High Voltage Regulator Question

[JM1366]

I'm in the process of building a 6L6 power amplifier (push pull), and I would like to regulate the screen grids. Attached is an idea I had, but I'm not sure if it's a good idea.

I could also swap the 7805 for a MOSFET like an IRF640, if that would be better suited to the task. I calculated that my absolute maximum current draw will be about 75 mA under full load, maybe 100 mA if I run the preamp and phase splitter tubes off it as well.

Thanks for the suggestions.

John

 

[PRR]

Review the minimum current of your gas-tube. Compare to the current of 5V over 16K. I believe the glow will just quit, or be super erratic.

And isn't 0.047u a bit large to put right across a gas-tube?

_IF_ you can find good neon lamps, 1mA in those will provide all the current a MOSFET gate needs.

A MOSFET _is_ the usual approach. (Back in 1978 I had to use a TV sweep transistor.)

Read up on gate resistor and diode or it will go "poof".

 

[jan.didden]

Agree. The min current for the OD3 is about 5mA. That will need to be sourced through the 16k giving rise to 80V at the input of the regulator, which will promptly release all it's black smoke ;-)

Jan

 

[JM1366]

Alright, I revised my schematic. I do see the issue, it looks like I miscalculated the 16K resistor. Should be more like 1.3K. Is this more in line with what was being suggested?