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Old 16th Jan 2020, 12:08 pm   #13
David Simpson
Join Date: Mar 2008
Location: Aberdeen, UK.
Posts: 2,079
Default Re: Valve testing a 4212

Aye Tinker, you'll be needing hefty Va & Vg supplies plus being able to measure in the region of 160mA Ia. Way beyond the VCM's & Valve Testers we all know. Plus you'll need to make a bespoke valve holder with sturdy valve pin connections. Don't be tempted to use cheapo crock-clip leads.
Jesus, was it all that long ago - 7th Oct.2015 was my "Testing the STC 4212D Triode" Thread.
My 4212D drew 6.3A at 14V Vh. And with 500V Va drew 160mA at -5Vg, but I started out gently at -50Vg. If you look at the STC family of Gm curves, you'll see that these fearsome valves were happy working in the 1KV Va region. Running Vh at 12V off a battery might do just to see the thing glow, but 14V would be needed to get comparisons with STC's data.
Caution - if your valve is a decent NOS one, it could be worth a few hundred quid, so don't phook it.

Regards, David
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