| johnferrier |
| quote: | Originally posted by john curl
Steve Eddy has little or no idea of what he is talking about in this case... |
I don't know, it strikes me as an honest effort here. Though it may not come across that way, I don't think he ultimately has an axe to grind (a rather petty victory if there was one). I think Steve truely would like to understand this. Personally, I like'd to know one way or another, where is ground zero.
JF |
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| john curl |
JF, there are more threads than just this one where SE attacks my input.
I have the equipment, the experience with the equipment, and the tech manual of the equipment. SE can't be bothered to have any real evidence that contradicts my statements, but he does so anyway. |
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| johnferrier |
| quote: | Originally posted by john curl
JF, there are more threads than just this one where SE attacks my input.
I have the equipment, the experience with the equipment, and the tech manual of the equipment. SE can't be bothered to have any real evidence that contradicts my statements, but he does so anyway. |
Understand. I don't have the details, but I understand you are an expert at amplifier design as well (to say the least). I'm glad (as many are) that you contribute to a public forum (the World Wide Web is a great tool for international communication--Hi again Frank in Belgium). I'm also glad that Steve shakes you guys up a bit. As you know, there are a lot of aspects to technology--nobody knows it all. If Steve was a crackpot, people would ignore him. He certainly is persistant at this, though. Reading the manual and calling the mfg is square one and more that some users do. He doesn't have equipment, but then many of us don't have the equipment (my plan is to see how much a local stereo shop charges to run measurements--my guess is about $30-$50 for fully certified measurements).
JF |
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| Steve Eddy |
| quote: | Originally posted by john curl
It is strange when people discuss test equipment that they have no experience with. |
Hey, I'm just relaying what I was told by the gentleman at Sound Technology. If you don't like it, take the matter up with them.
| quote: | | First, the 1700B is spec'd at: .0018% harmonic distortion at mid frequencies. So far as my experience is concerned, this includes the oscillator as well as the analyzer section. |
Great. But when I specifically asked what the 1700B was spec'd at, I was told it was between 0.0018% to 0.0025% for the generator, and the same for the analyzer.
Again, I'm only relating what I was told by the gentleman at Sound Technology. If you've got a problem with that, call them up and set them straight.
| quote: | The FUNDAMENTAL limitation of this system's measurement capability is the NOTCH. It is the fundamental limit and is almost all the meter reads, except for noise at low levels. After all, a -95dB notch is slightly less than .002% You can't measure with the meter alone, lower than the notch itself.
This can be seen with ANY spectrum analyzer, FFT, or wave analyzer. The added distortion components from the oscillator or the input stages are lower in level by a significant amount. I have further improved the performance by upgrading the input and oscillator op amps. |
Looking at your Mac The Scope plot of the van den Hul cable you use for reference, if we assume that you're notching the fundamental by 95 dB, we're looking at the third harmonic being down about -115 dB relative to the fundamental.
It doesn't matter what you did with the opamps. Your plots speak for themselves. Just as the AP plots speak for themselves. And it's abundantly clear that your system isn't measuring as far down as the System Two Cascade. Period.
That being the case, if the high order distortion products you're measuring are indeed being produced by the cables themselves, they would be even more obvious when measured using the System Two Cascade.
Yet there's no sign of them.
| quote: | | Steve Eddy is not an 'objective' arbitrator here. He minimizes the quality of the equipment, and its cost to duplicate it. |
How can I not be objective John when we're comparing actual measurements? The plots speak for themselves. Your system's measuring down to about 125 dB below the fundamental, the System Two Cascade's measuring down to about 145 dB below the fundamental.
These facts have absolutely nothing to do with me. They are what they are. So why do you continually attempt to personalize this issue?
| quote: | | In fact, if it is so cheap to obtain a ST1700B, then why doesn't he buy one, if only to pick it apart? |
Why? I've never said you're not measuring down to the level that you claim you are. Like I said, your plots speak for themselves. So why would I need to go buy a 1700B?
| quote: | | Steve Eddy has little or no idea of what he is talking about in this case, but that won't stop him from confusing the rest of you. |
Again, John, the plots speak for themselves. How much of an idiot does one have to be to not realize that a system that's resolving down to -125 dB relative to the fundamental isn't as resolving as one that's resolving down to -145 dB relative to the fundamental?
se |
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| Steve Eddy |
| quote: | Originally posted by john curl
JF, there are more threads than just this one where SE attacks my input.
I have the equipment, the experience with the equipment, and the tech manual of the equipment. SE can't be bothered to have any real evidence that contradicts my statements, but he does so anyway. |
Again, John, I have never said that you're not measuring to the levels you claim to be measuring. I've fully accepted that you are.
I have only said that your system's not resolving to the same levels as the System Two Cascade is. And by your own claims, it's not. Do we need to go through the math again?
Your system's third harmonic is about -115 dB relative to the fundamental. Your noise floor using FFT averaging is is about 125 dB relative to the fundamental.
The System Two Cascade's thrid harmonic is about -130 dB relative to the fundamental. It's noise floor using FFT averaging is about -145 dB relative to the fundamental.
So tell me, John, is -130 dB further down than -115 dB? Is -145 dB further down than -125 dB?
se |
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| Fred Dieckmann |
"If he was a crackpot, people would ignore him. But he certainly is persistant at this. Reading the manual and calling the mfg is square one and more that some users do."
Ah yes.............. I remember the last time he called the manufacturer, Jensen Transformers. They ended up trying to distance themselves from comments in confidentiality to him that did not stay confidential. They also asked to be left out of any involvement in discussion of the debate at hand. Steve Eddy later decided that one of technical statements made by the president of Jensen, Bill Whitlock in one of his articles was false and Jensen Transformers was quite the reference he needed. As for ignoring crackpots, try it some time when he spends a week trying to defend some erroneous position with methods that bring to mind the "it depends of what the definition of 'is' is" defense. At some point, the people worth reading will stop bothering, if being second guessed by people with no technical qualifications and a clear agenda, is the only reward for ones efforts. Ask yourself what Mr. Eddy has added to your knowledge of audio design and what exactly he hopes to accomplish with this week long harangues. For my part I can think of nothing except his desire for notoriety by his constant harassment of one the leading audio designers working. I am sure the targets of his obsessive fixation with would love to ignore him, if he would just shut up once in a while. |
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| john curl |
Actually, your last statements, attributed to me are off a little. The real noise floor is -120dB and therefore everything is moved up 5dB. This makes an even greater departure from Bruno's measurement, so be it. Please do not speculate on my very early input.
For the record, and the rest of you, my measurements were at first considered by me to be RELATIVE rather than absolute. Some cables have more distortion than others. When I first used my HP3580 linear spectrum analyzer and later the MAC the Scope with my MAC computer, I was unsure of the absolute accuracy of the distortion levels. Now, because I use a calibrated FFT in the HP3563 and the voltage levels are on the screen, it is much easier to pin down the absolute distortion level. Actually, it is still the changes in the harmonic levels between different wires, that is still the most important. |
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| Steve Eddy |
| quote: | Originally posted by johnferrier
Reading the manual and calling the mfg is square one and more that some users do. |
I did that to satisfy my own curiousity as much as anything else.
I couldn't imagine that AP would offer a multi-thousand dollar measurement system that couldn't do the same type of measurement as John, but I couldn't say for certain that it could. so I checked it out.
