fiftywat--(at)--ahoo.com wrote:
> A respected amp tech friend of mine now tells me that these old stock
> tubes still have unstable elements inside that are not inert and that
> NOS tubes are not reliable and essentially deteriorate over time even
> if they have never been used. Comments anyone?

I think you answered your own question, your experience indicates
otherwise, and you done seen & heard it yourself.This equates
with my experience.

I believe your amp tech friend is referring to thorium when he
refers to "unstable elements". AFAIK, the types of tubes used in
guitar amplifiers do not contain thorium.

I've seen some really, really old (we're talking 30's & 40's stuff)
tubes with a little layer of white sheen on the getter.
This will only happen if there are gasses in the tube to react with the
getter, whether the gasses in question were from the inside of the
tube or migrated through the glass, I don't know.

--
Ned Carlson Triode Electronics "where da tubes are!"
2225 W Roscoe Chicago, IL, 60618 USA
ph 773-871-7459 fax 773-871-7938
12:30 to 8 PM CT, (1830-0200 UTC) 12:30-5 Sat, Closed Wed & Sun
http://www.triodeel.com

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