Here's an interesting circuit problem, make a precision 1.5kV 1500V/us ramp, good to 1%.
It features a HV MOSFET current source with a feedback circuit to maintain a constant output slew rate. Related to the thread, "op-amp-controlled MOSFET cucrrent-source", the circuit uses a BUF634 gate driver, but without any "R2 C2" loop feedback elements.
Neat footnote about the 5D21. As might be expected, the Japanese have beaten them into plowshares for the golden-ear crowd: (
-- john, KE5FX
At first glance its amazing they'd use a 20kV 15A tube for a hi-fi amp, but then the 15A part of the spec perhaps reveals the reason. I purchased some 5D21 on eBay, and was preparing to use them in the 10kV ramp, but then noticed the 26V 2A = 52 watts filament requirement, and shifted my thinking to a set of ten cascode HV MOSFETs. Haha, I noticed in the video they had a separate heater-supply box in the shelf below the two amplifiers.
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