CryBaby: Is the Vocal Mod a bluff?

[Elijah-Baley]

Hi guys. TIme ago I bought an used CryBaby to modify, a lot!

True Bypass Foxrox Retrofit in the output done.

Now I started to mod other things. Gain pot, 500R with a resistor in front (82R); Mid pot, 2k with the 1.5k in front; Rotary Switch 6 position for range frequency; Volume/Wah switch.
And I had a great expectation about the Vocal Mod. I replaced the stock resistor with a 100k pot, but it doesn't do anything, except when is set to zero. The wah effect is cancelled.

How it could be possible? I can hear the effect in the other CryBaby on youtube!

[antonis]

Schematic???Schematic???Schematic???

[Elijah-Baley]

The CryBaby lovers knows what I'm talking about, but here it is.

This is interesting: https://www.electrosmash.com/crybaby-gcb-95

Schematic:


Frequency Range cap: C2
Gain resistor: R4;
Vocal resistor: R7;
Mid resistor:  R2.

But the mods are here: http://stinkfoot.se/archives/549

[antonis]

IMHO, you don't have to be a "Cry Baby Lover" to see, when R7 is set to zero, L1 is short-circuited..

[Elijah-Baley]

Thanks!
Do you mean this could explains the no wah effect to zero setting?

[antonis]

Of course..

Wah effect is primarily created due to 500mH inductor "self-resonance" in conjunction with R7/C3/R8 (LRC filter).

When R7 is set to zero Ohms, the whole current coming through R6 is going right to GND..
(not splitted through L1 and the other relative items.. - it's like to have L1 taken out of the circuit.. )

[Redvers]

I always found the vocal mod to be the most useful and pronounced mod. That said I hate the crybaby and bought a vox and never looked back.

[Elijah-Baley]

I can't measure the resistance of the pot through the board, (I guess beacuse the inductor), but I verified the connection of the pot with several spot: C2, R2, and C3.
I thought the inductor is the issue, but I hope I wrong, because I don't want to spend money for the a red fasel or someone else, too expensive, now. To the otherside the vocal po is useless.

(Actually, I have another little issue. The gain pot crackles, but works.)

[antonis]

The gain pot crackles, but works.

DC leakage..??
(through C5 or/and C4..)

[Elijah-Baley]

The pot works fine and I can measure the right resistance on the board. The other lug goes to the ground.
I didn't touch C5 nor C4.

The work had to be simple, but not I'm beginning to worry.

[Juan Wayne]

If you replace R7 with 100k pot, it should work. I added 27k (or 22k, can't remember) in series with mine, because anything below that is pretty much useless. When in doubt, go back to 33k, check that it works as usual, then do the mod. No way you cna go wrong.

[Elijah-Baley]

[...] No way you cna go wrong.

Indeed. I don't understand why it doesn't work. it just cancel the wah if set to 0R. I'll go back with the original, but it is a dead end.

[Juan Wayne]

The cancelling effects is actually normal, that's why I use a "minimum" resistor in series. However, just to be on the same page (and because I've spent so many hours cursing at unplugged equipment that worked perfectly it's not even funny), are you attaching the pot in place of R7, with no R7 in place? By this I mean, getting rid of R7 completely and using the same holes to connect the pot, acting as a variable resistor, affecting the Q of the filter.

Also, how ironic is it that I said "No way you CNA go wrong"? I can't even spell right, talk about messing with electricity and shit.

[Elijah-Baley]

I taken off the R7 resistor, a wire from the lug 1 of the pot and one of the hole, and a wire from the lug 2 and the other hole. Lug 3 is unused. Maybe it is wrong?
Same method for the Mid pot and the Gain pot.
Pics tomorrow.

[Juan Wayne]

I'm as puzzled as you. Maybe pic will help then.

[thermionix]

For a while my wah had a 33k fixed with a 50k pot (variable resistor) in series.  I found the effect to be quite subtle.  I kept going back to 33k, so I took the pot out.

The old wahs started with 100k, but moved to 33k within a few years.  Of all the wah sounds you've heard on records your whole life, probably >99% of them had a 33k.

I hate the crybaby and bought a vox and never looked back.

What's the difference?  The circuits of both have changed many times over the decades.  For at least one long stretch, they were the exact same product with different branding and cosmetics.

[pinkjimiphoton]

cutting to the chase cuz i'm an asshole.

dude, don't use a pot for the vocal mod. its pointless. stick a big resistor in there, be done with it.
as others have pointed out, with the pot all the way down, its GOTTA kill the circuit cuz you're shorting it out

[Elijah-Baley]

For a while my wah had a 33k fixed with a 50k pot (variable resistor) in series.  I found the effect to be quite subtle.  I kept going back to 33k, so I took the pot out.
[...]

Initially I had decided for a combination more ore less like yours, using resistor + 50k pot, then I convinced myself to use the highest range: 0-100k.
Actually, I heard this story about the subtle ot this mod sometimes, but at the same time some demos can disprove us. Indeed, somebody decided to keep the stock resistor, somebody use an alternative value and somebody use pot or resistor + pot.

This is the reason I say it could be the inductor type, but this is only a supposition. In my CryBaby there's a dark red one, on it there's written "FASEL". I don't think is the Red Fasel, but just the stock.

cutting to the chase cuz i'm an asshole.

dude, don't use a pot for the vocal mod. its pointless. stick a big resistor in there, be done with it.
as others have pointed out, with the pot all the way down, its GOTTA kill the circuit cuz you're shorting it out

Thanks for yout post.
As we can see someone use a pot. I could use a 22k + 50k pot, for example. But the problem is that modding the resistor I don't get any changing, and I found it weird. In this case I can settle with the stock resistor, but I really would a sort of Q pot.

Try to look here:



There's an alternative way to set the Q. Look the 1k pot for the Variable Q. That could be the same work of the Volcal pot, but, maybe, the position is a bit different. And maybe it could work?

This doesn't explain why sometime the Vocal mod is more than subtle.

[Elijah-Baley]

Pictures.
The wires of the Vocal pot are under the board, I soldered them twice because the issue, and the second time it's been easy solder them like that





Tell me about the Q pot of the Dime Wah version.

[antonis]

As we can see someone use a pot.

As we can also see, "he" uses the pot IN SERIES with the inductor..
(and the whole arrangement through 1k5 resistor to Q1 base..- "he" actually trims the overal NFB loop for a variable Q)

That's totally different arrangement than the one with Resistor/Pot IN PARALLEL with the inductor 'cause in this case "he" only can add resistance to the inductor and not short-circuit it, in any pot setting...