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Cryo'd Tubes Measured!

172.136.46.9
Posted on November 25, 2002 at 11:21:51
NEAR SOTA
Manufacturer

Posts: 2613
Location: MAINE USA
Joined: July 27, 2002
 I know of a local guy who does the cryo thing. His name is Bill Perkins and he's the man behind Pearl Tubes, a company which specializes in rebranding tubes after freezing them, amongst other things. Bill has lots of test equipment including devices which measure tube microphony. I've seen this equipment when I had him test some tubes for me. I do not want to misquote Bill, but he basically stated that if you take a tube, measure the microphony, then freeze it, and measure it again, there is a sig difference.

http://db.audioasylum.com/cgi/m.pl?forum=tweaks&n=14981&highlight=Cryo&r=&session=

Intresting read,but it did not state weather these measurements were for positive improvements

 

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Re: Cryo'd Tubes Measured!--Added comment, posted on November 25, 2002 at 11:26:28
NEAR SOTA
Manufacturer

Posts: 2613
Location: MAINE USA
Joined: July 27, 2002
 I've read about the seemingly dramatic improvements in certain instruments, tools, etc., from cryo treatment, but I'm not so sure freezing tubes is a good idea. The coefficients of contraction/expansion between glass and the tube's metal pins is different. On one hand, if the metal contracts slower than the glass you may microfractures at the metal/glass juncture causing air to be sucked into the tube's vacuum resulting in oxidation of the filament, etc. = tube failure. If the metal contracts faster than the glass, then the junction will again break resulting in air being sucked into the vacuum.

While there may be a sonic improvement, tube life will suffer.

Mike Masztal
Soundstage!

I would have thought something that was a danger in doing this,but we are talking about mechanical devices(or constructed components) and not conductors in raw form.Maybe if the components were Cryo's before assembly it would give a longer tube life.

http://db.audioasylum.com/cgi/m.pl?forum=tweaks&n=10418&highlight=Cryo&r=&session=

 

Re: Cryo'd Tubes, posted on November 26, 2002 at 10:58:58
John Escallier
Audiophile

Posts: 4425
Location: Long Island
Joined: October 3, 2002
 With transistors and hybrids, at least in the old days, kovar was used for the pins. Kovar is a metal that matches closely the glass seal expansion rate, but unfortunately, is magnetic and not high in conductivity.

I would think tubes would use something at least close to the glass TCE, but don't know.

I'd worry about cooling the envelope too fast, and cracking the glass that way.

TTFN, John

 

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