Dunlop CB535 variable 'Q' adjustment

[markphaser]

The Dunlop CB535 has a variable 'Q' adjustment

Is it a variable resistor in parallel across the inductor?

[markphaser]

How would i modify it to adjust the "Q" width? and "Q"s depth?

This is changes the Q's frequency?

Does the inductor have a RLC internal? how would i change the RLC?

The inductor has DC resistance and impedence how do i change the impedance of the Wah inductor?

[Mike Burgundy]

Read "the technology of the wah" at GEO.
That 'll provide answers, and lots of them.

[Paul Marossy]

The Dunlop CB535 has a variable 'Q' adjustment

Is it a variable resistor in parallel across the inductor?

If I had to guess, I would say yes. I did this same exact thing to my Vox grey wah clone and it does vary the "Q" - it makes it more or less vocal. In my case, it was a 47K resistor in series with a 50K pot wired in parallel with the 370mH inductor. I guess it's not really a Vox grey wah clone anymore by doing so, but it is a good sounding wah. After playing it for a while now, I think I like it as much as my Maestro Boomerang clone now...

[markphaser]

I read the technology of the wah" at GEO and i couldn't get any of the answers sorry

How would i modify it to adjust the "Q" width? and "Q"s depth?

This is changes the Q's frequency?

Does the inductor have a RLC internal? how would i change the RLC?

The inductor has DC resistance and impedence how do i change the impedance of the Wah inductor

[markphaser]

how do you get a moving resonant frequency out of a fixed inductor and a fixed capacitor?

the wah pot, the second transistor and the fixed capacitor implement an electronically variable capacitor? how?

The change in the effective current through the capacitor makes the capacitor look bigger to the inductor and rest of the circuit than it really is! We have a variable capacitor?

I still don't understand what the wah pot is or what is it doing. What is the Wah pot controlling? what kind of parameter is a wha pot?
can someone but a label on a wha pot?

What is the Wah pot changing?

[sir_modulus]

I read the technology of the wah" at GEO and i couldn't get any of the answers sorry

I'd Suggest giving it a read through again.

How would i modify it to adjust the "Q" width? and "Q"s depth?

Width and depth are modified by the Q control. A simple way of thinking is this: a high Q notch is a notch that is sharp and slender, whereas a low Q notch is fat and wider. This control is in the form of a potentiometer wired as a variable resistance placed in parallel with the wah inductor in a typical inductor based wah.

This is changes the Q's frequency?

The Q doesn't have a frequency. The Q control changes the shape (Q) of the filter the pedal creates. This filter is then swept by the pedal as you rock it.

Does the inductor have a RLC internal? how would i change the RLC?

The inductor is the L. The rest of the circuit acts as as the C. Hence, the inductor is half the sound 

The inductor has DC resistance and impedence how do i change the impedance of the Wah inductor

Wind yourself a new inductor.

Cheers,

Nish

[sir_modulus]

Read through it again slowly (the Geofex article on Technology of Wah Pedals)

how do you get a moving resonant frequency out of a fixed inductor and a fixed capacitor?

The change in the effective current through the capacitor makes the capacitor look bigger to the inductor and rest of the circuit than it really is! We have a variable capacitor! - R.G

the wah pot, the second transistor and the fixed capacitor implement an electronically variable capacitor? how?

The secret is this. The inductor looks to the second transistor like its far side is grounded, through the 4.7uF capacitor. To the inductor, the capacitor kind of looks like it's grounded because its far side is connected to the emitter of Q2. Q2's emitter has a low output impedance and therefore looks like "ground" if you ignore the signal coming out of the emitter. At the junction of the inductor, capacitor, and 1.5K resistor, the voltage looks like the voltage that would happen across a parallel L/C circuit. However - the current through the capacitor is NOT determined by the voltage across the inductor/capacitor, it is also determined by the voltage driving its "ground" side, and that voltage is increased or decreased by the position of the wah pot. If the wah pot setting increases, the capacitor will let more signal current through because the voltage driving it at Q2's emitter is bigger, so the capacitor has to let in more signal current. If the wah pot setting decreases, the capacitor will let in less signal current. A "capacitor" may be thought of as a special instance of ohm's law by the amount of signal current it lets through. - R.G.

The change in the effective current through the capacitor makes the capacitor look bigger to the inductor and rest of the circuit than it really is! We have a variable capacitor?

Replace the question mark with another exclamation mark, add a reference to R.G., and you've got the answers to your first two questions.

I still don't understand what the wah pot is or what is it doing.
What is the Wah pot controlling?
What is the Wah pot changing?
What kind of parameter is a Wah pot?
Can someone but a label on a Wah pot?

The Wah pot is working with the rest of the circuit to create this "variable capacitor" of sorts. Read the article through once more. Parameter? Label? What do you mean by those?

Cheers,

Nish

[markphaser]

Thanks alot sir_modulus

Wah pot is working with the rest of the circuit to create this "variable capacitor"

How is the wha pot a "variable capacitor" because in a block diagram where is the wah pot at?
At what stage of the circuit is the wah pot at? in the feedback or output or bleeding of the 2 stages

Like on most pedal every knob or parameter have a label like the rate,depth,feedback,volume

The wha pot parameter- what is it from looking at the schematic i can't tell if its a output volume or a feedback or a bleeder
                                    what is it doing or controlling or changing

[sir_modulus]

Wah pot is working with the rest of the circuit to create this "variable capacitor"

Yes, this is correct.

How is the wha pot a "variable capacitor" because in a block diagram where is the wah pot at?
At what stage of the circuit is the wah pot at? in the feedback or output or bleeding of the 2 stages

The wah pot is a voltage divider (to ground).

Like on most pedal every knob or parameter have a label like the rate,depth,feedback,volume
The wha pot parameter- what is it from looking at the schematic i can't tell if its a output volume or a feedback or a bleeder

This would be the manual filter freqency control. By putting it in a footpedal, you can sweep it, creating a wah sound.

What is it doing or controlling or changing

This is covered in the GEO article.

This article is loacted here:
http://www.geofex.com/Article_Folders/wahpedl/wahped.htm

Read this thoroughly, as this is one of the best articles on wah pedal operation out there.

Cheers,

Nish

[markphaser]

Thanks sir_modulus for correcting me

How is the wha pot a "variable capacitor" because in a block diagram where is the wah pot at?
At what stage of the circuit is the wah pot at? in the feedback or output or bleeding of the 2 stages

The wah pot is a voltage divider (to ground).

A voltage divider for what stage or function? it seems to change the frequency of the filter bank

Wah pot: is manual filter freqency control

How would i modify it to adjust the "Q" width? and "Q"s depth?

Width and depth are modified by the Q control.
This control is in the form of a potentiometer wired as a variable resistance placed in parallel with the wah inductor in a typical inductor based wah.

The Variable Resistance in parallel with the Wah inductor= Q depth

Q width= ?

How to change the wah inductor's resonance frequency? would to put a Cap. in parallel to change the wha inductors resonance freq?

The wah inductor is a Fixed Q?
The wah circuit is design to be like a "variable capacitor"
How can it be a variable capacitor when the Wah pot is a variable resistor "Which" capacitor is the Wah pot varying?

If the Wah pot is a "Frequency parameter" how can it be a "variable capacitor" ? is it varying the circuits capacitance?