Hey
I would be interested in looking at that if you have it handy.

RonL


wrote in message
...
On Thu, 30 Nov 2006 18:24:05 -0600, wrote:

Hi group:

Has anyone in the group found a switcher good enough for high voltage (180
VDC), low current (.010 amps)
audio use. When I say good enough, I'm referring to noise and EMI. I've
been
looking at LT, National and power integrations
but haven't found anything yet. I also need 12V @1.0 amp for filaments.
Any ideas appreciated.

RonL


I once made a 2 transistor power oscillator, and wound the ferrite pot
transformer myself. The collectors of the transistors feed an 8 turn CT
winding,
there is another "tickler" winding of maybe 12 turns, that feeds the
bases...
and a few bias resistors, and that's it. The secondary is a few hundred
turns,
with a small cap across it ( .01 or something) it created a "sine wave"
output
due to the resonance of the output "tank", and was around 250 volts if I
remember correctly. The supply was 12vdc.

It ran at 65KHz, and produced about 12 watts, enough for a portable amp.
It
didn't create any noise at all due to the "soft" wave output. (And it was
in a
VERY high gain circuit, 5mv input)

There are DOZENS of variations around of this circuit. I can get you a
schemo if
it interests you.

I'm going by memory of this circuit since I built it around 1985... The
transistors were "junk" in TO3 cases. If you can build the tranny, you can
build
this circuit.