I've had a little pcb in my draw for a while and powered it up to check working voltages. The board AFAIK, is a little flashing light type thing to music using a indicator valve as the display. I put 12v DC in and was very surprised to measure around 270v on some pins of the valve holder.
I was looking for a simple way to power a guitar pedal that uses an ECC82. This after building the "Valvecaster", see attached, a while back and also looking at this similar project -
http://www.dogstar.dantimax.dk/tubestuf/mctube.htm This sort of HV efficient lightweight PSU if able to provide a clean power source would be ideal for low powered valve projects.
As far as I can see it uses a MC34063A regulator IC to get the needed HT, but looking at the datasheet I can't see any OP voltage mentioned or for the life me figure out how with a few external components it "generates" this higher voltage.
Looking at the board all there is in way of PSU components is a few caps (timing etc) an inductor and an IRF740 mosfet. I presume the oscillator in the chip switches the fet to produce HV AC, which is then rectified.
Any light shined on the subject would be appreciated. Andy.