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

bajaman · Post by **bajaman** » 19 Aug 2008, 20:21

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

try it and see

bajaman

Bside2234 · Post by **Bside2234** » 19 Aug 2008, 21:02

Does anyone have a source for 4uf electros? They don't seem to be very common or maybe I just don't know where to look.

Fuzzer · Post by **Fuzzer** » 20 Aug 2008, 00:32

Parallell a 3.3 uF and a .68uF for the test.

Bside2234 · Post by **Bside2234** » 20 Aug 2008, 01:13

That would be fine but I don't have the 3.3uf so I would have to order something anyway. Thanks though.

bajaman · Post by **bajaman** » 20 Aug 2008, 02:37

I use a 3.3uf non polarised and parallel it with a film type 680n type.

bajaman

Bside2234 · Post by **Bside2234** » 20 Aug 2008, 03:00

I found a 4uf mylar that I think I might try. Still looking for an electrolytic though.

stephenxvp · Post by **stephenxvp** » 23 Aug 2008, 22:48

[quote][/quote]'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 ?

I've tried a couple of lower values .0082 and .0064, I think. They make my one sound thin and pinched and at gig volumes could very easily induce the dreaded ice-pick. My experience says with my set-up, small tube amp lots of different effects in a relatively small room the bigger ones sound much better. Currently using .018uF.

An interesting side-effect of having a variable resistor on the emitter of Q1 is that the sweep position changes on the main pot from toe-down treble to heel-down just by altering the emitter pot.

Next mod will be to try a 200k to see if I can extend the range of the foot sweep as it seems to sweep too quickly.

F

Post by **modman** » 24 Aug 2008, 16:53

Did some work on wahs inspired by Bajaman inital comments and after some time I realised that it was a real improvement putting in some of the original Vox V847 values, I built another wah using the original 1967 Vox V847 schematic.

I used Michael Manny's pcb reproduction files but used the correct values. Be aware that Hanney's component layout has a typo: the first 470k resistor should be 470R. I had a lot carbon comp resistors and a bag of tropical fishes, but not the correct values, so I went the "no mojo way" and opted for metal film resistors and WIMA 5% caps. As noted earlier, I am using two Jameco 2.2uF electrolytes in parallel - they measured 2.0x uF a piece.

The Whippple Inductor is an immediate audible improvement -- it just sounds absolutely WAHWAH. If anybody has a red or yellow fasel lying around it would be interesting to measure its resistance, but the Whipple has 29-30 ohms, and if we suppose that the inductance is a little over 500mH, it is supposed to be a replacement for the 1967 Vox halo - large centre hole inductor

Castledine says that "some Clyde McCoys used 100k," but that's the value in the factory schematic above. Anyway, the resistance of the inductor coil will always have more influence on the total resitance across the the coil (including the parallel resistor). Total resistance will be 29.97-29.99 R. My question is: does the parallel resistor influence the inductance of the coil?
What would happen if I would put a 47R resistor in there to bring down the resistance of a bad sounding cheaper coil like the 99 Cry Baby (58R).

I also bought an ICAR pot from MIke who sells the Whipple inductor, but at this moment his store doesn't list any separately (only in kits- but talk to the guy). They are also available from Small Bear I regret not having tried a Whipple in an stock Cry Baby yet, but I can say the Whipple in combination with the ICAR pot is wah heaven. It does gives you a steeper sweep - I believe it's reverse tapered. But as important as the taper is the dead zone at the tip - you reach 0k (maximum treble) before the end of the pot taper, so you still have space to push down the switch. I tested some Dunlop pots and none of them had a dead zone - which implies that you'll always have some resistance on the pot before you reach the switch. Even the Tawainese blue pots (cf Banzai etc) are better in this respect.

The transistor type is not important, in my opinion, as long as they are medium gain (around 250Hfe). High gain is not what the vintage wah likes, remember that since the original, the 470R resistor kept on decreasing over the years, Cry Babies now having 390R (?) - which increases gain. The known mod pages also list this as the way to get more bass - but it natural and logical for gain and bass to go hand in hand. Bajaman suggested 510R here, which got me thinking..
I do not know what the buffer is doing when it's doing nothing, so I always remove it and make them true bypass.

Anyways: here's my SWELL MOD to end my long story: replace the C5 in a Crybaby (10n) by 68n and you'll have a pedal that swells as nice as it wahwahed. Or use a switch.

Furthermore, I don't think I'll be able to try out the
SmallBear Wah Inductor Kit next time...

bajaman · Post by **bajaman** » 24 Aug 2008, 19:51

The Whipple inductor is THE best

- I too found it had more wah and very consistant inductance unlike Dunlop Fasels that are all over the place (300mh - 650mh on one batch I purchased through Aron's store - not his fault mind you!!).
The 100k - 33k resistor has the effect of smoothing out the peak which is swept through the two octaves that the wah works over ( or adjusts the Q of the tuned circuit). the smaller the value - the smoother and broader the peak and vice versa. Some folks put a 100k preset in here and dial in the sweet spot.

cheers
bajaman

stephenxvp · Post by **stephenxvp** » 24 Aug 2008, 21:41

Modman wrote:Anyways: here's my SWELL MOD to end my long story: replace the C5 in a Crybaby (10n) by 68n and you'll have a pedal that swells as nice as it wahwahed. Or use a switch.

