Are cryo'd tubes always better?

At the risk of pissing off half of the people who read this thread, here is my two cents worth:

As one with an extensive educational background in molecular crystallography and metallurgy, I have to say that IMO almost all of the claims and "scientific" explanations made by the cryo vendors are pure BS. Exposure to extremely low temperatures will almost always cause a weakening of the structural integrity for most metals and alloys. One of the guys I went to school with worked for NASA and NAA on the Space Shuttle project, and later on the initial planning for the ISS. Anyone who believes that cryo is universally good for any commercial metal structure should read some of the white papers and technical information that is available to the public.

But for those who insist that science has no relevance for audio and that it is all about the sound, for myself I cannot hear any difference between similar tubes, cryo treated and untreated (beyond the variation one would expect between any similar tubes). But if it's good for you, then it's good.

Geoffkait,

>>The improvement to the material is due to the atomic structure becoming more homogeneous, especially for metals that have pressed, bent, drawn or hammered. Thus, cryo 'd tools last longer, cryo'd golf clubs hit the ball farther, cryo'd brass musical instruments ring less and sound better, cryo'd Ferarri piston rods last longer, and the valves on cryo'd trumpets move more smoothly. Put succinctly, cryoing is cold tempering.

1- Cryogenic treating CAN is an important technique in modern metallurgy, IF the alloy and manufacturing methods are specifically designed to utilize these processes. Taking any old tube w/ steel pins and composite grids (for example) risks introducing molecular-level stress fractures and discontinuities to the matrix.

2- Using the examples that you mentioned above, Cryogenic treating methods are an integral part of the initial manufacturing process. These parts were specifically designed for such treatment, and would not perform to spec if the cryo steps were eliminated.

3- As an extreme oversimplification, cryogenic treating can result in physical properties such as improved tensile strength and improved grain edge boundaries that facilitate tighter machining tolerances. But show me one study that demonstrates how cryo-treating improves conductivity or electron flow in off-the-shelf steel parts. It doesn't.

I believe that both Siemens and Telefunken tested cold treating steel parts as part of their manufacturing process for special tubes in the early 1980s. The results were less than spectacular. To be fair, this was with much earlier technology and possibly under less than perfect conditions, but the reported problems (including spalling on carbon filaments and dislocation [flaking] of certain REE coatings on tungsten components) remain problematic to this day.

But again, if it works for you then it works (for you)

>>At least you seem to be coming around a little bit by acknowledging that metals are not made more brittle by the cryo process as you earlier opined.

You only cited a small part of my response. You be an operative for one of the major political parties.

As a matter of fact I have purchased cryo'd tubes and cables. Other than the KT88s that died a premature death I could tell no difference, either by ear or by measurement.