Building 4 x reg's HT PSU's?

[IslandPink]

A bit late to this discussion now ...
A few points , though :
(i) I would avoid any supply ( shunt or series ) that uses SS devices for the return path .
(ii) Shunt sounds better than series-reg, across the frequency range .
(iii) If you go to the trouble of making a shunt-reg main supply ( valve/s as the shunt element, mind ) then the need to decouple driver stages with extra supplies becomes much less critical .
(iv) The T-Rex shunt supply showed me that you can get away with running a shunt that is quite a lot less ( mA ) than the standing current in the circuit . My 300B circuit takes at least 250mA , but the KT88 shunt runs at around 55mA .

[thomas]

A bit late to this discussion now ...

(ii) Shunt sounds better than series-reg, across the frequency range .....

Hi Mark

I was wondering about that T-rex stylee supply you built last year. I'm using series regs (valve) at the mo', my one effort at a shunt reg (simple el84s) being quite underwhelming and quickly ditched. Could you please confirm the schematic you have ended up with, was it this?

Lots of bells and whistles on it, I may have to wholescale crib the design if thats OK!?

Thanks
T

[IslandPink]

Yes Thomas that is the last version I have on LTSpice and looks correct . That will provide 450V if supplied from a single ( beefy ) secondary of 390V at >=500ma . The only very minor change on the hardware is a 220u Black Gate now on the cathode of the KT88, but that's not essential - 100u works fine.

I'll just post also ( below ) the version for 325V that I have used for 6B4G's - only three small changes to the parts, if I remember correctly . The transformer there is a 290V tapping on the same secondary .

[thomas]

Thanks Mark....

Another on my list of 'to do' projects....