How cool is tube deep cooling?

[poynton]

Re: Re: Re: How cool is tube deep cooling?

On topic: Does each junction between crystals in a conductor act like a diode and how would this be changed by freezing?

A diode would only occur if there were different materials present, ie an oxide layer or something, not between pure crystals of the same material (or am I wrong??)

EDIT :- Having said that, some believe that cables are directional.

Andy

 

[rdf]

Re: Re: Re: Re: How cool is tube deep cooling?

EDIT :- Having said that, some believe that cables are directional.

Andy

Some cables have asymmetrical designs, typically connecting the outermost shield at one end instead of both. The directionality might not be operationally meaningful in short runs (broadcast engineers however will argue incessantly between the benefits of source vs. destination ground referencing in long runs) but it's far from a belief. Perhaps not exactly in the way you intended it's still a very good analogy for cryo treatment. Me, I prefer finding a different tube.

 

[Sunsun22]

Just want to add my personal experience with cryo treated tubes.

I have been using a number of 396A in the output stage of my DAC. The best I have is from Western Electric. Recently, I bought a cryo teated Ericsson 396A and put it in my DAC and things amazed me.

The background is darker.
The reproduction is having more details.
The bass is tighter.
The soundstage is more presence.

Although this is not an apple to apple comparison, people should expect the WE should be better than Ericsson. The next thing I want to do is to purcase a non-cryo treated Ericsson 396A and give it an AB test.

 

[ilimzn]

Just want to add my personal experience with cryo treated tubes.
Although this is not an apple to apple comparison, people should expect the WE should be better than Ericsson. The next thing I want to do is to purcase a non-cryo treated Ericsson 396A and give it an AB test.

Even so, it would be a biassed test. You seem to be working on several suppositions, one of them being that 'WE should be better than Ericsson'. Why should it be better?
Secondly, how many WE (or for that matter Ericsson) tubes have you tried against each other? Even SQ tubes have signifficant variations in their characteristisc, changing of one tube with another of the same age and manufacturer can have more than subtle effects.
Thirdly, it is impossible to compare a standard and cryo treated tube in an AB comparison, as in order to have two tubes to compare, you have to start with twotubes that are not the same to begin with (due to tolerances).
Fourthly, you cannot pin any of the positive impressions you note to the cryo treatment as you have never heared that tube in your system before it was done. Even if you did, cryo treatment is a process that takes long enough for your auditory memory to fade quite signifficantly. It's not just a matter of unplugging the tube, and then a few minutes later (plus warm-up period) re-plugging it and comparing. I have found that dishing out $ for a mod often has an amazing positive placebo effect - people WANT to hear an improvement, and as we all know, the mind is a powerful thing.

All that being said, cryo treatment can definitely change characteristics of tubes in a measurable way. However, saying it automatically improves them is, imho, a falacy.
As a comparison take the period of tube burn-in. It is very real and quite well documented. So are the processes that happen to various types of metal-to-metal boundaries, and the effects of temperature cycling and aging on them. Anecdotal evidence suggests that 'used good' tubes tend to sound 'better' than brand new tubes that are not burned-in. Even without it, parameters of the tube change (*) but, unlike cryo treatment, where the same happens, tubes are designed to withstand positive temperature gradients. I am not aware of any tube design that is made to even be exposed briefly, let alone stored for a longer time at temperatures even approaching liquid nitrogen. From that standpoint, you are probably better off doing a controlled burn-in of a tube than cryo treatment.

* - just recently i have tested some NOS sweep tubes, triode conencted high gm pentodes. brand new tubes initially had changes in operating current at constant voltage that were obviously due to thermal mechanics. Not to go into details, plate current changes due to thermal dilation of cathode and plate could be observed separately. Also, nosie effects due to thermal stressing resulting in mechanical 'pinging' of the tube while warming up. I tested a mixture of 24 tubes of the same type both NOS and used, from different manufacturers (several nominally equivalent pieces in each tube group), and it was very clear that all variartions were much smaller if even observable on used tubes. To test this furtehr i ran 4 NOS tubes for about 100 hours, and compared - after 100 hours they essentially behaved the same as used tubes in the aforementioned regards.
As an aside, I also observerd that some tube versions were much more prone to these problems than others, and also that parameter tolerances can be quite high, especially between different versions of nominally same tubes.

 

[planet10]

Let me just say that I think there are enough clues that suggest that the hypothesis that cryogenic treatment of tubes can yield positive results is worthwile for further investigation.

Some of those clues are in my power amp. Anytime i can afford the lengthy wait, i get Bill to do my tubes,

The process is way more than a night in the cooler. It is a synergistic process and every step is important. I have no doubt that a tube that has gone thru Bill's process is better (unless it started out as a JJ300B).

dave

 

[richwalters]

I will not contribue to this thread. Not worth a wet flannel.The weakest part of an electron tube is the copper glass seals in the base. Can't see what cryo can do except damage.

 

[nhuwar]

The cool down cycle most be very slow or I would expect the glass to crack from the diffrent rates of contraction.

Also I was just thinking about this a vacuum is a extremely good insulator so I wouldn't be surprised if the internals really dont get that cold with only 100 hour in the freeze.

Chances are they do but I bet they dont get as cold as most people think they do.

I will have to test a tube in my amp and then cryo treat it and see if I can see a diffrence running a sine wave throught before and after it into my spectrum analyzer.
It will be iteresting to see.

Nick

 

[planet10]

I will not contribue to this thread. Not worth a wet flannel.The weakest part of an electron tube is the copper glass seals in the base. Can't see what cryo can do except damage.

