Cryogenic treatment of tubes? Anyone with experience positive or negative?

I bought 2 pairs of Mullard NOS 12au7 (CV4003), one set cryoed and the other pair not cryoed.  I will be dammed if I could tell a difference.  Incidentally, one of the cryoed tubes started making noise right after the 90 day return policy ended.  I too got them from Upscale.

I've tried 3 or 4 diff. sets of cryoed tubes in the past and also after very careful comparison I really couldn't tell any difference either.One set of Mullard reissue el34 went fuzzy and noisy in a 2 month period and one tube went completely bad.

Maybe other people have had better experiences with cryoed tubes but I would'nt recommend them.

Kenny.

I have a Cryoset pair of Tungsol reissue 12ax7 that got a bit noisy after a month of use.  A standard pair was supplied with my Jolida amp and there seems to be no difference between them other than the standard pair did not get noisy.

The idea of Cryo'ing the tubes is to relax the metal parts to allow the  shapes to settle sort of it also improves  the electrical properties including less electrical resistance . similarly NOS tubes that have been sitting for a long time  don't need this because they have naturally relaxed over time. if the parts were already from old metal let say then you wont get as good of a change with the treatment. Some metals react differently as well so you get various results. if its cheep then its worth it, if done right, if not done right it can actually damage the tube and reduce the life of the tube. best way is to stick the tubes on a shelf for 50 years, oh that's NOS.

Not wanting to be the contrarian here but I have had very good results with Gold Lion 12 AU7s from Cryoset.  The pair in my linestage just stay quiet!  I have two more of the same in boxes in the stereo room closet waiting...

I too have the Gold Lion 12ax7 gold plated pins and Cryo treated that I use for my line stage, very quiet and very detailed sound. I highly recommend it.

Generally speaking, almost all materials benefit from Cryo, not only steel and aluminum tools because they become harder, less brittle, stiffer, more durable, don’t ring as much, etc. Many audio items benefit from Cryo for the same or other reasons, glass, metal, plastics, tonearms, cables, capacitors, resistors, CDs, records, etc. etc.

I have never heard any difference, when comparing from the same batch lot.

But I seen/heard from a few customers now their tubes got noisy or flared and died after cryo’ing.
If you guys think about it Cro’ing your precious tubes is great way to make them unreliable.
The glass tube envelope vs the palstic/bakelite base v metal pins, will all expand and contract at different rates when cryo’ed.
Therefore having a great chance of unsealing the glue bond between the three and the tube loosing all or part of it’s vacuum.

Cheers George

@georgehifi  My experience with the tubes mentioned above is just the opposite of what you posit.  I've had replacement tubes waiting in the wings for some time, expecting that my tubes would be getting noisy by now and would need to be replaced.  Not so.  They were quiet from the get-go and remain so.

Where I had trouble was with NOS tubes which got noisy so quickly that buying more of them after several tries just didn't make sense to me.  As always YMMV.

I cryo’d a brace of matched Sylvania Badboys and a Tung Sol 1942 Rectifier. Post Cryo with nominal one week rest period they all sounded great, no problems. Faint heart neer won fair maiden.

Here is an electronic engineers perspective on Cryo'ing Tubes.

Effect on Vacuum Tubes?

Two different crystal structures that occur in steel which have absolutely no measurable effect on tone. 

So cryogenic treatment works to improve the hardness of ferrous metals such as steel, but what about a vacuum tube – a tube is not a lump of steel – it’s a delicate and complex component made up of many different materials. The metal electrodes are mainly nickel for the plates and heater cover, titanium for the heater wire, molybdenum for the grid wire and copper support posts. The heater is coated with strontium/barium oxides. The electrodes are supported by mica washers within a glass envelope. 

One can only guess as to what effect cooling a tube down to so such low temperatures will do to it as there’s been no serious scientific research investigation into this. Additionally, tube vendors have done little in the way of publishing noise measurement figures and life tests comparing treated and untreated tubes. 

