GeoFX Crybaby Buffer Mod

[OnFire5210]

Hey guys,

I'm getting ready to tackle V2 of my GCB-95 mod. It switches between 3 different Q, Mid, and Sweep value combinations. I want to add a buffer like the one on GeoFx, but the photos he's got on the site are different from my more current circuit board and I think his instructions conveniently leave out the name/function of one resistor.

Here's his pic. What is the equivalent of the top most resistor in a Rev H GCB-95 board? It looks like the one in the pic is 83k, but I'm not seeing an 83k resistor in my GCB-95 schematics.



Other than that it's just the input resistor and the same +9v and ground I'm using for the LED. (right? lol)

Thanks!

[R.G.]

A picture of your circuit board would be most helpful here.

[OnFire5210]

Here you go! This was stock, of course.

[R.G.]

With three transistors on it, it may already be buffered. You might want to research the schematic to see if that model is already on the net, or make a similarly sized picture of the back of the board for tracing to find out what is already there.

[joegagan]

that bigger board is the post 1990 style dunlop wah , buffered. below is the schematic



the 82k resistor replaced the old 100k to ground off inductor, presumed by me to be to dampen the Q a little since the buffer probably made the wah a bit ' spikey'

[joegagan]

woah, that was big.
here it is a little smaller:

[OnFire5210]

Got it, so the Geofx Buffer mod I posted is redundant with my wah circuit then? It's already got an input buffer?

[joegagan]

correct. no need for 2 buffers.