>Don't go destroying tubes for these unless you have
>verified their death on a calibrated tube tester of adequate quality [TV-7,
etc]
You don't need a tube tester to find an open circuit filament/heater, or shorts
present when cold. Blue glow in the space between electrodes is a pretty good
indicator of gas, too. I've never actually found enough requirement for a tube
tester to make its acqusition worthwhile. If I'm building something from scratch
and am doubtful about a tube, I'll make a jury rig on the bench and check
currents and transconductance. The amount of time that I have spent on that over
the years is so miniscule that investment in a tube tester isn't worthwhile.
If you're servicing some gear, replacement is a good start. I haven't yet met
anything that was critical as to the brand of tubes - unlike some sand stae
gear, where I've known of designs that would only work with one manufacturers
brand of op amp!
73
Peter G3RZP
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