MFOS Signal to Gate Generator

[Satyricon]

This is going to sound like the biggest newb question ever, but how would I go about constructing the proper +/-12V power supply for this? It's biased so that ground is effectively 12V, is that right?

Here's the link to the scheme:
http://www.musicfromouterspace.com/index.php?MAINTAB=SYNTHDIY&VPW=1356&VPH=537

Any help would be amazing. I've been looking for a way to trigger the envelopes on my kraftzwerg with external audio for a while and this would be just the ticket.

[Satyricon]

Either that, or can anyone suggest a simple alternative way of doing the same thing that doesn't need a specific bi-polar power supply? I had an idea of using a simple amp (like an LM386 with a bit of gain) to beef up a signal to trigger a comparator in some way, but I don't know how to implement this idea. Any help would, again, be amazing.

[expanoncolin]

If you want to use the original MFOS design, you can very easily build or buy a bipolar 12V supply.  I'm confused by what you mean by "It's biased so that ground is effectively 12V, is that right?".  Here's a kit: http://www.paia.com/proddetail.asp?prod=9770R-12 There are hundreds of suitable schematics, kits, and ready-made supplies.

If you want to try to use this schematic with a non-bipolar (+V only) supply, you'd need to make some modifications.  You'd need to wire up a reference voltage at 1/2 of the supply voltage and use that as ground, and use ground as -V and +V as +V.  You also would probably need to add decoupling capacitors depending on what you are feeding into the circuit.  I don't know of any other saw to tri converters off the top of my head.

-Colin