And while I didn't think that Sound Technology was making current models of their 1700 series, looking at how it was presented on their web page, it looked as if they were. So I called 'em. And while I was on the phone with them, I asked about that 0.0009% figure that Charles was ascribing to the 1700B.
John likes to think that I'm just out to get him. I don't know if he truly beleives this or if he intentionally uses this as a smokescreen.
The only thing I'm out to get at is the truth. And it doesn't matter to me where the truth lay. If I'd have found out that not even the System Two Cascade could do the same type of test as John, I'd have reported that, just as I reported that my suspecting that ST was producing current model 1700 series equipment was incorrect.
se |
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| johnferrier |
| quote: | Originally posted by Fred Dieckmann
Ask yourself what Mr. Eddy has added to your knowledge of audio design... |
Okay, I don't have time to polish a reply...
Maybe indirectly learned (averted learning):
AP System II is the best equipment to use to test an amplifier.
From the AP datasheet, 25mVrms (which as John Curl indicates is a typical signal and I concur) is more challenging to measure than a 2Vrms signal--the noise/distortion floor moves up (okay, everyone knows this but the graphs in the datasheet made it clear).
Silver is the lowest electrical and thermally conductive metal (useful for pulling heat out of parts...yes sorry, learned it because of these threads).
I also, like Eric's idea of making a "directionless" cable--if nothing else the parallel conductors lowers the resistance.
Solid wire may be better than stranded.
And, if it's important enough, by asking questions, one can get answers.
And other things that don't come to mind right now. Of course, other people have contributed equally, but Steve did start these threads.
I will add that the rest of my circuit has been narrowed down. Information on conductors and interconnects is what I'm finalizing.
The subler phenomena in conductors is still forumulating and is not concrete yet. Though, it doesn't seem to harm to care about the details.
Again, it's a lot of work even to make a small amplifier. I just want to get the details right...
I could learn this other ways alone, of course. But why do we bother with a public forum then?
JF |
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| millwood |
| quote: | Originally posted by Fred Dieckmann
Ask yourself what Mr. Eddy has added to your knowledge of audio design |
to give you one data point: Steve has contributed to this forum infinitely more than you have.
other than your superficially convoluted answers, you, Mr. Dickmann, have added nothing, zipo, positive to this forum.
If you really really want to sound sophisticated by writing in such a convoluted way, you can at least go through a law program. even one at a local community college will help you a long long way in that regard.
Again, please respect Steve's wish and let this discussion be a technical one, not about how over-inflated your ego is.
For that, you can open another thread of yours and I am happy to take it out with you there. |
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| Steve Eddy |
| quote: | Originally posted by john curl
Actually, your last statements, attributed to me are off a little. The real noise floor is -120dB and therefore everything is moved up 5dB. This makes an even greater departure from Bruno's measurement, so be it. Please do not speculate on my very early input. |
Fine. But whether -120 dB or -125 dB, when resolving down to -145 dB, there's still no sign of high order harmonics.
| quote: | | For the record, and the rest of you, my measurements were at first considered by me to be RELATIVE rather than absolute. Some cables have more distortion than others. |
But you also say that after a time, a given cable will measure considerably less distortion than it did orginally. Which means that its level of distortion might end up being the same as that of another cable which originally measured considerably better.
You also say that distortion levels can change depending on whether you've cleaned the contacts or not.
You seem to have quite a lot of moving targets.
| quote: | | Actually, it is still the changes in the harmonic levels between different wires, that is still the most important. |
But you also get changes in harmonic levels with the same wire.
Perhaps SY can help pin down some of these moving targets and maybe we can make better sense of this as a result.
se |
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| mefinnis |
Can we please stop with the personnal b.u.l.l.s.h.i.t.
For the record, I don't know SE, I neither like nor dislike him. He reminds me of a "fixated terrier" with a rag. This is not to be insulting ..... it is actually a characteristic we look for in trainees. "Obsession is a virtue."
The concept, that members of the general community here are going to form their opinion of a given member based upon what another member tells them they should think, is pathetic.
SE's fundamental question (as it appears to me .... and a few others with no axe to grind), seems to have scientific validity.
1. JC has report a finding which is outside of mainstream "knowledge". No-one has argued that JC has not seen this, fabricated this, or in any way been dishonest
Certain people have suggested, well JC is an industry leader, this is therefore real ...... ****!
This is not meant to be offensive in any way to JC, but if we are going to accept he is infallable we should be referring to him as "The JC". Any scientist can err, be tricked by erroneous findings etc. (I am NOT saying his findings are erroneous, just that this is a possibility)
2. SE has said, hang-on, this may be real or alternatively a measurment artefact. Now, I acknowledge he can do this a little abrassively at times, but I don't think I would hang him for this just yet.
Science would suggest that we:
1. Find someone with the same equipment and see if this is repeatable.
2. Find someone with "better" equipment and see if this is repeatable.
OK now, for those of us who have an interest in reality here. JC has delineated the performance of his equipment adequately (I think).
JC and Charles, do you agree that Bruno's system is able to measure at least to the same level as John's system?
If not, why not?
If not, what specifically would need to be changed so that it was?
Also, there must be more people "out there" with this kind of equipment. Can we find them and get them to make measurements.
OK, they will not be measuring the same cables as JC/Bruno, but the first step is to see an "effect" ..... we can work on exact categorisation etc later.
mark
PS: SE, how "friendly" were the folks at Sound Technology? Do you think we could interest them in doing this as it is "at the edge" of their systems performance???? |
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| john curl |
I find that 'moving targets' make sense. Let me explain to the rest of you.
You have heard of 'dirty contacts' haven't you? Well, I seem to be able to measure them. I start with some adaptors that I must use to make the test possible. I clean them at first, BUT over time they seem to get 'dirty' I clean them again, and the extra distortion goes away. Is this an impossible concept?
You also have heard of 'break-in' of cables. It seems that when I find a particularly 'bad' cable, I tend to use it for testing more often, sometimes accidently leaving it in the machine running with a test signal for days. You might ask, am I not paying attention? Yes and no. Sometimes I turn off everything EXCEPT for my ST analyzer. It likes to be on all the time, and with something connected to it. If I forget to replace the test cable with a reference, the test signal will continue to flow through the cable until I go back, which might be days later. Just last week, I accidently left SE's steel leaded cable in the analyzer, overnight. Well, overnight was not enough to change it much, so I can still use it for testing. However, many of my original RS cables that much is still made of, have changed for the better. Darn, but I still have one RS cable that measures pretty poorly, and I have yet other examples of cables. |
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| Charles Hansen |
Hello -
I was wrong about the ability of the AP to perform an FFT spectrum analysis on the residual output coming out of the analog notch filter, and Steve Eddy was right.
While I was verifiying that this was indeed possible, I decided to try and run a quick "Curl-type" test. Now the AP only has a choice of XLRs and bananas for I/O. Rather than complicate things by adding adapters, I chose to measure an XLR cable. Since I don't have a large selection of XLR cables, I decided to compare the signal through the cable against the direct output of the distortion analyzer (an internal bypass, presumably through relays). Here are my results of a single test run, done at 2.0 Vrms @ 1.00 kHz:
Frequency L Cable R Cable L Gen R Gen
1.00k -120.75 -120.72 -120.56 -120.55
2.00k -120.11 -120.12 -120.09 -120.55
3.00k -134.07 -134.04 -133.62 -133.55
4.00k -142.18 -142.42 -145.54 -145.60
5.00k -139.69 -139.88 -142.14 -142.23
6.00k -149.55 -149.71 -151.12 -150.73
7.00k -146.34 -146.22 -144.13 -144.11
8.00k -145.75 -145.90 -147.24 -147.16
9.00k -145.46 -145.43 -150.57 -150.79
(Please excuse the difficulty of reading this table. I don't know how to insert a tab, and the HTML apparently parses multiple spaces down to just one.)
