diyAudio Forums Archive > Top > Other Stuff > Everything Else Pages: [1] 2 3 4 5  Cable distortion and "micro diodes" - Click HERE for Original Thread Steve Eddy In the cable directionality thread in post 144, John Curl made the following claim: Hate to be the one to tell you, BUT there are diodes in your metal wires. More than you will ever bother to measure. I have measured them. Indeed, John has measured the distortion of something. But is it distortion caused by "micro diodes" in the wire? Is it distortion caused by some other component of the cable? Or is it distortion produced by his test gear? Here are three distortion spectrum plots of John's measurements of three different interconnect cables; a Radio Shack Gold series interconnect, a model from JPS Labs, and a model from van den Hul respectively: When I first saw these plots and the claims made by John that they were distortion products caused by "micro diodes" in the wire itself, I was a bit skeptical. While I could see such gross nonlinearities in copper wire being overlooked by the audio industry, particularly the high-end audio industry, I didn't think it was very likely to have escaped the notice of the materials science crowd. Another thing which caught my attention was the 15.75kHz interference spike which in this set of plots seems to diminish in level along with the distortion components. I thought perhaps what John was measuring was the distortion being produced by his test gear being variously attenuated by the loads of the different cables. There was a correlation to this and cable capacitance, with the Radio Shack cable having the highest capacitance of the three and the van den Hul having the lowest. To make a long story short, John claimed that the interference spike changed its magnitude depending on how many TVs people in his apartment complex had turned on and that the distortion products were definitely not being produced by his test equipment, which for these plots was a 25 year old Sound Technologies 1700B which John says he's replaced some of the opamps in, and his Macintosh's internal sound card using Mac the Scope software. So I sought to have John's measurements duplicated. If the distortion products were being produced by his test equipment, it wouldn't serve to try and duplicate his measurements using the same analyzer so I wanted to try and duplicate his results on a more modern system, preferably an Audio Precision rig. I don't own one or have direct access to one so I contacted a few individuals who did. While they were interested in doing the measurements, neither of them had the free time to do so at the moment. Then about a week ago or so I came across a post on one of the newsgroups by Bruno Putzeys, an engineer at Philips' Digital Systems Lab. Bruno had recently done a suite of tests on some audio interconnect cables using his Audio Precision System Two Cascade and reported that he was unable to turn up any distortion. His post read in part: Recently I've done a collection of measurements on interconnect cables to see what I could find that would explain the sonic differences that many people, including myself, have grown accustomed to hearing. The test equipment was an Audio Precision System 2 Cascade. Test objects were a handful of cables of varying construction and claims to audiophile performance. Distortion: Not only sine wave, but also extremely complex full-spectrum multitone testing (including signal sequences derived from actual music). There was no difference between the cables tested. Phase noise. While this would have shown up anyway in the above tests, it was separately checked at frequencies well above the audio band. Nothing showed up. "Micro phase shifts". The AP2's resolution is so good you can read the length of a 1m cable by measuring the phase difference between input and output. Apart from this, nothing turned up. In-Out difference. Actually, two different cables of equal length were fed the above distortion test signals in opposite phase. The two outputs were summed through a trimmable network to null the output. Well, the output nulled completely (better than 120dB across the audio band). In short, apart from a constant time delay of a few nanoseconds (depending on length), an interconnect will have the same voltage at its output as at its input. I replied, mentioning John's measurements and John's claim that the distortion he's measuring only shows up at low signal levels (in the case of the plots above, 30mV) and asked Bruno if he'd done any of his tests at such low levels. Bruno replied that he had, down to several microvolts, but nothing turned up there either. I EMailed Bruno asking him if he had any plots of his low level measurements. He responded by doing a set of measurements duplicating John's test conditions of the plots above using a 1kHz sinusoidal stimulus at 30mV. Here are the plots with Bruno's accompanying text in bold: Page 1. THD spectra taken from four different cables. One was a cheap A/V cable: a triple coax with serve shield, all bare copper. One was a Japanese manufactured cable with audiophile pretenses by a brand named Hisago. It was the only cable in the test field I've actually listened to, and I remember feeling the sound was exceptionally apalling (without "e" and two "l"). Conductors are bare OFC, insulator is foamed PE. The third cable was a 50ohm RF coax with solid PE insulator and bare copper conductor. Shield is tinned copper. The fourth is a coax with Teflon jacket (sheath), teflon insulator and silvered conductors/shield. Source setting was 1kHz, 30mV, 20 Ohms impedance. The plots show 256 times power averaged FFTs of the residual. This means the 30mV fundamental was notched out such that the distortion/noise performance of the ADC does not affect the result. All dBs are relative to the fundamental. The generator third harmonic at around -130dB just peeks out. No other distortion products are visible. Page 2: Same objects, same test condition. The FFT analyzer was now set to synchronous averaging. Instead of smoothing out the noise floor, it artificially lowers all non-synchronous components (ie. noise), allowing much lower distortion levels to be resolved. Third, second and fifth harmonic are visible, at the relative levels known from the generator. The noise floor also causes some statistical deviation of the measured levels of the harmonics that are close to it. (most notably the 5th). Page 3: The test of page 2 was repeated with the generator impedance and the input impedance set to 600 ohms. This should reinforce any nonlinearity present either in the dielectric or in the conductor. Note that the actual signal level on the cable is now 15mV, which accounts for the relative increase in noise level. For comparative purposes, here are the levels at which John claims his tests are measuring: Steve, the notch filter in the 1700B notches out to somewhere between -94 and -100dB This can be shown by the RESIDUAL of the THD at all levels is a little less than .002% or -94dB. Of course at very low levels, NOISE makes the residual appear to increase on the meter. This residual includes the unnotched fundamental ( the highest peak on the left side at 1KHz), the averaged distortion residual, and NOISE. At low levels, noise is all important, and this is why I must use signal averaging or very narrow bandwidth filtering to remove enough noise to look at the distortion residual. If you start with my graphs with the IKHz (notch) then you can see that the noise boundary is about -125dB. The distortion occurs in this case about -115 to -120dB, or even as much as -110dB if the notch is not complete. Bruno's measurements using the System Two Cascade are measuring a good 20dB lower than John's measurements yet even with a cheap A/V cable of the kind typically supplied with mass-market consumer gear, there are no signs of the picket fence high order harmonics that appear in John's measurements. Whatever John's measuring, it ain't diodes in the wires and it ain't being produced by the cable itself. So if there are diodes in our wires and they're causing diodic type nonlinearities, their effects are flying below the radar of the System Two Cascade which is significantly below where John's measuring and in spite of John's claims, remain thus far unmeasured and unproved. se tiroth Very thorough. As much as I have respect for Mr. Curl, there is clearly something odd going on with those graphs. Cables simply don't produce that kind of distortion, and you don't need an AP to know that. This measurement doesn't have anywhere near the fidelity, but doesn't turn up such distortion even though it passes though about 12' of Radio Shack cable. The signal level is about 8-16mV. Steve Eddy quote: Originally posted by tiroth Very thorough. As much as I have respect for Mr. Curl, there is clearly something odd going on with those graphs. Cables simply don't produce that kind of distortion, and you don't need an AP to know that. This measurement doesn't have anywhere near the fidelity, but doesn't turn up such distortion even though it passes though about 12' of Radio Shack cable. The signal level is about 8-16mV.