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Life Test - How Important?

Been testing some 27's for use in the SE 27 - 6A5G amp I've posted about on the DIY board. I have a couple of ST mesh plates that test new or near new, depending on the tester. Results on my Eico 666 were 111 and 110. The Hickok 600A has them at 1050 and 940 (1000 is new). No shorts or inter-element leakage. But they both fail the life test on the Hickok.

I'm never surprised if a weak tube fails the life test but it seems odd that a tube that tests so strong would fail the life test. Anyone have any insights?

I've used these before in a previous version of the amp. That was before I had the Hickok. They sounded great so I'm not concerned about using them again now.

I guess I'm wondering what to expect. Does anyone have any experience with how long a tube that fails the life test will actually last? Is the transconductance likely to drop quickly? How important and/or accurate is the test?


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Topic - Life Test - How Important? - FlaCharlie 09:59:27 09/17/16 (2)

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