(The number reported at 1.00 kHz shows the depth of the analog notch filter.)
There are a couple of interesting points to be seen. The first is that the two channels track each other quite closely. This would tend to support the idea that the measurements are relatively repeatable. The next thing to note is that there are significant differences to be seen. For example, the 9th harmonic is roughly 5 dB higher when going through the cables.
At the same time, this is hardly a definitive test. One odd thing that pops up is that some of the harmonics are *lower* when the signal is going through the cables. So perhaps there is a random component to the measured values, although the comparative consistency of the two channels would tend to negate that possibility. Also, it would presumably be more fair to have two different sets of cables rather than comparing a cable to a bypass.
At any rate, this is a tantalizing beginning. There are a lot of other things that I could do (such as try to figure out if I can average multiple runs to lower the noise floor), but currently I am suffering from the flu. I am heading home for the day to try and recover.
Charles Hansen
PS -- In my test setup it was important to turn the computer's CRT monitor completely off when running the test. Leaving it on raised the noise floor significantly, obscuring the low-level harmonics. |
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| Steve Eddy |
| quote: | Originally posted by mefinnis
For the record, I don't know SE, I neither like nor dislike him. He reminds me of a "fixated terrier" with a rag. This is not to be insulting ..... it is actually a characteristic we look for in trainees. "Obsession is a virtue." |
Not taken as an insult.
Though I am a bit curious... trainees for what exactly? :)
By the way, with regard to your previous request:
You may well be absolutely correct in what you say to Charles ...... for the sake of the rest of us, could you verify Bruno's set-up for Charles.
I just received Bruno's reply a moment ago.
I'd sent him the following commentary from Charles:
Actually I think Curl's method is rather simple and easily reproduced.
1) Use a high-quality, low-distortion analog oscillator.
2) Run the signal through the DUT.
3) Notch out the fundmental tone with an analog notch filter.
4) Make multiple time-windowed digital readings of the resultant residual output.
5) Perform an FFT on the averaged signal to generate a spectrum of the residual distortion.
However as near as I can tell, Putzeys has not done this. Based on what I've read on this forum and in the AP manual, I think what Putzeys has done is to:
1) Use a high-quality, low-distortion analog oscillator.
2) Run the signal through the DUT.
3) Convert the analog signal to digital.
4) Notch out the fundmental tone with a digital notch filter.
4) Make multiple time-windowed digital readings of the resultant residual output.
5) Perform an FFT on the averaged signal to generate a spectrum of the residual distortion.
If this is true, the problem is in step #3 where the analog signal is converted to digital. The ADCs used in the AP have insufficient resolving power to replicate Curl's findings.
Of course, I could be wrong. I am waiting for Eddy to confirm in an unambiguous way Putzeys' setup.
Here is Bruno's reply:
The AP2 certainly notches out the fundamental in the analog domain before sending it over to the digital analyser. That's the big deal about Audio Precision products ever since the first Dual Domain came out. It's been their main selling argument since ever. Of course, you *can* tell it not to - I mean if you really want to cut your finger no good knife will stop you (actually this option is only used to measure the onboard AD itself). Even more interestingly, while the AP has a digital notch filter capability (to directly read THD+N figures from A/D converters), it has no way to feed the signal from that notch filter into the FFT analyser. It's one or the other, but both DSP programs can't be run at the same time and you certainly can't pipe data between them. It means the experiment the poster suggests can't even be performed.
It is quite clear that this poster has *no* idea what he was talking about. Suppose the signal did get converted fundamental and all. Once you have the signal in the digital domain, there is no point in removing the fundamental. You don't improve the resolution of an FFT by removing the fundamental. An FFT of a data set representing a measurement and an FFT of the same data set with the fundamental removed are perfectly identical - apart from the fundamental. There are no more distortion mechanisms to worry about once digitisation is done (discounting numerical effects at -190dB).
This is why FFT plots showing the distortion performance of D/A converters always (should) have the fundamental removed: to prevent the analyser's AD from dominating the measurement. Plots showing distortion performance of A/D converters always have the fundamental still in.
So, that's out of the way.
se |
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| fdegrove |
Hi,
John F,
| quote: | | I also, like Eric's idea of making a "directionless" cable--if nothing else the parallel conductors lowers the resistance. |
It doesn't lower the resistance any more than twice the gauge would, if there were to be more resistance one way or the other, it would be easy: measure and arrange accordingly.
What I assume Eric does is determine the directionality of a piece of wire and from that decides the direction of the send and return wires in his star quad configuration.
He's happy with that, so I'm happy for him...
Just running a pair of wires in parallel will give you more problems than you're trying to solve.
A star quad doesn't measure the same as a twisted pair on all parameters concerned and directionallity is not going to alter those facts.
As far as I'm concerned, I don't care all that much about the directioanlity of a piece of wire, once it's run in I don't hear a difference untill I reverse the direction. Why would I want to do that in the first place?
What I do think happens is a conditioning of the wires according to the way they're run in.
More later, perhaps.
Millwood,
| quote: | | to give you one data point: Steve has contributed to this forum infinitely more than you have. |
Do you have proof of that? I seriously doubt it for I know Fred has contributed in a big way and still does...With Fred you have to know what he's on about though...
It may take some effort but let me assure you he knows more than he's letting on lately.
In short, I know where's coming from, understand what he means but don't expect too many other members do.
This is not a personnal attack against anyone, just my observation of what I consider facts.
Which, in anyone's book is a subjective one....
So it was Al Gore inventing the internet or was that a subjective observation as well?
Cheers,;) |
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| mefinnis |
| quote: | | SE asked ...Though I am a bit curious... trainees for what exactly? |
Sorry, I am an examiner for the Australian+NZ College of Anaesthetists. I work fulltime in Intensive Care and spend a lot of time in teaching/training.
While the finer engineering points here pass me by, I have a deep-seated interest in scientific method.
cheers
mark |
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| Steve Eddy |
| quote: | Originally posted by Charles Hansen
I was wrong about the ability of the AP to perform an FFT spectrum analysis on the residual output coming out of the analog notch filter, and Steve Eddy was right. |
Thank you, but you could have left out the "I was wrong" and "Steve Eddy was right." That just feeds this notion that it's all about scoring points for me. I'm no more interested in your saying "I was wrong" than I am your saying "Steve Eddy was right."
When it comes to getting at the truth of something, let's keep things impersonal. Something either is the way it is or it isn't. And whichever way it ends up being, it doesn't end up being that way because someone said it is or it isn't. Or because someone was right or someone was wrong.
se |
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| johnferrier |
| quote: | Originally posted by fdegrove
It doesn't lower the resistance any more than twice the gauge would, if there were to be more resistance one way or the other, it would be easy: measure and arrange accordingly.
What I assume Eric does is determine the directionality of a piece of wire and from that decides the direction of the send and return wires in his star quad configuration.
He's happy with that, so I'm happy for him...