[/IMG] Well the first thing John would tell you is that you need to notch out that fundamental in order to achieve sufficient dynamic range to measure at the levels he's measuring at. And he'd be correct on that account. :) Do you have any means of notching out the fundamental in your measurements? Oh, and by the way, you do have the same picket fence of high order harmonics that John's got. Be aware that the horizontal axis is plotted on a linear scale in John's and Bruno's plots. Yours are logarithmic. Switch to linear and you'll see the same evenly spaced distortion components that you see in John's plots. se johnferrier I'm getting uncomfortable in this lotus position so I have to ask: was there any need to have brought up the directionality thing with Bruno Putzeys? Perhaps moot in light of the above... Happened upon that thread today and now understand what was going on yesterday with the Bybee thread. Very interesting to have the hard data presented here. How long have you known about these results? You're not just trying to psyche out the can-hear-a-difference crowd are you? It seems that tiroth's graphs are more like John's. Maybe John's notching wasn't so good. JF Steve Eddy quote: Originally posted by johnferrier I'm getting uncomfortable in this lotus position so I have to ask: was there any need to have brought up the directionality thing with Bruno Putzeys? Huh? I didn't bring up any directionality thing with Bruno. quote: Perhaps moot in light of the above... Happened upon that thread today and now understand what was going on yesterday with the Bybee thread. Very interesting to have the hard data presented here. How long have you known about the results? I received the plots from Bruno on November 24th. By the way, the issue of John's measurements and his claim of the distortion he's measuring being due to diodes in the wire goes back several years, most of the discussion about it done over on Audio Asylum's Cable Asylum. It's erupted at different times since then but here's the genesis of it: http://www.audioasylum.com/audio/ca...ages/42469.html se Steve Eddy quote: Originally posted by johnferrier It seems that tiroth's graphs are more like John's. Maybe John's notching wasn't so good. Just love that edit button. :) Tiroth's not notching out anything that I can tell. John says his notch is about -94dB or thereabouts. Also, you can't directly compare the decibel scale on John's plots to Bruno's. There was some gain applied after the notch and before the Mac the Scope FFT. So you'll have to go by what John says his plots represent relative to the 30mV fundamental. The dB scale on Bruno's plots is relative to 30mV. Gets confusing. :) se john curl Folks, I am not trying to get a Nobel prize for my efforts. I have and do measure differences in cables at levels of approximately -110dB below the test signal level, BUT I have to use lower level signals than are typically used with a THD analyzer. The graphs that I put out, that have now been put on this website, were out-takes from a series of tests that I did several years ago. They were an example of my test procedure, but they were not my best measurements. These measurements were put up in response to someone deciding that cable break-in was impossible, because he measured the cable with a Fluke multimeter and found no difference in DC measurement before and after a 'break-in' period. I have never heard the end of it, but I still can and do make similar measurements. Am I actually measuring cable distortion? I can't be absolutely sure, but I can say this: My measurements are repeatable, and each cable type has its own harmonic signature. Also, if I do not keep my connectors clean, I get a build up of harmonics even on my reference connectors, which will go away if I clean my connections with isopropyl alcohol. This implies some form of diodic distortion. I also know that the order of distortion changes at higher working voltage levels, like 1V or so. Steve Eddy thinks he is the 'Amazing Randi" of audio. If he can personally discredit me or my associates, he will do so, as he has attempted to do for years. johnferrier This is all very curious. It's great that you take the time to try help with something difficult to understand. quote: Originally posted by john curl I have and do measure differences in cables at levels of approximately -110dB below the test signal level, BUT I have to use lower level signals than are typically used with a THD analyzer. ... My measurements are repeatable, and each cable type has its own harmonic signature. However, it seems that the Philips engineer (Bruno Putzeys) was not able to measure a difference in cables. Is there an explaination why? quote: Originally posted by john curl Also, if I do not keep my connectors clean, I get a build up of harmonics even on my reference connectors, which will go away if I clean my connections with isopropyl alcohol. Do you find connections that are left alone (never made and broken) get harmonic build up too? JF johnferrier quote: Originally posted by john curl I have and do measure differences in cables at levels of approximately -110dB below the test signal level, BUT I have to use lower level signals than are typically used with a THD analyzer. And -110db below test signal (30mV) is getting down there. Some people consider that inaudible. quote: Originally posted by john curl Steve Eddy thinks he is the 'Amazing Randi" of audio. Probably not the intention, but it's humorous. Frankly, I wouldn't have known anything about Jack Bybee and the Amazing Randi, if it wasn't for you and Steve. So in a way, you two are advertising them. JF johnferrier I ran into a lighter side of Steve. The miniature clothespin: http://db.audioasylum.com/cgi/m.pl?...ddy&r=&session= JF john curl For the record, the reason that the 15.7KHz interference signal is different in one of the measurements is possibly that someone in the building turned off their TV while the test was being run. This happens frequently. Also, it could be that the solid 100% shield of the JPS cable (it is like a solid aluminum tube rather than a normal wrapped shield), is filtering out more of the airborne 15.7KHz signal, compared to the other reference, or the Radio Shack cable. Steve Eddy quote: Originally posted by john curl Folks, I am not trying to get a Nobel prize for my efforts. No. But you're trying to tell people that there are diodes in their wires and that you've measured it. quote: I have and do measure differences in cables at levels of approximately -110dB below the test signal level, BUT I have to use lower level signals than are typically used with a THD analyzer. Which is why, when I sought to duplicate your results, I made sure that they were done at the same level that you used for your measurements. quote: The graphs that I put out, that have now been put on this website, were out-takes from a series of tests that I did several years ago. They were an example of my test procedure, but they were not my best measurements. They don't have to be your best measurements in terms of how far down you're measuring. Even these measurements unambiguously show significant amounts of high order harmonic components. quote: These measurements were put up in response to someone deciding that cable break-in was impossible, because he measured the cable with a Fluke multimeter and found no difference in DC measurement before and after a 'break-in' period. It doesn't matter what these measurements were put up in response to. They're the same measurements which you have used to support the "micro diodes" claim. And as of the other day on another forum, even in light of Bruno's measurements, you say you