Dunlop - Cry Baby GCB-95: how to improve it for cheap

[Bside2234]

Here's another Wah mod - lifting the negative end of the 4.7 uF cap in order to make your Wah into a volume pedal. Easy, and works except the volume on my Vox V847 won't go all the way down, even after disconnecting the gear from the pot and turning it all the way down. Any ideas on getting the volume to go all the way down?

Here's a schematic:

http://www.geocities.com/j4_student/voxwah.gif

I had the same result with a Crybaby. I sold it so I haven't thought about it in a while. I just bought another one and was thinking about doing the volume mod again but I think it needs to be better. Anyone have any ideas?

[vhollund]

I've got a Crybaby ive had for 15 years and got it modded for TB 10 y ago

I really like the stock tone
Actually i like it even better when the battery is going 7volt or so
BUT changing "who who" more into "wha wha" could be nice

I just change the R 33K to 56k
Is that really all?

Is it the only change or does it change the tone overall abit too?


Vaughn

[bajaman]

I just change the R 33K to 56k
Is that really all?

Hi vaughan,
please read the thread from the start - many options and changes - this is but one thing to change - it may or may not be an improvement - a lot depends on the inductor type, value and make.
cheers
bajaman

[vhollund]

Thanks
I did read the thread 2-3 times including the links

Vocal mod: Replace the 33K resistor in series with the inductor with a higher value, like 56 or 68K. This will make the resonance peak of the circuit sharper (with a smaller "Q" value), which in turn makes the "wah" sound more like "woh".

Im really quite new to how circuits work but

What I mean is does the 33K change have effect on the rest of the circuit
or does it just change the "who" to "wha" ?

I have a stock dunlop crybaby

[Emanuele]

I want to make a maestro boomerang clone into my standard crybaby an I have just seen that it uses a 25k pot, can I mimic this by putting a 33k res across thelug 1-3 of the standard hot potz that I have? It should work, right?

[Emanuele]

none?

[Tonebender]

Hey guys,

I'm planning on modding my Dunlop GCB95. What kind of transistors and hfe would be best? Thanks!

[modman]

Hey guys,

I'm planning on modding my Dunlop GCB95. What kind of transistors and hfe would be best? Thanks!

hi there, yes I merged your question in our big 'Improve your wah for cheap" thread, because most of the into you're looking for should be here. You really should have a look at Baja's inital suggetions, but there are also reports on transistors changes:

https://www.freestompboxes.org/viewtopic ... 2565#p2565

Do share your experiences when you've done the changes (or before )

[Tonebender]

My bad..... Thanks modman!

Where can I get the MKT caps mentioned earlier?

I did some googling and apparently they're metallized polyester. Would AVX caps be just as good?

[dajm]

I've done a few mods to my GCB 95 wah ( resistor value changes, q pot, new inductor ) and it sounds 100 % better.

The next mod I was going to try was adding a rotary switch to select 5 or 6 different sweep caps, I see that some people like caps higher in value, ie. 0.015uf or 0.022uf to lower the sweep but has anybody found any useful tones from using lower values than the standard 0.010uf ?

does anyone have any reccommendations for cap values to use ?


thanks for any info

[RnFR]

I put a WHIPPLE inductor in my Wah - very worthwhile improvement - US$20.00 from Mike on Ebay - search for Whipple on Ebay - you will find him
cheers
bajaman

the whipple is where it's at.

[modman]

Trying to work my way through a bunch of wahs I had lying around. I posted on the Schaller Yoy Yoy Wha Wha, but it's a crappy shell not not such a useable sound, so I turned my attention to an old Crybaby that I had lying around to perform Bawahman's mods

First - replace all those shitty little blue capacitors with some better quality ones - I used those little grey MKT film types, but you could use xicon film for still better results. (They are 10n x 2, and 220n x 2).
Second - find the 4.7uf electrolytic capacitor and it's 82k ohm bypass resistor - replace them with a 3.3uf BP paralleled with a 680n film type (for close to 4uf) and a 100k metal film resistor (or metal oxide).
Third - replace the 390 ohm resistor with a 510 ohm ( or parallel 2 x 1k ohm)
That is it - just plug in your guitar and enjoy wah wah sounds ( not woh woh as in the stock GCB95)

Used 2.2uF electrolytes in parallel, for lack of anything better - did measure 4.05uF. But wonder why bipolar was specified? Comparing the sound to a stock Crybaby (with input buffer) it sounds sweeter and rounder, though there is a considerable volume drop. I left the input resistor at 68k - though I should have lowered it.

I already removed the buffer and put a 3pdt switch with led in and did some directionless changes. After reading some websites, I still cannot believe why there is not more knowledge on the 4uF cap noted by fuzzcentral with regard to the Clyde McCoy:

# The electrolytic capacitor in the circuit is a Ducati 4µF non-polarized instead of the standard 4.7µF polarized capacitors found in other wah circuits.

and even geofex notes 4.7uF

Cbp: Important that it be large enough to bypass all signal at its (+) terminal to ground. From 4.7uF on up, little effect on sound. As it gets smaller, the sound becomes more of a loudness variation and less of a wah. If this cap is defective, wah pedals sound like volume pedals.
(...)
Rq: This resistor is the primary determiner of the Q, or sharpness of the bandpass/resonance effect of the filter Values lower than 33K make the filter less sharp, reducing the quality of the wah effect. Values up to 100K contribute to sharper, peakier, more resonant tones. If it gets too sharp, the wah effect can be lost because it may not hit harmonics to emphasize.

