Re: The "Sussex" Homebrew Valve Tester.
Hi folks !
My tube tester is finally up and running. For reminder it's a modded version, which is able to test power tubes as well. I also had to design an "AC to DC" circuit because I couldn't find the right panel meter for gm reading. This was maybe the toughest part as I wasn't too familiar with floating circuits but now it's working great with great precision (I checked the measurements with a scope across the 10R anode resistor to make sure I calibrated my circuit correctly)
That being said, I ran a lot of different tubes in the tester at "typical characteristic" from their datasheet, and I noticed that I keep having low results for the anode current at the specified bias, and also for gm (I generally increase the bias to reach the specified Ia).
As the tester is still in "test" I double check the voltages with my multimeter and they are correct.
So my question is : do tube makers have a tendancy to be over-optimistic about their tube specs ?
Thanx in advance for sharing your experience.
Best regards.
Eric
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