Guitar synth\F-CV converters

[NegatvNein at aol.com]

I am a guitarist and not a keyboardist and would prefer remaining a
guitarist,not that i have anything against keyboards, but i want to build a
guitar synth, i plan on using the GK-2a to control at least one vco per
string (none of those silly scanning circuits) but i dont want to use midi, i
want to build an analog interface from the gk to produce the cv for the
vco's,i was wondering if anyone has any expierience with this or could help
me with the frequency to cv conversion.
Thanks