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


I'd be interested in hearing from audiophiles that have actually tried Cryogenic treated tubes and listened to them vs non-treated. 

I would really prefer not to hear from folks from a theoretical point of view, or that have no experience.

The last time I bought a set of tubes for my amp, just for fun I got the Cryogenic treated ones. They are replacements on my Audio Research Ref 160s. My KT150s were approaching the end of life and I heard them getting hard sounding. So I switched them out. The new tubes immediately restored the amp to its beautiful normal sound. I heard no difference from Cryo... although if it was subtle... no way I would... this was no purposeful comparison. I guess I'll have to wait 3,000 hours to see if they last longer. 

Just wondering if someone with good equipment and a trained ear has done listening tests (not measurements) and made a conclusion. 

ghdprentice

"One would have to assume one any verification of process would have to come from a third party inspection or process monitoring. Doubt that is included with the tubes."

@bolong Certificate of Compliance. You can ask for that at the time of sale. The buyers in just about any industry especially electronics are required by the company’s internal controls to request one with every purchase from their vendors.

Certificate of Compliance

Hmmm - the certificate sounds rather generic. Proprietary or patented processes don't sound like they would be covered by such certificates.

Certificate of Compliance 

Hmmm - the certificate sounds rather generic. Proprietary or patented processes don't sound like they would be covered by such certificates.

@bolong Didn't you even read the document you provided a link to? Did you ever work in High Tech or any area of the electronics industry? Its standard practice! Raw materials will never make it from the receiving dock to QC and then to the stock room for kitting or WIP without one.

I would not describe cryogenic treatment as a "raw material." The only way to certify genuineness is to have a permanent plant observer watching the process as it proceeds and then making sure what was observed correlated to a given batch of treated tubes marked with serial numbers.

Cryogenic basics-

Some materials become superconducting when passing current at cryogenic temperatures (some beryllium alloys). They in effect lose all of their resistance- (e.g. 10 to the -29th power ohms ! ).  Do your E=I/R calcs on that one ! 

But ONLY at cryo temperatures- e.g. minus 270 degrees F.   

Some materials become brittle at cryo temperatures e.g. carbon steel. 

Some do quite well, e.g. stainless steel, copper)

Cryo capable  metals do undergo micro grain structure re-alignment when submerged in liquid nitrogen.  Some re-alignment does become permanent,  Whether it changes or improves the sound while conducting an audio signal is not proven. 

 Because of the large range of temperature differential between room temp and cryo temp (e.g. 340 degrees) the materials are subjected to a relatively large amount of thermal contraction.  A risk for audio electronics durability is that an assembly of different materials that are closely connected may experience some thermal related stress because the materials contract at different mounts per degree of temperature change.  Without doing any calculations I would be hesitant using cryo treated vacuum tubes that have a sealed assembly of steel pins, mica insulators and a glass vacuum vessel.  The materials will contract at different rates and the stresses involved could cause material fractures.