Converting Wha wha to Volume pedal

[punkykatt]

Hey Guy's, I'm converting a Dunlop Crybaby wha wha GCB-95 into a volume pedal. I removed C-3  4.7uf and it works pretty well but the tone is a bit dark. Can I brighten it up by changing out C-4 or C-5  or both from a 0.22 to a 0.1? Any suggestions are welcome. Thanks in advance.

[pdf64]

Have you left the buffer in place, or have you converted it to true bypass and taken the Q0 buffer out of circuit?

[sluckey]

I have a Dunlop volume pedal. Nothing in it except two jacks and a volume pot. No batteries required. Very simple.

[punkykatt]

This schematic does not show the on/off switch. When I put a 1/4" phone plug in the in and out jacks, hook my meter leads to the tip connections of the plugs  with switch in open position my meter reads .5 r the same as if I connected the leads together. With the switch in the on position I get no reading. Can I assume it is true bypass? The tone is brighter when the switch is off/open. The tone is a little darker when the switch is on  in the volume mode.

[punkykatt]

Steve. what is the value of the pot you have in your volume pedal?

[sluckey]

I don't know and it's buried. Not gonna dig it up.   

It's the one that looks exactly like the wah pedal but the front says High Gain. You can find it on the net. Probably get info on the pot too.

[punkykatt]

Thanks for the info Steve. Much appreciated.

[pdf64]

This schematic does not show the on/off switch. When I put a 1/4" phone plug in the in and out jacks, hook my meter leads to the tip connections of the plugs  with switch in open position my meter reads .5 r …

There’s more to what I was asking about than that.
Can you provide decent photos?
Does connecting a buffered (eg Boss) pedal between guitar and wah help with the issue?

[Blueboozer]

https://www.jimdunlop.com/content/manuals/GCB80.pdf

This says 250K

[sluckey]

https://www.jimdunlop.com/content/manuals/GCB80.pdf

This says 250K

That's the one. Mine has a PEC sealed pot. Don't know the taper. Don't use a cheap unsealed pot.

[punkykatt]

https://www.electrosmash.com/images/tech/crybaby/dunlop-crybaby-gcb95-pcb.jpg


Pdf64, I hooked up a Boss SD-1 pedal between the guitar and the the converted wah ,the buffer in the Boss pedal did not make any difference. Not sure the picture in the link above will work. Everything but the on/off switch is on a PCB.

[pdf64]

Ok, if no other mods then your pedal is buffered, so ignore the concern I raised.
FYI my GCB95 has a much better wah effect with its buffer removed. But a DPDT switch then really needs fitting, for true bypass.

[punkykatt]

My question should have been. Can I brighten up the tone by changing out a cap or two on the PCB? Would removing the buffer do that? If so, what would be involved doing that?

[Blueboozer]

My question should have been. Can I brighten up the tone by changing out a cap or two on the PCB? Would removing the buffer do that? If so, what would be involved doing that?

Here’s a Dunlop pot for the Dunlop volume pedal

https://www.tubesandmore.com/products/potentiometer-dunlop-250-k-audio-dunlop-gcb80

Gut shot.

https://forum.seymourduncan.com/forum/the-pedal-board/308415-treadle-resistance-stiffness

[pdf64]

My question should have been. Can I brighten up the tone by changing out a cap or two on the PCB?

Dunno, there’s nothing obvious to me.

Would removing the buffer do that?

No

[punkykatt]

Thank you everyone for your time and help.

[jjasilli]

See:  https://missionengineering.com/volume-pedal-qa/     

[pdf64]

See:  https://missionengineering.com/volume-pedal-qa/     

A wah pedal with the volume pedal option mod doesn’t really fit into either the passive or active categories described on the mission article. Yes, it’s active, but if you wanted a volume pedal, a wah circuit wouldn’t be a logical place to start.

[punkykatt]

Well I ordered the 250kA pot listed in reply#13. Gutted every thing in the Dunlop casing and hand wired the new pot, jacks and bypass switch. Adjusted the gear so it would go from just starting to sound and allowed enough forward travel to activate the true bypass switch. The volume ramps up too fast, hard to make those country swells.  I tried  readjusting the gear position several times with no improvement. I tried rewiring the pot swapping the wires around. It seemed to work better with the wires reversed but you had to rock the pedal back to increase the volume. Reverse audio needed? I tried a 100kA pot  from an early 70`s King Vox wah I had in my stash. That seemed to work a little bit better than the new 250kA pot, but not much.  I was getting better swells with the wah circuit with the 4.7uf cap removed, just a darker tone.  What gives !!! 

[pdf64]

Are you using a clean or overdriven tone?
If overdriven, where’s the overdrive happening, before or after the volume pedal?

[punkykatt]

Clean tone. Set up is: Guitar- volume pedal- full drive 2- klon centaur- boss flanger bf2- mxr carbon copy delay- nano holygrail reverb.  When testing on the bench I use guitar- volume pedal- amp.