[sdiy] Variable Voltage Regulator as replacement?

[Theo]

This trick is often used in high voltage supplies for tubes.
The thing is to keep the input ripple in the range the regulator can handle.
Also a 5V regulator would need a fairly low ripple to start with.

Theo

From: Seb Carr <star at all-carrs.demon.co.uk>

>
>
>
> >
> >     I have also used zener diodes in the ground leg.  Like if I need a
10 volt
> > regulator, you put a 5 volt zener in the ground leg of a 5 volt
regulator.
> >
> >
> >
> Up to what point does this work e.g. could i put a 43.0v zener in the
ground
> leg of a 5v regulator to get a 48v supply for phantom power, or is this
> taking things way too far?
>
> Thanks
>
> Seb Carr