Use the pictures as a guide. Let me know if you need to know specific details, other marks/screening etc. 

Tubes are tested on a B&K 707 mutual conductance tube checker. The tester was recently calibrated. As is probably obvious, I sell no tubes that fail the shorts or grid emission test (i.e., everything checks out as good for those tests).

These tubes tested as follows, where the first number is a scaled Gm and the parenthetical number is life rating; a Gm rating of approx. 66 or higher is considered "good" for side one (12AU7-type side) and 22 or higher for side two (12AX7-type side):

       side 1      2

1. 87 (86) / 61 (58)

The test ratings on this type of B&K tester may require a bit of explanation. Their "life test" is considered "good" if the meter rating is within 25% of the Gm rating. e.g., a tube with a mutual conductance (scaled) rating of 80 would still be passable if the life test registered a 60 on the meter. Most of their test settings correspond with a 0-120 scaled reading where the "good" area is about 66 and higher on the meter. Some types, in particular 12AX7/ECC83 tubes, display differently under test conditions, and are considered good at values different from the meter's bad/good scaling - e.g., a 22 and higher for either side of a 12AX7.

Remember, the best test for a tube is to simply employ it within a circuit!

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