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

A forum devoted to mod, tips and suggestions for upgrading and rehousing your VERY CHEAP commercial stompbox to near boutique excellence.
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reece_26
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Post by reece_26 »

devastator wrote:I modded mine. Sounds good but it's noisy in spite of mods. I changed the transistor for 2N3904 (I tried BC550C too) I've put trimpot for "mid" (2K5), Q (100K) and "gain" (500ohm at first transistor emetter).

Any idea to kill that noise ? ("hum" at bass posistion and "hiss" I treble)

I incorporated a jfet buffer like I read at "fuzzcentral.com" .
Hi all, long time reader but never posted!
Well im in the same boat as this guy, slight hiss and hum in both heel and toe positions. Also I have gone down the true bypass route and removed the buffer but the pedal still tone sucks! i guess because the jacks are solder to the pcb and not directly to the switch? would it be possible to add switchcraft jacks? the pedal is REV G.

Reece

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Post by jrjoe21 »

I run my wha at a lower voltage (PP2). I like it better than way... it reduces the noise (lower gains) and make it less spikey.
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Post by floris »

reece_26 wrote:Also I have gone down the true bypass route and removed the buffer but the pedal still tone sucks!
When you did the true bypass correctly with a 2PDT switch, it can't "suck tone" anymore. In "true" bypass, the input and outputs should be directly connected to each other and the wah pedal circuit completely removed from it.

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reece_26
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Post by reece_26 »

floris wrote:
reece_26 wrote:Also I have gone down the true bypass route and removed the buffer but the pedal still tone sucks!
When you did the true bypass correctly with a 2PDT switch, it can't "suck tone" anymore. In "true" bypass, the input and outputs should be directly connected to each other and the wah pedal circuit completely removed from it.
Right well perhaps i wired it wrong :? I used a 3DPT switch, possible that is the problem?
There is a definite tone suck, with just the guitar plug'd in it sounds sparkly and crisp. when it just the wah in the signal chain it sounds a tad dull.

*Edit* just had a thought, well the jacks are solder to the PCB so the signal is still running through that? possible cause?

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Post by floris »

A 3pdt switch is also fine.
Follow this:
http://www.stinkfoot.se/andreas/diy/mods/dunlop.htm

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Post by CHEEZOR »

reece_26 wrote:Right well perhaps i wired it wrong :? I used a 3DPT switch, possible that is the problem?
There is a definite tone suck, with just the guitar plug'd in it sounds sparkly and crisp. when it just the wah in the signal chain it sounds a tad dull.

*Edit* just had a thought, well the jacks are solder to the PCB so the signal is still running through that? possible cause?
This could also be caused by adding more cable length. I'm assuming that when you plug directly in you are using 1 less cable.

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reece_26
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Post by reece_26 »

CHEEZOR wrote:
reece_26 wrote:Right well perhaps i wired it wrong :? I used a 3DPT switch, possible that is the problem?
There is a definite tone suck, with just the guitar plug'd in it sounds sparkly and crisp. when it just the wah in the signal chain it sounds a tad dull.

*Edit* just had a thought, well the jacks are solder to the PCB so the signal is still running through that? possible cause?
This could also be caused by adding more cable length. I'm assuming that when you plug directly in you are using 1 less cable.

:slap: Of course! I had completely to forgot put that into the equation, Well ill have a look at the cables but they are high quality Neutrik jacks and 3m oxygen free cables.
Hmm, might have to go fiddle around :wink:

Cheers guys.

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Post by the_ungod »

Hi everyone,

I have a REv.E and i bougth the whippler and the ICAR.
I also planning to switch for better caps and metal film resistors...
I've read a few replys ago that there's a way to tune the circuit in order to fit the whippler inductance... how do i do this?

Thanks

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Post by jagermonster »

Thought I'd report my experiments with some hot-shit mojo caps.

I replaced the green chiclet type caps in my crybaby with these:

https://cgi.ebay.com/Original-Crybaby-V ... 4cee7cf5cf

I wasn't expecting much, but I was pleasantly surprised to find that it sounds terrific. I swapped out the sweep cap for a cheap .022uf and that made a marked improvement as well. Gonna swap around some resistors soon.

All credit goes to this board. Thanks guys.

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Post by timbo_93631 »

Reece_26,
You can always check to see if your True bypass mod was sucessful by removing the battery from your wah and checking for signal in the off position. If wired correctly there should be no difference than with just a straight cable. Of course the best thing you can do with a GCB-95 is to get a repro V846 or V847 PCB from ebay and set it up with proper switchcraft jacks, a NOS clarostat hotpotz-1 and some decent C's and R's. I have never been too impressed with the GCB-95 even after going the True Bypass/Whipple Inductor/Common resistor changes route. The PCB mounted jacks have always been a nightmare.
As a side note I have just ordered some Italian V846/Clyde repro PCB samples from Bangkok that I am thinking about making a bulk order on. If they are good quality, I am going to develop a Whipple inductor based drop in assembly as well as a retrofit DIY kit for an affordable price. I will repost when I get them and see. I still have a small stash of vintage US Thomas Organ boards, but they are getting harder and harder to find.
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zeppe
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Post by zeppe »

Hi, I'm a new member and I've been reading this thread with interest.

