Questions about Tube Testers
We have done so much, for so long, with so little, we are now qualified to do anything with nothing.
This answer, we sometimes hear from very old companies, not for the first time.
In this context, please let me tell you, how we lost our Italian distributer, in the days when we were the exclusive distributer for AVVT electron tubes. This was in the year 1999.
We sold quite many 2A3-Mesh tubes to them, and they always re-tested the tubes, before sending them out. Which is a good thing of course.
Then, one day we had a complaint about a pair of 2A3-Mesh, of which one tube of the pair, right out of the factory box, burned out the heater wires, directly after switching them on. After a long time talking with him, I found the reason. The distributer tested them by mistake on 5V heater voltage, instead of 2.5V. He became very silent, and this seemed to have clarified the problem.
After a few days, he came back to me. The distributer took the position, the broken tube was less quality than the other one, otherwise it would not have gone broken. I objected, saying the "good" one is now also damaged, even though it appears to work fine on 5V. Since heater voltage tolerance is 5% only.
So I realized, he pre-damaged every tube he send out. Ever since! Instead of saying sorry, he said something else. He said: Either replace that bad pair, or we go to your competition. So we advised him to become part of our competitor's tube test team. Which is what he did indeed.