[Amps] Screen supply for pentode

[Traian]

Hello Oleg,

Even if exist, the negative screen current may be low enough to permit
the use of a (higher value) bleeder resistor at the series regulator
output.

But, before building a such project, I allways think for what may be the
worst...
When failing, the semiconductors are usually becoming shortcircuited.
This is a good enough reason for me to decide using parallel regulator
for the screen and series one for the grid because in the case of
regulator power device failure the tube will be cut off.

GL,
73,
Traian



Oleg Skydan wrote:

> Hi, All !
>
> I am going to build an amplifier using GU-46 tube. It is glass
> pentode. You know in the tetrodes we need to use a shunt
> regulator to cure the negative screen current problem.
> But is it safe to use a series type regulator for pentodes ?
> I.e. can the screen current be negative (at first sight it can't)?
>
> All the best,
> Oleg
> 73 de UR3IQO
>
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