Cryo Treatment: does it provide improvements in sound or longevity?

Thank you for all the great responses. I suspected that at best the difference would be very small. I’m still surprised that cryogenic treatment doesn’t destroy a lot of tubes.

It makes sense that if cryogenic treatment helps align the internal structure of wire it would reduce smear and improve the sound. If I didn’t have my ideal interconnects and cables and was experimenting to save money… I would experiment. But I’ve left the research up to Transparent. They did what they had to do to create the amazing interconnects and cables I enjoy daily.

I purchased some cryo'd EL34 some years ago, these were hand picked SED.  They were superior to my regular SED and Svetlana, cryo or hand picked meaning better spec and match, can't say which was most responsible. 

My original experience with cryo'd tubes was marred by the fragility of the glass enclosures. Makes one wonder if a technique has been developed to cryo the internal wiring first and then apply the glass and vacuum afterwards so as to take the glass being cryo'd out of the picture.

I may be completely off track, but is not a Cryo'd Tube, a tube that has received a post production treatment to treat wire used for the tubes assembly, but as Copper is unsuitable within a tube, and Copper is usually the metal scientifically showing grain shape and alignment. Where the reports are that a particular shaping or grain orientation / alignment is beneficial to the signal path. It makes it difficult to see where metals used for the valves production will benefit from a Cryo' Treatment, when it comes to a electronic circuit is the consideration.

 Most of the metal inside a tube is nickel, which has a number of desirable properties. First, it has a high melting point. Copper, for example, would be unsuitable because it would soften and distort. Secondly, it does not absorb a lot of gas onto its surface (the technical term for this is “adsorption”). Such adsorbed gas is gradually released into the vacuum of the tube, and it is important to minimize it. An exception to the use of nickel is the heater (or filament) which is generally made of tungsten because of the high operating temperature.  

Additionally, Typical metals found in a tube are likely to respond well to a Cryo' Treatment if to be selected for other roles that a metal can be used.

Cryo' will harden a metal which does make it have a longer usage life in another application, it does seem fair to suggest a tube being cryo' treated will have a selection of parts, that can be used for longer than the non-cryo' treated material.

Probably worth mentioning the nano treatments on wires and metals are also known to have a very positive influence. 

The link is not quite nano treatment, but where the use of a Thermionic Valve might go in modern circuit designs ??   

https://ntrs.nasa.gov/api/citations/20190030489/downloads/20190030489.pdf

Plenty to be familiarised with in this link.

 http://www2.ee.ic.ac.uk/ngai-han.liu08/yr2proj/group_40.pdf

Cryo of tubes is hilarious, as when using the tube, it gets heated! Red hot heated! So the entire "benefit" of cryo literally evaporates when using the tube. LOL!

AFAIK, cryo is most prevalent in tubes, so cast further doubt on it. The only half way reasonable argument I have heard is that cryo treatment puts stress on the tube and will cause failure of structurally bad tube due to cryo treatment. Not loosing sleep over that.

Kevin sure is a great sales person. I have to give him that.