If there were CMCs with 100k then they must have sounded different from the ones with 33k it seems. I guess my next wah will have trimpost

4uF 100V mylar BP capacitors

[analogguru]

Interesting..... For bipolar I am always using these:

But who needs bipolar in a wah ?
There is always a positive DC-voltage at the electrolytic.

But for real mojo you have to take one of these:

analogguru

[TheBlackCrayon]

I'm noticing that when I switch my Vox standard wah on it kills some of the output and it's also not so crazy when I stack it with high overdrive pedals or fuzz pedals. Is there anything I can do to fix this? I know there's kits out there that upgrade your wahs, but I'm looking to simply up the volume level and maybe make it more fuzz friendly. I wasn't sure where to post this.

[Rocket Roll]

Find a 510R resistor and change it to 390R - you'll get 6dB boost. You should do it alongside the true bypass conversion, but I suppose it'll work even if you don't convert your VOX to true bypass.

[wildschwein]

If you haven't done so already go over to http://fuzzcentral.ssguitar.com/axiswah.php and follow some of the links on the page. These are some of the coolest mods for Vox and Crybaby wahs. I've done nearly all of them to my GCB-95 and the improvement is huge.

[stephenxvp]

by dajm on Tue May 20, 2008 12:22 am

I've done a few mods to my GCB 95 wah ( resistor value changes, q pot, new inductor ) and it sounds 100 % better.

The next mod I was going to try was adding a rotary switch to select 5 or 6 different sweep caps, I see that some people like caps higher in value, ie. 0.015uf or 0.022uf to lower the sweep but has anybody found any useful tones from using lower values than the standard 0.010uf ?

does anyone have any reccommendations for cap values to use ?

Any replies yet? I'm going to do the same thing next. I've got the cap socketed at the moment but because the sound is so different at home and at gig volumes it has been a slow process and then of course you can't remember what the sound was like.
,
I have also put a 1k linear pot on the emitter of the 1st transistor, different positions sound better in different situations, at home it likes less resistance 180/190 ohms but at gig volumes probably 240+ My wah is going to have more knobs than my amp.

[cpnyc23]

Find a 510R resistor and change it to 390R - you'll get 6dB boost. You should do it alongside the true bypass conversion, but I suppose it'll work even if you don't convert your VOX to true bypass.

FYI - I did this mod (510 to 390) without switching to true-bypass... I recommend against it. It just lead to my wah being a mess of distortion right when it gets to the sweet part of the sweep.

Of course, if that's what you are looking for - mod away!

-chris

[modman]

I'm noticing that when I switch my Vox standard wah on it kills some of the output and it's also not so crazy when I stack it with high overdrive pedals or fuzz pedals. Is there anything I can do to fix this? I know there's kits out there that upgrade your wahs, but I'm looking to simply up the volume level and maybe make it more fuzz friendly. I wasn't sure where to post this.

You should have a look at this page:
http://fuzzcentral.ssguitar.com/mccoy.php
all the way down, where it says:

Adding an Output Buffer
A common problem is that the wah pedal simply won't wah when put in series before a fuzz pedal. Unfortunately, this is the way it sounds the best to most people. This problem can be solved by adding an output buffer to your new McCoy clone, which won't alter the tone of the pedal. This is a simple JFET buffer that's based on the Wah Wah project at Tonepad, and can be added to any wah pedal that doesn't have an output buffer, namely the Vox V847s and the Dunlop Crybabys. The input impedance of this buffer is set by the 1M resistor from the Gate of the JFET to ground. Since this buffer can give a slight volume boost, a 100K trimpot is on the output of the buffer to act as a volume pot so you can keep the volume of the wah pedal at the same level as when it's off. Below is a schematic of the Clyde McCoy wah with the output buffer highlighted in red.

Find a 510R resistor and change it to 390R - you'll get 6dB boost. You should do it alongside the true bypass conversion, but I suppose it'll work even if you don't convert your VOX to true bypass.

FYI - I did this mod (510 to 390) without switching to true-bypass... I recommend against it. It just lead to my wah being a mess of distortion right when it gets to the sweet part of the sweep.

Of course, if that's what you are looking for - mod away!

-chris

390R is now the stock value for the Cry Babies, but they use MPSA18 transistors with much higher gain. I am leaning towards the conclusion that a nice wah should have medium gain, i.e. hFE 200-300. In his initial posts Bajaman suggested using 510R in a Crybaby.

[Solidhex]

Forget about Teese wahs and all the bullshit about specially manufactured parts etc., here is how to make any standard cry baby wah sound much better.
First - replace all those shitty little blue capacitors with some better quality ones - I used those little grey MKT film types, but you could use xicon film for still better results. (They are 10n x 2, and 220n x 2).
Second - find the 4.7uf electrolytic capacitor and it's 82k ohm bypass resistor - replace them with a 3.3uf BP paralleled with a 680n film type (for close to 4uf) and a 100k metal film resistor (or metal oxide).
Third - replace the 390 ohm resistor with a 510 ohm ( or parallel 2 x 1k ohm)
That is it - just plug in your guitar and enjoy wah wah sounds ( not woh woh as in the stock GCB95)

No need for special taper pots, fasel inductors or any of the other bullshit stuff - just good quality capacitors and the correct value resistors is all you need
Cheers
bajaman

Hey Bajaman,

What effect on the sound does bringing the 4.7uf down to 4uf have?

--Brad