I'm about to go buy some parts from my local shop, and started wondering what would happen if a wah was run at 18V?
I know in distortion and OD pedals, it often results in greater headroom and dynamics.

If all the caps were rated properly for 18V operation, does anyone have an idea of what would happen to a standard crybaby at 18V?

I am going to hazard a guess that it would sound no different to 9 volts. There are transistor gain stages in a Crybaby but you can run a clean guitar through one in to a clean amp and the wah-ed sound is still clean, so that suggests to me that 9 volts already provides enough headroom.

Yup.  There is no reason to want to run it at 18v.  On the other hand, if you have a bunch of other things running at that higher voltage, and there is current left over in your supply than can power the wah, there would appear to be no harm in doing so.  The benefit will simply be one of convenience, not sound quality.  Just remember that all electrolytics need to be scaled up appropriately for the safety margin.  I would surprise me, however, if they were not already 25v-rated caps.

Okay, cool. I was just curious as to why the Slash wah is at 18v...but I guess that has more to do with the fact that it has a distortion circuit.

I all depends.

First what wha circuit do you want to change the voltage of?  If inductor what inductor circuit?  If inductorless what circuit?

Then you do the math or raise the voltage and measure the operating points and gain of the stage(s)

When you change voltage upward you need to check voltage ratings of caps and power rating of components.

... just kidding

Quote from: MikeH on July 17, 2009, 01:18:38 PM







... just kidding

Ha! That's a great picture. Is that from a nuclear test at the Nevada test site? That's about 100 miles from where I live. I'm guessing so from the Joshua Trees in the foreground...

Quote from: Gus on July 17, 2009, 11:22:57 AM
I all depends.

First what wha circuit do you want to change the voltage of?  If inductor what inductor circuit?  If inductorless what circuit?

Then you do the math or raise the voltage and measure the operating points and gain of the stage(s)

When you change voltage upward you need to check voltage ratings of caps and power rating of components.

I guess it would've just been a modified crybaby circuit, haha.

Maybe that Slash signature wah is running on a bipolar power supply? That would theoritically give you more headroom, and you could do it with a pair of 9V batteries...

^Possibly. I have no idea, I've never looked at the schem or seen the inside, actually.

BTW, I noticed you're the dude who owns DIYGuitarist. 
Big thank you to you, I think your site was the first one I saw, that got me all into all this. Also recently did the Crowther "Fat wah" mod specified on your site. Haven't tried out the circuit yet, because I'm overhauling my wah, but much thanks for it! Hoping it'll make my wah more aggressive and "vomit-y".

You asked what would happen with no specifics given about the circuit.

Measure the transistors Base, Collector, Emitter voltages and the supply voltage before and after.

If it is a three transistor Crybaby note what happens at the input buffer as well.

Make a note of the EF operation point.


Here is something from the layout gallery section a different take on the wha.  The operation points are independent of each other.  It inspired from threads at this forum and posts of Paul M. about the boomerang and colorsound inductor and other whas.

http://www.aronnelson.com/gallery/main.php/v/gus/wha1.gif.html?g2_imageViewsIndex=1

It might open larger than your screen.

Quote from: Gus on July 19, 2009, 01:38:23 PM
You asked what would happen with no specifics given about the circuit.

Sorry, I assumed that you would assume it was just a Crybaby-type. Like 90% of wahs are based on that design, so I figured it would've been implied My bad.

Quote from: Gus on July 19, 2009, 01:38:23 PMHere is something from the layout gallery section a different take on the wha.  The operation points are independent of each other.  It inspired from threads at this forum and posts of Paul M. about the boomerang and colorsound inductor and other whas.

http://www.aronnelson.com/gallery/main.php/v/gus/wha1.gif.html?g2_imageViewsIndex=1

It might open larger than your screen.

I'll take a look at it.

I haven't built a crybaby with parts rated to take 18V (Yet, I guess:) ), I was mostly owndering if anyone here had built one or modified one to do so.


EDIT: Took a look. Interesting. I'm not that knowledgable on circuits yet...so...
-What would be the thought process behind this circuit? Why redesign it this way?
-What's the value of the input cap there?

Quote from: azrael on July 19, 2009, 01:14:13 PM
^Possibly. I have no idea, I've never looked at the schem or seen the inside, actually.

BTW, I noticed you're the dude who owns DIYGuitarist. 
Big thank you to you, I think your site was the first one I saw, that got me all into all this. Also recently did the Crowther "Fat wah" mod specified on your site. Haven't tried out the circuit yet, because I'm overhauling my wah, but much thanks for it! Hoping it'll make my wah more aggressive and "vomit-y".

Yep, that's me. Guilty as charged. 

I like that Fat Wah mod, I think it sounds pretty good. 

The output emitter follower stage is inspired from the boomerang.  The boomerang does not have the 470K clean mix/bias resistor and uses a +9VDC resistor to collector bias.   I "designed" a bootstrapped output stage set for a high input resistance and about 4.8VDC at the emitter.

Input cap and input resistor to taste. 

Have you built it before?

If so, how does it sound?