still stand by these measurements. quote: I have never heard the end of it, but I still can and do make similar measurements. Since you keep using the same 25 year old distortion analyzer for the measurements, why would it be any surprise that you still can and do make similar measurements? quote: Am I actually measuring cable distortion? I can't be absolutely sure... But there was no ambiguity whatsoever when you made this claim: Hate to be the one to tell you, BUT there are diodes in your metal wires. More than you will ever bother to measure. I have measured them. quote: but I can say this: My measurements are repeatable, and each cable type has its own harmonic signature. Again, what's it matter if your measurements are repeatable but you keep repeating them using the same 25 year old distortion analyzer? If the distortion's being produced by your distortion analyzer, you can repeat them from now 'til Doomsday. That's why I sought to try and duplicate your results on a more modern, reference standard system. quote: Also, if I do not keep my connectors clean, I get a build up of harmonics even on my reference connectors, which will go away if I clean my connections with isopropyl alcohol. This implies some form of diodic distortion. It's been well known for quite some time that poor/corroded contacts can cause distortion. That's nothing new. What's new is this notion that wire itself causes some form of diodic distortion. quote: I also know that the order of distortion changes at higher working voltage levels, like 1V or so. Doesn't this rather describe class B crossover distortion in a high global feedback circuit such as an opamp and why in such circuits distortion increases as signal level decreases? quote: Steve Eddy thinks he is the 'Amazing Randi" of audio. If he can personally discredit me or my associates, he will do so, as he has attempted to do for years. You can only discredit yourself, John. I simply question that which I see as questionable. And I question regardless of who is making claims I see as questionable so this notion you try and pass off that I'm only out to get you and your "associates" is just your trying to avoid the issues. If my questioning has no merit, there can be no discrediting. Simple as that. You've only yourself to blame, John. Or don't you recall these words you said to me way back in the Mr. Huyn thread? Steve, you are an insolent fool. You have NOT shown anything! Either seriously attempt to duplicate my results, or find another sandbox to play in. Ok. I have seriously attempted to duplicate your results with the help of Bruno Putzeys. And when using a modern, reference standard system and including even the most bog standard giveaway cables, your results were not able to be duplicated, even though the measurement system used is measuring well below your capability to measure. And after taking your advice and doing just what you told me to do, when presented with the results, what was your response? Steve is full of it, as usual. That says it all, John. se Steve Eddy quote: Originally posted by johnferrier I ran into a lighter side of Steve. The miniature clothespin: Aw man, what'd you have to go and bring that up for? Woodie went walkabout a few weeks ago and I was just getting over the loss. :bawling: :bawling: :bawling: se dhaen Are these measurements being carried out in a screened room? If so what is the attenuation figure for the room? Cable differences are mainly due to the "stuff" picked up, and the stuff leaked out. On that basis, experiments will never agree. Steve Eddy quote: Originally posted by dhaen Are these measurements being carried out in a screened room? If so what is the attenuation figure for the room? Bruno's you mean? Not that I'm aware of. I'll ask him though. quote: Cable differences are mainly due to the "stuff" picked up, and the stuff leaked out. On that basis, experiments will never agree. Perhaps. But this was an investigation into whether the cables themselves produce any harmonic distortion. se Richard C Are we talking about distortion 110dB below 30mV?:bigeyes: Does anyone own an audio system with a noise-floor approaching this? If detectability of this distortion is questionable even with precision measuring equipment then it might seem reasonable to conclude that this effect is not the cause of audible differences between cables. Christer quote: Originally posted by johnferrier I ran into a lighter side of Steve. The miniature clothespin: http://db.audioasylum.com/cgi/m.pl?...ddy&r=&session= JF Some people build gainclones. Steve obvoiusly build clothespin clones. :) Christer quote: Originally posted by Steve Eddy No. But you're trying to tell people that there are diodes in their wires and that you've measured it. Actually, just to be fair to John, I can't remember him claiming the effect to be micro diodes, only that he has mesasured something which he believes, but isn't sure, is micro diodes. Steve Eddy quote: Originally posted by Richard C Are we talking about distortion 110dB below 30mV?:bigeyes: Does anyone own an audio system with a noise-floor approaching this? In light of Bruno's measurements, we're talking about distortion which if it's there at all but just below the AP's capabilities is well more than 130dB below 30mV. :bigeyes: :bigeyes: :bigeyes: quote: If detectability of this distortion is questionable even with precision measuring equipment then it might seem reasonable to conclude that this effect is not the cause of audible differences between cables. Personally I'm not looking at this in terms of issues of actual audibility. Until actual audibility has been established, it's rather pointless to look at this in such terms. I find it interesting purely for the sake of curiousity. se Steve Eddy quote: Originally posted by Christer Actually, just to be fair to John, I can't remember him claiming the effect to be micro diodes, only that he has mesasured something which he believes, but isn't sure, is micro diodes. Quoting John: Hate to be the one to tell you, BUT there are diodes in your metal wires. More than you will ever bother to measure. I have measured them. I dunno about you, but I don't see any ambiguity at all in that statement. se Christer quote: Originally posted by Steve Eddy Quoting John: Hate to be the one to tell you, BUT there are diodes in your metal wires. More than you will ever bother to measure. I have measured them. I dunno about you, but I don't see any ambiguity at all in that statement. se OK, I didn't remeber that post. He did another recent posting where he did have a discalimer that he wasn't sure if it was a diode effetct, but that he believed so. Steve Eddy quote: Originally posted by Christer OK, I didn't remeber that post. He did another recent posting where he did have a discalimer that he wasn't sure if it was a diode effetct, but that he believed so. Ok, I didn't remember that post. :) se john curl Look folks, I am just trying to understand how wires work. I can measure 'differences' even today. Is it exactly 'microdiodes'? Who knows? Seems like a good hypothesis. Could it be something else, that gives similar results? I am open to any real suggestion. So far, no effective suggestions have yet been offered that are consistent with the actual test set-up. For those who would like more info on this hypothesis, I recommend looking around the VandenHul website and look at VDH's comments. fdegrove Hi, quote: What's new is this notion that wire itself causes some form of diodic distortion. New? Depends on what you call new but I'm pretty sure this has been discussed for at least a decade. And that diodic distortion should be totally absent in solid core wire or Litz constructions for that matter. Cheers,;) fdegrove Hi, quote: Do you find connections that are left alone (never made and broken) get harmonic build up too? That's precisely what causes the build up of debris in the connector. Simply breaking and making a connection has a mild cleaning effect already. Cheers,;) Steve Eddy quote: Originally posted by john curl Look folks, I am just trying to understand how wires work. Great. So am I. quote: I can measure 'differences' even today. But the "differences" you're measuring are differences in distortion. Distortion which, in light of these most recent measurements, apparently isn't distortion that's being produced by the cables themselves. quote: Is it exactly 'microdiodes'? Who knows? Seems