how AC cords work. It's nothing more than a limited understanding of noise and harmonics and explains NOTHING about how 'audiophile AC cords' actually work. That sort of pseudo-scientific blathering may impress the ignorant ones around here, but it would not last 10 seconds in an engineering environment.)
Another example of where sticking to "I know what I hear" would have been a better idea.
Please don't assume that having a degree equates to skill, knowledge, experience or the practical application of all of the above when designing / building a product. Many times, these people know just enough to pass their tests and obtain their degrees. That degree does not necessarily give them the knowledge and / or experience that is needed in real world product development or manufacturing. Nor does it proved them with the required skills necessary to troubleshoot and resolve the problems that their lack of education and skills have created in the multitude of under-designed and under-engineered products that proliferate the market in most any given field. Sean
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does not mean you get away with failing to explain THIS statement:"These power cords aren't really up to the task at hand, especially since the AC lines are so heavily polluted in highly populated areas."
So, please define for us what exactly constitutes this important "task at hand" and why audiophile cables are "up to this task" and why stock cables are not.
That's not asking for the moon is it? Your "explanation" of why AC cables are important stops with that statement - it's as if the meat of your explanation fell off the end there. It's one hell of an introductory paragraph to a thesis on the subject, but a definitive technical explanation it is not.
I mean, you've "been there done that" with this theory, and have 1000+ posts on the subject. So now that you are an authority on the subject, you may be required (from time to time) to simply refer to the "cable science" you are well versed in.
Let's start with how stock cables can't deal with line noise NOT caused by local sources of RFI, and how Audiophile cables CAN. Because it sounds like you are supporting the "water filter theory", that AC cables don't just keep out noise, they can clean up what's aleady there.
Looking forward to a more definitive explanation...
Most stock cords are highly inductive by nature and prone to escalating ground loop noise. Many "audiophile approved" cords are no better. A well designed cord takes into account multiple different aspects of electrical performance, not just gauge and series resistance. Please see my other response to you in this same thread for more detailed information. Sean
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One may hear improvements simply because of the superior metalurgy and design of the plugs themselves. If this line of thinking makes sense to you, get a better outlet too. I also think the geometry, type of wire, etc. can influence the sound further (for better or worse). If you are looking for a scientific reason, I don't think it exists.....yet.
Q: Which persons electrons move more? The person 10 miles away from the power plant? Or the person 10,000 miles away?A: Whether the power plant is 10 miles away or 10000 miles away, the electrons will move the exact same distance , and this distance has everything to do with voltage and nothing to do with length of the power lines. (Electrons do not migrate in an AC system with no DC drift or "DC Offset" - they just vibrate back and forth. The small back and forth distance is a function of voltage. How MANY electrons are involved is a function of current.)
Only in DC systems do electrons actually migrate, and "water in pipe" models become even close to being 'philosophically' correct.
When an AC cord costs more than it would cost to convert an entire signal chain to battery supplied DC operation, I'm putting my money on the battery bank.
Here's another riddle for you.
Q: What is the best AC power cord?
A: None. The best power cord is wires that connect batteries to your components that recharge when your components are off, thus being totally isoalted from the AC supply when on.
If someone thinks $10,000 worth of artistic braiding and an AC cord so heavy it puts mechanical strain on the wall plug and IEC connector on the back is better than spending $5000 on supplying their components with pure DC - then they're surely a faith-based audiophile.
With Audiophile grade AC cables, it's not just the cable that's really thick...
The only advantage to esoteric cables is that you can bend them (with the right machinery) so that your components are suspended mid-air by the IEC plug, this precluding the need for stands.
or is that a riddle as well?
Not sure what you're asking. Perhaps you already know this so I apologize if this is redundant, but once you get past the power supply rectifiers and filters, ALL audio components - that is, their audio circuitry - run off DC. That's what a power supply does - it converts AC from the wall socket into DC. Way back in the old days, when the triode was the newest device on the block, that power supply often WAS a battery, which of course, supplies DC. Look at a schematic some time, B+ on the diagram is historic, it refers to the positive terminal of the BATTERY when the terminology was invented.Nowadays is B+ is mostly suplied by an AC power supply that uses rectifiers, capacitors, and sometimes chokes and active devices to approximate an ideal battery. There are a few components out there that actually use batteries to supply power because the designer feels they bypass the problems of making a clean, stable DC power supply from household AC, for example the Sutherland PhD phono preamp. The AST Emitter II Exclusive has a battery power supply option for its front end. There are probably a few others but those are a couple I thought of off the top of my head.
the energy equirements of running a Sutherland PhD or the front end of the AST Emitter II Exclusive compared to the requirements of running the output stage of an even moderately powered amplifier!But that's hardly the point, after all spending $5,000 for a separte battery supply for the Sutherland PhD would be simply absurd (how many lifetimes worth of replacement batteries could you purchase for $5,000?... Sutherland says the batteries should last for more than 800 listening hours!), and who's to say the $5,000 battery supply would make sense for the AST Emitter II Exclusive, i.e. I asume those AST boys already know a thing or two about building the required battery supply, no?
