metalman said:
Essentially negligible?? Not quite.
Entirely negligible? Yes.
There is nothing I can do at room temperature to distinguish a difference in RRR between coppers. In fact, it is not possible to measure it electrically at room. Been there, tried that. (ask the CERN guys about it...
It has been measured in another way, however. Dead soft annealed 7 nines copper (and aluminum) is sometimes used at 4.5 kelvin where conduction cooling is the only viable method. If it is worked too much (work hardened), the cryogenic thermal conductivity will change too much for the app. Then, the surface hardness can be measured, and the slip plane texture is also visible via microscope.
Invokation of RRR for any room temperature entity is entirely without merit.
metalman said:
Speak for yourself.
Some of us do it for a living..Cheers, John
scott wurcer said:
Yup..which is why I posted the real info on RRR. Those who do it for a living would love to be able to measure any change at room temperature due to RRR. But alas, the best nano-ohmmeter found cannot distinguish anything nonlinear within copper at room. We try, but no joy..
I wuz keepin it real.
Cheers, John
john curl said:
The best researchers on the planet have been working on this for several decades now. They find nothing weird going on. Of course, they've only looked in the current range of picoamperes to kiloamperes per mm squared (engineering density of course), and voltage from about 100 down to nanovolts. So, it's not like they have any real experience...
We're putting together a setup as I "speak", using horizontal geophones to measure nano and micrometer vibration in a roughly 5 ton magnet at 4.5 kelvin. All the wires to the geophone run differential from room temp, through a vacuum, into the liquid helium. We're looking at nanovolt signals up to about 100 hz..
No anomolies anywhere. nuttin. (you would have loved this problem JC, a real low signal low noise differential transducer application...sitting on top of a 4 tesla magnet with 7 kiloamps of current within...)
It would be so great if there were any possibility of using room temp testing of any kind for the residual resistivity...but so far, nothing.
Cheers, John
jneutron said:
I have been helping a customer with a more mundane pursuit, ground mineral characterization and UXB search, the Schauman resonances are actually quite a nuisance to them. Van der Ziel has a lot of research on 1/f noise in metal thin films , I don't recall any unexpected or remarkable results either.
Well, I was afraid of this. I am trying to point out something that MOST people here do not know anything about, that is, the extra resistivity in a metal conductor due to impurities, annealing (or lack of it), and the general state of the crystalline structure.
IF someone like Dr. Hawkford or Dr. Van den Hul, who have actually studied audio cable, and done research in physics, talk about problems in cable, they are attacked by the same people posting here at this time.
Again, it comes down to the 'believers' and the 'non-believers' who have been with us for generations.
It's like someone saying that they are a physics researcher, and that they still use zip cord for their loudspeaker cables, and proud of it. However, when they do physics, ... .
I don't claim to know all the answers as to why cables, to me, and half the people contributing here, sound different. Why we should have to spend big dollars for the highest quality connecting wire for the interior of the Blowtorch that we can find, sonically, and how I could hear a real difference between wiring a Blowtorch with the highest quality copper wire that we could find and Bear's silver wire (properly broken-in of course), although Bear warned me this would happen.
This is reality folks! It works! It makes a difference in musical enjoyment. That is what I am trying to bring out here.
IF someone like Dr. Hawkford or Dr. Van den Hul, who have actually studied audio cable, and done research in physics, talk about problems in cable, they are attacked by the same people posting here at this time.
Again, it comes down to the 'believers' and the 'non-believers' who have been with us for generations.
It's like someone saying that they are a physics researcher, and that they still use zip cord for their loudspeaker cables, and proud of it. However, when they do physics, ... .
I don't claim to know all the answers as to why cables, to me, and half the people contributing here, sound different. Why we should have to spend big dollars for the highest quality connecting wire for the interior of the Blowtorch that we can find, sonically, and how I could hear a real difference between wiring a Blowtorch with the highest quality copper wire that we could find and Bear's silver wire (properly broken-in of course), although Bear warned me this would happen.
This is reality folks! It works! It makes a difference in musical enjoyment. That is what I am trying to bring out here.
Patrik Floding said:That's a Mickey Mouse system!
You guys know nuttin'!
Now your sounding like my ex..
scott wurcer 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
john curl said:
It's always nice to point stuff like that out...it's invoking it as audible even though the scientific community can't measure it at room temperature that begs questioning.
john curl said:
They've been attacked here??? Where?
So far, all I've seen is a discussion of the flaws in a non peer reviewed "article" (for lack of a better descripter) that did not contain sufficient information to be reproduced by anybody else on the planet. If I recall correctly, even you stated that John A was unable to reproduce the results..
john curl said:
It is of no concern that a physics researcher uses zip cable and hears no difference..they either hear no difference, or care not if there is one. That was a lame duck argument..
john curl said:
That hasn't stopped you from posing "interesting" stuff like RRR figures for cryogenic appications as being a reason for non-linearities at room temperature. I only point out that the best researchers on the planet do indeed worry about that kinda stuff, and use it everyday...and they WISH there was a room temperature indicator they could measure..
Posing the stuff is not a bad thing. Attributing a difference in sound to an obscure effect, and then using it in AD copy or non peer reviewed publications for profit..is a different animal..
john curl said:
You may or may not hear a difference, your customers may or may not. It's your business John, you certainly are free to do as you wish, and I wish you well in that persuit. I've not stated you can hear a difference, I've not stated you can't..
john curl said:
Well, it's your reality. It may well be that of others..and honestly, it is of no concern to me if it is a true reality or not...you do what makes you happy, and if that pleases others, you are successful..