like a good hypothesis. Given that the most recent distortion measurements indicate that the distortion you're measuring isn't being produced by the cables, why does this seem like a good hypothesis? quote: Could it be something else, that gives similar results? But John, on a much more modern, higher resolution system measuring significantly below where you're measuring, and even using the most bog standard cables commonly available, we don't get similar results. We don't get anything other than the generator's known distortions. quote: I am open to any real suggestion. So far, no effective suggestions have yet been offered that are consistent with the actual test set-up. One real suggestion, and a good hypothesis is that what you've been measuring has ultimately been, for whatever reason, the limitations of your antiquated distortion analyzer. There's no question that the Audio Precision System Two Cascade has significantly greater resolution than your 25 year old 1700B. Therefore by all rights if the distortion you're measuring is being produced by the cables themselves, that distortion should be far more evident when measured using the System Two Cascade. But there is simply no sign of the picket fence of high order harmonics that your measurements show when by all rights they should be sticking up well above even the low order harmonics of the System Two Cascade's generator which are clearly evident in the AP plots. Back in the old Mr. Huyn thread, Bob said to Mr. Huyn of your distortion plots: Sorry if the graphs shake up your cozy little world... What goes around seems to come around. quote: For those who would like more info on this hypothesis, I recommend looking around the VandenHul website and look at VDH's comments. And it's worth noting that van den Hul's measurements, which you say he also used as evidence of his theory, were made with equipment as old if not older than yours. se Steve Eddy quote: Originally posted by fdegrove New? Depends on what you call new but I'm pretty sure this has been discussed for at least a decade. I meant new with regard to the field of materials science which has had a very good understanding of the behavior of copper wire for decades. quote: And that diodic distortion should be totally absent in solid core wire or Litz constructions for that matter. But thus far, it hasn't been shown to be present at all in any type of conductor. se fdegrove Hi, quote: But thus far, it hasn't been shown to be present at all in any type of conductor. Certainly. I don't expect it to be easy or at all possible that the effect IS indeed diodic in nature. Unless we're talking about heavily oxidized multi-strand copper wire perhaps. We all know that that kind of wire has no place in audio or, do we? Sp, what's going on? Is it electrons jumping from one strand to another? Hard to believe when you think it's electro-magnetic propagation that travels across the wire and electron movement is comparatively slow.... When we think about diodic or diode like behaviour, rectification at some frequency or frequencies should occur causing distortion. All diodes, to some extent, present resistance which again would cause a voltage drop that, once again would be frequency dependent as diodes are non-linear resistors. So, is this another urban myth? Maybe, maybe not...I just don't think that with good, airtight insulation this is not likely to happen. Other phenomena may be at work but diodic effects don't seem likely to me under the above conditions. It is my feeling/experience that crossing of different metal boundaries can cause more worriesome artefacts than this one if at all it is real. I've seen articles showing photos of this so called diodic effect but it doesn't prove a that it is indeed that and not somethong else that is being shown. After all what was shown was distortion, not rectification effects. To my ears solid core wire is preferable. Why? I can only guess, present suggestions, educated guesses, not prove. Cheers,;) john curl Frank, we are now talking about 3 separate possible distortion mechanisms. First, your primary interest is diodic distortion from current moving across strands probably already oxidized by exposure to air. This could be very real. Second, we have distortion in the external contacts of a cable as they are also exposed to air and vibration (yes, this matters). Third, is the distortion that I was looking for which would be intrinsic to the wire itself, and would be there with solid core as well as stranded. I think that all three are possible, and probably measurable. Steve Eddy quote: Originally posted by fdegrove Certainly. I don't expect it to be easy or at all possible that the effect IS indeed diodic in nature. Unless we're talking about heavily oxidized multi-strand copper wire perhaps. We all know that that kind of wire has no place in audio or, do we? Sp, what's going on? I don't know that there's necessarily anything going on. But if there is something going on and we truly want to find out exactly what it is and why, we first need to establish actual audibility of SOMETHING at least so we can have a known and reliable reference in order to put any subsequent theories to the test. Otherwise we can sit here and speculate from now 'til Doomsday and not get any closer to the truth than we are now. What's frustrating is that while thus far actual audibility hasn't been established, and while that's at least some evidence that there may not be anything going on, it's still not absolute proof that there isn't anything going on. While the failure thus far to demonstrate actual audibility may be sufficient for some to reach a firm conclusion that there can be no audible differences, for me, there's that bit of nagging doubt. And I hate nagging doubts. Which is why I would REALLY like to see someone once and for all demonstrate actual audibility. And why, instead of just dismissing the issue out of hand, I'm looking forward to these directionality listening tests. quote: To my ears solid core wire is preferable. Why? I can only guess, present suggestions, educated guesses, not prove. Can't explain my particular preferences either. But personally I haven't any interest in speculating as to why until I can first demonstrate to myself that they've anything to do with actual audible differences. And since when it comes to the bottom line of enjoying reproduced music I don't really care why, I haven't much desire to demonstrate it to myself. Though in the realm of general knowledge and curiousity, I would like to see the Great Cable Debate eventually resolved one way or the other. That would free up much more time to spend doing um... er... hmmm... ALL CABLES SOUND THE SAME!!! :D se fdegrove Hi, quote: Frank, we are now talking about 3 separate possible distortion mechanisms. First, your primary interest is diodic distortion from current moving across strands probably already oxidized by exposure to air. This could be very real. Second, we have distortion in the external contacts of a cable as they are also exposed to air and vibration (yes, this matters). Third, is the distortion that I was looking for which would be intrinsic to the wire itself, and would be there with solid core as well as stranded. I think that all three are possible, and probably measurable. First of all, apologies for the way too hectic proofreading of my preceding post. It contains a number of spelling and synthax errors I'm not too proud of. John, Let's just say I'm in absolute agreement with the three most obvious and plausible causes of distortion here. Just that you're already as I was too, addressing causes outside the cable proper, namely contact resistance at the connector side. It's also at the connector that oxidation of wire is most likely to occur, or let say that region; the I/Cs extremities. Mere soldering may set this of already.... And, to be sure not just that one single aspect: Peltier effects can be another player to name just one example. Back to topic. Yes, most cable is carelessly manufactured and at best exposed to air for a few hours (not just O2) before properly finished...But there's more than just that, insulators can chemically react with a copper wire as well, causing oxides of all kinds on the surface and in between strands. This kind of contamination could theoretically cause all kinds of oddities. Question is, how do you make this visible? Not only that, how