Problem with tube regulator

[denny9167]

I would lower R14 to possibly 330K maybe even 220K, but connect EF80 in pentode mode, this will lower the output impedance of the supply also.

 

[denny9167]

What's U7 for?

U7 is the pass tube, it handles most of the work load.

 

[denny9167]

This thread makes me want to learn about regulators... Say I have 350VDC and I want 300VDC regulated and I have a 6N2P for the error voltage, a VR tube for the reference, and a 6080 for the pass device. How would that look schematic wise?

Or say I want a regulated 300VDC power supply for up to 1A of current. What then? Several 6080's in parallel would work but would be such a waste IMHO. A MOSFET would be better in this case? Could I use an NE-2 at the VR reference?

Explain it like I'm 5 years old if you care to.

I don’t think you will have enough voltage swing to drive the 6080 grid without configuring it in a cascode, the cathode coupled design wouldn’t have enough gain.

 

[denny9167]

I took your basic setup and did some prototyping, except I’m using a 6080 pass a EF86 For control tube and a 12AT7 for the error amp. Works nicely so far, very similar to my spice simulation. My voltage reference and voltage divider are a little different.