Does it swell as it wahs or just swells?

I'm gonna have to try that one too and putting a trimmer in place of Rq seems like another idea of genius.

Just when I thought I'd finished with the wah...

Post by **modman** » 24 Aug 2008, 22:29

stephenxvp wrote:
modman wrote:Anyways: here's my SWELL MOD to end my long story: replace the C5 in a Crybaby (10n) by 68n and you'll have a pedal that swells as nice as it wahwahed. Or use a switch.
Does it swell as it wahs or just swells?
I'm gonna have to try that one too and putting a trimmer in place of Rq seems like another idea of genius.
Just when I thought I'd finished with the wah...

As you increase cap size, the wah effect dissapears. You can try 47n or 100n. More something you should switch in with a toggle.

Bside2234 · Post by **Bside2234** » 24 Aug 2008, 23:17

Does increasing this cap work better than lifting the negative leg of the 4.7uf electro. cap?

Post by **modman** » 25 Aug 2008, 01:11

Bside2234 wrote:Does increasing this cap work better than lifting the negative leg of the 4.7uf electro. cap?

That's the Volume pedal mod, haven't tried that one. I wouldn't call this change a volume pedal, but more of a real swelling. Hard to explain. Try it if your playing around with the caps...

Bside2234 · Post by **Bside2234** » 25 Aug 2008, 02:24

Actually, I have done it and it doesn't work very well. Especially if you use distortion. On a Clean channel/signal it works ok. I would classify it as a volume swell. It lowers the volume and increases it to normal volume. It doesn't mute at all. With distortion the volume difference is barely noticable.

So how is the swell different from the volume? I may just have to try it to see the difference.

Solidhex · Post by **Solidhex** » 26 Aug 2008, 06:54

Yo

The whipple is great. I bought an inductor kit from small bear but have been too lazy to use it. I will be modding my bandmates crybaby and will find out soon enough what putting the parallel equivalent of 4uf in place of the 4.7uf cap does.

--Brad

FloydFan · Post by **FloydFan** » 04 Sep 2008, 18:48

Hi folks !
I'm going to place an order at Banzai (lots of components..i've more than 450 items

) but I'd like to mod also my crybaby with top-quality caps. I've seen Sprague 225p in lots of modded wah but - Are they the best ? (I don't want to go for tropical fish or other vintage caps)
At Fuzz Central it's said that polyester (or metallized polyester which are maybe even better) are the way to go for the 0,22uf ones and polystyrene (Xicon..but which?) in place of the old Ducati 0,01uf.
Banzai has :
Cornell Dubilier DME
Panasonic Ecq-p and SMF-V stacked metal film
MKT standard
Wima Foil FKP , FKS , MKP , MKS
Xicon greenies or polypropylene MPP
Sprague 225P , 715P,716P
Epcos MKH
Mallory 150
Nichiden Audio
Roederstein

The last but not the least I wanna change also the 4,7uf according to Bajaman's suggestions and try in addition a "normal" 10uf .
Which one do you recomend ?
Panasonic FC , NHG
roederstein EKO
Frolyt
ELNA
For the Bipolar 4uf I've found only a 3,9uf from Mundorf which is HUGE like 10mm x 30mm and is rated for 75Volts.

My crybaby is one of those erlier Dunlops with 5117 and no dc jack ; the inductor is strange one ... I've never seen any other inductor like mine

Fortunately this wah was given to me free by my guitar teacher

..that was luck

However I already made the True-bypass mod ...when it was stock it sucked bags of tone

I hope you'll help me , masters

Regards
Floyd Fan

PS: sorry for have written too long..but it's my first post

FloydFan · Post by **FloydFan** » 05 Sep 2008, 15:40

Anyone ?

Boutique Wah wah's like Budda, Rmc , Fulltone , etc, which kind of conds do they use ?
There will be any differences between an all Mallory and/or Sprague wah wah ?

I know that's a bit foolish to spend so much for a couple of components but I'd like to try that mojo factor

Fuzzer · Post by **Fuzzer** » 05 Sep 2008, 17:58

Check this out man,

viewtopic.php?f=11&t=286&st=0&sk=t&sd=a ... heap#p2517

Bernardduur · Post by **Bernardduur** » 06 Sep 2008, 10:38

I really like tropical fish caps for the 220n caps; it is my friends best wah.

Post by **modman** » 06 Sep 2008, 12:13

FloydFan wrote: I know that's a bit foolish to spend so much for a couple of components but I'd like to try that mojo factor

Ok, here is the MOJO test: buy both the most expensive and the cheapest ones. We're only talking four caps for a wah wah.

2pcs 0.22uf 10% 250v-Mullard-Tropical-Fish-Capacitors at $14.99
2pcs 0.01uf 10% 250vMullard-Tropical-Fish-Capacitors at $1,79

Totals at almost $17 without shipping.
Wima's are excellent and would cost you about $2 max
Even new production high grade amp tone caps would be no more than $3.5

I really think the Wah pedals made the Mullard Tropical fish caps famous, because everybody had to open up their wah to change the battery. There is no doubt that early effects all have strange components because the companies just used parts they had lying around for making 'serious' stuff, like amps or organs. Hence the HV rating.

The 4uF was a standard value before the war, afterwards everything standardized to 4.7uF. I think you would find them in Thomas Organs a lot.

Do let us know the results of your mojo experiment!