can we be sure it's that what we're showing and only that? Surely, I'm not equipped for that. I'd need assistance from the local university. (A tip, Steve?) quote: Third, is the distortion that I was looking for which would be intrinsic to the wire itself, and would be there with solid core as well as stranded. Indeed, but I assume we can, to some extend, assume that diodic effects should be less present in solid-core wire? Less detrimental is perhaps a better way of wording. Less total surface area being one argument. Thank you very much for the reply. Cheers,;) Steve Eddy quote: Originally posted by john curl Frank, we are now talking about 3 separate possible distortion mechanisms. First, your primary interest is diodic distortion from current moving across strands probably already oxidized by exposure to air. This could be very real. But don't see much likelihood of it in typical twisted stranded cables. That illustration on AudioQuest's site showing a strand alternately changing its position from the outside of the bundle to the middle of the bundle to illustrate their notion of "strand jumping" due to the different current densities between the outer periphery of the bundle and the center due to skin effect is highly misleading. In a twisted strand as they show here, the individual strands don't alternately dive to the center of the bundle and back out to the outside of the bundle. Instead, the individual strands maintain the same radial distance from the center of the bundle. Even their own drawing shows that much. Now, if the strands were braided rather than twisted as they typically are, that would have strands changing position concentrically. Or if the cable were a rope lay (i.e. several bundles of twisted strands twisted together). But for your basic twisted multistrand wire, that doesn't happen. quote: Second, we have distortion in the external contacts of a cable as they are also exposed to air and vibration (yes, this matters). By exposed to air do you mean oxidation or other airborne contaminants? quote: Third, is the distortion that I was looking for which would be intrinsic to the wire itself, and would be there with solid core as well as stranded. Except that this seems based on some rather wild speculations which I haven't seen any evidence to support. I can't access van den Hul's website at the moment, but I seem to recall his claiming that this effect was due to copper oxide forming at crystal boundaries within the wire itself. Such a thing should be common knowledge to metallurgists, but I haven't been able to find any evidence of this being the case. quote: I think that all three are possible, and probably measurable. Perhaps. But at this point, whatever nonlinearities might be caused by these, they're currently below the System Two Cascade's radar. se Bratislav quote: Originally posted by Steve Eddy But at this point, whatever nonlinearities might be caused by these, they're currently below the System Two Cascade's radar. Not to mention far below the resolution of ANY transducer used to hear it. Even if we take John's results for granted, the difference between El Cheapo and VDH are in order of 0.001% . Hearable ? Errrr ... on what speaker exactly ? Bratislav PS if a piece of coax cable was making THAT much difference, I assure you that signals from the detector in a radio telescope would be carried by top of the range ultra high end interconnects at x000$ per foot. They are NOT. And signal levels we're dealing with there will make your average audio application look like a joke. fdegrove Hi, Allow me to reply in your own house-style: quote: But don't see much likelihood of it in typical twisted stranded cables. Why not? quote: to illustrate their notion of "strand jumping" due to the different current densities between the outer periphery of the bundle and the center due to skin effect is highly misleading. No, you've just been mislead by the paper...How to prove it is another matter. They never do that, or do they? quote: Except that this seems based on some rather wild speculations which I haven't seen any evidence to support. Not as wild as you imagine... Why do you need Aalt Jouk for? We (me as a designer and my partner doing the commercial work) supply a lot of bare wire to VDH, anything he fancies has been developped...Including dielectric barriers. Uh? Yes. Uh? Wazzdat? I'll tell you. Some day...;) Steve Eddy quote: Originally posted by fdegrove Allow me to reply in your own house-style: Sure. quote: Why not? I thought I'd explained why not right after I said what you'd just quoted? quote: No, you've just been mislead by the paper...How to prove it is another matter. They never do that, or do they? Eh? quote: Not as wild as you imagine... Well, since I haven't seen any evidence that grain boundaries are comprised of copper oxide, I guess all I can do is imagine, eh? quote: Why do you need Aalt Jouk for? We (me as a designer and my partner doing the commercial work) supply a lot of bare wire to VDH, anything he fancies has been developped...Including dielectric barriers. Ok, so Aalt Jouk gets what he wants. What's that to do with his claims? se Steve Eddy quote: Originally posted by fdegrove And, to be sure not just that one single aspect: Peltier effects can be another player to name just one example. Careful. Sully mentioned Peltier/Seebeck effects on another forum and John chewed him out. :) quote: Back to topic. Yes, most cable is carelessly manufactured and at best exposed to air for a few hours (not just O2) before properly finished...But there's more than just that, insulators can chemically react with a copper wire as well, causing oxides of all kinds on the surface and in between strands. This kind of contamination could theoretically cause all kinds of oddities. Question is, how do you make this visible? Well, I guess you'd need to figure out what kind of distortion it would likely produce, either frequency domain nonlinear distortion or time domain linear distortion and attempt to make the appropriate measurement. quote: Not only that, how can we be sure it's that what we're showing and only that? As opposed to what? Some other distortion mechanism in the cable? quote: Surely, I'm not equipped for that. I'd need assistance from the local university. (A tip, Steve?) Well, if I hadn't mentioned it previously, Bruno works for Philips there in Belgium. You anywhere near Leuven? :) se fdegrove Hi, quote: I thought I'd explained why not right after I said what you'd just quoted? Audioquest's stab at it is just that, a stab. Honestly, I don't believe a word of it. That's not to say the phenomenon doesn't exist. I just have a hard time believing strands changing position within a bunch of wires. quote: By exposed to air do you mean oxidation or other airborne contaminants? Depending on the manufacturer, I suppose we can have both types at once. quote: Well, if I hadn't mentioned it previously, Bruno works for Philips there in Belgium. You anywhere near Leuven? Yes, I'm only half an hour away from Leuven. More importantly, I should get back in touch with a friend who works there as an assistant in the "Materials Research Department". We lost touch when I moved to Germany a few years back. I'll see what I can find on vdH's website regarding crystal boundary contaminants. Cheers,;) fdegrove Hi, I think this is the article you were referring to: CCD Cheers,;) peranders John Curl, couldn't you publish the performance of your test equipment so we can substract those results from the one you already have shown? Noise level at - 70 dB for instance???? Bricolo I don't know where and what was Mr Curl's answear about the Peltier effect, but I'll also try to give mine: I've dealt with Peltier modules some years ago, and I studied basicly how they work. From what I still know about that, it's one of the 3 thermoelectric effects (one other is the thermocouple, I don't remember the last one) and has to do with semiconductors. A peltier module is made of many P and N parts with a defined spacial organisation. Current flowing through this causes a temperature difference between the module's two faces. I don't know how we could find any Peltier effect in a metal fdegrove Hi, quote: I don't know how we could find any Peltier effect in a metal In a single metal you won't. Here's a more indepth explanation: PELTIER EFFECT. See also Seebeck effect on the bottom of the page. Cheers,;) Bricolo Some