[AMRadio] Tube ID

Jim Wilhite w5jo at brightok.net
Mon Feb 24 16:41:58 EST 2014

The question was what tube the one I had, and there was no trouble 
identifying it as a VR tube or how it operates, that is well understood. 
The question was, when in operation, it displayed a color I had never seen 
before.  The tube envelope did not have any markings as to the type, either 
US or European and the manufacturer's logs was so smeared as to be 

The tube was not as the manual for the equipment designated, an OB2 so I 
asked, based on color of the tube when operating, if anyone could recognize 
what type it was.  I have the answer and, given the stages it regulates, I 
am not changing it for an OB2.   I had never seen a miniature VR tube with 
the yellow/orange glow which turns out to be neon and regulates voltage to a 
lower value than the OB2.

Thanks to all who commented and provided links to similar examples.


-----Original Message----- 

I don't understand what could be  so mysterious or complicated about ID-ing
a VR tube. The miniature versions and octal versions all  have  the same
pin-out. Just plug the tube into a piece of equipment and measure the output
voltage with a voltmeter. Then  look in the tube charts to see which tube
type regulates to that voltage.

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