"Cryovalve" Tubes

[postjack]

What is the story on the "cryovalve" process?

Quote from Tube Depot CryoValve Story:

An Overview of the "CryoValve" Treatment and Grading Procedures

The series of operations through which an electron tube must pass before it can be called a Pearl CryoValve is lengthy and in some ways, arduous. As received, a typical electron tube exhibits several problems that deleteriously impact its sonic performance. Most serious are the many internal stresses in the construction materials that accumulate during most of the stages of manufacture and a very hard, heavy oxide-coating on through-glass pins to which direct connection is made. Seven-pin & nine-pin miniature tubes are typical of those whose pins are heavily oxidized while power tubes such as KT88 and EL34 are fitted with bases whose pins are tinned. Where required, through-glass pins are cleaned back to base metal and polished, with the result that contact quality is much improved. The degree of sonic improvement is substantial.

The initial 100hr. burn-in allows the tubes' characteristics to stabilize while providing an opportunity to cull any "infant mortals."

During cryogenic tempering, the tube is slowly cooled to the -196

[NotoriousBIG_PJ]

I couldn't tell you if cryo makes a difference in the sound of tubes or not. The valve art el34b's I bought were cryoed (they were the same price as the non-cryo so I thought why not) and certainly sounded better then the valve art el34b's I had before them, but the non-cryo el34b's I had were crooked and some were microphonic.

Biggie.

[kevin gilmore]

Open offer still stands. You send me a dozen of the same tubes. You label them in any way you want

that will not rub off. I will randomly cryo half of them. I'll send them all back. You try and tell the difference.

Your choice of 2 days at liquid nitrogen temperatures, (77 degrees kelvin) or if you really want,

2 days at liquid helium temperatures (4 degrees kelvin)

No charge for the cryogens or use of the dewars.

Students at northwestern university can verify that i actually did this.

So far no one wants to take me up on the challenge...

[Nanoha]

Haha, interesting. It's quite easy to get access to liquid nitrogen in university labs. Heck, it'll most definitely be easier for me to get access to a chamber for cryo than get access to a lathe. Maybe I should go cryo some random tubes.