Maestro Phase Shifter PS-1 clone project - need some guidance

[Leftwing73]

Hey everyone,

I've been working on a project for a customer who wants a PS-1 clone. I have an original as a tone sample and the schemtic looks pretty straightforward, however I have a few things that hopefully yuou guys can offer some advice or direction.

Here's the schematic:

http://files.effectsdatabase.com/docs/schematics/oberheim_ps-1.pdf

The big questions are: 1) how to power this thing, 2) can I modify it to control the ramping speed?

1) The power. It needs 15v and I don't want to put 2 9v batteries in it. Do you guys recommend a charge pump or to find an external 15v wall-wart? Does it have to be 15V or can I go higher, assuming the components are rated for the voltage.

2) looking at the schem, I'm trying to figure out what component controls the ramping speed. I think it's the 220uf cap across the emitter of the transistor before the speed switches. Anybody have any ideas on this? I'd like to add a fast/slow ramp switch if possible.

ANy ideas/direction would be greatly appreciated. Thanks!