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Old 23rd December 2003, 07:37 PM   #101
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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.


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Old 23rd December 2003, 07:44 PM   #102
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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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Old 23rd December 2003, 07:57 PM   #103
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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).


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Old 23rd December 2003, 08:13 PM   #104
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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?

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Old 23rd December 2003, 08:26 PM   #105
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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?

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Old 23rd December 2003, 08:55 PM   #106
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Unhappy Crackpot or Despot?

"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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Old 23rd December 2003, 08:59 PM   #107
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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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Old 23rd December 2003, 09:18 PM   #108
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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.

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Old 23rd December 2003, 09:25 PM   #109
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Default Re: Crackpot or Despot?

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?


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Old 23rd December 2003, 09:33 PM   #110
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Default Re: Crackpot or Despot?

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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