My grandfathers home was in the 2nd world war located in the highest part of the village, so the Wehrmacht has choosen their house to setup the radio. In 1944 when the Russaian army was closingm they decided to flee, so left a complete AM radio there. My father was using the tubes as radio amateur (DX), but those times are over and now I have the tubes in my hand to build an SE amp.
Tried to check if Tube can operate in Triode mode (G2 on Anode, G3 on K or A). Well, yes an no. Issue is that G2 is extremely hot, having 20% of the Anode current, while the maximum rating of G2 is 200V. So putting it on anode is driving it crazy (can the tube do 70Watt or more with 600V on Anode and G2–> Yes… Do not try at home, guess it kills the tube) .
Max shirmgitterspannung ist 200V
Schirmgitterverlustleistung 5W
Kathodenstrom 150mA
Anodenverlustleistung 30W
Interesting pages:
https://m.cafe.daum.net/tubework/WD9c/26
https://www.bartola.co.uk/valves/tag/rl12p35/
http://www.tube-classics.de/TC/Klangfilm/Projects/RL12P35/Lorenz/Lorenz-RL12P35-amp.htm
https://www.diyaudio.com/community/threads/rl12p35-se-amp.364033/
I am still unsure if my aim is to build an triode SE amp with ~250V-350V anode, while trying to limit G2
or
Pentode operation with Anode to screen resistor as NFB. G2 = 240V, Anode = 350-450V, G1= -25 – -30V (need to set 85mA – 90ma Ia)
Feedback: plate to driver plate, 10%, simple cathode bias
Driver: C3M
Power Transformer nktes for me:
400 (A)–> 320V AC 0.5A, assume 50V DC drop while filtering…
240 (G2)–170V AC, (assume no drop…)
12V-15V (G3)–> 9.5-11.63V AC (assume 1V drop while filtering)
-28.1V (G1)–> ?….
12.6V 2-3A for heater (AC heater) 2x 6.3V?
Nfb
Philips AG9015 