Unfortunately there is no correlation between what an emissions type tester shows and actual current flow performance to the tube's datasheet. It was up to the discretion of the tube checker's engineers. Even high end transconductance testers vary by quite a percentage.
You would have to establish a baseline of your own to a good new tube of the same type.
cheers
Rob
You would have to establish a baseline of your own to a good new tube of the same type.
cheers
Rob
It's a realative scale but gives general condition. If you look at the setup book you'll see that many tubes use the same control setup. But many of those tubes have slightly different performance characteristics and will give different meter output levels even if all are NOS, new or perfect... So you have to get to know how a good tube of any certain type tends to perform on the scale. Rectifiers, 5U4, 5T4, 5R4 all use the same settings but have different performance and will read differently on the meter. The book gives no "specs" to compare to.
Emission testers can provide only a very general guide to tube condition, and may indicate a tube is still good when it will not perform its intended function in a properly designed circuit, and conversely the reverse as well.
A much better figure of merit is the tube's transconductance which can be measured and compared to a range of values determined by the tester manufacturer to confirm whether a tube is good or bad.
In some instances testing the tube in an actual application circuit is the only way to know if a tube is good or not.
Leakage tests and tests for shorts are useful extras that hopefully this tester supports.
A much better figure of merit is the tube's transconductance which can be measured and compared to a range of values determined by the tester manufacturer to confirm whether a tube is good or bad.
In some instances testing the tube in an actual application circuit is the only way to know if a tube is good or not.
Leakage tests and tests for shorts are useful extras that hopefully this tester supports.
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