Well i know for a fact that over 10,000 tubes have been thru the process with no negative side effects (except the afforementioned JJ300Bs which, according to Bill, had badly designed glass (as Bill had a hand in the final version of the KT90 i'll assume he has familiarized himeself thoroughly with glass design issues)

That is fairly substantial empirical evidence.

dave

 

[richwalters]

There is a standard tube test....look at the Tung-sol 5687WA data sheet and it mentions the glass strain and dunking boiling water test . notes K.

The irony is the KT90 has a poor reliabilty, but thats to do with the innards not the glass.

richj

 

[Sir Trefor]

Also I was just thinking about this a vacuum is a extremely good insulator so I wouldn't be surprised if the internals really dont get that cold with only 100 hour in the freeze.

Chances are they do but I bet they dont get as cold as most people think they do.

Nick

Metals are excellent conductors of heat, though; even if only the pins were subjected to a liquid Nitrogen bath, I imagine that quite a bit of heat would be drained from the internal components. Think about it- subject one end of a length of wire to an open flame and it won't be long before the other end is untouchable. The other end will not be, however, as hot as the flame (as in your point, nhuwar), but it will be very hot; just as I imagine the internal components will get very cold.

Cooling processes like this are permored in other fields, too. I have heard some companies will perform this process on rifle barrels for the same reason; that it reduces this "stress" and "relaxes" the metal. Supposedly this makes a rifle barrel more "true" or "straight;" less "warpage" I suppose.

I am somewhat apathetic in my opinion of this process; the reasoning seems to be based in physics, but as aforemented I think the placebo effect has a large contribution to any perceived difference.

The core problem that I have with these "cryo tubes" is that I wonder not only how much of a difference in sound they make, but what the Cost/Benefit ratio is. These tubes are EXPENSIVE, and I wonder if one actually calclated the Cost of what it would be to install these tubes in one's system and then use that Cost to make other modifications to the system that would make a slightly more... dramatic difference.

I wouldn't even consider installing these tubes/having the procedure done unless I had explored EVERY other avenue of improving my system; So if you're that guy who has the perfect amp, perfect preamp, perfect speakers, and perfect room acoustics, but still feel like you haven't spent enough money yet; then, by all means! Go for it!

 

[SY]

My guess is that most of the cooling of the internals happens from radiation rather than conduction. I've got a neat little test jig set up to see if cryoing has the claimed effect; at some point, the queue will clear long anough for me to get to it.

This is one of those deals that makes absolutely no physical sense to me (for goodness sake, you HEAT the tube!), but given that several guys whom I respect claim that there's something there, I'm certainly willing to do some testing.

 

[Hartono]

I wonder how it affects transformers................

 

[planet10]

The irony is the KT90 has a poor reliabilty, but thats to do with the innards not the glass.

The 1st 2 versions certianly do. That is why Manley called in Bill to see if he could help sort things out for a 3rd version

dave

 

[mpeg2]

With a background in materials engineering, I find most of the explanations of cryo cooling tubes to be rather amusing. Steel is often pointed to as being affected by these cooling treatments - for good reason, the microstructures and phase diagrams for Steel alloys can be affected by very low temperatures (look up ductile-brittle transition for an example). Most of the materials in tubes - Cu, W and so on have very different crystal structures and very simple phase diagrams - nothing interesting happens at cold temperatures.

For these materials, the cold actually stops any changes from happening in the crystral structure (the kinetics are roughly exponential with temperature). Cu microstructures can change significantly, if heated high enough (grain growth for example) - when cooled, the structure is frozen in.

Be a little cautious when reading pseudo-scientific explanations from folks that have little background in the area they're marketing.

Rich

 

[Hartono]

more reason to cool transformers then ?

and speaker pole piece

 

[Cal Weldon]

Be a little cautious when reading pseudo-scientific explanations from folks that have little background in the area they're marketing.

This why I wonder about the cryo treating of wire. One of our members here will be treating some wire for a show on the island. I got the distinct impression their feeling was the treatment will be good for only as long as the wire stays in the box. If you pull it out to straighten it, you have lost any perceived value from that treatment.

Thoughts?

 

[astouffer]

After reading what people will spend their money on, I wonder as to why I'm not raking in cash selling audiophool stuff on ebay. Too honest I suppose

 

[mpeg2]

Cryo treating of wire? I assume you mean copper wire - I'd speculate that there'd be a negligible effect on the Cu from cooling - FCC metals (Face Centered Cubic) won't change at cold temperatures. Heating Cu up will have an effect (meaning heating significantly above room temperature) will tend to anneal out crystalline defects - although I'd assume that an annealing treatment was already part of the manufacturing process. Again, the annealing would have effects that could be seen in the microstructure - but nothing that you'd hear.

Don't know what'll happen to the insulation (depends upon the materials used there).

Rich

 

[Cal Weldon]

Cat 5e used for speaker wire.

Dave, you wanna pipe in here?

 

[Salas]

Re: Re: Cryo-cr-ap

Of course, that's part of the point. Anyway, a lot of people (inc me) knows that old tubes sounds much better than same new ones.
We have not yet sat. explanation of that, have u?

Secondly, I know russian company which made similar envestigations and they said that results was really great.

That's why I'm asking do anybody hear more about the topic.

Old tubes mainly were made with superior attention and cost in cathode chemistry, better general metal quality-purity, more time spent in good vacuum creation process practice. R&D of the time and quality competition led to formation of practices, and even secrets. Tubes were in the center of attention back then simply, now they are a niche revenue maker in the bigger scheme of things industrial.

As for treating in deep frost, I have experience with tools and cables. Cables lost sonic edge, and corrode much more slowly, when tools got harder and lasted longer. I have heard that competition engines benefit of cryo, losing friction and gaining power, as well as that everything going to space is cryoed.