To the OP.. As others have pointed out, most plastics and glues are very unhappy in cryogenic environments. Internal manufacturing stresses on either can cause tensile or shear failure between dissimilar materials.
Also, the rate of cool down cannot be fast, as large thermal gradients will kill plastics and glass quite easily.
High conductivity epoxies such as stycast 2850 loaded with alumina encasing a large aluminum core I've simply dunked into liquid nitrogen directly from a 150 C oven, no problem. Unfilled epoxy, such a structure cannot even survive the cold, never mind the rate.
Anything dealing with safety, such as power cords, parts with ground insulation, I certainly cannot recommend cryogenic treatment. You don't know how compromised the insulations become.
Jn
Also, the rate of cool down cannot be fast, as large thermal gradients will kill plastics and glass quite easily.
High conductivity epoxies such as stycast 2850 loaded with alumina encasing a large aluminum core I've simply dunked into liquid nitrogen directly from a 150 C oven, no problem. Unfilled epoxy, such a structure cannot even survive the cold, never mind the rate.
Anything dealing with safety, such as power cords, parts with ground insulation, I certainly cannot recommend cryogenic treatment. You don't know how compromised the insulations become.
Jn
Sure. At liquid helium temp, the only thing known to man with any heat capacity is helium. Everything else has practically none. If you for example, take a stainless steel resistor at room in a vacuum and put 1 watt for one second, it might rise 1 degree. Depending on size of course.
Drop it to 4.5 Kelvin in a vacuum and pulse for 1 second 1 watt, it will fly up to roughly 50 Kelvin. From there, it recovers heat capacity and will slow down it's rate of rise.
During cooldown of large things like the LHC, feeding liquid helium in one end you see the thermal measurements dropping slowly with the typical gradient since the fed end has the coldest gas. When the magnets get to roughly 50 Kelvin, the cold end suddenly drops quickly into the 4.5K range, and that drop propagates along the magnets rather quickly. They refer to it as a "cooldown wave" or some such thing, they called it that on this side of the pond..
IIRC, about 22 years ago I wrote a simple analysis paper showing how a 24 AWG copper wire would heat up given a 100 amp pulse waveform. The initial climb is quite dramatic. IIRC, I used the CRC handbook for the resistance and heat capacity profiles from 4.5K to about 150 C, that being the upper limit of the insulations.
I recall there is an analysis detailing this heat capacity drop, but don't ask me to explain it, all I can do is stare dumbly with zero comprehension. I leave that stuff to the physicists.
Jn
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I work with kapton, tefzel, nomex, and epoxies for the most part. The properties do not change as long as they survive the thermal shock. Kapton is outrageous for voltage withstanding, 6kV per mil (.001 inch), but it also has huge absorption. Put 5kV DC across 5 mils of it for a minute, discharge to zero, and if you remove the short, it recovers about 20% of it's voltage in a few minutes.
But otherwise, we don't notice plastics changing properties.
Since most of what we built and test will go into an environment where radiation is also present, we cannot use many plastics. PVC for example won't last long.
Many plastics also become extremely brittle at cryogenic temps. If you examine code (NEC), you see that wires will have a minimum bend radius spec, never go less than.... that is because as the insulation ages, it would tend to crack on the outer radius. Tightly bent wires put into cryogenic temps easily crack the insulation just from thermal changes even if cooldown is slow.that is why I would not consider cryogenic cooling of anything safety related. Normal everyday things are not designed for it.
The cryogenic guy said 3D printed objects work down to 4.5 K, so that gives me a chance to test PLA, PETA, ABS, and PEEK at least for physical properties and voltage withstanding.
Jn
But otherwise, we don't notice plastics changing properties.
Since most of what we built and test will go into an environment where radiation is also present, we cannot use many plastics. PVC for example won't last long.
Many plastics also become extremely brittle at cryogenic temps. If you examine code (NEC), you see that wires will have a minimum bend radius spec, never go less than.... that is because as the insulation ages, it would tend to crack on the outer radius. Tightly bent wires put into cryogenic temps easily crack the insulation just from thermal changes even if cooldown is slow.that is why I would not consider cryogenic cooling of anything safety related. Normal everyday things are not designed for it.
The cryogenic guy said 3D printed objects work down to 4.5 K, so that gives me a chance to test PLA, PETA, ABS, and PEEK at least for physical properties and voltage withstanding.
Jn
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I screened 880 3 inch diameter diodes used at 4.5 Kelvin. They are bypass diodes to carry ring current around a superconducting magnet that has quenched. There are two 3 inch cube copper masses clamping the silicon wafer, their job is to keep the silicon below 170 Kelvin.
Now...in English.
The machine has 144 inductors in series per "ring", a complete loop of magnets 2.4 miles round. Normally the inductors are zero resistance, so the 6300 amps generate no heat. But they store megajoules of magnetic energy.
