Cryogenic Treatment of Tubes, and why you should not.

I have received cryo'd tubes that  had 2 out of 6 cracked in shipment even though they had been wrapped in foam. My impression was that the metal/glass interface may be the weak point.

Prevalent 

For F1/Moto GP piston rods that must endure 15K RPM- sure.

Vacuum tubes- another audiophool extravagance?🤣

I read the Effectrode paper a few weeks ago - I own a number of their effects pedals.

As with everything from the company, comprehensively researched and argued.

I have had the "Mullard's", 12AU7, purchased from Upscale and manufactured in Saratov, Russia in my preamp for about 3 years now. Yeah, I had them cryo'ed. 

I listen (average) about 3-4 hours a day. They would have to be well over 2,500 hours by now. They sound sweet and have never had any issue. I feel that the $120 I paid for the pair was fair, and without question, they were well worth replacing the JJ tubes that were initially installed - also mfg in Russia.

Sure, it may be snake oil sales at work, but we are talking $20-$30 dollars. As for the article, the author states that, "I’m the kinda guy who likes to know what he’s buying." That makes sense. But try that with just about any product nowadays. The global economy made that difficult, or even impossible, many years ago.

Pair that with the fact that the old world tubes are about dried up and those that have what is left have increased prices for them that go well beyond what any snake oil salesman would add to the tally. Pick your poison, old tubes are rare, expensive, and not guaranteed for any amount of time, while the newly mfg "old stock" tubes are matched and, in my case, will last at least 2,500 hours. I would also point out that Russia still uses tubes militarily and the expertise at that plant would be better than anywhere else in the world. Try that in America!

This paper is an example of pseudoscience masquerading around as a thorough scientific investigation. It really is not. Reminds me of ASR. 

The methodology is cursory and full of cliché. Anyone attempting a serious evaluation would center around comparing a large number of tubes and extensive listening with a high end system... Observation would be the key... not measuring a couple parameters, saying the designers would know and only putting one comment on a blind A/B test... "“blind” A/B audio testsrevealed no tonal differences or improvements between the treated and untreated tubes. The amp didn’t sound more “holographic” or “possess more subtle inner resolution”; and, unsurprisingly, it wasn’t any quieter either. This result was not unexpected." Also, embedding a bias towards not hearing a difference. 

To me, this paper says nothing. It does not show that Cryo improves, does nothing or degrades the sound. It is just a puff piece. 

I would be really interested to hear from any folks here that have compared cryo to non-cryo tubes. I would be really interested to hear the results.  

Always interesting to read confirmation bias.

I always choose cryod when I ordered my 9000es Modwright when it still alive. No problem. The laser gave up. 

kofibaffour

415 posts

07-17-2025 at 04:21pm 

it never made sense and is part of the hoodoo voodoo schtick that is so present in this space.

Yeah, anything beyond zip cord and you are out. We get it. Over and over and over......

It’s a (maybe) engineer pondering things. In parts interesting, in parts long-winded, definitely not scientifically rigorous - just pondering, which I do a lot of myself. All we can really do is decide for ourselves. I have indeed thought about the "structrual" problem, and subjecting tubes to an unecessary freezing cycle. But what do I know? I’m not a structural, materials, chemical, electrical, nor tube engineer. Tubes don’t have a virtual machine or compiler for me to get into how they work.

I’ve had cryo tubes from various sources over the years. At times I thought some of them sounded "awfully" good for that tube type/brand. So when I started regularly buying sets of 6H30 and KT120 from Upscale (every 2 years or so), I would often tick the "Cryo" option, at an extra 8 bucks a tube. Did this for several sets over the years. But then just stopped - realized I wasn’t hearing a meaningful difference versus non-cryo sets of the same tubes. Got a mix of both now in my stash. But I haven’t bought cryo in years and won’t anymore.  I won’t kick the cypos out of the stash either, but it’s just a "meh" and "cool sticker" when I think about it now. Nothing takes the "exotic" feeling out of something like repitition and familiarity. 

Cryo'd anything is a marketing scam. Ask an actual metallurgist and they'll straighten it out for you.

The ability to hear a difference is a function of how resolving your system is.

If your whole system is below ~$30k, there’s an awful lot you’re not going to be able to hear.

In my own case, a few years ago I concluded I could not hear any difference between using the volume control on my DAC, which has a remote, and using the volume control on my integrated 300B amp, which doesn’t have a remote.  Since then I have made lots of upgrades in other parts of the system.  Out of curiosity I went back and compared the two again.  Now it’s apparent that not using the volume control on the DAC improves the depth of the soundstage significantly.  All of my friends can hear it’s deeper

As Einstein probably said, everything is relative.

My feeling about cryo’d power tubes is the stress from extreme temperatures weakens or makes brittle, the center alignment plastic guide.

I am in the camp that Cyro (on TUBES) does make a difference. At first I thought how can CRYO process improve the sound. As a side note, where I used to work (Space and Satellite) R&D / Manufacturing, we use CRYO machines to change the metallurgy molecular structures of components for the programs we build. So CRYO is not snake oil, but proven to work for certain Applications, BUT for Music? Hmm.

So, a Friend and I purchased 2 sets of the same tube, one CRYO and one not (SED winged C EL34) and did the proper break in on both tubes. when the time came, we listened and boy, we hear a difference, Not Night and Day difference but there is a difference. 

To me, if you have a resolving system (which we had) CRYO may? make sense. If not resolving enough, dont bother. just like speaker cables and power cables. it all depends on synergy and weakest link.

That's just my opinion.

Machine Tool Cryogenic Treatment

This doesn’t prove anything about audio tubes, but I wouldn’t argue with the proven physics demonstrated in these other applications (above link)

I can certainly see why the more adventurous tube dealers would experiment with cryo. It may be an experiment paid for by the buyers, but the buyers are willing to be experimented with. It's an understandable urge. Some particular resolution of the question may one day rule, and it may have been hinted at by the machine tool manufacturers' experience.

Post gets deleted that explains Cryo. Wow what a dump... 

Saw that post before.

First you cryo the tube, then you heat it up again when using it. LOL! That's all I need to know. Kevin is an excellent sales person, for sure.

Re scientific testing, the null hypothesis is no difference: scientific methodology 101. For listening test, please point me to a published double blind study on the effect of cryo on sound. Personal anecdotes are just that, personal anecdotes, without any sci. credibility. Sorry!

@mulveling 

Same with me. I think I checked Cryo a couple times. But never did a comparison. Never replaced a tube and thought wow that is better and went back and figured out it way Cryo treated. So, I really have no idea.