reading about the Peltier effect, and the 2 other ones (Thermocouple (Seedback effect), and the Thomson (aka Lord Kelvin) effect) http://www.marlow.com/TechnicalInfo...stions_faqs.htm http://www.thermoelectrics.com/introduction.htm Bricolo quote: Originally posted by fdegrove Hi, In a single metal you won't. Here's a more indepth explanation: PELTIER EFFECT. See also Seebeck effect on the bottom of the page. Cheers,;) another googler ;) sully The conversion of current into heat transport is Peltier.. The amount of heat that is transported across a two metal junction is dependent on the current, and the peltier coefficients..so, the amount of signal energy lost through the conversion to heat transport is proportional to current..Resistive loss within a conductor is proportional to current squared.. The efficiency of the peltier process depends on the conductivity of the metals, and the coefficients of the two metals.. Silicon is used for peltier modules for control of the material coefficients, and to reduce the efficiency lost when the heat tries to conduct in a direction opposite of that desired. The parameter being optimized is called the figure of merit..which relates the seebeck coefficient, the electrical conductivity, and the thermal conductivity of the materials...silicon is tuned to increase that figure. Seebeck conversion is the opposite process..BUT, the efficiency is proportional to the difference in temperature of the two sides of the metal interface. For small signal wires carrying little current, this temp difference is very small, rendering the Seebeck energy return possibility moot.. As to being "dissed" by John Curl in another forum regarding peltier......none of his criticisms had any validity, so will not be addressed by me.. Cheers, John Steve Eddy quote: Originally posted by peranders John Curl, couldn't you publish the performance of your test equipment so we can substract those results from the one you already have shown? Noise level at - 70 dB for instance???? The Mac The Scope software references to 1 volt. So John's analyzer is applying some gain to the residual output making direct comparison of the Mac The Scope plots difficult at best. To get an idea as to how the Mac The Scope and AP plots compare, I included this in my original post: Steve, the notch filter in the 1700B notches out to somewhere between -94 and -100dB This can be shown by the RESIDUAL of the THD at all levels is a little less than .002% or -94dB. Of course at very low levels, NOISE makes the residual appear to increase on the meter. This residual includes the unnotched fundamental ( the highest peak on the left side at 1KHz), the averaged distortion residual, and NOISE. At low levels, noise is all important, and this is why I must use signal averaging or very narrow bandwidth filtering to remove enough noise to look at the distortion residual. If you start with my graphs with the IKHz (notch) then you can see that the noise boundary is about -125dB. The distortion occurs in this case about -115 to -120dB, or even as much as -110dB if the notch is not complete. Using this as a guide to make a comparison of the levels John's measuring at versus where the System Two Cascade's measuring at, this is approximately how John's Radio Shack measurement would compare: Or to put it another way, if cables were producing the high order harmonic distortion components at the levels that John says he's measuring, then if measured on the System Two Cascade, we should see their peaks reaching up into the region of the red band in this image: se Steve Eddy quote: Originally posted by fdegrove I think this is the article you were referring to: CCD That's it. Thanks. I'll try and run that by a few metallurgists and see what they have to say about it. se Pjotr Just to add my 2 cents: Here a loop trough measurement of 5 m el cheapo Belden CATV cable. It is an average of 256 synchronous measurements. Averaging was done in the complex domain of the FFT. Signal was – 10dB below full scale. The audio card was an M-Audio Audiphile 2596, @ 24 bit / 48 kHz. The very low noise floor is due to the averaging. The real measurement floor is probably something of -130 dB, I guess. The harmonics seen are for sure the distortion of the card. They rise a lot at 0 dB signal level, just before clipping. At -40 dB signal the distortion vanishes completely from the plot BTW no cleaning of the cable connectors and card jacks was done (cinch). :cool: Pjotr Another 2 cents: Who can say the distortion seen in Jonh's measurements, is due to diode effects and not caused by dielectric hysteresis :confused: Steve Eddy quote: Originally posted by Pjotr Who can say the distortion seen in Jonh's measurements, is due to diode effects and not caused by dielectric hysteresis :confused: Because in light of the AP measurements, it appears that the distortion John's been measuring is being produced by his distortion analyzer, and not the cables. So the issue of diode effects versus dielectric hysteresis is rather moot, yes? The AP measurements are measuring well below here John's measuring, but even with a bog standard A/V cable, there's no evidence of the kind of distortion that appears in John's measurements. se Steve Eddy quote: Originally posted by Pjotr Just to add my 2 cents: Here a loop trough measurement of 5 m el cheapo Belden CATV cable. It is an average of 256 synchronous measurements. Averaging was done in the complex domain of the FFT. Signal was – 10dB below full scale. The audio card was an M-Audio Audiphile 2596, @ 24 bit / 48 kHz. The very low noise floor is due to the averaging. The real measurement floor is probably something of -130 dB, I guess. The harmonics seen are for sure the distortion of the card. They rise a lot at 0 dB signal level, just before clipping. At -40 dB signal the distortion vanishes completely from the plot Thanks. Though until you notch out the fundamental, the measurement isn't quite comparable, as I'm sure John would be the fist to tell you. :) se Pjotr quote: Originally posted by Steve Eddy Because in light of the AP measurements, it appears that the distortion John's been measuring is being produced by his distortion analyzer, and not the cables. So the issue of diode effects versus dielectric hysteresis is rather moot, yes? Agree, I just mentioned dielectric hysteresis because not many seem to be aware of. But anyhow even that did not show up. The distortion profile of John’s pics has much resemblance with cross-over distortion IMHO. Even if there is such thing as a diode effect in a cable, why should those many diodes be aligned in one direction so it can cause a rectifying effect? And when it can cause a rectifying effect, one can measure a DC component at the cable. Measuring DC is possible to deeper levels than measuring distortion with an AP if proper measurements are taken to get rid of thermo electric voltages. Cheers janneman quote: Originally posted by Steve Eddy That's it. Thanks. I'll try and run that by a few metallurgists and see what they have to say about it. se Hi guys, I followed this thread with interest; finally somebody at least tried to measure if there is anything to the stories. I looked at the CCD page from VDH. I find the contamination story convincing; even silverware quickly changes color after some time in open air due to chemical contamination. But one thing keeps bugging me. If we accept that this contamination changes (decreases) cable conductivity, why can't we just measure that with an ohmmeter? Or can we? Jan Didden "Can I have this speaker cable, sir?" "Yes, of course. Will that be smoking or non smoking, please?" fdegrove Hi, Pjotr, quote: And when it can cause a rectifying effect, one can measure a DC component at the cable. Measuring DC is possible to deeper levels than measuring distortion with an AP if proper measurements are taken to get rid of thermo electric voltages. Funny you'd mention that... I was thinking about this this afternoon and had planned to post the exact same thing. Cheers,;) john curl For the record, Steve Eddy likes to second guess me, and the nature of my measurements. SE, to the best of of my understanding, has not done any testing himself, and has no access to the schematics of the circuitry that is in my test equipment. His assessment of my measurement is pure conjecture, based on ONE NULL RESULT, that someome else made with another measurement system with