A little over a year ago, I posted a request for help (1) in designing
a circuit to get 300VDC out of a power supply that was pumping out
~520VDC. I got many helpful replies, but unfortunately, I was unable
to complete the circuit. I now have three transmitters (2,3,4) that
would like
a nice source of high voltage and I must now admit that I really do
need your help in completing this project.

I own a really nice, heavy transformer that I'd like to use-
unfortunately, the voltage is a bit too high- it puts out ~520VDC
(after a 3-pole filter 10uF/10H/10uF with 40kOhm bleeder
resistor). I am looking for some ways to bring this down to the
voltage I need.

Although I consider myself a competent builder, I am unfortunately not
much of a designer - this is what has prevented my progress for the
past year! I own the '05 ARRL handbook and Art of Electronics, but I'm
just not comfortable doing this myself. Specifically, telling me the
type of transistor/tube and not specifying the part number or an
article describing a similar HV regulator would leave me somewhat
stranded. I know I'm asking a lot here -- please understand that I
am immensely greatful for any of your help!

Here is my specification / wish-list, in decreasing order of
importance:
* produce ~370Vdc at 120 mA
* cost less than $50
* not require modification of the transformer
* also be able to produce ~240Vdc at 40 mA
* also be able to produce ~300Vdc at 70 mA
* be hollow-state
* be elegant

References
(1) One link to this thread is at
http://sci.tech-archive.net/Archive/.../msg01268.html
(2) The One-Tube Three-Band Novice Transmitter: see
http://www.bignick.net/Morgan_Radio/Radio_11.htm and download the
article on the mid-bottom right side of the page.
(3) The Novice Special transmitter: ARRL members only, download at
http://www.arrl.org/members-only/tis...df/71hb181.pdf
(4) The Simple Transmitter: ARRL members only, download at
http://www.arrl.org/members-only/tis...f/55ra019t.pdf