Just running a pair of wires in parallel will give you more problems than you're trying to solve.
|
Frank,
I understood it as simply running a wire A to B and then a second wire B to A. And yes, at minimum, parallel resistance, etc.
I'm waiting for the results of the cable directionality test before going any further...
However, why would parallel wires give more problems?
Thanks.
Millwood,
How many threads have you ended, or triggered the end?
JF |
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| Steve Eddy |
| quote: | Originally posted by mefinnis
Sorry, I am an examiner for the Australian+NZ College of Anaesthetists. I work fulltime in Intensive Care and spend a lot of time in teaching/training. |
Ah, thanks. Was just making sure it wasn't something like accident/injury attorneys or other lower forms of life. :)
| quote: | | While the finer engineering points here pass me by, I have a deep-seated interest in scientific method. |
Yes. And you don't need to be an engineer to apply it.
se |
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| fdegrove |
Hi,
| quote: | | You have heard of 'dirty contacts' haven't you? Well, I seem to be able to measure them. |
Sure can and even my ears can...more to the point it seems that some here are missing at least ten pages of electronics industry and I don't mean you John C....
I work with mainframes and vaxes and contact reliability is of the utmost importance here...The same contact enhancing products are out there for eveyone to buy often in dilluted sollutions.
They work, preserve and protect...Thank god.
These same products are also used in aersospace applications and an audio derrivative was marketed many years ago under the name "Tweak".
Regarding break in of cables, well that's the whay we call it but has it occured to anyone that there may be a rearrangement of electron allignment occurring during this period? I could be wrong with my guesses but I sure do hear it...Someting's happening...
Maybe something for a scanning electron microscope too...It seems just the perfect tool to solve many pending questions.
I'm starting to find nanoelectronics a very interesting topic...
Let me rephrase that: I'm starting to be aware that much of what I've learned in audio has it's roots in nanoelectronics.
Fascinating stuff...;) |
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| Charles Hansen |
| quote: | Originally posted by Steve Eddy
When it comes to getting at the truth of something, let's keep things impersonal. Something either is the way it is or it isn't. And whichever way it ends up being, it doesn't end up being that way because someone said it is or it isn't. Or because someone was right or someone was wrong.
se |
Hello -
I disagree with you on this. I think it is extremely useful to know when someone has changed their point of view. For example, after reading Putzeys' reply that you quoted a few posts up, I agree with him point by point, and my previous supposition was wrong.
After I make a public statement like this, there is no ambiguity by any of the readers of this thread that we are all heading in the same direction, and that nobody is surreptitiously "dragging their feet".
On a separate topic but related topic, I would still like to know the details of Putzeys' setup. There are still a lot of important things being left out of his results. For example, how many measurements were averaged, and what adapters did he use, et cetera?
If I can figure out how to make my AP average multiple measurements, I will repeat his tests on my machine. If not, I will try the test on a colleague's System Two.
Charles Hansen |
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| mefinnis |
| quote: | | Originally posted by Charles Hansen I disagree with you on this. I think it is extremely useful to know when someone has changed their point of view. For example, after reading Putzeys' reply that you quoted a few posts up, I agree with him point by point, and my previous supposition was wrong. |
SE, I would tend to agree with Charles on this. From his opening discussion he clearly has experience with this type of equipment and for him to confirm that Bruno is "correctly aligned" useful for the "fringe dwellers" like myself.
There are no "points" attached to his comment, excepting that he has defined himself as someone who will examine the evidence before him and is prepared to accept/acknowledge when he is in error.
I would rather work with this individual than the man who is "always right" any day!
Another favourite quote: I thought I was wrong once, but then I realised I was mistaken ....
cheers
mark |
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| Steve Eddy |
| quote: | Originally posted by Charles Hansen
I disagree with you on this. I think it is extremely useful to know when someone has changed their point of view. For example, after reading Putzeys' reply that you quoted a few posts up, I agree with him point by point, and my previous supposition was wrong.
After I make a public statement like this, there is no ambiguity by any of the readers of this thread that we are all heading in the same direction, and that nobody is surreptitiously "dragging their feet". |
Fair 'nuff.
| quote: | On a separate topic but related topic, I would still like to know the details of Putzeys' setup. There are still a lot of important things being left out of his results. For example, how many measurements were averaged, and what adapters did he use, et cetera?
If I can figure out how to make my AP average multiple measurements, I will repeat his tests on my machine. If not, I will try the test on a colleague's System Two. |
The power averaged plots were made using 256 averages. I don't know how many averages he used for the synchronous averaged plots. I just EMailed him and I'll let you know as soon as I hear back.
se |
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| Steve Eddy |
| quote: | Originally posted by mefinnis
SE, I would tend to agree with Charles on this. From his opening discussion he clearly has experience with this type of equipment and for him to confirm that Bruno is "correctly aligned" useful for the "fringe dwellers" like myself.
There are no "points" attached to his comment, excepting that he has defined himself as someone who will examine the evidence before him and is prepared to accept/acknowledge when he is in error. |
Fair 'nuff. I just couldn't help cringing at the "Steve Eddy was right" comment.
| quote: | | Another favourite quote: I thought I was wrong once, but then I realised I was mistaken .... |
:D
se |
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| Charles Hansen |
| quote: | Originally posted by Steve Eddy
Fair 'nuff. I just couldn't help cringing at the "Steve Eddy was right" comment. |
Hello Steve,
If it makes you feel any better, I also cringed when I wrote it. :D
Charles Hansen |
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| SY |
Charles, ROFL!
| quote: | | but has it occured to anyone that there may be a rearrangement of electron allignment occurring during this period? |
Could you explain to me what you mean by that? How does one "align" an electron? |
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| fdegrove |
Hi Jon F,
| quote: | | However, why would parallel wires give more problems? |
The size of the problem is trivial but just think about the extra insulating material you're hosting and for what good reason?
Add to that extra capacitance and so on...Not harmful per se in some situations but I can't even second guess the application you have in mind.
I understand your logic drawn from Eric's but I'm afraid I can't support it and this way of putting wires in // wasn't what Eric had in mind...
Either way I don't feel it solves directionallity if that were such a problem at all.
Cheers,;) |
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| HDTVman |
You guys are a trip.
Later BZ:geezer: |
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| fdegrove |
Hi,
| quote: | | Could you explain to me what you mean by that? How does one "align" an electron? |
'Fraid I can't..Not too sure what's going on, whether it's electrons, atoms, molecules or whatever....
We'll have to skip that for the time being as I just don't have anything acceptable to offer right now and I won't hold my breath either if I were you.
Let's see later if there's anything to it at all.
Cheers,;) |
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| Steve Eddy |
| quote: | Originally posted by john curl
I find that 'moving targets' make sense. Let me explain to the rest of you.
You have heard of 'dirty contacts' haven't you? Well, I seem to be able to measure them. I start with some adaptors that I must use to make the test possible. I clean them at first, BUT over time they seem to get 'dirty' I clean them again, and the extra distortion goes away. Is this an impossible concept? |
Not an impossible concept at all. But problems associated with dirty or otherwise poor contacts is something which is well-known.
