My Guitar's Tone Control ROCKS My Wah!

[Joe Hart]

I haven't heard about this before, so I was wondering if anyone could clear a few things up (and it may help someone). It seems SUPER obvious, but again, I never saw this mentioned anywhere. If I turn my guitar's tone control all the way, bu wah pedals all sound better (to me, of course). They sound thicker and the little "hump" in the sweep that I don't like is smoothed out a little. My guitar has a Seymour Duncan JB humbucker and the tone control is a 500K pot with a .0047 capacitor (it rolls of some highs, but stays totally useful all the way down to "0" -- not muffled).

Now, I know that thickening the tone is obvious, but it DOES NOT seem to change the "heel down" position of the wah's sound (it does not get more bassy). In fact, all it really seems to do is tame a lot of the high end, so the sweep moves smoother from low to mid to high end. Actually, the "toe down" position seems to be pretty much my guitar's tone with the wah off and the tone control full up! I'm sure that's just a strange coincidence.

Why does it only change the "upper end" of the wah's travel and not just lower the tone across the board? I'm thinking it has to do with the lower limits of my amp/speaker and the lower limits of my hearing. Or maybe something like the mathematical thing where a 100W amp is not twice as loud as a 50W amp (all other things being equal).
Is this the same thing as lowering the sweep by changing a capacitor in the wah circuit? I'm leaning towards no, because it only seems to change the high end response, but I could be wrong (see question directly above).
If this is something having to do with the interaction of my guitar and the wah circuit, could I put a resistor/capacitor at the input of the wah to achieve the same result?

Thank you!
-Joe Hart

[nexekho]

As far as I know a wah is a sweep up the frequency response, and a tone pot just rolls off higher frequencies.  I'd expect it to reduce the potency of the higher end and do nothing to the lower end.

Nothing unusual here?

[R.G.]

... phase...

[nexekho]

This at least is how I see it - the frequency response of the wah and the tone pot multiply together:

[Joe Hart]

As far as I know a wah is a sweep up the frequency response, and a tone pot just rolls off higher frequencies.  I'd expect it to reduce the potency of the higher end and do nothing to the lower end.

Nothing unusual here?

Right, which is why I said that it's super obvious, but why isn't this common knowledge in wah mod circles? Or have I just completely missed all the times it's mentioned? Everyone talks about how a newer, stock Cry Baby is shrill on the top end and how they swapped out resistors, capacitors, transistors with special gain ranges, and (of course) inductors to make the wah fatter. But I've never seen/heard of a simple cap to ground at the input.

Or am I missing something? I mean, if you take a simple booster and add two diodes to ground, you now have a whole different circuit. Would a cap to ground change things? Or is this just reinventing the wheel? Is it the same as changing the sweep cap?
-Joe Hart

[Joe Hart]

... phase...

It's doing something with the phase of the signal?
-Joe Hart

[newfish]

Probably a technically inelegant solution, but could you simply put a larger input cap in there?
Would give you a permanent 'reduced tone' condition...

[Joe Hart]

Probably a technically inelegant solution, but could you simply put a larger input cap in there?
Would give you a permanent 'reduced tone' condition...

Well, that's what I'm wondering. This isn't the same cap that you would change to adjust the sweep. It seems so simple, yet I haven't seen this mod mentioned anywhere. I also thought this would garner a little more discussion than it has. Maybe it's just me that likes the sound, but it took a decent sounding wah and made it much, much better sounding (to me, at least).
-Joe Hart

[aron]

Well Joe,

Maybe you have your own nice little mod there? :-)

It's nice because most people would adjust the pot travel. This doesn't affect the low sweep and makes it less shrill.

Aron

[newfish]

Thanks to Joe for starting this ball rolling.

I'm in need of 'taming' my CB's top-end, as it gets difficult to control the feedback from my (solid-bodied) electric violin.

Probably shouldn't punch it through a Bigg Muff beforehand... 

The tone pots are *way down* on both the EV and the Muff.

Must be the 'massive' amount of overtones produced by the violin. Sounds awesome though... 

[Joe Hart]

I'm in need of 'taming' my CB's top-end, as it gets difficult to control the feedback from my (solid-bodied) electric violin.

Strangely, turning my guitar's tone pot down doesn't do much with my Cry Baby. It works wonders with my VOX 845. Hmmm.
-Joe Hart

[DougH]

I've had a lot of fun with the tone controls in my guitars this way. I usually end up with a smaller than stock cap and it keeps the control useful dialed all the way down. IIRC I've simmed this and the reaction of the "turned down" tone control to the pickup creates a peaky resonance that sounds similar to the bandpass filtering of a wah. Definitely can produce som fun interaction with a wah, as you would expect.

[newfish]

For those of us who play / love 'Strats', I found something out the other evening.

Turn the tone control all the way down for the middle pickup, and select bridge and middle Pups.

Going into an overdriven (SD-1) Valve Jr., I could swear I had a 'nasal', '%^&*ed-wah' sort of tone.

This was quite late at night - so I didn't turn up - but am utterly convinced this is what I'd heard.