6922 Tubes!

lewm
5,221 posts
01-19-2017 10:30am
Geoff, Is your information about the putative benefits of refrigerator and home freezer temperatures based on real world direct experience or on what you have read elsewhere? Back when I did some reading on the physical effects of cryo treatment, it seems to me the papers I could access state that there is no effect unless you go "all the way". And I even think liquid nitrogen is not technically cold enough, but I may be wrong on that last bit.

I was one of the very first in the US to use Cryo for audio applications and one of first to use the trusty home freezer for audio applications. Gee, there’s no info on the Internet? Imagine that.  I suppose folks could use liquid hydrogen or vapor which would colder but as I just intimated what's the point? Besides IIRC hydrogen has its risks, whereas nitrogen is relatively safe. But don't try this at home, kids.

Liquid nitrogen is actually not much colder than nitrogen vapor. I also suspect Jena Labs uses the vapor for most of the Cryo process with a dip into the nitrogen liquid for a brief time at the very end. Otherwise thermal shock would be an issue. Furthermore the temperature difference between vapor and liquid within the dewar is only around 20 degrees F so there may be a bit of an exaggeration regarding the temperature advantage of direct submersion. Of course even lower temperatures could be achieved by pressurizing the dewar. In addition, the ramp down time, dwell and ramp up times are probably more significant than the temperatures in terms of effectiveness. Thermal shock would almost certainly occur if the tube or cable or whatever was immersed in liquid nitrogen right away without the slow ramp down and dwell times in vapor. Another indication that temperature per se is probably overrated is that very good results can be obtained with the home freezer, leaving the tubes or cables or whatever in the freezer for 48 hours. You can even ramp up in the main refrigerator section for 6 hours. I estimate that home freezing at -10 F can get within 80% of the results of real -300 F Cryo. Tell all your friends.