29-11-2016, 03:48 PM
I have now tested a number of valves, with realistic results. I have seven or eight HL2 triodes, the various conditions which have been known to me for some time because of their individual performance. The test results match my observations. I note that when testing pentodes, they don't bother with the supressor grid at all - there is no connection for it. I did try linking it to the cathode, but that just sent the test readings way out, so I suppose G3 can just be ignored when testing! I found that my dirtiest, disreputable looking EF39, testing up round 90% with correct gm, where several nice clean red ones showed 50% or less! I am very pleased with this ancient 79-year-old device now that it is working properly! It probably was from the start, but I didn't know how to use it! 
Bob
Bob