If one of the inductors decides it has resistance (a quench), the IR drop of the magnet turns the bypass diode on. That way, the magnet consumes it's own energy as heat, and the other 143 inductors can be discharged into massive resistor banks.
Since there is so much inductance, energy and current, we cannot quickly discharge lest the voltages reach extreme levels and destroy something. It takes about 30 seconds to decay to zero.
In that exponential decay from 6300 amps to zero, the diode has to support that current and not overheat. The 2 pieces of 3 inch cube copper does that well, but the initial heat pulse cranks the copper temp fast, as the thermal conductivity is about two orders of magnitude better than room (etp copper) and the heat capacity starts real low.
Jn
Now...in English.
The machine has 144 inductors in series per "ring", a complete loop of magnets 2.4 miles round. Normally the inductors are zero resistance, so the 6300 amps generate no heat. But they store megajoules of magnetic energy.
If one of the inductors decides it has resistance (a quench), the IR drop of the magnet turns the bypass diode on. That way, the magnet consumes it's own energy as heat, and the other 143 inductors can be discharged into massive resistor banks.
Since there is so much inductance, energy and current, we cannot quickly discharge lest the voltages reach extreme levels and destroy something. It takes about 30 seconds to decay to zero.
In that exponential decay from 6300 amps to zero, the diode has to support that current and not overheat. The 2 pieces of 3 inch cube copper does that well, but the initial heat pulse cranks the copper temp fast, as the thermal conductivity is about two orders of magnitude better than room (etp copper) and the heat capacity starts real low.
Jn
Agreed. So far, people who cryotreat for a living, measuring effects at the PPM level, have found none of the "effects" that have been "reported".
It would be so neat if somebody showed a change. However, those at the top level of science and physics report none of this. And they can afford (and need) the best instrumentation on the planet for the totally ridiculous stuff they do.
Jn
It would be so neat if somebody showed a change. However, those at the top level of science and physics report none of this. And they can afford (and need) the best instrumentation on the planet for the totally ridiculous stuff they do.
Jn
In addition to all these I'd want to see an "improvement." A speaker cable that has higher resistance after cryo treatment could indeed give an audible change (not just lower volume, but woofer response being different around resonance due to reduced damping factor), Some may well claim this improves sound in their system, but this could be duplicated by adding a resistor in series with an untreated cable. I'd want to find a difference that's not so easily duplicated by other, "ordinary" means.
But don't worry, I'm not holding my breath.
This is fascinating. I learned in high school it takes a fixed amount of heat to raise a fixed volume of water by 1a fixed temperature delta, except for phase change (melting/freezing, boiling/condensing) which takes many times that to turn ice at 0C into water at 0C.
Now I learn that heat capacity changes continuously with temperature!
I looked around to confirm this - Figure 2 shows many materials, and it even has helium gas:
https://arxiv.org/ftp/arxiv/papers/1501/1501.07100.pdf
It may be hard to find a layman's explanation for it, as most laymen aren't even aware the phenomenon exists. Heat capacity being constant is a good enough approximation for making ice and boiling water in the average kitchen.
I guess this can be more impactful than treated metal itself for both subjective / objective differences, better or worse.
Member
Joined 2006
Well....I was at one time a solid state scientist/ experiemental semiconductor physicist and often performed electrical measurements down to 4.2K (−269 °C), and optical ones all the way to superfluid helium at 1.8K (-271°C ).
Since I dont have any first hand experience, I could only speculate on what possibily the cryogenic treatment could do to the copper in copper cables.
Several group members did point out that certain metals could go into mechanical phase transition at low temperatures (but not copper or silver), so hardness is one property that could be altered or strengthened by this method.
Electrically (to copper)? Perhaps not as obvious.
When we start chilling down copper....copper atoms will begin experiencing less vibrations...and tend to go into the lowest energy states for comfort... oh, oh..before we go on though...we need to know inside and on the copper surface there exist many defects, dislocations, impurities, grain boundaries, voids, traps and surface states, etc, etc, which can degrade the degree of the material's conductivity.
One thing can't be ruled out is...although cryogenic treatment might not show much of enhancement to the copper's general electrical measurement itself per se (guessing), but... the extreme temperature cycling might help ameliorate some of the imperfections as mentioned above.
One example is the possible reduction of surface states (partially coming from the plastic jacket's interface maybe). By gaining some surface passivation formation via this process, the number of electron traps (surface states) on the surface could be minimized. (Note: electrons can undergo - trapped and released in random fashion there)
And...my honest opinion would be....I would say, instead of...just buy a pair of better cables that have higher copper purity and with care taken on surface passivation (oiled or tinned properly - tin oxide is a conductor, unlike copper oxide which is a semiconductor!! surprised?), and no plastic jacket please (say using cloth or air to avoid interfacial surface states generation)...
Well guess what, looks like those vintage Western Electric cable designers had already done it..
Anyway, just sharing some of my thoughts...
