Can you test triodes with laboratory power supplies? (rather than buying a designated tube tester?)

Another very basic question regarding the point by point method of getting voltage/current curves: How long do I leave the tube to sit and equilibrate at each point? The plate current of some of the weaker tubes tends to drift downwards when the triode is at the higher end of its current carrying capacity. I think that it is related to plate temperature. Hotter plate results in a higher voltage reading for a given current. So the results of the test are influenced by how quickly I stay at each point. Which I feel is not a true representation of the tubes behavior.
 
Tube manufacturers used pulse testing methods even very early in the history of tube production, so I'm guessing that you don't want to wait around before logging a measurement. Tubes and transistors are imprecise devices in any case. A big part of most analog circuit designer's jobs is working around those challenges to get accurate and repeatable results. All bets are off when it comes to audio design, however. If you like the sonic coloration of a particular tube, then you may find yourself compelled to tolerate its other idiosyncrasies as well.
 
Hmm, ok I see what you mean. That seems to make sense with how I imagine curve tracers operate. I presume that to clearly trace multiple curves on a phosphorous oscilloscope screen a designated curve tracer must very rapidly sweep the plate voltage and switch the grid voltage to the next setting to repeat.
So that at least does not confirm that this tube is ready for the junk heap. It just means that its a bit unstable. (I have not built a tube amp yet so I still have much to learn about how stability of a tube affects its operation.)
 
Another general tube question: Are scratches in the glass envelope a serious concern for breakage? Has anyone ever experienced a scratched tube breaking as it heated up? Some of my old balloon tubes have mild to deep scratches from wear and tear over the years. They could be polished out if there is sufficient worry that they would break.
 
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