Thread: Frankenvalve
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Gareth Magennis[_3_] Gareth Magennis[_3_] is offline
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Default Frankenvalve

Found 2 12AT7 valves inside a Fender (Evil) Twin today.

Both branded 12AT7, National, made in USA.

Except one is way bigger than the other one.

http://i67.tinypic.com/fc0ehi.jpg



The bigger one has a plate structure some 1.75 times taller than that of the
smaller one, yet both are apparently 12AT7.


On my valve tester, the larger valve traces showed approximately twice the
current of the smaller one.
The curves basically look like this is a double current 12AT7.



What is it?




Gareth.