john curl said:
50nV of what with respect to what? That's actually a large number as these things go. As was stated yesterday decades of research on several continents have yielded no evidence of these so call residual resistances. I would think Phillips would have published results. You stated cable quality mattered at 1ppm for you to calibrate your setup but I (and others) have not been able to measure problems at the -150dB level in even the most ordinary wire.
Science can bracket both what we know or what we don't know, that is we can determine that if problems exist they are below what we can already measure.
BTW another comment on yesterday. Using #28 wire as speaker cables would involve self heating at even moderate levels that would be easily measureable. A massively non-linear problem as the wire resistance increases and decreases out of sync with the music.
john curl said:
Has anybody duplicated the work?
Has enough detail been presented so that others could?
Has the hypothesis, the test setup, the results, the conclusions been examined by anybody else?
Whenever a new, better piece of equipment comes out, the first thing that happens is new owners make errors with them. Not old errors, new ones. Errors not previously obtainable. "State of the art errors", so to speak..
That's what happened when the first 10 digit meters came out...new and wondrous ways to find thermal gradients that alter voltage and resistance measurements..
That's why peer review is important.
john curl said:
Um, to sell wires? Is this a trick question?
john curl said:
Did you ever baseline your distortion analyzer like I mentioned years ago?
Did you ever try to track down the shield current question?
john curl said:It might be found that this 'residual' resistance contains real nonlinearities that most people ignore, and explains our listening experience with 'break-in', cryoing, differences between 'linear crystal' and typical wire, and finally, wire purity.
Of course, it could be all our imagination.
You forgot another possibility: That it was measurement error of a new type caused by unfamiliarity with newfangled equipment. But never detailing the methodology guards one against being proven incorrect, doesn't it?
RRR was defined to provide a clear equational methodology for determination of the electrical resistance and thermal conductivity of metals as they go towards absolute zero. In the 4 Kelvin domain, copper will become anywhere from 10 to 1000 times more conductive, and that depends on how many "collisions" (or transfers of momentum from the entity we call electron to the entity we call "lattice") the electrons will encounter per cm. A very good copper sample can exhibit mean free paths up to 10 centimeters, while at room temperature, that length is measured more conveniently in nanometers.
Cheers, John
john curl said:
Yah, I remember you reported that you were reading tv horiz scan frequencies.. Hey, you never know....as all your neighbors switch to LCD's and plasmas, that hash may drop..
But the dimmers and CFL's, oh well..
Did you ever evaluate the ground currents on your ST rig? Last you stated, you used a cap to ground at the output to shunt harmonics, and I asked where that shunt current was going?
The reason was, I was concerned that you were providing two paths for the shield current, one through the cable under test, the other by the equipment metal. As you recall, you had related an issue with cleaning of the shield contacts, it being a problem every time you plugged a cable in.
What, if anything, did you do to resolve that? I remember you upgraded the electronics, but didn't do anything to the packaging.
Cheers, John
ps...John, I really really recommend you give Prof Tom Van Doren at Missouri U of Science and Technology a call. He runs the Electromagnetic Compatibility Laboratory there, and he is a good one to speak with. His lecture to us this year covered what I told you about, what, 4 or 5 years ago?? He's excellent, I think you'd like him..if you do, refer to figure 2-4 and 2-12 of his booklet..
jneutron said:
Or not :-( I have a 40" plasma upstairs and I can certainly tell from the analyzer screen when people are watching TV in the family room. A 19" LCD computer monitor 6ft. away from the setup is also clearly visible. All between 60 and 70KHz and at around -120dB. Can reliable measure -130dB only at 3AM when everybody (including neighbours) are sleeping and lights are off, TV's are off, etc...
I was once about to think I got a RRR effect, but then there was only a CFL on in the cold cellar. That's how I missed a Nobel prize
Nelson Pass said:
Perhaps that's why men seem to be more avid audiophiles.
We should also always remember that we, as men, have a slight peak in our sensitivity and mental orientation at 4kHz, where we are excited by special and locational cuing 'information' at that frequency area.
Now... with women, on the other hand..they are sensitized to hear the crying of children at that frequency and to be capable of figuring out what is wrong with the child.
So..a spacial and locational emphasis in that frequency range must be AVOIDED AT ALL COSTS...if one wants couples or women to listen to the given design at all.
What men tend to sonically love in audio gear..drives women out of the room....grinding their teeth all the while.
This is a great concern in audio speaker design, as one might imagine.
The 'BBC Dip', is a critical aspect of speaker design that should be followed religiously, if one wants to create a design that is acceptable and pleasing to the biggest audience as is possible.
The speaker designers that miss this, may make it to the cover of Stereophile, but they will also find their designs on Audiogon for less than half the price of new in fairly short time, compared to other designers who do their homework and execute a design properly.
hitsware said:
An externally hosted image should be here but it was not working when we last tested it.
And gentlemen, Please, please, please, please...put down the engineering rags and texts..and go out and read, read, read on the human hearing mechanism. Not old stuff, but NEW stuff..and then you'll be able to correlate what audiophiles say they hear, with what is going on in the active device.
You are working with incomplete information when a much larger scope of information is there to access and ponder on and about.
You'll get much further down the road that way. If you are trying to deal yourself a hand at the table of BEST in audio design..don't sit down with only half a deck of cards being accessible to you.
You are working with incomplete information when a much larger scope of information is there to access and ponder on and about.
You'll get much further down the road that way. If you are trying to deal yourself a hand at the table of BEST in audio design..don't sit down with only half a deck of cards being accessible to you.
jneutron said:Hmmm..what an interesting thought, I'd never heard of Schumann resonance before.. The fundamental frequency they are looking at here is roughly 8 hz. I'll mention it at the next meeting.
We had a cryostat that was closed off to the outside world plumbing wise, but yet had 5 PSI peak pressure oscillations internally in the helium at 10 hz... My first suspicion was thermo-acoustic oscillations around the joule-thomson line due to a flaw in the superinsulation...but whaddooo I know (just ask the brit)
Cheers, John
Now these are the sort of anomalous things that catch my attention. That make me sit up and pay attention. What was the conclusion?
jneutron said:
picoamps ... hah, I was performing measurements down to femtoamp resolution!
But you are right, once past the 4 nines purity level, I couldn't measure any resistivity (or inductivity) differences between various impurity compositions, or between various grain sizes, or between strain hardened vs. annealed, or between crygenically treated (either by quench or by slow cooling plus soak).
Of course, all that means is my measurement method did not detect any differences. Doesn't mean that there weren't differences that weren't measureable by my technique. My opinion about whether such differences exist, I shall keep to myself, as I do not wish to be annealed in the heat of the flames.
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