Bias Curves

[oliverwestby]

I am designing a fixed bias, EL34 Push-Pull amp which will have an HT of 350VDC

for sake of argument, I'll pick 325VDC for the screen grids.

Can anyone tell me what the formula is to work out the Bias Voltage (Vg1) for different anode and screen grid voltages.

Similar to the first 3 graphs in this datasheet,

http://www.drtube.com/datasheets/el34-philips1969.pdf

Thanks,

Oliver

 

[Arnulf]

There is no formula, the curves are obtained empirically. EL34 is extremely well docummented so you should have no problems finding multiple datasheet for it.