Retrotech(NVCF) - not long now

[ppppenguin]

Indeed delta Vg should be kept to a minimum. For the 300A the voltages I used are on a pretty linear part of the published curve. My main problem was that the Solartron SRS153 HT PSU doesn't have a fine output voltage control. Also it's only semi-stabilised. So keeping the anode voltage at 300V was rather touchy. I may modify it with a 10 turn pot or a coarse/fine arrangement. I have a fully stabilised SRS151 but it's a hefty beast that only comes out for special occasions.