What we're looking for is nonlinearity being produced by the wire itself.
| quote: | | You also have heard of 'break-in' of cables. It seems that when I find a particularly 'bad' cable, I tend to use it for testing more often, sometimes accidently leaving it in the machine running with a test signal for days. You might ask, am I not paying attention? Yes and no. Sometimes I turn off everything EXCEPT for my ST analyzer. It likes to be on all the time, and with something connected to it. If I forget to replace the test cable with a reference, the test signal will continue to flow through the cable until I go back, which might be days later. Just last week, I accidently left SE's steel leaded cable in the analyzer, overnight. Well, overnight was not enough to change it much, so I can still use it for testing. |
And this is where a more systematic approach could be helpful.
Get two, brand new, unused, identical cables. Do a quick baseline measurement on both of them. Run one of them in for a time. Then measure both cables again.
se |
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| Steve Eddy |
| quote: | Originally posted by Charles Hansen
If it makes you feel any better, I also cringed when I wrote it. :D |
Hahaha! That's the spirit!
se |
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| johnferrier |
| quote: | Originally posted by fdegrove
Hi Jon F,
The size of the problem is trivial but just think about the extra insulating material you're hosting and for what good reason?
Add to that extra capacitance and so on...Not harmful per se in some situations but I can't even second guess the application you have in mind.
I understand your logic drawn from Eric's but I'm afraid I can't support it and this way of putting wires in // wasn't what Eric had in mind...
Either way I don't feel it solves directionallity if that were such a problem at all.
Cheers,;) |
Okay, I know the detail of my circuit would be rather trivial to a lot of people, but here is one of my ideas (since it's good for everyone to contribute). I want to use a thermal epoxy to glue the components upside down (dead bug style) on a heatsinking material (maybe a good copper ground plane as the substrate). Then, I will wire the components point to point. Air dielectric, less capacitance. I like the idea of silver wire aiding heatsinking through the leads (okay, it will be just slightly better than copper...). I had already thought about doing this, before I read about JCarr also doing the point to point wiring. This made me think that it wasn't such a bad idea.
This should be in the other thread, but I'll remain with Frank's post.
JF |
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| Steve Eddy |
| quote: | Originally posted by SY
Could you explain to me what you mean by that? How does one "align" an electron? |
Where did that quote come from? Can't find it in any of the posts.
se |
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| Steve Eddy |
| quote: | Originally posted by johnferrier
Okay, I know the detail of my circuit would be rather trivial to a lot of people, but here is one of my ideas (since it's good for everyone to contribute). I want to use a thermal epoxy to glue the components upside down (dead bug style) on a heatsinking material (maybe a good copper ground plane as the substrate). Then, I will wire the components point to point. Air dielectric, less capacitance. I like the idea of silver wire aiding heatsinking through the leads (okay, it will be just slightly better than copper...). I had already thought about doing this, before I read about JCarr also doing the point to point wiring. This made me think that it wasn't such a bad idea. |
Are you actually needing the heatsinking? Otherwise, why not get some terminal posts and just do your point to point wiring without any glue? Are you primarily just wanting to eliminate circuit boards?
| quote: | | This should be in the other thread, but I'll remain with Frank's post. |
Oh what the hell. It's nearly Christmas. :)
se |
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| Steve Eddy |
Oh. Duh (on my part that is). I didn't notice that alignment was misspelled when I did a text search of the last two pages looking for it. :)
se |
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| SY |
| It's the Flemish spelling. The only thing I can say in Flemish is, "Knorr zegt het varken." |
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| Steve Eddy |
| quote: | Originally posted by SY
It's the Flemish spelling. The only thing I can say in Flemish is, "Knorr zegt het varken." |
Sounds more like Phlegmish to me. You still getting over the flu? :)
se |
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| fdegrove |
Hi,
| quote: | | I didn't notice that alignment was misspelled when I did a text search of the last two pages looking for it. |
Mind you I was so much in dubio with another word in that post of mine that I couldn't care less when, as I ran it through the Micoshaft speller and that didn't want to recognise it one way or or another, I just gave it the go ahead and to hell with it....
Those decissions always backfire, don't they?
| quote: | | "Knorr zegt het varken." |
Knorr is a make of soup you silly...
Do you actually know what you're saying?
| quote: | | Sounds more like Phlegmish to me. |
Must be a Phredian slip of yours...
Now if you can translate and spell that correctly in a few more linguae I might just salute you with the utmost respect...:D
More ad hoc; merry X-mass to all you,;) |
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| johnferrier |
| quote: | Originally posted by Steve Eddy
Are you actually needing the heatsinking? Otherwise, why not get some terminal posts and just do your point to point wiring without any glue? Are you primarily just wanting to eliminate circuit boards?
|
Letting the heat escape freely out of the components, of course, is not a bad thing. The circuit board (heatsink) will be primarily a conduit for heat rather than for signals. With P2P, I'll be able to better control the proximity of signal paths. As JCarr mentioned, more 3D. Lead lengths potentially shorter. Do I need to do this? Again, since I'm going through the effort, I'd like to do the best I can. My circuitry is rather conventional so I'd like to try a few different things. If only Frank gives us hint #5 before the end of the year...
JF |
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| SY |
| quote: | | Do you actually know what you're saying? |
Most of the time, no. Ask my wife, she'll tell you that.
But electrons I know. |
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| fdegrove |
Hi,
| quote: | | Most of the time, no. Ask my wife, she'll tell you that |
LOL...
The key is one R in knor not two, you're doing just fine no matter what the missie says...
(Told you this before, bad pupil. Or is it the memory?)
| quote: | | But electrons I know. |
I don't mind to be corrected at all, I just try to offer plausible causes for things people perceive...
So far, I've rarely been proven totally wrong when it comes to audio related matters.
In fact, I'd be honoured to learn from you and I really mean it...
I just hope you don't think I wasted over 20 years + of my life researching audio ?
If there's one thing I know in this particular department for a fact : mere measurements as we know them are not going to tell us anything.....
Extrapolating results from research in the nanoelectric fields is what has made high-end audio what it is today.
I was there and saw it happen, so did John Curl and it all happened many years ago...
We measured and tinkered, dedicated our life till it wasn't pretty anymore...
Hint#5 The ability to crosslink one science to another.
Thank you,;) |
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| Steve Eddy |
| quote: | Originally posted by mefinnis
PS: SE, how "friendly" were the folks at Sound Technology? Do you think we could interest them in doing this as it is "at the edge" of their systems performance???? |
Sorry, missed this one the first time through.
Well, I wasn't hung up on. :)
Don't know that they'd want to jump into this mess. They seem to be rather um... "private." There's not a phone number or an address anywhere on their web site that I could find. I don't suppose it could hurt to ask them, but I don't know that I want to be the one asking. :)
se |
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| johnferrier |
| quote: | Originally posted by fdegrove
Hint#5 The ability to crosslink one science to another.
|
There's at least one book on that topic--Consilience: The Unity of Knowledge. It's an interesting book. Where are we going to go with gathered knowledge...might as well try to leverage what we know in one area with something in another area, if it works. Some of it will, some of it won't. New kinds of possibilities with cross-pollenization...
JF |
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| Steve Eddy |
| quote: | Originally posted by fdegrove
So far, I've rarely been proven totally wrong when it comes to audio related matters. |
Well sure. Anyone who's as vague and ambiguous on matters as you routinely are couldn't be proven totally wrong. How can something be proven totally wrong when one is given but half a measure?
| quote: | | If there's one thing I know in this particular department for a fact : mere measurements as we know them are not going to tell us anything..... |
Not going to tell us anything about what exactly?
| quote: | | Extrapolating results from research in the nanoelectric fields is what has made high-end audio what it is today. |
A laughing stock you mean?
