Cryogenically treated vacuum tubes...?

[Bruce / Mission Amps]

http://search.store.yahoo.net/cgi-bi...2Fnsearch.html

and

http://store.tubedepot.com/bsctfaq.html

I'm wondering if this is near total BS or not.
Also, would anyone with any common sense pay this much money for a Cryo treated vacuum tube?
Anyone had any experience with cryogenics and vacuum tubes?
I have unrestricted access to a 70 liter Nitrogen tank and and all that rot but I hate wasting my time.

[Enzo]

Well one thing is, what is the best thing to keep temperatures apart? As in keeping cold things from warming up or warm things from cooling off? A vacuum. Like what is inside our tubes. That is the basis of a thermos bottle. SO the only way substantial cooling from the surrounding liquid nitrogen would get to the innards is conduction through the pins at the base. Or so it would seem to me.

Decreased noise floor for blacker blacks

What does that even mean?

I don;t know how long it takes to make a 12AX7, but there's a sucker born every minute.

For further information, see "Tice Clock."

[martin manning]

Well one thing is, what is the best thing to keep temperatures apart? As in keeping cold things from warming up or warm things from cooling off? A vacuum. Like what is inside our tubes. That is the basis of a thermos bottle. SO the only way substantial cooling from the surrounding liquid nitrogen would get to the innards is conduction through the pins at the base. Or so it would seem to me.

There is radiation, too. That's why the outside of the glass liner in your thermos bottle is silvered- to reflect the IR back in to the contents.

MPM

[Don Moose]

Are you the sort of HiFi Tweako willing to shell out $300 for a hand-turned wooden volume knob for the way it promotes clarity in the upper mids?

How about a Rosewood one for Chamber Music and a Birch one for Opera?

[Five_E35]

This guy is doing it too - see Kuhl Tube.

https://www.tubeworld.com/index_high.htm

I have heard of cryo-treatment being used on newer brass instruments to relax the stresses from bending and forming that build up in the tubing. With tubes, I'd wonder if freezing would cause mis-alignment of the grids & screens and what it does to the cathode coating. The military and manufacturers probably have maximum & minimum storage specifications. I seem to recall that the Blackplate process RCA & Sylvania used involved heat treating.

IMHO the selection process itself is going to influence the result and I'm reluctant to buy the non-treated version(or any tubes) from these guys.

[NorCalTuna]

Are you the sort of HiFi Tweako willing to shell out $300 for a hand-turned wooden volume knob for the way it promotes clarity in the upper mids?

How about a Rosewood one for Chamber Music and a Birch one for Opera?

or a solid spruce one for classical guitar

mahogany with maple top for led zep

bright chimey brass one for british invasion

one made of cobalt for the blues

a knob made of sarcasm for steely dan?


oh yah, and as for the cryo: I can understand why it's used in motorsports, as the properties of the metal are demonstrably improved by the treatment- especially in areas like gear box and differential parts- but question if this "alignment" of the crystalline structure would positively effect the operation of the tube.

assuming that the radiation and conduction- through the pins, up the tiny tinsel leads to the massive plates and such- could actually bring the temp of the internal elements of the tube down to the point where there would be actual treatment, would it be beneficial? Worse, doesn't it seem that such slow methods of conduction would present an irregular treatment?

Perhaps an EE would better be able to say, but I would think that smoothing out a surface which electrons are expected to move to and from- as in a tube's cathode and anode- would actually inhibit the departure and arrival by providing less little edges for them to channel through. It's a question of area: a rough surface of given dimensions will have a higher skin surface area than a smooth one of equal given size.

The way Colorado, unfolded, is nearly the size of the US and how Maine has a thousand mile coast.


flame on!

[Euthymia]

I can see one theoretical benefit to it, and that is that getting the tubes very cold pre-heat-stresses them. It's like a freeze-in rather than a burn-in, but it has the same effect of getting heat-based anomalies to either appear or disappear, and at least stabilize.

I wonder how many tubes are noisier (or otherwise defective, hence culled) after the process.

So for me, it would be more of a testing/heat stress thing, and of some real value, but not enough for me to get a tank of nitrogen!

[Enzo]

It is easy to rationalize how it MIGHT work or what it MIGHT do, but a lot harder to find real reasons.

[defaced]

How many here have grabbed a hot tube? If it can be heated, it can be cooled, it's just not as efficient because of the partial vacuum inside our tubes.

Perhaps an EE would better be able to say, but I would think that smoothing out a surface which electrons are expected to move to and from- as in a tube's cathode and anode- would actually inhibit the departure and arrival by providing less little edges for them to channel through. It's a question of area: a rough surface of given dimensions will have a higher skin surface area than a smooth one of equal given size.

This is true. It's the reason why when TIG welding the tungsten electrode is ground so that the lay of the grinding is parallel to the tungsten. If it's ground centrifugally, the arc spreads differently because it's following the ridges from the grinding. Basically, a ridge has more free electrons which can be used for conduction.

assuming that the radiation and conduction- through the pins, up the tiny tinsel leads to the massive plates and such- could actually bring the temp of the internal elements of the tube down to the point where there would be actual treatment, would it be beneficial? Worse, doesn't it seem that such slow methods of conduction would present an irregular treatment?

