You will most likely not be able to consistently tell a used tube from new with a simple emissions tube tester. Shorts yes and that is about it. If you buy a tube tester buy a true transconductance tester. Many Dynamic Mutual Conductance testers only test for transconductance on some tubes (B7K 707 for example).
It is also true that suitcase testers do not test most power tubes are real world levels and as such they do give these tubes a true test. I have found that gm testers like Hickok and Triplett do a fine job on everything but power tubes.
It is also true that suitcase testers do not test most power tubes are real world levels and as such they do give these tubes a true test. I have found that gm testers like Hickok and Triplett do a fine job on everything but power tubes.