Typically all you’ll find are references to surface hardening, maybe nice magnified images of the surface of cryogenically treated steel and even rhetoric about NASA and Einstein on vendor websites. All this is about as relevant to your guitar tone as the colour of your guitar cable or your underwear. Could it be that cryo-treatment is pants?

I did find several scientific papers indicating that cryogenic treatment hardens aluminium. Perhaps it hardens copper, nickel and the other metals used in the construction of tubes too. Although there are no moving parts in a tube and no mechanical wear, hardening the electrodes would theoretically make them stiffer. Stiff electrode structure is good thing in a tube as it should reduce microphnony, which is caused by the electrodes moving relative to one another.

 However let’s keep this in context. Cryogenic treatment is just a finishing process used to complete the conversion of austenite to martensite in steel as described earlier. The metal components inside a tube aren’t quenched to make them super hard in the first place so there is no conversion to complete. At this level cryogenic treatment achieves nothing and I’m inclined to think that it could potentially damage the tube. 

Cooling a tube to cryogenic temperatures would put undue thermal stress on the glass envelope and delicate internal parts. The manufacturers never designed or specified tubes to be stored at such low temperatures. The act of putting one of these delicate devices through cryogenic treatment will cause contraction and expansion of the different materials and increase the chance of loosening some of the internal parts. The mica may no longer stay in secure contact with the glass envelope causing the tube to become more microphonic.

Cheers George

George,

Thanks for sharing the engineer's perspective!  Until proven otherwise through I'm sticking' with what's workin'.

Engineers sometimes think too much. It sounds like he had a close encounter with a Wikipedia page.

Engineers sometimes think too much. It sounds like he had a close encounter with a Wikipedia page.

Now that's funny,Lol.

Kenny.

Don’t knock these electronic engineers they designed everything your listening to, without them you’d have nothing but voodoo/Geoff to listen to.

Cheers George

georgehifi
Don’t knock these electronic engineers they designed everything your listening to, without them you’d have nothing but voodoo/Geoff to listen to.

Cheers George

Georgie old boy, this is simply a case where experience and education Trump someone’s opinion. That someone being your electronics engineer. Let me explain. Electronic engineers don’t get any courses in Materials Science, Engineering Science and Strength of Materials as do Aerospace Engineers and he obviously has zero experience in cryogenics whereas I have 20 years of experience. Therefore his opinion is irrelevant. Your use of his opinion is actually an excellent example of Appeal to Authority. For that you get a gold star.

I am aware of at least 2 speaker manufacturers  in the past and present that cryo(ed) the internal components/wires of their speakers. I can't imagine it is based on anything other than perceived improvement or possibly for the reason given by Glennewdick. His explanation is my understanding of the overiding benefit aside from having no benefit to NOS tubes, 1st time I heard that. I would say that sonically I have THOUGHT I heard differences, output tubes in an amplifier years back,  this would have to be revisited before I decide. My understanding that there are different methods and that not all cryo treatment is the same. Someone else with more experience might chime in on that point?

tubegroover
I am aware of at least 2 speaker manufacturers in the past and present that cryo(ed) the internal components/wires of their speakers. I can’t imagine it is based on anything other than perceived improvement or possibly for the reason given by Glennewdick. His explanation is my understanding of the overiding benefit aside from having no benefit to NOS tubes, 1st time I heard that. I would say that sonically I have THOUGHT I heard differences, output tubes in an amplifier years back, this would have to be revisited before I decide. My understanding that there are different methods and that not all cryo treatment is the same. Someone else with more experience might chime in on that point?

>>>>>Right. Not to mention high end electronics manufacturers who Cryo their components, e.g. Meitner, and most high end cable manufacturers, and many aftermarket fuses manufacturers who also routinely Cryo their products. I’m pretty sure Cryo Tube or some such company sells cryo’d tubes. Walker Audio used to Cryo tonearm and other parts for their $100,000 turntable, dunno if they still do. Hel-loo!