"Thermionic"-DIY tubetester

Well, maybe not DIY, the pcb is from Rimlok's great eBay shop "AUDIO RADIO ELECTRO STORE"
(Highly recommended, full of unobtainium stuff). Anode voltages from +2V to +400V and currents up to 340 milliamps.
You might think "no way with that tiny transformer", but hey, this is one clever toy.Anodes are fed with highvoltage SMPS
and pulse mode measuring (done twice a second with 0.8 millisecond bursts) keeps power demand low (250mA@6.3Vac).
Pulse mode testing also ensures you can beat the crap out of the tube under test without hurting it, neat!

With some basic math it's easy to get emission, transconductance, plate resistance and mu and check if tube is shorted.










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