Built this, this evening...
Main switch is a 2N4401. Draws about a watt at 15V, making 60-120V at up to ~1.5mA, with pitiful efficiency (but it's only a watt, so who cares). Regulation is extremely good, thanks to the TL431's high gain.
I built it for avalanche pulse generator experiments, but I'm posting it here as it would be excellent for a small tube preamplifier for battery, automotive or "wall-wart" operation.
Tim
Main switch is a 2N4401. Draws about a watt at 15V, making 60-120V at up to ~1.5mA, with pitiful efficiency (but it's only a watt, so who cares). Regulation is extremely good, thanks to the TL431's high gain.
I built it for avalanche pulse generator experiments, but I'm posting it here as it would be excellent for a small tube preamplifier for battery, automotive or "wall-wart" operation.
Tim
Not really necessary for such a circuit, but it goes with said pulse generator's styling (where the RF performance *is* needed!).
I often use 2-transistor converters, same sex or complementary to create supplies from a single cell or to light an LED.
The same principle can be used for higher voltages, see extrapolation.
The efficiency is ~ 80%, not very good by today's standards but not catastrophic either.
PS
This type of converter can also be used for applications like this one: http://www.diyaudio.com/forums/power-supplies/159705-when-you-need-15vdc-have-only-one-pole.html at power levels up to ~500mW (higher with Zetex superbeta transistors)
The same principle can be used for higher voltages, see extrapolation.
The efficiency is ~ 80%, not very good by today's standards but not catastrophic either.
PS
This type of converter can also be used for applications like this one: http://www.diyaudio.com/forums/power-supplies/159705-when-you-need-15vdc-have-only-one-pole.html at power levels up to ~500mW (higher with Zetex superbeta transistors)
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