0-350V 0.2A Bench Power Supply

[oldway]

My interest in talking about kikusui power supplies was to see which technology was used in a linear solid state commercial HV power supply.

This does not change my point of view that, for a hobby application and home-made power supply, the vacuum tube solution is the simplest and safest.

I'd choose a switched mode power supply myself. It's not that difficult nowadays, even for hobbyists, with the vast range of controllers and high performance MOSFETs available.
...

Yes I fully agree with this  , but did you looked at the crap schematic that 001 has posted.

Do you really believe he is able to developp and to build a switch mode power supply ? 

In first instance, we should try to answer to him with an answer he is able to use....

And who will developp this switch mode power supply for him ?
Have you time and money to do it ?
You will not only have to post the schematic but also to give him all the informations about how to build the ferrite transformer and inductors....

[oldway]

I'm asking for some schematics suggestions.
My minimum requirement are the following:
- 0-350 Vdc (higher can be better)
- 0-30 mA (my MAXIMUM needs)
- regulation: CV/CC
- low ripple
- good stability

At this date for my experiments I'm using a Tennelec TC-952 power supply (0-3000Vdc, 10mA, 2mV ripple typ.) but it has no current regulation.
I also own a Fluke 415B (0-3000Vdc, 30mA, even more precise and with lower ripple) but it also has no current regulation; BTW this one uses a valve/tube, just to satisfy people who love them! 

What I'm asking is for some good suggestions on a schematics which can satisfy my requirements: output voltage can even be higher than 350V but current limits will never be higher than 30mA.
Otherwise any hint on a not too expensive instrument (used or new) is welcome.

P.S.: as you can see, from the output voltage of my power supplies, I already have some experience working with high voltage... 

Hybrid linear power supply 0 - 450V 30 mA Max.

Schematic of isolated power stage.
Solid state control CC/CV through opto coupler

NB: pass tube: 40W power pentode LS50 / GU50 with 12.6V heating voltage + ceramic socket
https://tubes-store.com/product_info.php?products_id=183

ERRATA : T2 BF421 or BF423, not BC327

[eliocor]

Thanks for the hint:
may I ask the origin of the schematics?
Was it tested before? I ask this because is clearly incomplete.
Nothing to worry about: I can simulate it to see if it really works
Any suggestion for the pentode to be used? Regarding Valves/Tubes I'm really a noob!

P.S.: I only now note your references to LS50/GU50 and the filament voltage!!! Sorry!!!!

[oldway]

Origin: my project.
Not tested.
I don't need a HV power supply, I'm retired but I'm repairing a lot of vintage audio stuffs (tubes and transistors), I'm very busy and I have no time to developp such a project, nor time and money to build a prototype.
If I should make one, it would be a 0-450V at least 300 mA in two ranges.

Solid state control CC/CV is quite easy to design for who's have knowledge and experience in op amps.
It can be very stable as every solid state power supply.
Also low ripple.