Do you think superconductors will make a difference to audio??

[Ron Texas]

Electrically, maybe.

Sonically, no.

And you're likely to be dead before it happens anyway.

Are you planning for his demise?

 

[Cbdb2]

An interesting summary of the properties of super conductors. Explains some of the problems with using them.

Superconductivity | Physics, Properties, & Applications

Superconductivity, complete disappearance of electrical resistance in various solids when they are cooled below a characteristic temperature. This temperature, called the transition temperature, varies for different materials but generally is below 20 K (−253 °C). The use of superconductors in

www.britannica.com

 

[egellings]

Refrigeration and pressure requirements will keep superconductors in the lab or submerged in liquid helium, an unobtainium if I ever saw one for the foreseeable future.

 

[DonH56]

Refrigeration and pressure requirements will keep superconductors in the lab or submerged in liquid helium, an unobtainium if I ever saw one for the foreseeable future.

There are a number of "high temperature" types, but "high" means nitrogen (77 K) instead of helium (4 k), still not terribly user-friendly. AFAIK all the room-temperature ones have been disproven (i.e. fraudulent) or impractical so far. There were some promising models but I quit following some years ago when I was no longer running into them on research contracts and such.

 

[JSmith]

This is the reason why nearly all superconducting materials only superconduct at extremely low, near-absolute-zero temperatures: the electrons in the solid material must spontaneously develop that critical energy gap in their spectrum, and then that gap must be filled not by individual electrons, but by pairs of electrons that form and remain in these Cooper pair states. Electrons cannot “jump up” from the filled energy levels from below, and they must not be too energetic so that they pop up out of this band into the higher-energy excited states above it. The hotter your system is, the more particles there are that will spontaneously have enough energy to cause one of those two conditions to be violated, bringing an end to your superconducting state.

Room temperature superconductivity is hard. LK-99 illustrates why

LK-99, almost certainly, isn't a room-temperature superconductor. The underlying physics of the phenomenon helps us understand why.

bigthink.com

JSmith

 

[mhardy6647]

Yeah... physics.
Kind of a wet blanket.
Ask the folks looking for "breakthroughs" for safe, rapid charging, long-lived, economically feasible batteries with high energy density.

 

[Cbdb2]

Room temperature superconductivity is hard. LK-99 illustrates why

LK-99, almost certainly, isn't a room-temperature superconductor. The underlying physics of the phenomenon helps us understand why.

bigthink.com

JSmith

Interesting article but is this true?
"Either the electrons within a material are being forced through the entire material, both on the surface and on the interior, or they’re all traveling exclusively on the surface of the material. When electrons move only on the surface, that’s evidence that you have a conductor; when electrons move all throughout the material, those are the properties of an insulator" And he says it again in his coax cable figure.
What happened to skin depth? Or is he talking about superconductors?
OK I just clicked the link "move only on the surface" and it goes to a wiki skin depth page. So the professor seems a little confused.

 

[LTig]

There are a number of "high temperature" types, but "high" means nitrogen (77 K) instead of helium (4 k), still not terribly user-friendly. AFAIK all the room-temperature ones have been disproven (i.e. fraudulent) or impractical so far.

AFAIK most (all?) HTS come as kind of a powder which makes it really hard to produce a wire.

 

[EERecordist]

I worked in superconductivity building sub-micron III-V Josephson Junctions using molecular beam epitaxy, then testing them. Superconductivity can do things like SQUID magnetic sensors and heterodyne converters. I doubt it will change audio. But I think refrigerating circuits can reduce noise. We worked with helium. The outer glass thermos was filled with liquid nitrogen to cool the inner thermos. Then the inner thermos was filled with liquid helium. Once that got down to the boiling point of helium, we sealed it and ran a vacuum pump to go towards 0. We used glass thermos' because we had a good size electromagnet around our experiment. It was all in a Faraday room.

There was a proposal IBM pursued out of Zurich to build a superconducting CPU the size of a grapefruit. That project was canceled. The problem with extreme thermal cycles is mechanical degradation, including due to thermal expansion and contraction.

 

[LTig]

Superconductivity can do things like SQUID magnetic sensors and heterodyne converters. I doubt it will change audio. But I think refrigerating circuits can reduce noise.

It does. There are probes for NMR spectrometers which use cryocooled preamps to reduce noise.

 

[Speedskater]

First searching for a room temperature superconductor solution.
Then searching for an audio equipment need for that solution.

 

[DonH56]

First searching for a room temperature superconductor solution.

Yup.

Then searching for an audio equipment need for that solution.

Marketing has no "need", just "want", and ignorant consumers guided by sleazy dealers.

 

[DVDdoug]

Conductivity isn't really a problem in audio. Class A/B (and class-A) amplifiers work by "semi-conducting". They simply don't work without "resistance" or without wasting energy as heat.

Class-D amplifiers work by switching (almost) fully-on and fully-off so superconduction might help (if it's even possible to make a superconducting electronic switch) but class-D amplifiers are already very efficient and of a lot of the inefficiency is related to switching-time (when it's in-between on & off) so the main efficiency-factor is how fast it can switch.

Speakers are essentially motors and a quick-search tells me you can gain 1% more efficiency with superconducting motors. Not much, and of course you're going need tons more energy if you have to cool it. ...Just super-cooling a regular voice coil would allow the speaker to handle a LOT more power (depending on mechanical limitations) but that's not worth the cooling cost (or energy) either.

 

[KSTR]

Then searching for an audio equipment need for that solution.

Inductors, transformers, loudspeaker voice coils and field coils, basically everything where ohmic resistance is an unwanted parasitic property.

 

[egellings]

It would be theoretically better, but entirely impractical to implement. Now, if there's a room temperature one that operates at regular atmospheric pressure, needs no other extreme conditions met and is affordable, then we're talking.

 

[Cbdb2]

Inductors, transformers, loudspeaker voice coils and field coils, basically everything where ohmic resistance is an unwanted parasitic property.

I can see an advantage in speakers where voice coil weight matters, to a point where the cone weight swamps the voice coil (are we already there?). Transformers, not so much. There already at 90% efficiency, most of the waste is non-ohmic, and most of the weight/cost is in the core. (is there such a thing as supermagnetic?) You could make air core inductors smaller but they certainly would be a lot more expensive.

 

[Zapper]

Audiophools will pay a fortune for Meissner effect cable lifts.

 

[KSTR]

I can see an advantage in speakers where voice coil weight matters, to a point where the cone weight swamps the voice coil (are we already there?). Transformers, not so much. There already at 90% efficiency, most of the waste is non-ohmic, and most of the weight/cost is in the core. (is there such a thing as supermagnetic?) You could make air core inductors smaller but they certainly would be a lot more expensive.

The main advantage in speaker voice coils is, of course, better thermals but not only. Damping (local feedback) via back-EMF would be adjustable over a much wider range (by amplifier source impedance) and would be much more stable.
For audio signal transformers there would be advantages, too, for the same reason as the #1 issue for maximum fidelity (within the constraints of the magnetic circuit, of course) is parasitic resistance, both for voltage- and current-driven modes.