That's cool. I'll probably do a version with power supply sans silicon and increase the cap size 2X. I'll also use a fixed resistor instead of the MOSFET. I'm thinking about doing a building block approach where I can jumper in a CCS in place of the fixed resistor. That way I can hear the differences in different configurations, resistor, choke and various forms of active constant current sources. 'Spose the power supply could be modular too, just put a decoupling cap directly across the B+ side of the tube's plate load and ground.

Wayne