superconductivity and audio ideas – let’s brainstorm

[DaveThreshold]

How could superconductivity be used in audio, and what would the benefits be? It seems to me it would improve EVERYTHING. Have any high-end dealers used it? I guess the major drawback is not only cost, but the use of liquid nitrogen. The stuff boils off so quickly. I bet a number of people on THIS forum, would even know how to implement it.

Suspended turntables, and their platters, tonearms, power amps and speakers that would hardly overload.

Any Ideas?

[DF96]

Suspended turntables, and their platters, tonearms, power amps and speakers that would hardly overload.

?? Turntables don't depend on electrical resistivity for their suspension. Power amps don't overload because of resistivity.

Drawbacks: cost, safety, doesn't actually achieve anything!

[SY]

Other drawback- the boiling noise of LN2. And LN2 only allows the use of a very few ceramic superconductors- metal superconductors require liquid helium.

[marce]

Also inductance and capacitance would still be present.

[jneutron]

The place it could be the most advantageous is the voice coil. Zero dissipation would be great. The problem is, all HTS wires are made using a CVD (continuous vapor deposition) or a PIT (powder in tube) process. PIT isn't there yet. CVD is getting better, but it requires a substrate which is either stainless or hastalloy, and the wire is a flat ribbon. The conductors cannot be bent very tightly, I believe the G-2 super from American Superconductor is now capable of a 50 mm bend radius without significant degradation.

A more important issue is that of eddy currents. They are still working on the eddy loss problem at 60 hz, a prime target application. Mid bass, worse.

The more severe application headache is that of transitions from room temperature to 77K. Do it in a short distance, you have huge nitrogen losses. Do it in a long distance, you have large resistive losses. The warm to cold transitions are a constant battle between reducing thermal transfer by conduction, and dissipation by resistance.

Epoxies also become brittle at 77K. The nature of the beast with VC's is such that the wire-to-form bond is excersized in shear, worst case for cryogenic operation.

The magnetic structure would also need to be cold, as proximity to the coil would heat the coil.

Oh, and putting liquid nitrogen in a residential setting is scary. ODH and frostbite..

Making the magnet super could work. The problem here however, is the diminishing returns available as a result of iron saturation. No matter how powerful you make the magnet using super, the gap won't get much over two tesla easily. Many speakers are already there with gap flux intensity, and they just use neodymium.

Research is being done on semiconductors at 77K, but that is very early and extremely cost prohibitive.

Cheers, jn

[jcx]

Data Converters | Analog-to-Digital Converters (ADCs) | Digital-to-Analog Converters (DACs) | Time-to-Digital Converters (TDCs) | Hypres Inc.

while they concentrate on high frequency, if you extend their frequency-resolution plots down to audio "real" 24 bits (at least inside the converter) looks possible

[jneutron]

Originally Posted by jcx

Data Converters | Analog-to-Digital Converters (ADCs) | Digital-to-Analog Converters (DACs) | Time-to-Digital Converters (TDCs) | Hypres Inc.

while they concentrate on high frequency, if you extend their frequency-resolution plots down to audio "real" 24 bits (at least inside the converter) looks possible

Thanks for the link.

Yah, they like the 30 to 80 Ghz range, don't they?

Not ready for prime time though...cryocoolers are expensive to buy and operate as well. They did have some good pubs on warm to cold transitions..I am somewhat familiar with those...

Oddly, I didn't find any pricing..


Cheers, jn

[cbdb]

Unless your recording or processing in the digital domain, 24 bit audio is over kill and you cant hear the difference.
(and there are double blind tests to prove it)

[DaveThreshold]

Originally Posted by jneutron

The place it could be the most advantageous is the voice coil. Zero dissipation would be great. The problem is, all HTS wires are made using a CVD (continuous vapor deposition) or a PIT (powder in tube) process. PIT isn't there yet. CVD is getting better, but it requires a substrate which is either stainless or hastalloy, and the wire is a flat ribbon. The conductors cannot be bent very tightly, I believe the G-2 super from American Superconductor is now capable of a 50 mm bend radius without significant degradation.

A more important issue is that of eddy currents. They are still working on the eddy loss problem at 60 hz, a prime target application. Mid bass, worse.

The more severe application headache is that of transitions from room temperature to 77K. Do it in a short distance, you have huge nitrogen losses. Do it in a long distance, you have large resistive losses. The warm to cold transitions are a constant battle between reducing thermal transfer by conduction, and dissipation by resistance.

Epoxies also become brittle at 77K. The nature of the beast with VC's is such that the wire-to-form bond is excersized in shear, worst case for cryogenic operation.

The magnetic structure would also need to be cold, as proximity to the coil would heat the coil.

Oh, and putting liquid nitrogen in a residential setting is scary. ODH and frostbite..

Making the magnet super could work. The problem here however, is the diminishing returns available as a result of iron saturation. No matter how powerful you make the magnet using super, the gap won't get much over two tesla easily. Many speakers are already there with gap flux intensity, and they just use neodymium.

Research is being done on semiconductors at 77K, but that is very early and extremely cost prohibitive.

Cheers, jn

Yes, speakers came to my mind the most, as something that could benefit from this. That would be even much more complicated than I thought, thanks to your explanation.

[magnoman]

Originally Posted by jneutron

Research is being done on semiconductors at 77K, but that is very early and extremely cost prohibitive.
Cheers, jn

In the spirit of cost prohibited semiconductors:

NASA - Amazing Miniaturized 'SIDECAR' Drives Webb Telescope's Signal

Thanks
-Antonio