[sdiy] Formant and ASM-1

[mikko.a.helin at nokia.com]

> For all you budding tube mongers, Mouser has a itty
> bitty transformer that has dual 115VCT 25mA
> secondaries. So it could do 100V, 200V, or a doubler
> gets you even higher. 25mA is not much, but for small
> circuits, its plenty. For example, it can power my mic
> preamp which sports a 12AX7, 12AU7, and 12BH7. Of
> course there are plenty of transformers for heaters,
> including switchers.
> 

Maybe you could use two 115/230AC : 12V (or 6.3V) transformes in series and take the heater supply from the 12V. So the voltages would go like this: 230VAC : 12VAC : 230VAC -> rectifier -> cap -> +B1 -> resistor -> cap -> +B2 etc.
-Mikko