> i'm building my first tube amp on 2m with a gs-35b grid grounded.
> yesterday i made a try with the full bias circuit but when the ht (3500)
> arrives the grid meter jump quite high then the fuse of the power supply
> blown. I replace the fuse with a smaller one, i removed the bias circuit
> and i have connected a 10K resistor between the cathode and the -HT.
> Same result. I do not understand why the tube is not blocked and why i
> have so many current on the grid.
> any idea ?
Something is allowing conduction between the anode and grid. Maybe gas
inside the tube, maybe cathode material on the grid, maybe a short.
Try following the instructions here: http://www.nd2x.net/tube-prep.html
to see if there is any improvement. You need to be able to apply a
variable voltage through a high value high voltage resistor for safe
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