Quote:
Originally Posted by methusela
|
I had a look at this, he makes a big deal about voltage sag when the valve goes under test in Hickok testers.
But in the TV-10 at least, the line voltage master calibration control & metering is derived from the transformer secondary, so for heavy heater current valves its easily tweaked back to standard after the heater has warmed up and all voltages derived are from the one transformer and effectively re-calibrated. It is not a problem in the TV-10 tester, but he mentions all sorts of other Hickok units that I am not familiar with, so I can't really comment if they have a problem in that area, or not.
I think we both agree that valve testing has a limited but not zero utility value. Any test data obtained should be interpreted with caution.
I think the test is off to a better start if it can provide the user with direct transconductance data, to compare with the manufacturer's suggestions of what is an expect normal range (on that tester) for that part.
After that though, beauty is in the eye of the beholder and the data can be interpreted in a number of ways.