different wires. I would concur that if there is a problem with my measurements, there should be an engineering level reason for it. SE likes to say 'crossover distortion', well why does the analyzer system give a different result with each wire type? Inherent crossover distortion in either the oscillator buffer or the input stage of the analyzer should be consistent with a similar load in each case. Could it be a special oscillation that is specifically dependent on the properties of each cable? Yes, if the cables were directly connected to the active devices, BUT they are resistively buffered on both sides, with more resistance than would typically be used with an audio stage. The reasons should be noted, first the oscillator operates at about a 3V level and this must be resistively attenuated to 30 mV, at the same time a 600 ohm drive impedance is created. On the input, there are relays across each input to protect from overvoltage. These relays need to be current protected to keep them from being destroyed the first time they are used. Therefore, each input, both hot and ground have a 500 ohm resistor in order to limit peak currents. This has not been changed in my equipment. Therefore it is very difficult to see how a specific cable can effect my equipment to make different measurement results. I am open to serious suggestions. Steve Eddy quote: Originally posted by Pjotr I just mentioned dielectric hysteresis because not many seem to be aware of. But anyhow even that did not show up. Yes, I'm aware of hysteresis in dielectrics, but I don't recall ever seeing anything about their exhibiting hysteresis anywhere near the audio band. Doesn't dielectric hysteresis occur more around the X-ray region of the spectrum? If you've some sources on the matter, I'd be interested. quote: The distortion profile of John’s pics has much resemblance with cross-over distortion IMHO. Yes. quote: Even if there is such thing as a diode effect in a cable, why should those many diodes be aligned in one direction so it can cause a rectifying effect? And when it can cause a rectifying effect, one can measure a DC component at the cable. Measuring DC is possible to deeper levels than measuring distortion with an AP if proper measurements are taken to get rid of thermo electric voltages. Yes, I'd mentioned the same in the past. If there's any nonlinear I/V relationships, one needn't use AC signals to measure it. As I'd related before, I recall reading somewhere that some researcher thought he had observed rectifying effects in copper wire, but on further investigation it turned out to be the contacts of his aparatus. In any case, I simply don't see how copper wire could have the gross nonlinearities shown in John's measurements. I find it rather hard to swallow that a length of copper wire can be more nonlinear than than a complex active circuit such as an opamp. And I find it even more difficult to believe that such gross distortions in copper wire could have wholly escaped the entire notice of everyone, including materials science researchers. se Steve Eddy quote: Originally posted by john curl For the record, Steve Eddy likes to second guess me, and the nature of my measurements. SE, to the best of of my understanding, has not done any testing himself, and has no access to the schematics of the circuitry that is in my test equipment. So? What has that to do with the measurements which Bruno made? quote: His assessment of my measurement is pure conjecture, based on ONE NULL RESULT, that someome else made with another measurement system with different wires. Of course it was made on another measurement system, John. That was the whole point! If the distortion you were measuring were being produced by your measurement system, what the hell good would it have done to repeat the tests using the same system? It likely would have turned up the same result and we'd still be wondering whether the distortion was being produced by the measurement system or the cables. And what's with this "ONE NULL RESULT" nonsense? We're not talking about blind listening tests here, John. Cable distortions don't suffer from test anxiety. And so what if the wires weren't the exact same wires you measured? You mean these micro diodes only inhabit the wires that you an van den Hul measure? In any case, if you want to look at it in such terms, then these new measurements have shown that a bog standard A/V cable with plain Jane ETP copper wire, PVC insulation, molded RCA plugs, etc., clearly demonstrated that they were far better than your best van den Hul reference cable. And by the way, I have offered you the opportunity to measure the same cables that Bruno will be measuring. I have an old 12 foot set of Radio Shack Gold interconnects as well as a brand new, never used set that I bought the other day specifically for this purpose. I also have an 8 foot set of cheap A/V cables that came with my DishNetwork boxes. I've taken each of these and split their left/right channels in two so that you and Bruno can each have as exactly the same cables as possible short of shipping the same cables back and forth. Bruno has already kindly accepted and I'll be mailing out his set this week. I made you the same offer back on the 28th on another forum but have not heard from you at all on the matter. Perhaps you haven't been there since the 28th. The offer still stands. Will you accept so that the issue of measuring different wires can be properly addressed? quote: I would concur that if there is a problem with my measurements, there should be an engineering level reason for it. SE likes to say 'crossover distortion', well why does the analyzer system give a different result with each wire type? Inherent crossover distortion in either the oscillator buffer or the input stage of the analyzer should be consistent with a similar load in each case. Could it be a special oscillation that is specifically dependent on the properties of each cable? Yes, if the cables were directly connected to the active devices, BUT they are resistively buffered on both sides, with more resistance than would typically be used with an audio stage. The reasons should be noted, first the oscillator operates at about a 3V level and this must be resistively attenuated to 30 mV, at the same time a 600 ohm drive impedance is created. On the input, there are relays across each input to protect from overvoltage. These relays need to be current protected to keep them from being destroyed the first time they are used. Therefore, each input, both hot and ground have a 500 ohm resistor in order to limit peak currents. This has not been changed in my equipment. Therefore it is very difficult to see how a specific cable can effect my equipment to make different measurement results. I am open to serious suggestions. Bottom line, it's not my problem. It's your test equipment. You figure it out. You're one of the "big boys" remember? All I know is that on a modern, reference standard measurement system known to have significantly greater resolution that what you're using, there are no signs of the high order harmonic distortion products that you've been measuring even when measured at levels far below what your system is capable of and even when the cables measured included a bog standard giveaway A/V cable. So you'll excuse me if I take this as pretty good evidence that the distortion that you're measuring is being produced, for whatever reason, by your distortion analyzer. Again, my offer still stands to send you a duplicate set of cables. Take it or leave it. se sully quote: Originally posted by Pjotr Even if there is such thing as a diode effect in a cable, why should those many diodes be aligned in one direction so it can cause a rectifying effect? And when it can cause a rectifying effect, one can measure a DC component at the cable. Measuring DC is possible to deeper levels than measuring distortion with an AP if proper measurements are taken to get rid of thermo electric voltages. Cheers I've seen no indication of any dc effects with any combination of currents from picoamperes to 30 kiloamps...with nano-ohm measurements, nor with nanovolt dc measurements...but I've only checked from 4.5 Kelvin to room temp..so I'll be the first to admit a lack of resources.. quote: Originally posted by john curl For the record, Steve Eddy likes to second guess me, and the nature of my measurements. SE, to the best of of my