The problem with many of these "extrapolations" is that they never go beyond extrapolation and remain ultimately nothing more than unsupported assumptions and speculations.
But they certainly make for great marketing literature and the illusion that the company is on the "leading edge" of technology when more often that not they're simply trying to do something "different" in order to compete in a saturated market.
| quote: | | We measured and tinkered, dedicated our life till it wasn't pretty anymore... |
And after all that, to this day no one has yet demonstrated that any of it is even actually audible, prefering instead to rely solely on speculation and assumption leaving our knowledge and understanding no more advanced than it was decades ago.
| quote: | | Hint#5 The ability to crosslink one science to another. |
But when you don't show that the one is in fact relevant to the other, all you've got left is more speculation, assumption, and spiffy marketing literature.
se |
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| Steve Eddy |
| quote: | Originally posted by johnferrier
There's at least one book on that topic--Consilience: The Unity of Knowledge. It's an interesting book. Where are we going to go with gathered knowledge...might as well try to leverage what we know in one area with something in another area, if it works. Some of it will, some of it won't. New kinds of possibilities with cross-pollenization... |
But as I said to Frank, no one to speak of is actually doing real research to see if any of it "works" in different contexts. Instead they just automatically assume that some behavior known to occur in one specific context under certain specific conditions must also be occurring in every other context and conditions.
And that ultimately gets us nowhere other than perhaps to sell more product.
se |
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| Steve Eddy |
| quote: | Originally posted by johnferrier
Letting the heat escape freely out of the components, of course, is not a bad thing. The circuit board (heatsink) will be primarily a conduit for heat rather than for signals. With P2P, I'll be able to better control the proximity of signal paths. As JCarr mentioned, more 3D. Lead lengths potentially shorter. Do I need to do this? |
Dunno about NEED per se...
But even if you just want to do it for purely philosophical or aesthetics, that's cool too. I'm firm believer in holistic subjectivity. :)
What I'm getting at is that unless you really need the heatsinking for heat dissipation, then there's not much sense in introducing elements in proximity to the circuit which aren't necessary such as glues and whatever it is you plan to glue them to.
| quote: | | Again, since I'm going through the effort, I'd like to do the best I can. My circuitry is rather conventional so I'd like to try a few different things. If only Frank gives us hint #5 before the end of the year... |
:D
se |
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| fdegrove |
Hi,
| quote: | | And that ultimately gets us nowhere other than perhaps to sell more product. |
Isn't that what you want ?
Not that you helped the industry any as far as I know but we had at least some plausible topics and look around you:
When I started the average engineer was convinced that a resistor was just that, we knew better and over time this was accepted....Still little proof is there...
Could go on and on and the same topic will...., no doubt...
What you're so fiercefully and unscientifcally discussing (even if you wanted to) is bound to haunt you ten years later as time has already caught up with it so long ago, only you want proof of it first....
The proof was there already and what you're persueing here is already old hat to me and a number of others, so old in fact that I've forgotten most of it.
There's only one to convince and that's you, yes, you.
I won't do that, Steve, learning is one thing, teaching is quite another and convincing one of their auditory experience, making them hear what one thinks to hear is simply impossible....
Merry X-mass,;) |
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| Steve Eddy |
| quote: | Originally posted by johnferrier
As I wrote, most likely I'll use sheet copper (also the ground plane) that doesn't harm anything. |
Well, it'd increase parasitic capacitances. Which if you're ultimately shooting for something more "ideal" wouldn't necessarily be good.
But I'm still unsure as to what your goal is and what your priorities are.
| quote: | | As for the thermally conductive epoxy--though the conductivity is good, it's best to use a thin glue line (so the minimum amount). And some of these epoxies are also electrically conductive (so again it will be ground). These are plastic packaged components (so presumably it's okay to heatsink it to ground--the leads already connect within the plastic material). |
I'd guess it'd depend on the materials involved. Perhaps SY can offer some guidance in this regard.
| quote: | | Thanks for spending a little bandwidth on this... |
Sure. More fun than discussing religion. :)
se |
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| johnferrier |
| quote: | Originally posted by Steve Eddy
Well, it'd increase parasitic capacitances. Which if you're ultimately shooting for something more "ideal" wouldn't necessarily be good. |
Well, there usually is a ground plane anyway. I'm just also using it as a heatsink. And the dielectric is air, rather than FR4 (or Teflon--which I could use too). Air, of course, is the next best thing to a vacuum.
| quote: | Originally posted by Steve Eddy
I'd guess it'd depend on the materials involved. Perhaps SY can offer some guidance in this regard.
|
SY is a good guy. I appreciate his policing efforts. He has a good touch with it.
I guess I'd just like to know where I can find some information on the electrical properties (conductivity/leakage and dielectric strength) of the plastic material used for ICs and active discretes. I'll look at some of the Mfg's sites, too. Though, I guess it would help me to know what it's called other than "plastic material".
JF |
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| johnferrier |
Hi Steve,
Something more interesting. (Texas Instrument's search engine is down at the moment...)
"Pierre Boulez has observed that loudspeakers have the property of 'anonymizing' the sound of musical instruments, that is, of making them all sound the same. 'Le haut-parleur anonymise la source reelle.'"
Maestro Boulez's music (as composer and conductor) is most what I want to reproduce well. So when I think about the larger picture of what is possible with reproduced music, I keep his comment in mind.
The quotation is from a patent on a new type of speaker (Directional tone color loudspeaker) that never took hold (that I'm aware of).
http://patft.uspto.gov/netacgi/nph-...&RS=SPEC/boulez
JF |
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| SY |
JF, the thermally conductive epoxies and silicones are normally loaded with things like beryllium oxide, and normally nonconductive.
There are quite a few people out there making these, starting with Dupont and Dow-Corning. You might check through the Thomas Directory for a pretty complete list. One useful key phrase is "potting compound." Another is "conductive adhesive." My long-time favorite producer, Amicon, seems to be gone now, alas. They were part of the WR Grace empire, which has withered away following Peter Grace's passing.
Frank, sorry for the misspelling. Knor. Knor. I need to tattoo that on my palm for reference. As my three year old likes to say, "Boe zegt de koe!" |
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| sully |
| quote: | Originally posted by grataku
SY,
I am not talking about this thread specifically but I always seen some type of affinity, or like-mindedness, between you and SE. Maybe it's just geography. ;)
As far as opening-up laboratories I think it's a bit pretentious on anyone's part, and it's almost never done, at least in science there is an unspoken sense of how far you can go even with a conversation. Going in to check a colleague's work is certainly beyond the boundaries. In industry investment bankers are probably the only ones to be allowed in. |
You are, in totality, incorrect..
We just had a Fermilab physicist here, presenting their latest results and designs for a 12 tesla common coil niobium tin superconducting magnet..
Lots of discussion, many relevant questions and issues. We presented many design irregularities, helped with strain issues, asked of materians and processes..
I went to Cornell with a collegue, overviewing their CLEO wigglers, another superconducting magnet..
So, your asertion that overviewing, collaboration,..is incorrect
Cheers, John |
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| Steve Eddy |
| quote: | Originally posted by sully
I went to Cornell with a collegue, overviewing their CLEO wigglers, another superconducting magnet.. |
CLEO wigglers? Sounds more like a fishing lure than a superconducting magnet. :)
se |
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| mrfeedback |
Originally posted by fdegrove
The size of the problem is trivial but just think about the extra insulating material you're hosting and for what good reason?