That's quite ok with me..
Cheers, John
john curl said:
You always say that when you have no argument..
Stick to your guns John..
Oh, btw...your posts on mu metal and iron? Absolutely dead nuts on. What suprises me is you said something about not being measured??
Just had a guy here give a two day lecture on EMI/shielding..Tom Van Doren, nice guy, very sharp.does it for a living..University of Missouri.
One of his demonstrations was the effect of metals on magfield shielding. He had a scope setup to view on the overhead, so 40-50 people could easily see what happened when he used mu metal vs aluminum vs copper.
The mu metal saturated right away, the distortion was hugely evident. He relayed a problem one of his customers had, where the mu-metal was actually causing modulation distortion, as on one side the metal was hit by a sine that caused effective mu changes with time, and the circuit on the other side was seeing that time varying mu...
I would be inclined to agree with you on steel based chassis...
Cheers, John
john curl said:
Hmmm..graphene...that wouldn't be
""Cooper pair propagation and superconducting correlations in graphene"" by
J Gonzales and E Perfetto, Feb 1, 2008
If you look at figure 1, page 3, you see the graph of critical current vs temperature..
The critical current is 10 e-6 amperes maximum, this at .5 Kelvin, and drops to zero at 4 Kelvin...
Room temp? 4 Kelvin?
Boy, you must have your heat turned WAAAY down dude..
ps...you seemed to have forgotten, you were invoking "near superconductivity" with the bybee stuff..I asked for proof.
Cheers, John
YupPMA said:
PMA said:
Sure. I have a ttable, a cd player, and a piece of garbage mp3 player (it died, I'm taking it apart to determine if it failed as a result of tin whiskers). An amp, some speakers, and a pair of decent headphones..
PMA said:
I love Cheryl Lynn, Stephanie Mills, Cate Brothers, I have fun listenin to Iron Butterfly, and more fun listenen to Sam the Sham and the Pharoes. (just seein how old everybody is..)
And what does that have to do with RRR? Or cooper pair formation, or even mu metal permeability variations?
Do you believe that is of importance? Have I stated that speaker wires don't make a difference? Have I stated PC's or IC's don't?
Forget categorizing my on either side of a silly fence.
What you really should be asking is:
1. How does one measure localization parametrics reproduced by a stereo reproduction chain to the level humans are sensitive to?
2. Does anybody even understand the localization requirements?
3. Why is it I never heard of the demise of the goofball who invented the pan pot?
4. How would one measure the changes to these metrics within a black box with power gains on the order of 10e6 or 10e7? (this, btw, requires two channel intercorrelation to the 2 uSec level).
5. Why has little work been done resolving the NEC requirement for safety bonding against the generation of loop voltages within that bonding structure (remember that Faraday guy?)
6. How does one measure the mid freq damping factor of an amplifier output in all four quadrants while it concurrently drives a LF high power reactive load?
7. How do they stuff those stripes into the tube of toothpaste so that they come out perfect?? (ooopps, no wait...wrong forum)
8. Does anybody here even know how to make a load resistor that doesn't exhibit B dot anomolies at high current slew rates and low loop impedances? Wanna see a 40 watt puppy at 4 ohms that is below 250 picohenries and zero b dot?
Let's stay on topic, shall we?
Cheers, John
syn08 said:
John,
I'm with JC on this one: it's indeed pointless. The only remaining question is if JC and his dolphins don't get it, or there's some vested interest in spreading such :bs:But then I can live without an answer and still have fun around
What is pointless is bringing unsupported anything into play and ascribing an audible difference. Near superconductivity?? Please..RRR? again, puhleez.. Those I have fun with..
Theorizing is great. Gets the mind ta thinking.
JC's point of keeping an "open mind"...I agree 100% on that.
Disagreeing with another's point is not attacking them, as JC would have us believe.
While I agree in principle with the Rich article, I cannot condone the lambasting of Hawksford, either by Rich, or by the anonymous player. The papers of Malcolm Hawksford that I have read (other than his two "flights of fantasy"), are to me, amazing works. I have nothing but admiration for all I have read from him.
Which is why his skin effect article was such a shock to me.
Cheers, John
PMA said:
Okay
I know nothing about copper pair formation.
My "belief" is that HF EMI voltages are responsible for different sound of signal cables, and this is something I can really measure, after change of any 2 different types of cables.
I cannot discound HF EMI, nor can I discount LF EMI. The generation of current as a result of faraday induction is not a very well understood entity. Yes, we all grew up with a general concept of shielding, but from 10 hz to about a kilo, magnetic field sheilding and induction is far from well understood. Shielding a line cord certainly does nothing below a kilo w/r to stopping induction, nor does it alter IC's significantly w/r to induction.
What is needed is an industry wide understanding of magnetic induction effects on star grounding, chassis currents, NEC based loop currents we have to live with, and how to get that garbage to stop interfering with our music...ESPECIALLY the power modulated haversine stuff.
I do magfield stuff for a living, and the biggest problem we have is magnetic induction issues. (it doesn't help having a 5 megawatt cycling transient load a quarter mile away).
Cheers, John
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