GCB95 Crybaby "Fatwah" mod problem

[Seven64]

i just put in the fatwah mod with bypass switch into my gcb95 as shown here:



i am not sure if it is working correctly or not,  when the switch is on, it sounds GREAT.  when the switch is off, my pedal becomes a volume pedal.......

[azrael]

Sounds like you're somehow lifting the 4.7uF cap from ground.

[Seven64]

how?

[slacker]

I think that diagram is wrong, compare it to this one, the switch is in the wrong place. How you've got it now, the 100k resistor is basically disconnecting the 4u7 cap from ground, so you get the volume pedal effect.



If you used a DPDT On-Off-On switch you could have Fat-Wah, Volume pedal, normal Wah

[Seven64]

that diagram looks like the switch is after the 100k resistor, which would still be disconnecting the 4.7uF cap from ground.  it just looks like the switch is in between the 100k and 10uf

[slacker]

On the second diagram when the switch is open you get the fatwah setting, exactly the same as when the switch is closed on the first one.
When the switch is closed it connects the point where the 4.7uF, 10uF and 100k meet to ground, so you get the standard wah.

[Seven64]

so should i run one of my wires into the pcb along with the 330r resistor, and the other where i connect the 10uf to the 100k/4.7uf?

which direction should the negative be facing on the 10uf?  towards the 4.7/100k or the 10k/330r?

[slacker]

Yeah one wire of the switch goes to ground, so you can use that end of the 330R, the other goes to the 100k/4.7 join.
The negative of the 10uF should be facing the 4.7/100k, the positive end goes the to 330R/10K join.

If it helps, the first schematic should look like this.

[Seven64]

hows this look?



**edit**


sounds about right 

[SISKO]

sounds about right 

So, how this mod sound compared to the stock wah? 

[Joe Hart]

So, how this mod sound compared to the stock wah? 

Yeah, what SISKO said!
-Joe Hart

[Paul Marossy]

Uh oh, sounds like I have a little error on my diagram. I need to fix that.

[Seven64]

i have a vintage 1981 crybaby with an original SOD inductor:



and i thought it was the bees knees, because it had so much more "funk" than my buddies gcb-95

i picked up a gcb95 off of craigslist yesterday to tinker with, and i must say i am debating selling my vintage one already.

all i did was all of paul's suggested mods with a few changes of my own.

i changed the sweep cap to a .022uF and put in the 2k2 resistor in place of the 1k5.  i replaced the Q resistor with a 100k pot, and the 'volume' resistor with a 1k pot.  i converted it to true bypass with an LED, and added the fatwah mod with switch. 

It is a GREAT sounds pornographic funk now (yes, it makes me tingle in silly places too), and i really don't see the point in changing out the inductor AT ALL.

[Paul Marossy]

i have a vintage 1981 crybaby with an original SOD inductor:



and i thought it was the bees knees, because it had so much more "funk" than my buddies gcb-95

i picked up a gcb95 off of craigslist yesterday to tinker with, and i must say i am debating selling my vintage one already.

all i did was all of paul's suggested mods with a few changes of my own.

i changed the sweep cap to a .022uF and put in the 2k2 resistor in place of the 1k5.  i replaced the Q resistor with a 100k pot, and the 'volume' resistor with a 1k pot.  i converted it to true bypass with an LED, and added the fatwah mod with switch. 

It is a GREAT sounds pornographic funk now (yes, it makes me tingle in silly places too), and i really don't see the point in changing out the inductor AT ALL.

Thanks for proving the point I keep making about wah inductors. 

[Seven64]

i still think it would be interesting to try a dual inductor setup, but i would prolly just try it with 2 stock ones first.

[Govmnt_Lacky]

i changed the sweep cap to a .022uF and put in the 2k2 resistor in place of the 1k5.  i replaced the Q resistor with a 100k pot, and the 'volume' resistor with a 1k pot.  i converted it to true bypass with an LED, and added the fatwah mod with switch. 

Kinda new to wah modding. Can someone kindly point me in the right direction to where I can find these mods at? 

Thanks 

[Seven64]

http://www.diyguitarist.com/

>Guitar FX > Wah mods parts 1 and 3 are what i used.

he recommends just changing the Q resistor (33k) and volume (470r/390r) but i had done that on my buddies already so wanted to see what different sounds i could make with the pots instead.

i also converted it to true bypass with LED and 3PDT switch as per a few youtube videos lol.  i can layout the info here if you would like.....


on another note, i think this is my cleanest mod to date (and the first time i have used shrinkwrap and zip ties, so that could have something to do with it!)

[SISKO]

Replacing the transistors with lower gain ones also have a deep impact on the sound of the wah

[Seven64]

that seems a little excessive because then you have to make sure they have the same pinout and stuff too.  it may be interesting to tinker with tho....... 

[Paul Marossy]

that seems a little excessive because then you have to make sure they have the same pinout and stuff too.  it may be interesting to tinker with tho....... 

Just use sockets.