True enough - depends on the sound of the insulation.
Add to that extra capacitance and so on...Not harmful per se in some situations but I can't even second guess the application you have in mind.
Standard interconnect application, but intended to be non directional.
Capacitance and RF pickup did not seem to be an issue (5 mm spacing).
I understand your logic drawn from Eric's but I'm afraid I can't support it and this way of putting wires in // wasn't what Eric had in mind...
I think John got it right..........
I mentioned a (spaced) star quad construction where active and earth legs are all made from the same length of wire (cut into 2 pieces).
Each piece is bent back on itself at the middle point to form active or neutral dual conductor in direction cancelling configuration.
In past experience with four strands (0.8 mm) per channel of very high quality copper, this configuration worked exceedingly well. This experiment gave 3 dimensional imaging with sounds from miles in front of the listening position, and from miles behind the listening position on natural sound recordings.
Close mic'd sounds sat in a thin depth band between the speakers, and more distant sounds sounded, well... more distant.
I recall a thought experiment at the time was to try eight spaced wires to theoretically better cancel wire directional and wire to wire field effects - have not actually tried it yet.
The correctly configured 4 or 8 wire plaited wire might be another solution.
Either way I don't feel it solves directionallity if that were such a problem at all.
I have (using) audio coaxial interconnects that have not lessened their viciously distinct directional/dynamic bias effect despite how long they have remained in service in either physical direction.
Periodic direction A/B comparison has confirmed this.
Wether this bias is due to the conductor materials, the insulations or the manufacturing process I do not know.
This cable is guitar cable with multi-strand center conductor inside clear/translucent dielectric that has a black conductive polymer layer on the outside.
The braid is in contact with this tubular conductive polymer layer and a normal sheath encapsulates the whole lot.
This cable gives strong depth imaging differences according to direction.
I have not tried standard enamelled wire twisted pair in this application so I have not studied it for losing direction efffects.
Eric. |
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| fdegrove |
Hi,
Eric,
What John F. had in mind, I think, was using your kind of configuration for internal wiring inside of an amplifier.
If you view my comments witihn that context I think you may agree.
Sy,
| quote: | | Frank, sorry for the misspelling. Knor. Knor. I need to tattoo that on my palm for reference. As my three year old likes to say, "Boe zegt de koe!" |
Now that's funny.:)
No need to apologise for the spelling though...
I'm flattered young Jimmy (?) is learning some Flemish and I'm sure it's not the only language he's learning either besides English.
Happy Hanuka, ;) |
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| Steve Eddy |
By the way, just received an EMail from Bruno. The synchronous averaged plots were made using 256 averages as well. Same as the power averaged plots.
Need to work on graphic output next so we can better relate the measurements. If need be, Charles can send me the PostScript files output from the AP and I can convert them into pdf and jpg files.
se |
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| jam |
Steve,
Not taking a day off? ..............................:D
Merry Christmas,
Jam |
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| sully |
| quote: | Originally posted by johnferrier
I want to use a thermal epoxy to glue the components upside down (dead bug style) on a heatsinking material (maybe a good copper ground plane as the substrate). Then, I will wire the components point to point. Air dielectric, less capacitance. I like the idea of silver wire aiding heatsinking through the leads (okay, it will be just slightly better than copper...).
JF |
For many components, the leads provide absolutely no heat path. Ic's and transistors will have wirebonds, which are not designed for heat transfer. Only the solder bump technology will be thermally doing anything with the leads, but those chips are already upside down.
The surface mounts will, but only through the leads, not the top surface. The top will usually be just encapsulant, with no thermal properties.
Cheers, John |
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| mrfeedback |
Glueing those components to substrate/heatsink will cause cooler running no question - epoxy encapsulations get hot and dragging heat away from them will allow somewhat cooler running for the internals.
Mounting the active devices to an earthed backplane allows mechanically stable P-P wiring and least parasitics no question.
It also allows optimum and effectively infinite earthing techniques.
I built a DAC on the edge of a sheet of 0.8 mm copper using P-P techniques and the result was spectacular.
Effectively the DAC stage local earth was quite infinite, and this paid sonic dividends bigtime in terms of effortlessness and solid stability.
Heatsinking however was not an issue in this case.
Eric. |
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| johnferrier |
Yes, I think some heatsinking is possible through the leads and the encapsulation epoxy. I know that touching a device (JFET current source) causes a change in it's operating point. As John Sully mentions, the small wires within a device will not conduct much heat (I think they will conduct some small amount heat).
Also, I expect that a hefty ground plane is a plus. Steve made me a bit worried about adding parasitic components (very small capacitors and very large resistors). Trying to find information on the internet I found that the encapsulation epoxy has about a 3.5-4.0 dielectric absorption. Compared to 2.1 Teflon and about 4 for PCB material (FR4). It's good to think through these things. My thinking now is that using a thin glue line to a ground plane shouldn't be much different than a ground plane used in a printed circuit board (exactly the same leads, similar parasitics etc).
Thanks for a few of your thoughts on this, Eric.
Going back to cable distortion measurements, to some extent we are testing the capabilities of the test equipment. And this has been pointed out. At such an extreme low signal level, how do we know the measurements are correct? Following the procedure for NIST calibration traceability, a meter of 3-10 times accuracy can be used to calibrate/verify another meter. I wonder how distortion meters are calibrated. Also, Sy's idea of a Gauge R & R (Repeatability and Reproducibility) study can also be used to verify a meter's capability, but I'm not very familiar with what is involved with this. What may be audible, yet escape notice of a meter is an even more interesting question (for another thread).
JF |
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| mrfeedback |
Originally posted by johnferrier
Yes, I think some heatsinking is possible through the leads and the encapsulation epoxy. I know that touching a device (JFET current source) causes a change in it's operating point. As John Sully mentions, the small wires within a device will not conduct much heat (I think they will conduct some small amount heat).
Hi John, Yes locking active components to a thermal coupler ought to stabilise operating points.
Also, I expect that a hefty ground plane is a plus. Steve made me a bit worried about adding parasitic components (very small capacitors and very large resistors). Trying to find information on the internet I found that the encapsulation epoxy has about a 3.5-4.0 dielectric absorption. Compared to 2.1 Teflon and about 4 for PCB material (FR4). It's good to think through these things. My thinking now is that using a thin glue line to a ground plane shouldn't be much different than a ground plane used in a printed circuit board (exactly the same leads, similar parasitics etc).
These parasitics should be shunt to ground and cause only loading to ground and not intercomponent coupling, and will be rather less than any pcb.
Different DA's of different materials cause different spectral loadings and sonics - IME different pcb materials add particular sonic characters.
Encapsulation materials too - ceramic DIP opamps sound fundamentally different to epoxy encapsulated DIP opamps.
Thanks for a few of your thoughts on this, Eric.
No worries - anytime.
Going back to cable distortion measurements, to some extent we are testing the capabilities of the test equipment. And this has been pointed out. At such an extreme low signal level, how do we know the measurements are correct? Following the procedure for NIST calibration traceability, a meter of 3-10 times accuracy can be used to calibrate/verify another meter. I wonder how distortion meters are calibrated. Also, Sy's idea of a Gauge R & R (Repeatability and Reproducibility) study can also be used to verify a meter's capability, but I'm not very familiar with what is involved with this. What may be audible, yet escape notice of a meter is an even more interesting question (for another thread)
The first error as I see it is that sinewaves do not and cannot replicate dynamic behaviours of an arbitary or music waveform, but are none the less a start in measurements.