Would it be beneficial, that's one for the voodoo people to argue. But for the cooling question, yes, if you do it fast enough you will get uneven thermal gradients that will kill your process. Because of the poor thermal conductivity of a partial vacuum, the cooling process has to be slow to ensure saturation of the parts of interest is achieved. It's no good cooling the glass envelope to -300F is the innards are still at room temp. This is what would happen if you just dropped a tube into a bath of liquid Nitrogen. But if you slowly cool the tube, both the envelope and the innards would be approximately the same temperature.

When I read this, there are two things that raise flags. First, with the materials used in tubes, do the operating temperature negate the effect of the cryogenic treatment? For example, if I cryogenically treat a steel, then it sees some post treatment process that takes it above the A1 temperature (annealing temperature), then everything done by that cryogenic treatment is undone. Now think about a red plating tube or a glowing screen. If that red plate is above it's annealing temperature (assuming it has one), then you're cryogenic treatment just went by-by.

Second, do any of these materials undergo a martensitic transformation at cryogenic temperatures? If these are left unchecked, you could kill the mechanical properties of the tube components. How does a nice brittle screen grid sound?

[Enzo]

SInce cathodes are coated, why should we assume that "annealing" the metal under it will have a beneficial effect?

[tedmich]

lots of theory as to what it might do but

exceptional claims require exceptional proof,

thus its up to the brilliant fellows who developed it to prove its worthwhile: design a n=20 double blinded experiment in about an hour and carry it out in 2-3 weeks with a budget of ~5k all nice and clean....

BUT why bother to take the chance its spurious...just market to people who are irrational...no shortage.

[stingray_65]

Cryogenics is just recently come into the grasp of retail America.

Some of it is pure HYPE, but it has been proven time and agin that cryogenics does change the grain structure in metals.

The question is do the changes make any significant OR beneficial changes.

with the exeption of longevity of the tubes, simple signal path caps will have more of an influence on tonal quality (I have no proof , just guesssng)

to me this sounds like HIFI hype.

When I worked on High performance racecars back in the late 80' early 90's the cryogenic treatment of brake rotors were the rage and could only be afforded by the very wealthy or heavily sponsored raceteams.

I pretty much thought it was all BS, but time has shown that there is a significant advantage to it and today almost without exception all nascar, formula 1 and cart racecars use them.

Like heat treating metal to change the grain structure in metal the cryo process is rather involved. cooling and holding the tempratures at specific levels for specific times for different controled changes to occur.

simply "deep freezing" a part will NOT accomplish a controlled change in grain structure no more than heating up a piece of iron with a torch.

I can say this much as fact:
Cryogenics DO change metal grain structures measurably.

FWIW

Ray

[mpeg2]

This comes up periodically. IMO, BS.

Cryogenics changes the grain structure of SOME metals - most notably Steels (which undergo a martensitic transition at low temps). For most of the metals used in tubes - there are no phase transitions at low temps. To make matters worse, much of the claims about changing grain structures are actually backwards.
The kinetics decrease markedly as the temperature goes down for these materials (colder = slower). If one wants to modify the grain structure, then the temp needs to be raised.

What's happening is that the benefits of cryo for hardening steels (ex for automotive use) are being translated into propsed benefits in audio - without any scientific basis (most of what I've seen at these sites is pseudo-science at best).

Rich

BTW: Even though I'm in another field now, I think having earned an ScD in Nuclear Materials from MIT (and studying radiation induced phase transitions) may give me a little bit of credibility on this topic.

[Vaughan]

Cryo Tubes

Seems to be quite a few valve specialists in UK doing this.

http://www.watfordvalves.com/products.asp?id=10

I've tried cryo and non-cryo tube, and while the do seen to sound slightly different, I'm not sure whether it's an inprovement or not. They do seem to have a lower noise floor.
Seems like a good way to improve profit margins!

[tedmich]

This comes up periodically. IMO, BS.

Cryogenics changes the grain structure of SOME metals - most notably Steels (which undergo a martensitic transition at low temps). For most of the metals used in tubes - there are no phase transitions at low temps. To make matters worse, much of the claims about changing grain structures are actually backwards.
The kinetics decrease markedly as the temperature goes down for these materials (colder = slower). If one wants to modify the grain structure, then the temp needs to be raised.

What's happening is that the benefits of cryo for hardening steels (ex for automotive use) are being translated into propsed benefits in audio - without any scientific basis (most of what I've seen at these sites is pseudo-science at best).

Rich

BTW: Even though I'm in another field now, I think having earned an ScD in Nuclear Materials from MIT (and studying radiation induced phase transitions) may give me a little bit of credibility on this topic.

This is correct, and I think (as is the case with much hype) there is a grain (pun intended) of technical reality in the ridiculous claims, and that is the growing use of amorphous metal which uses an extreme and fast temperature shift to affect a phase transition which gives maximal disorder in the metallic structure; a LACK of grain structure. This metal has many useful properties, but it ain't happening by taking various metals and plunging them into LN2. This may stress relief the metals resulting in longevity and minor sound differences or it may actually thermally stress the tube and degrade its performance, but since its performance is completely subjective its untestable (lifespan is NOT, thus never tested), thus a religious faith by definition, like superstrings...

As to NASCAR using it, they weigh cost vs. POTENTIAL benefit, they have money to burn and its cheaper to assume a negligible effect, or an improvement, than to actually test the result. Since the consumer is unconcerned only a foolish producer would even inquire.