But even that misses the point even large point, and I find it nearly incredible to have to state this (actually reiterate since mentioned in my other post), but there is no ready supply of off the shelf components that could utilize the $5,000 battery supply!
No Guru, No Method, No Teacher
you said components that run on DC and of course they all do. But it's true that there aren't very many components for sale that run on batteries. That's another matter entirely. However, if an audiophile is willing to pay $5000 for a power cord, I don't see why, as a matter of reason, they wouldn't be willing to pay a like sum for a battery supply, which would recharge itself when the system was "off", that could be hooked up to a component or series of components that would run off batteries. The advantage, of course, is total freedom from the noise, hum, RF, etc. of the power line. It's just that nobody so far, except possibly a few fringe Japanese companies (those ultra fi nuts! :-D) have done so. And of course, you would be limited to components from that company, or those few companies - assuming that they would cooperate enough to agree to a common battery supply, which is doubtful - BluRay, anyone? But conceptually, it's a much more attractive idea than a $5000 power cord, isn't it?
"but there is no ready supply of off the shelf components that could utilize the $5,000 battery supply!"So... we'll just use AC cords as thick as fire hoses and call it good then?
Sounds kind of lazy if you ask me.
I thought audiophiles would go to any length...
Hmmmmmmmm....
Too bad no one make a $100,000 power cord, now that would be something too really spark your creative juices.
No Guru, No Method, No Teacher
nt
A $5000 big amp hour low resistance battery supply is no doubt light years ahead of what any power cord can do, but spending say $150 on some new connectors and outlet has brought slight improvements to what's not already on batteries in my system.
I'm not a big fan of exotic and expensive AC power cords. ;-)
Of course building a pure DC supply for a power amplifier of even moderate output power will prove to be a daunting task that may consume a lot more than $5,000!LOL
it's just the thought of a $10,000 power cords (like everyone buys those!) that clouds the thinking process?For example Presto tells us that it make more sense to spend $5,000 on providing pure DC to components than spend $10,000 on a power cord. Well that superfically seems to make sense until you consider that to use pure DC one must:
a) Build their own components that can utilize pure DC (not everyone is a DIYer!), or
b) Have custom components commissioned that can use pure DC (hardly a cost effective option), or
c) Have existing components radically modified to utilize pure DC (likely expensive work, and in addition it would kill the resale price of the modified components).
Seems to me that the advice only makes sense for the talanted DIYer, otherwise it's equally as ridiculous as the notion of buying a $10,000 power cord... unless of course funds are absolutely not an issue in which case all sorts of wieird and wacky ideas can be explored!
The real question was; why do some sound better?It is more than just gauge and more than just shielding. It is not a subtle effect and does not have to cost much. Mine cost $7 apiece.
Bill
I believe there are many excellent and inexpensive power cords.In my opinion, paying more than a hundred bucks or so on a "fancy" power cord is silly and spending anything close to or more than 4 figures for a power cord is foolish.
Hello there:You are right, my friend: it doesn't make any sense that after thousands of miles traveling to our home, the power will be "better" just because of an aftermarket power cord.
But try a good one with any of your components (specially amplifiers and preamplifers) and you'll inmediately listen a real improvement.
As in everything in this hobby, "The proof is in the listening".
Sense or non-sense, if something betters your sound and the effect is suitable to your taste, keep it, otherwise discard it.
I was the most skeptical audiophile regarding to High-end Power Cords until I tried the King Cobra v.1 (from Power Snakes) in my McCormack DNA225 "Platinum Edition" Power Amplifier, the improvement was real, easily audible and beyond any expectation. Since then, even without "making any sense" I am a preacher about High-end Power Cords.
Same is applicable to Interconnects and Speaker Cables.
...so we're instructed anyway.
What type of listening?
.
The proof is always in the pudding.
