Thanks for advice!
I did some calculation and attempts in order to understand better the trouble...
-initial circuit run at 55v between gnd and cathode, with 220ohm cathode resistor are 250ma current, 3 times and something over normal operation. Not good, this working point destroyed first resistor
- I added a 2,7k resistor from power supply to g2 of el34, a little better situation, but Always too much current. 37.5v gnd-K, 170ma anode current. (normal working point "should" be 300v, 83ma with -15v Vg)
Components are new and show correct measure with multimeter.
There remains only the anode choke, maybe the tube doesn't appreciate so much. Maybe turns of copper are not enough, and inductance need to be really higher, like in commercial product.
I got 2 way, for what I see:
- recalculate a coil with 100H of primary inductance. Lot of copper, this time I use lathe
- Try a high power alu resistor as you said, maybe 50w or more, and throw to the air some 25w. This way allows me to raise B+ for this circuit to 500v.
...everyday a new problem