Polarity inverter

[Madkatb]

I've been searching for a way to run a negative DC power supply for a PNP fuzz pedal that "plays well with others". I've seen the AMZ page about running the V+ to the ground side of the circuit and searched through previous posts on this site. I'd prefer to not have to use a battery. Has anyone tried this:
http://www.reconnsworld.com/power/voltinvert.gif
or does anyone have any opinions on it or whether it would work for this application? It means that a regular 9V negative ground power supply could be used.
It also makes it easier to use an negative ground relay driver circuit for switching.

[R.G.]

Read geofex.com.

In this case: http://geofex.com/circuits/+9_to_-9.htm, which shows how to make -9V from +9V with an IC intended specifically to do just that. Note that the MAX1044 was an early one. It works, but the LT1054 is pin compatible, more capable, and more rugged.

[Madkatb]

Thanks RG. Thought I'd read everything at geofex but missed that one.

[R.G.]

The 555 inverter works, it's just a PITA if you don't need the other stuff a 555 does.

Having lived through the "do everything with a 555" era, I have an aversion to casting everything in a 555. Reacting against my upbringing sor' u'fing. But I recently ran into a situation where a 555 was a better answer than most other things. I had to make 600V at a few microamps, regulated and adjustable, and the 555 was just the ticket.

[Madkatb]

Maybe a silly question but do both the +9V and the-9V share the common ground?

[R.G.]

Yes. The intent was for that circuit to power opamps needing bipolar (+9 and -9 at the same time) power supplies. Same ground, both supplies.

You have to be careful with wiring to be sure none of the power converter ground pulses flow in the ground wire to the circuit it powers, otherwise you get whine. But this is common to all switching converters.