CryBaby: Is the Vocal Mod a bluff?

Started by Elijah-Baley, December 04, 2017, 04:46:13 AM

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Elijah-Baley

I guessed, I was sure this Q pot was different, I meant that the someone uses the Vocal pot as I wanted.

Is it normal that the two sides of the inductor are in contact?
«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel

antonis

Quote from: Elijah-Baley on December 05, 2017, 08:10:45 AM
Is it normal that the two sides of the inductor are in contact?
They shouldn't be..

You've probably checked them with continuity tester (beeper) so you've got an audio signal but also some resistance reading..
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

Elijah-Baley

So, the thing is suspect. ???

The beeper beeps when I touch the two pins of the inductor, on the board, of course. But also the lug 1 and 2 of the pot result in connected. I treid to measure the resistance, and on the inductor measure as the pot.
It seems that the pot has put in contact the sides of the inductor each other.

Tomorrow I'll try to desolder the vocal pot, but not the wire. I have available the stock 33k resistor and some other value, and even a 50k pot. I have to make some experiment to understand what is happening.

I add a layout + schematic found in the web.
I don't have really follow this schematic, but accidentally, it was really close to my intentions, so a bit I was inspired.

«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel

thermionix

The inductor has a fairly low DC resistance, probably low enough to get a beep from a continuity tester.  You should measure resistance, zero ohms means it's shorted somehow.  I can't remember a number specifically, but I think a working wah inductor is usually a few hundred ohms.

Other than that, seeing that you have true bypass and the FoxRox output buffer, I would HIGHLY recommend omitting the input buffer.  Your wah will be less subtle overall, probably the "vocal mod" would be too.

Elijah-Baley

So the inductor is ok. :( And then the Vocal mod doesn't work.
The input buffer is already omitted. The input start from that red cap.
«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel

thermionix

My bad, I saw 3 transistors and assumed you still had the input buffer.

Elijah-Baley

No worry! ;)

Now I don't know what to do... :-[

Here the PCB, meanwhile I can study a method to replace the Vocal pot method with the Variable Q method. And I hope that will work! :icon_eek:

«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel

Elijah-Baley

I avoid to draw the layout with the Variable Q pot beacuse even this doesn't work. :-[
I tried to rotate the wah pot some step higher, for more open sound. Maybe the Vocal mod start to hear? Maybe very subtle? I'm not sure, anyway. But I don't like this wah pot settings. Too much treble, hurt the ears.

Did someone use a working Vocal pot?
«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel

thermionix

I'm still confused.  Looking at your board compared to the stock GCB-95 it sure looks like you are still going through the input buffer.  Have you cut traces under the board and just bypassed it with wire?

Elijah-Baley

Yes, there's a cut track. You can find this method on the web.
No worry about it. ;)
«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel


Elijah-Baley

Ok, for my CryBaby let go the Vocal mod. For the moment, at least.

I know it's not the main topic, but can we manage a couple of things?

Quote from: antonis on December 04, 2017, 06:41:23 AM
Quote from: Elijah-Baley on December 04, 2017, 06:23:49 AM
The gain pot crackles, but works.
DC leakage..??
(through C5 or/and C4..)

I got a sort of white noise while I turn the gain pot. It's pretty weird, coulde be the little 500R pot? I'd exclude mistakea, even this time. I just replace the resistor with the pot and a resistor in front. Is this noise normal. :o

Another little issue is the pop when I switch the cap with the rotary. This I would absolutely solve it. It is like if an hammer hit a little tin can box ;D.
I guess I need one or more resistor, but I didn't get how I should connect them.

I found these schematics with a solution, a bit different, and I don't know if they are verified.



«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel

thermionix

The gain pot adjusts Q1 emitter resistance, right?  It would have DC on it by nature, no leaky cap required.  So, not a bad pot, just don't adjust it in the middle of a song.

Is your rotary switch Make Before Break, or Break Before Make?  Probably the latter.  The resistors might help tame the pop, but it still won't be something you want to switch while playing.

Elijah-Baley

#33
About the gain pot, it sounds weird to me because I never heard about its scratchy or noise during the adjustment. Nor seen it on some video.

This is the rotary switch: https://www.musikding.de/Rotary-switch-2P6T-open
I don't remember the kind, I bought it a lot of time ago, maybe for a Rat.

I will not adjust the gain "while" I play, neither to turn the rotary switch, but at least I would adust it when the wah is engaged, and these two noise are a bit annoying. Not too much the gain pot, but  the pop, at the beginning it is enough loud, then less. Of course I could turn three or four times the rotary switch, so it will be almost silent, and I can settle like that for the moment. But it's not the perfection, I would to know how fix this issue.
Sorry, I ask again: is there a verified method?

Update:
I just found this wah pedal.


The brand has some wah version and this has some of the mods I want in my CryBaby. I can hear exactly the same pop when the cap changes (around 2:00 and 6:00), and when it ajdust the gain (around 3:43) when the same noise.
It has even the Sweep control to smooth the wah effect. Right in these days I was thinking about it. You can see that control in the Dimebag version CryBaby.
«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel

PRR

> I don't know if they are verified.

What do you want, a note from the Dalai Lama? Just try it.
  • SUPPORTER

Elijah-Baley

Of course, in case I'll try. ;)
It just for saving time. I have just those caps and I want make a clean work, probably I'd do another board if one of those tricks work. I can use the breadboard. We'll see.
Meanwhile I'm planning to let it go the Vocal mod and make the Sweep pot like the Dimebag CryBaby version, or the Wilson Wah posted above.
«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel

Elijah-Baley

Quote from: thermionix on December 10, 2017, 09:55:01 PM
The gain pot adjusts Q1 emitter resistance, right?  It would have DC on it by nature, no leaky cap required.  So, not a bad pot, just don't adjust it in the middle of a song.

Is your rotary switch Make Before Break, or Break Before Make?  Probably the latter.  The resistors might help tame the pop, but it still won't be something you want to switch while playing.

I should buy a new Make-Before-Break rotary switch, I need it also because the one I have got has the shaft too long and the knob are very high.

I have almost finished, I have just to adjust the resistor gain pot.
«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel