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Tube Life: 6SN7, 6DJ8, 12AT7 et al.

Does the rate of decline increase with age or is it linear?

Assuming a new tube had a reading of 107/107 which for the sake of this example would represent 107% of new stock specification and it was sold after considerable use with readings of 102/102. Can the purchaser assume that for all intents and purposes that the tube will last as long as a brand new tube that specs 2% over new spec?
anacrusis

Showing 1 response by elevick

elevick
2,638 posts
 
Most readings have nothing to do with a % over new. A new 12ax7 will read 90 on my SICO tester while a new EL34 will only ready 80. It's all relative. This 102 probably has nothing to do with 102% of life.

Most 12ax7's will last 5000 hours
6dj8's usually go 10,000 hours
12at7s fall in between
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