Why kryo first and then burn in? Just to get the state of plain copper wire?
Best regards!
It's easy the search the literature for studies on the change of bulk resistivity (3-5%) possible with copper with treatments at -185C or so. What gets ignored is that the time/temperature profiles need tight control you do not dip cables into LN2 in your garage. The rest of the mechanical property changes have nothing to do with transmitting electrical signals. As I see it cutting 6" off of a 10' cable achieves the same benefit. The rest of the usual burn in etc. remains nonsense that will never go away, but you knew that.
While it may be written there, does the article cite any relevant published research in support of lower electrical resistance, or is it a simply a free standing assertion dropped in amongst accurate information in order to lend credence to an unverified belief?
Five, six, seven nines copper and aluminum very heavily annealed are used in cryogenic applications where very good heat and electrical conductivity are needed. We have to be very careful with it however, as those properties can be easily ruined by any bending/work hardening. We have no way of determining at room temperature, if we have compromised the properties. Also, taking compromised material down to 77 Kelvin (LN2), 4.5 Kelvin (LHe), or 1.8 Kelvin (superfluid helium) will NOT recover the desired properties.
If we had a method of measuring this problem at room temperature, life would be so much easier.
Jn
We crossed, I took it that the data here was real and not made up. No idea what they started with but it does not seem to be one of those silly audio patents with specious claims. There is also no data on what happens with subsequent bending or working.
CN102994921A - Cryogenic resistance reduction treatment method for copper and copper alloy
- Google Patents
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Isn't trying out new things a major source of fun in this hobby?
Especially for someone who hears substantial differences between cables.
Just trying to understand. And no, trying does not equate to buying.
It's hard to tell. I assume patent examiners do not attempt to replicate test methods to determine repeatability nor accuracy of claim.
I never use a patent as proof of anything, I would prefer a rigorous peer review with repeatable verifiable results.
In a true published scientific paper, I would also expect a verification that further processing can diminish the results. Since no test methodology has been presented, it is not possible to verify the accuracy of any of the tabular data.
Because all the end use of stuff I build is cryogenic, it would be so much easier if we could ignore work hardening effects, and trust the cold instead to repair any damage. One of the end use apps worked on was a space based superconducting solenoid running in persistent mode with no cryogens, and once in location, the cost of failure is rather expensive..
jn
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There are cryogen free cold heads (refrigerators) that can bring objects down to 4 kelvin. Of course, they still use helium in the head, but no liquid throughout the magnet structure.
Everybody is trying to go helium free because it is getting more and more expensive.
The big problem with helium free is that at 4.5K, no materials have any heat capacity other than helium. As a result, even microwatts of dissipation will cause LTS conductors to quench. (sorry, Low Temp Superconductors, such as niobium titanium and niobium tin.) By using obnoxiously pure aluminum or copper annealed to within an inch of it's life, the thermal conductivity of the material is used to carry heat to the cold head. (thermal and electrical conductivity go hand in hand).
Insulation is typically several hundred layers of alternating aluminized mylar with very thin gauzelike paper, called MLI (fancy acronym for multi layer insulation.
One of the best parts of work is the acronyms...keeping LTS (NbTi and NbSn) and HTS (RBCO, YBCO, CORC, PIT) cold using LH2, LN2, surrounded by MLI blankets and WTC (warm to cold) transitions...
A veritable alphabet soup of meaningless-to normal-people acronyms... I could be makin this stuff up, nobody would know the difference....
jn
Because simply choosing a thicker wire will take away things to
I have lost the ability to hear anything over 12k (Small engines, not music) and blew all the tweeters I owned before giving up. Took me months to find the source of what I thought was tendinitis (it was a cap in a power supply) I am not sure why I would jump through hoops to preserve over 15k. Although I have had fun using a 14k tone to annoy the youngsters like that damn 9846hz cap squeal was doing to me for a year or more.
Theory is fine, but in practice snake oil is just profit from the people with more money than time to learn practical application.
I'll spend my efforts on making Infrasonic Ground shakers and use whatever conductors I can get my hands on. The exotics simply don't make that big of a difference if you have to use a scope to find what you can't hear, does it really matter ?
Theory is fine, but in practice snake oil is just profit from the people with more money than time to learn practical application.
I'll spend my efforts on making Infrasonic Ground shakers and use whatever conductors I can get my hands on. The exotics simply don't make that big of a difference if you have to use a scope to find what you can't hear, does it really matter ?
Thanks for the explanation! Is it simply heat that's the problem, or is the very low electrical resistance need for other things?
I got a call out of the blue the other day. I had sent a 1000 foot roll of teflon jacketed CAT 5/6 cable (after i had stripped it all down to single pairs) to an associate to get croed, but he does not have the kit anymore. He sent it off to another guy who, after i had not seen it for some 5-years, called me and siad he would send it directly. If he does i’d be happy to send a chunk to you.
Try it, it might work, speaker wire is very system dependent.
dave
For several projects, it is the thermal conductivity. Apparently, both electrical conductivity and thermal conductivity are intimately tied together at very low temperature. I also made some magnets for an accelerator project that had to use crazy copper as the support tube as well as for thermal cooling.
Another customer wanted to use 0.013 inch diameter crazy copper wire for a 2 inch diameter 6 inch long solenoid. They needed to keep the dissipation extremely low, and wanted to avoid using niobium titanium at all because copper has a lower Z (atomic cross section) so less of the radiation products would be absorbed before it reaches the detector.
Unfortunately, the problem with extremely pure extremely annealed copper wire is that it has to be insulated, spooled, shipped, and wound into a coil, and even those processes kill the advantages. Nothing we can do will keep the cryo parameters good enough for the application. So we went with a cable using 6 copper wires spiralled around one copper clad niobium titanium conductor, with an outer dimension of 13 mils.. we keep having to hire younger and younger workers that can actually see the wires...eh?? speak up sonny, I can't hear you.
jn
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I want those as interconnect cables. Preferably no longer than 1 meter.
Thanks for the explanation .
That only takes one example to illustrate.
At a trade show Fostex was showing off their big FE208e∑ horns, which are specifically designedd for high output impedance amps (mostly SETs), but were using Luxman amps that are not really suited (given their low output impedance), so tungston speaker cables were used so that the system was matched.
This situation is not unique althou likely not on your radar if your speaker of choice does not care about impedance and it was assumed when designed that the amplifier has very low output impedance. Many have so painted themselves into this corner that they cannot imagine anything else, and call SETs (and by extention Firstwatt F1 & F2 are broken).
dave
But a speaker cable is zero ohms (or should be.)
You match the amp to the speaker not the speaker cable.
Its just hi fi snobbery and audiophoolery.
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