Since I dont have any first hand experience, I could only speculate on what possibily the cryogenic treatment could do to the copper in copper cables.
Several group members did point out that certain metals could go into mechanical phase transition at low temperatures (but not copper or silver), so hardness is one property that could be altered or strengthened by this method.
Electrically (to copper)? Perhaps not as obvious.
When we start chilling down copper....copper atoms will begin experiencing less vibrations...and tend to go into the lowest energy states for comfort... oh, oh..before we go on though...we need to know inside and on the copper surface there exist many defects, dislocations, impurities, grain boundaries, voids, traps and surface states, etc, etc, which can degrade the degree of the material's conductivity.
One thing can't be ruled out is...although cryogenic treatment might not show much of enhancement to the copper's general electrical measurement itself per se (guessing), but... the extreme temperature cycling might help ameliorate some of the imperfections as mentioned above.
One example is the possible reduction of surface states (partially coming from the plastic jacket's interface maybe). By gaining some surface passivation formation via this process, the number of electron traps (surface states) on the surface could be minimized. (Note: electrons can undergo - trapped and released in random fashion there)
And...my honest opinion would be....I would say, instead of...just buy a pair of better cables that have higher copper purity and with care taken on surface passivation (oiled or tinned properly - tin oxide is a conductor, unlike copper oxide which is a semiconductor!! surprised?), and no plastic jacket please (say using cloth or air to avoid interfacial surface states generation)...
Well guess what, looks like those vintage Western Electric cable designers had already done it..
Anyway, just sharing some of my thoughts...
All of copper conductivity is based on the mean free path of the electrons.
Cryogenic environs will increase the mean free path specific to the temperature as well as the defects which interrupt ballistic trajectories.
Bringing the copper back to room re-establishes the same conductivity it had prior to cooldown.
It the temp cycle changes any of the room parameters, it is below our (my work) measurement capability.
We are not slouches with respect to test, as we cannot afford sloppiness.
Semiconductor physicist.. so you can appreciate the cold diode stuff. 26 years ago I did not know that below 10K give or take, a diode junction starts to block forward conduction. Spec for me was 3 to 8 volts forward blocking at 4.5K. MRI people typically use 30 volt blocking.
Who knew?
Jn
Cryogenic environs will increase the mean free path specific to the temperature as well as the defects which interrupt ballistic trajectories.
Bringing the copper back to room re-establishes the same conductivity it had prior to cooldown.
It the temp cycle changes any of the room parameters, it is below our (my work) measurement capability.
We are not slouches with respect to test, as we cannot afford sloppiness.
Semiconductor physicist.. so you can appreciate the cold diode stuff. 26 years ago I did not know that below 10K give or take, a diode junction starts to block forward conduction. Spec for me was 3 to 8 volts forward blocking at 4.5K. MRI people typically use 30 volt blocking.
Who knew?
Jn
I just want to comment on what a pleasure it is to see a reasonable scientific discussion regarding cryogenic treatment of audio components on this forum. There is another forum, audiocircle.com, where this subject as well as other controversial ones cannot be debated.
That forum is dependent on manufacturers paying it to allow posting on their individual ‘circles’. In essence it’s a form of paid advertising disguised as objective discussion. And as result you cannot criticize or disagree with what the manufacturer says. If you do the board monitors will remove your comments.
There is one particular cable manufacturer with their own ‘circle’ who proudly promotes that they use cryogenic treatment of their cables and it makes them sound better. In fact, they claim significantly better. And there are ‘happy customers’ who will confirm everything the manufacturer says. Often in gushing terms.
Anyone wanting objective information rather than biased opinions will be well served to get their information here rather than at that website.
That forum is dependent on manufacturers paying it to allow posting on their individual ‘circles’. In essence it’s a form of paid advertising disguised as objective discussion. And as result you cannot criticize or disagree with what the manufacturer says. If you do the board monitors will remove your comments.
There is one particular cable manufacturer with their own ‘circle’ who proudly promotes that they use cryogenic treatment of their cables and it makes them sound better. In fact, they claim significantly better. And there are ‘happy customers’ who will confirm everything the manufacturer says. Often in gushing terms.
Anyone wanting objective information rather than biased opinions will be well served to get their information here rather than at that website.
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You are probably right. Here is their standard bullet line item on just about every cable they offer:
"Deeply Cryogenically Treated Conductors & Connectors, which provides Accuracy and Naturalness."
No test data to support of verify the claim. No listening tests either.
Just another easy throw away marketing line that anyone can make up. Particularly when you have a large fan boy following and a forum that doesn't allow any criticism or contradictions.
"Deeply Cryogenically Treated Conductors & Connectors, which provides Accuracy and Naturalness."
No test data to support of verify the claim. No listening tests either.
Just another easy throw away marketing line that anyone can make up. Particularly when you have a large fan boy following and a forum that doesn't allow any criticism or contradictions.
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