[Amps] GS35 QUESTION

[ON4IQ]

I have a 2m amp running a gs35 tube and a G3SEK triode board in it.
While runnning the anode at 3.2kv , i get good bias control and all is well.

Raising the voltage to 4.2kv off load gives met correct Ia when in ptt, but once
the tube goes in cut off , the Ia drops to zero ( thats good) but grid current goes
completely negative. After changing tubes with brand new one still have the same problem.


I suspect there is something wrong in circuits or  power supply.
I've checked power supply and find no leakage to ground.

Would you have any idea where this negative grid current comes from when tube is in cuttoff.

Its abt 50ma.

Best regards


Johan