diytube.com

I need about 400vdc and I have a power transformer that's 290-0-290, not quite enough voltage. PSUII says I need another 50 volts. I thought of a 50vdc power supply feeding the bigger transformer's center tap. Or a couple of 35 volt windings added to the transfomer. Which would be best?

- Take an inexpensive 48V Triad from Digikey or Mouser with about twice the current rating you'll need.

- Fullwave rectify it and toss a 1,000uF or so on it for filtration.

- Tie the negative to the chassis and the positive to the HV transformer CT.

- Enjoy the boost!

(caveat - if the HV transformer has a bias tap, it's rendered useless by this method)

Run 580V as a full wave bridge choke rectifier through PSUII. 522V is the theoretical max, but it's unloaded. You'll need a high-quality choke, and you'll have to tape the center-tap, however - if the voltage is close.

http://tubes.nekhbet.com/power.shtml#fulbc

Greg, I ordered a 0-24-29-34-55 @ 850ma transformer a couple of days ago, maybe that would do it.

kheper, I put the ps in PSUII and it came out with 469VDC @200ma, a bit too much for the tubes, they are rated at 375. Absolute max is 550.
I do have a 240-0-240 @ 200ma that comes out to 379VDC, but it doesn't have enough current left 188ma.

That's 469v unloaded, right? Which tubes are you using?