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Tube test numbers - what exactly do they mean

I recently sent 2 pairs of 845 tubes to Tube Depot for testing, just to see if they were still good.  They sounded ok, but one pair was 10 years old and one about 4-5.   They both came back marked 70/200.  What does that mean exactly?  Another pair of 845s I had were marked 130 on the box.  I'm sure you guys must know. 
Thanks. 
chayro
amg56's avatar
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amg56
887 posts
 
Ring Tube Depot and ask them?
tomcy6's avatar
tomcy6
2,544 posts
 
Just about every tube tester uses a different scale. If you knew what tester they used someone might be able to tell you, but I think you’re going to have to call them to find out what tester they used, what is average new on that tester for your tube (maybe the 200) and what is minimum good (usually 65% of average new).
brf
1,715 posts
 
Call Tube Depot they are very accommodating and they are one of few Dealers who have a proper 845/211 tube test that applies over 1,000+ volts to the plates.
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