Just a quick question, does anyone know what make the capacitors are on the newer GCB 95 boards(with PCB mounted jacks)?
They look like MKTs but I could be wrong. Is it worth upgrading to Xicons?

Thanks!

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boxnix
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Post by boxnix »

Is asking for a fat clean wah like asking for a horny faithful wife?

I did one wah, whipple inductor, fish caps, ICAR and replaced just about everything on the board with better stuff and went through every upgrade on the net. I finally ended up doing pots for Q, gain and volume, I can get it close, fat with bad clipping or really clean and really thin.

So I started over, whole new wah, Arteffect inductor, switch, ICAR pot, I did the mods one at a time this time, I never could get it. It's much fatter, but much muddier.

BOTH wah's have Q1 replaced with a... whatever smallbear sells for that. I forget what it is. I did a before and after, it cleans it up quite a bit, just not enough.

I can safely say the problem is not in the gain/volume resistors. Do I need to get a smaller gain Q1 trannie? I thought perhaps it was just a lack of mojo but if $20 worth of fish caps doesn't do it then I give up.

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zeppe
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Post by zeppe »

Is asking for a fat clean wah like asking for a horny faithful wife?
Classic :applause:

What value is your sweep cap? I changed up to 22nF, 18nf and 15 nF respectively and they all made the wah really muddy.
I just stayed with the stock value 10nF, but use a better quality cap.
Maybe try a lower gain trannie like the 2N5172? I believe they were used in the old Clydes?

Like yourself, I've been in a similar situation, done every mod under the sun.
I guess I'm still trying to get my wah to sound like an old V847 I once had.

All I do with my wahs now is the vocal mod to 68K, get a better sweep cap(keep it at 10nF).
Change the resistor at the emitter of Q1 to a 330K, and the input resistor to a 47K.
I dont hear much differences in changing the pot but I really like the new Fasel resistors, especially the red.
1% metal film resistors are perfectly fine, and I do hear a difference when I use better quality caps, I use Xicon greenies.
I like the BC109 trannies too, nicer than the stock and I just bought a quantity of 2N5172's which I'm gonna try out.

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Post by boxnix »

zeppe wrote:
What value is your sweep cap?
On both wah's I upgraded whatever caps I could. The whipple wah is a lot more nasally and thin than the Arteffect so I did more lowering and bass boosting on it. However it is much cleaner and gets a GREAT 70's porno sound with a tele.

The arteffect inductor wah is much warmer so I left the cap values the same, just upgraded them. I'm actually thinking of shifting the range UP from stock to see if that helps. So that would be a .068 or .047 instead of the .1u right?

I think I got the arteffect too hot and loud, I have the gain at 220 ohms and the volume res at like 33K. I'm going to raise them both a bit and see what that does.

The Q1 trannies are both some variance of the BC109. I may have to order a couple of the others to see what that does.

Thanks!

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Post by zeppe »

This is from Stuart Castledine's very informative site wah-wah.co.uk.
Sweep Range

Change the sweep by swapping the 0.01µF cap between the emitter of Q2 and the inductor. A smaller value will make the wah sweep more trebly and vice-versa. If you're converting to or from a bass wah, this is the one to change. Try 0.068µF for a bass wah.
My wahs were a little trebly and I tried adding a higher sweep cap, but everything higher than 0.012uF was unusable for me, way too bassy.
I was using stock Crybaby inductors at the time though.

I really think that your gain resistor is a bit low. I'd personally never go below 330ohm, too much distortion and mud IMO.
Actually this could be the root of your problems. I keep the volume res at 47K too.

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Post by devastator »

I've just put a 4 positions rotactor on that "sweep cap" and it works perfectely to me. not really "bassy" , even with a 32n cap it's still useable .

It's the good thing (and I think starting modification with that can avoid a lot of other modifications) to take off some higs really noisy and "harsh".

But , I'll change the inductor for a better one I'm not really sastified about the sound (espcially compared to my snarling dog wah)

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boxnix
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Post by boxnix »

Ya dropping that input resistor helped a lot. Its actually really nice now, it is a bit thin but it did not go nasally like my other one, its pretty vocal. Arteffect inductors get a big thumbs up from me, he responds to my questions almost instantly over email and I think the inductor is great. I guess the guy is from Israel so you get an international freight box with all the fancy stickers. It made me feel pretty important.

I am getting a good bit of noise now, need to research that one.

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zeppe
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Post by zeppe »

Arteffect stuff is great.
I had the Bonnie Wah for a while and it was definitely the nicest and well built of all the boutique wahs I owned.

I also played a gig last night with my standard Crybaby wah that I modded with 2N5172 trannies.
Huge difference, much quieter and a nicer sound. No insane squealing either when I boosted with a fuzz or
TS9 for soloing. I'm really happy with this wah now and I havent even changed the inductor or sweep cap yet!

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Post by boxnix »

Did you replace both? I put the stock Q2 trannie back in and i swear it helped. I read somewhere Q2 does not effect tone but that the gain needs to be over 200.

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Post by CHEEZOR »

boxnix wrote:Did you replace both? I put the stock Q2 trannie back in and i swear it helped. I read somewhere Q2 does not effect tone but that the gain needs to be over 200.
I believe that R.G. Keen said that in his "Technology of Wah Pedals" article.

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