Cryotubes? Cryogenically Frozen valves

[Alastair E]

Absolute nonsense, or is there something to it??

(Personally, I would think thios is rubbish, as the tube heats up to normal temps, any possible 'benefit' from freezing would be lost anyway.........)

Whats it supposed to do anyway???????

AND if I put my trusty 6SL7 in the fridge, will it sound better tomorrow!!!!!!!!!

[DigitalJunkie]

They become superconductors!

[dstockwell]

http://www.tubedepot.com/cryovalvestory.html

[ilimzn]

It is pretty safe to say that if the method was not used for military, hi-rel and measurement applications, then it's likely bogus. many manufacturers in the aforementioned fields used various selection processes for tubes, but IIRC cryo treatment was not one of them. OTOH, I may just not be aware of ti, input from more experienced (read older ) members would be most welcome.

[tade]

Functioning tubes do involve the transfer of electrons and therefor the transfer of charges. Charged objects do exert physical effects on other charged objects. By this way, I can agree that the mechanical compliance could be a factor; unlike a semiconductor on a solid piece of silicone embedded in epoxy. So if parts are moving, they are moving closer and farther apart, or laterally. These things vary capacitance, and the distance an electron has to travel. Also, there will be some doppler effects created by emmitting a particle from a moving object (vibrating plate). Now i am not sure i believe that any of the effects may be audible, but if the resonance is in the audio band, it could be. Then we may consider the cryo treatment. I supposse this treatment works by contracting parts forcing their crystal structures to rearrange. I know that annealing does this, but not that 300F degrees is hot enough. If what they say is true then we would be left with materials with slightly higher damping than non treated ones. Will this slight change in damping be audible?

Now, i disagree with the comment about milspec tubes. I doubt this treatment adds to the power handling or the durability of the tubes, nor does it expediate their manufacture. Chances are a complex process like this, with little applicable benefit, would not be high on the military's priority list.

If I was sitting around with a system I could not think of any other way to improve, I might pick up a set of treated tubes.

I dont know the first thing about tubes.

[Miles Prower]

"I dont know the first thing about tubes."

That's what these charlatans at "CryoValve" are counting on. Unforch, you aren't the only one who doesn't know what he's talking about:

During cryogenic tempering, the tube is slowly cooled to the -196ºC/-320ºF temperature of liquid nitrogen, "soaked" for many hours then slowly returned to ambient. By means of this unique and vital process, the interior stresses to the materials of the tube are substantially and permanently relaxed.

This is utter nonsense. You DO NOT soften work hardened metals and/or alloys by means of extreme cooling. They don't even know what they're talking about! The process is properly called "annealing", and it always involves heating the metal. )In fact, this is already done during the initial pump down and getter flashing.) What they are describing is impossible. Furthermore, you will not find any data comparing a regular VT before and after this "treatment" (of course not too much chance that no one could tell the difference.)

It's just another BS scam to get you to pay $200.00 for a $5.00 12AU7A.

If more people would put all that creative energy into actually designing, testing, and building quality VT amps and/or VTs, we'd really have something.

[Tweeker]

Would not annealing the tubes also end up undoing other heat/cold treatments? Possibly just by running your tubes hot even, or do the metals they use not get hot enough in normal service?

[pinkmouse]

Originally posted by dstockwell
http://www.tubedepot.com/cryovalvestory.html

From the above website...

The "Q" of the (self) resonant (electro) mechanical systems responsible for the output of (self) microphonic spuriae is thereby drastically reduced. By this important reduction, both the peak amplitude and the "ring down" time of these systems is reduced with the result that the "apparent gain" of the device is increased-even in feedback controlled circuits-while the "dynamic noise floor" is lowered.

Excellent. That should produce some really impressive measurable data. If I had a process that could do that I would have charts and results right across my website. But I don't see any there...

[Miles Prower]

Would not annealing the tubes also end up undoing other heat/cold treatments? Possibly just by running your tubes hot even, or do the metals they use not get hot enough in normal service?

The tube internals have already been annealed as a by product of the bake-out during the pump down to drive off the occluded gasses, and the flashing of the getter material that chemically entraps reactive gasses. In normal operation, the metallic parts don't get hot enough to anneal, and running metallic plates at red heat will probably ruin them before they have a chance to anneal.

There is no reason whatsoever for any "magical" heat/cold treatments beyond what's already been done other than to have an excuse to sell you a $5.00 tube for eighty times what it's legitimately worth.

[richwalters]

Agree with Miles.....However Quote << the interior stresses to the materials of the tube are substantially and permanently relaxed.>> Rubbish treatment.... The MiL specs of most tubes for which many were designed for is far more than adequate.
Running power tubes hot enough in normal operation with getter fixed to anodes i.e 6550B's makes the getter function properly.That's all. xx Millions were made without speciality treatment and wouldn't be cost effective. I don't think my grandfathers eons ago would have even thought of this new coined marketing idea for cry'enic tubes. "....another ploy of worthless flannel.

richj