understanding, has not done any testing himself, and has no access to the schematics of the circuitry that is in my test equipment. He isn't second guessing you..he has presented tests which are more accurate than yours, showing none of the harmonics you report. quote: Originally posted by john curl His assessment of my measurement is pure conjecture, based on ONE NULL RESULT, that someome else made with another measurement system with different wires. Four wires, exact same test criteria...how many null results are necessary?? quote: Originally posted by john curl I would concur that if there is a problem with my measurements, there should be an engineering level reason for it. . We've been saying that all along..but you have to date resisted any discussion of that possibility.. quote: Originally posted by john curl SE likes to say 'crossover distortion', well why does the analyzer system give a different result with each wire type? . Why not test your 1700 with an AP?? quote: Originally posted by john curl Therefore it is very difficult to see how a specific cable can effect my equipment to make different measurement results. I am open to serious suggestions. We've been trying for a while to no avail...Hopefully, you are really earnest in this desire? Cheers, John Christer This is just a speculation but since John did his measurements at home and this is obviously a far-from-ideal lab environment, which is obvious from his own explanation of the TV interference, could it be that also the other frequencies are some kind of outside interference picked up by the cables? Come to think of it, could it even be that the cables actually pick up stray magnetic/electric fields from the signal generator? John, would it be possible for you to move your test equipment and repeat the experiments somewhere else, where there is less outside interference from neighbours, less **** on the power lines etc.? That would be a first reasonable way of trying to repeat the experiments. Steve Eddy quote: Originally posted by janneman I looked at the CCD page from VDH. I find the contamination story convincing; even silverware quickly changes color after some time in open air due to chemical contamination. Sure. On it's SURFACE. But van den Hul's claiming that this contamination (or rather the contamination that he's talking about) is INTERNAL. In other words, at all of the internal interfaces of the crystals that make up the wire. I've done quite a lot of searching but I have yet to find any evidence substantiating this claim. He also says that the process is on-going and becomes worse with time. Yet there are copper artefacts which are THOUSANDS of years old, and except for surface patina, are in excellent shape, even though these artefacts were produced using very primitive methods compared to how copper is produced today. quote: But one thing keeps bugging me. If we accept that this contamination changes (decreases) cable conductivity, why can't we just measure that with an ohmmeter? Or can we? Don't see why not. Though if you want to get a bit more exotic, you could measure residual resistivity (resistivity measured while the wire is supercooled to 4.2 degrees Kelvin), let it age and then measure it again. se Steve Eddy quote: Originally posted by Christer This is just a speculation but since John did his measurements at home and this is obviously a far-from-ideal lab environment, which is obvious from his own explanation of the TV interference, could it be that also the other frequencies are some kind of outside interference picked up by the cables? Come to think of it, could it even be that the cables actually pick up stray magnetic/electric fields from the signal generator? I find it rather odd that the interference (aside from the 15.75kHz spike) would just happen to be at harmonics of 1kHz. In any case, I believe John says he's also measured at other frequencies so that would rule that out. se fdegrove Hi, quote: I find the contamination story convincing; even silverware quickly changes color after some time in open air due to chemical contamination. First of all silverware isn't pure silver or it would bend in all kind of directions when you use it. Secondly, given the above it also oxidises more easily. Thirdly, in the factory it does get treated differently due to intrinsic value. Fourth, if you're a big enough customer they will do specials for you such as very slow die draws, after glows and lab reports etc. In short, higher purity of the metal and longer crystals can contribute markedly on better sonic performance. Cheers,;) Steve Eddy quote: Originally posted by fdegrove In short, higher purity of the metal and longer crystals can contribute markedly on better sonic performance. I'm sorry, I must have forgotten. That was proved when? se hitsware >Therefore it is very difficult to see how a specific cable can effect my equipment to make different measurement results. I am open to serious suggestions. How do you make your connections for these tests? Seems that may be where the distortions arise.......... fdegrove Hi, quote: I'm sorry, I must have forgotten. That was proved when? To my and other ears and eyes ages ago, Steve. Let's see...1994? Something like that. Instead of talking to a metalurgist try talking the a material scientist that also happens to have an interest in audio. Incidentally this what I did and vdH was/is in touch with the same person I mentioned before. I hate to dissapoint you but the documentation for it is at KUL Leuven. Since they get paid for research I'm not at large to divulge it. Cheers,;) sam9 For the record, I posed that very question to my offspring who is completing a PhD in materials science. She asked her three faculty members she works with/for (including one with a Nobel) the consensus was ---Bull ! By the way these folks work with nano structures. fdegrove Hi, quote: By the way these folks work with nano structures. Yes, the research is done at nano levels. Also at nano levels are LEDs made of crossed wire structures etc. Now, next time you see your LS cable aglow you know what's going on... Cheers,;) Christer quote: Originally posted by Steve Eddy I find it rather odd that the interference (aside from the 15.75kHz spike) would just happen to be at harmonics of 1kHz. In any case, I believe John says he's also measured at other frequencies so that would rule that out. se Yes, I realized that, which is why I also suggested the other possibility of the cables picking up stray fields from the equipment. On the other hand, there is a lot of strange rubbish signals both radiated and in the mains in the modern society. fdegrove Hi, quote: Yes, I realized that, which is why I also suggested the other possibility of the cables picking up stray fields from the equipment. Under the testing conditions stated, not very likely. Cheers,;) Steve Eddy quote: Originally posted by fdegrove To my and other ears and eyes ages ago, Steve. Let's see...1994? Something like that. Ah, ok. Your original claim seemed rather all-encompassing. quote: Instead of talking to a metalurgist try talking the a material scientist that also happens to have an interest in audio. What's an interest in audio to do with anything? quote: Incidentally this what I did and vdH was/is in touch with the same person I mentioned before. I hate to dissapoint you but the documentation for it is at KUL Leuven. Since they get paid for research I'm not at large to divulge it. Jeeez, Frank. That's right up there with "I could tell you but then I'd have to shoot you." se Steve Eddy quote: Originally posted by sam9 For the record, I posed that very question to my offspring who is completing a PhD in materials science. She asked her three faculty members she works with/for (including one with a Nobel) the consensus was ---Bull ! By the way these folks work with nano structures. What question was that? About micro diodes? se fdegrove Hi, quote: What's an interest in audio to do with anything? It helps communication between individuals in explaining what it is you're looking into. If you have the education and measuring equipment of a Materials Research Dep. then you won't need to TALK to these guys, right? It's important for you and them to know exactly what to look for. Having a person with pre-knowledge in audio terminology was a big help. < quote: Jeeez, Frank. That's right up there with "I could tell you but then I'd have to shoot you."