AW: [sdiy] getting +/- 12V from a 9V source

[Nils Pipenbrinck]

Paul wrote:

> !!!!I can assure you that by the time you futz around with ".. a
> wien-bridge sine oscillator, a fat tranny as a driver and the
> output through two little transformers. Then add a rectifier,
> some caps and> a 7912/7812 pair." you will be wishing you had
> just got an  AC plugpack & done the usual!
> Quite apart from the expense, and sourcing the components, your
> upconverter will likey leak interference into everything & make
> the whole project pointless, especially for a preamp.
> Don't bother using those single chip voltage doubler/inverter
> things either. Really!

That's the reason why I asked. I had the same thought about that, but I
wasn't sure. (besides - have you actually tried to use the voltage doublers
for audio? They will output a noisy voltage, that's for sure, but you could
always clean up the signal with some caps and resistors ).

I think Philip's idea of just powering the opamps with +/- 4.5V is not that
bad. I have to check, but I think my  TL072 will be happy with that voltage.
After all it's just a RIAA preamp which I want to power, so it should work
without changing any values. All resistors are part of the filter circuit
and not related to the supply at all. 4.5V are plenty of headroom for a line
signal.

I just give it a try.

Thanks,
	Nils