I agree: it doesn't make any sense to me; however, I can't deny that I've consistently heard major differences in total system sound over many years with various power cord swaps. Here's a further implication: if it's true that the sonic improvement wrought by a power cord has something to do with emi/rf rejection, or whatever, then shouldn't it be advantageous to have the longest possible high quality power cord connecting the system? The longer the cord, the more substantial the effect?
I can tell you I hear bigger changes in power cords than I do with speaker cable or interconnects. I believe power cords can make or break a system and my system 'sings" with the addition of seven (7) Purist 20th Anniversary AC cords.
SK:Forgetting for a moment my skepticism about certain "AC cable topologies"....
Them's are some mighty sweet looking cables! :o)
I like that they are not ridiculously fat with disgusting amounts of black heat shrink built up at each end.
(Anyone who says gear aesthetics is NOT part of this hobby *is* in the wrong hobby! lol)
One does need to consider the man hours in constructing these kinds of cables BY HAND and the layers of sometimes exotic materials that are used when looking at the price.
One also needs to be aware of "Belden in a Braid" designs though too.
In that case, I'll take the stock Belden wire without the braid! :o)
z
Maybe the shielded cables happen to have lots of capacitance and are acting like a bit of a filter for noise in addition to the RFI benefits of the shield? Just a wild guess really. When I get my wooferTester, I am planning on measuring as much as I can with those.I was really surprised that a power cord actually had an effect. I stumbled upon it by accident. I mistakenly used a cheap PC cable and the magic really went away. The next day I put the original cable in just for kicks and the magic was back. I did multiple double blind tests with folks and they all said the same thing without knowing what I was changing.
Bill
Bill:You don't need 'fancy' OR 'expensive' to use the right gauge of cable with any component!
Even prosound guys will tell you - if you starve a big amp for current using too small of a supply cord, or the wrong sized branch circuit, then the amps bass performance goes out the window.
Cable gauge after the amp is equally (if not moreso) important because now you're driving even MORE current (at a lower voltage of course).
Now, if a cable that costs $1000 sounds better for use with a subwoofer, is it because it's a superior design? Or just because it has larger conductors?
6 feet of #8 or #10 SOWA or SOOW service cord (cab-tire) with 2 cord ends does NOT cost $1000.
Then again, if you're a REAL audiophile and you don't spend $1000 on an AC cord you just might not hear a difference!
Mine cost me $7 apiece and they sound great. :) Simple shielded 14g Volex.
nt
of line at residential voltage from the transformer to your power meter. The transformer acts as isolation device from the major issue with the high transmission lines. Now does that matter? I guess so since I and many others can hear a difference when power cords are swapped (though we could all be self-deluded also). I certainly can't say why (though reduction of RFI/EMI strikes me as important) there is a difference but subjectively I hear one.
Have you introduced a new power cord into your system and now find yourself perplexed by a sonic change and wondering if you're somehow decieving yourself?Or are you just expressing a sense of wonderment on a topic of which you have little or no practical experience?
A little elaboration would be helpful because one witnesses so many apparently innocent one-liners posts on controversial subjects that in the end would appear to be little more than invitations to bitch (IMHO of course).
im thinking of buying one, actually. I just cannot reason it properly.
In terms of a simple picture of connections to the electric grid that speaks to the "... thousands of miles of power lines from power plant to our apartment" scenario see:http://www.canuckaudiomart.com/forum/viewtopic.php?p=66666&highlight=transformer#66666
The following post can be followed to locate some simple documents from an established company that speaks to the source of electrical noise, in particular noting that typically the worst sources of contamination originate from within a building (which can be generalized to within a residential apartment or house), not from the external power grid.
http://db.audioasylum.com/cgi/m.mpl?forum=prophead&n=27834&highlight=powervar&r=&session=
Now none of the above speake directly to the question of aftermarket power cords; for that perhaps you may find the Jon Risch Website interesting. As others have said however one should experiment to discover (or not) for oneself. If you have access to local audio shops why not stroll in and honestly state your slepticism but say you wish to experiment firsthand and see if they'd be willing to let you audition something. It's amazing what a little candor will accomplish.
No Guru, No Method, No Teacher
Buy from someone who has a return program, demo program or small restocking program in place. Let the seller know up front that a possible return could happen in the future and that you want to try a cord to see what the hoopla (or not) is all about. This way if you keep it, both of you will be surprised.Look into the various vendors on this page and see if any of them will bite..to your needs.
...but I've heard it said that it can also be viewed as the first meter. Something about the current alternating or something such thing. I hope someone here can give us the Definitive Explanation to your question. ;-)
(nt)
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