I think that it should be kept in mind that these measurements are an attempt to quantify heard differences in different cables, and if the tests are not revealing then perhaps the test methodology requires modifying.
There are plenty of sonic effects that sinewave TDH+N testing does not reveal.
Eric. |
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| Steve Eddy |
| quote: | Originally posted by mrfeedback
The first error as I see it is that sinewaves do not and cannot replicate dynamic behaviours of an arbitary or music waveform, but are none the less a start in measurements.
I think that it should be kept in mind that these measurements are an attempt to quantify heard differences in different cables, and if the tests are not revealing then perhaps the test methodology requires modifying. |
It should be kept in mind that these measurements are NOT an attempt to quantify heard differences in cables.
These measurements are an attempt to reproduce the distortion measurements that John Curl has been doing in order to determine whether or not the distortion he's been measuring is being produced by the cables themselves.
| quote: | | There are plenty of sonic effects that sinewave TDH+N testing does not reveal. |
Sure. But that's not the purpose of these particular measurements. With these particular measurements, we already have someone who has been measuring simple harmonic distortion using a simple sinewave stimulus.
By the way, before Bruno did the measurements I'd requested in order to try and reproduce John's results, he also did a much more comprehensive series of measurements to see if he could turn up anything.
Here's Bruno's original report on these measurements which he originally posted on the rec.audio.high-end newsgroup under the title "Some serious cable measurements with interesting results."
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.
The rest of his post (which goes on to consider other aspects such as induced noise and microphonics) can be found here:
http://groups.google.com/groups?q=+...ttbi_s54&rnum=1
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| fdegrove |
Hi,
Stevie,
Within the context of your thread I have a nagging question.
Would you like me to get in touch with Dr. W. De Ceuninck and see what and how he measured or is that beyond the scope of this thread?
Or tell me what exactly it is you'd like to know from him, etc...
That is, assuming he can and is willing to share his findings of course.
I will contact him either way if only for the purpose of rekindling a long standing friendship so let me know.
Cheers,;) |
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| Steve Eddy |
So, earlier this evening I'm sitting at the computer doing something which I no longer remember when suddenly I hear this huge crash which caused the whole house to shake.
"WHAT THE !@#$% WAS THAT!?"
At first I thought perhaps a plane had crashed seeing as my house is in the landing path of the local executive airport which has everything from kit planes to Gulfstreams flying directly over my house at just a few hundred feet on a rather routine basis.
So I run out of the house to find this scene in my front yard:
This is my neighbor's truck. They live in the house across the street, with the Christmas lights you can see just above the truck's cab.
He'd had the truck parked on my side of the street about 15 feet from my driveway, which would be back toward the left in the photo (the photo was taken from my front porch while turned just to the right).
A drunk driver, who had neither a driver's license nor insurance came speeding down my street, crashed into the rear of the truck launching it about 50 feet until it crashed into the tree (it's not as dramatic looking in the photo, but the truck's chassis was bent considerably right in the middle between the cab and the bed).
Meanwhile, the drunk driver's car careened off that truck and into the rear end of the same neighbor's SUV which was parked directly across the street in front of another neighbor's house (his nextdoor neighbor to the left in the photo).
Amazingly, the drunk driver had no injuries and ran off down the street after the accident.
Truned out that he lived just down the street and had gone home, changed his clothes and then returned to the scene, claiming it was his cousin who was driving the car.
The police arrived, didn't buy his story (the neighbors across the street saw him run from the scene), handcuffed him and hauled him off.
The amazing part is that I had a car parked in my driveway and one parked in the street directly in front of my house. The truck in the photo was parked directly behind the car in the street about 30 feet in back of it.
Somehow, when the truck was launched, it went at an angle such that it went right between my two cars even though there was less than a foot of clearance to either side.
The somewhat scary part is that I was out standing in front of that same truck a couple of hours earlier while raking up some leaves.
Crazy night.
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| fdegrove |
Hi,
Geeezzz....
| quote: | | Amazingly, the drunk driver had no injuries and ran off down the street after the accident. |
They always survive, the drunken ones...Makes you wonder about the statistics on that one.
Luckilly you got away with so little damage....Gosh...
Cheers and sympathies,;) |
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| Steve Eddy |
And for those into things such as Divine intervention and whatnot, here's a bit better image of the inside of the truck's cab. Note the object hanging from the rearview mirror. :)
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| Steve Eddy |
| quote: | Originally posted by fdegrove
Geeezzz....
They always survive, the drunken ones...Makes you wonder about the statistics on that one. |
Yup. Didn't appear to be a scrach on him. Well, before the cops got there anyway. :)
Juuuuuuuuuuuust kidding!
| quote: | [Luckilly you got away with so little damage....Gosh...
Cheers and sympathies,;) |
Thanks. The only property "damage" was a 6 foot skid mark on the grass and a bit of sap oozing from the mullberry tree.
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| Steve Eddy |
| quote: | Originally posted by fdegrove
Within the context of your thread I have a nagging question.
Would you like me to get in touch with Dr. W. De Ceuninck and see what and how he measured or is that beyond the scope of this thread?
Or tell me what exactly it is you'd like to know from him, etc...
That is, assuming he can and is willing to share his findings of course.
I will contact him either way if only for the purpose of rekindling a long standing friendship so let me know. |
You can if you'd like. I already EMailed him back on the 22nd but haven't had any reply yet. Though he's probably been on holiday all week.
I told him of John's measurements and that you had said you'd had him verify them at a customer's and van den Hul's request and asked if he'd care to share his test setup so that we could attempt to duplicate his results.
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| fdegrove |
Hi,
Surely Jam will come up with a humorous picture....
Cheers and stop raking the autumn leaves.... ;) |
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| SY |
OK, no jokes about egg-nog and Asians.
I was watching a car wreck, too, the last game of the season for the '49ers. The only thing that saved the day was the sweet sound of my new preamp- passive, using the Jensen 11P-1s and an Alps Black Beauty pot. You could hear every bounce of the fumbled ball. |
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| fdegrove |
Hi,
| quote: | | I told him of John's measurements and that you had said you'd had him verify them |
Hmmm...I don't think he was aware of John Curls' measurements at that time, neither did I ask him to veryfy anyone elses' measurements.
I did ask him several related questions on behalf of my company's customers amongst which VdH (indirectly) and Deskadel.
This is the kind of confusion I wanted to avoid in the first place and knowing him as I do he won't ever reply to that e-mail.
Don't take offense, that's just how I know him.
Anyway, I'll try to reach him at home, I was just trying to find out if you could or wish to make a list of target QQ.
Cheers, ;) |
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| Steve Eddy |
| quote: | Originally posted by SY
OK, no jokes about egg-nog and Asians. |
Ok, how 'bout egg-not and Hispanics? :)
| quote: | | I was watching a car wreck, too, the last game of the season for the '49ers. The only thing that saved the day was the sweet sound of my new preamp- passive, using the Jensen 11P-1s and an Alps Black Beauty pot. You could hear every bounce of the fumbled ball. |
Hehehehe. | | | |
