Wah Component Comparison Chart

[PenPen]

Interesting. Then I probably WON'T like the McCoy either. I don't like the Crybaby, I thought the Vox would be closer to the whole Voodoo Child sound. Guess not.

[Paul Marossy]

Interesting. Then I probably WON'T like the McCoy either. I don't like the Crybaby, I thought the Vox would be closer to the whole Voodoo Child sound. Guess not.

You have to remember that there are a LOT of factors involved in that sound - not just the wah pedal. Jimi had his stuff tweaked by Roger Mayer, and his amps were modded, and he played an upsidedown Strat a lot of the time, the stars and planets were aligned just right (joke!), among other things... 

[PenPen]

I have an upside-down strat (I'm lefty also), and indeed just the strat itself helps with that sound, it just sounded more smooth and natural to me than the Crybaby I fixed and played around with. I don't really want to sound like Jimi, I just want a wah sound like that. I just always thought it was the McCoy circuit that did it.

[tcobretti]

That Vox was actually the V847, I updated the schem to include the McCoy.  I apologize for the confusion.

BTW, my V847 sounds much better than my Crybaby.  The differences may be small, but they are significant.  I haven't built the Clyde, so I can't comment on it's Hendrixiness.  Part of my current theory on the Hendrix wah tone is that since Hendrix ran his wah into his Octavia, which acted like an output buffer, that having a output bufffer on your wah is part of that tone.

[alderbody]

Interesting. Then I probably WON'T like the McCoy either. I don't like the Crybaby, I thought the Vox would be closer to the whole Voodoo Child sound. Guess not.

btw, talking about Hendrix Wah sound...
The BBC Sessions "Burning of the midnight lamp" sound is what i would like to get from my wah.

my definition of Wah sound!

just awesome!

[tcobretti]

Yeah, that is a classic.  I had the old BBC single disc, and just a couple of days ago I got the new 2 disc set but I haven't heard it yet.  I hadn't thought about it, but since I posted this schematic I've been doing some serious work on my wah, and this song is a good reference point for me to use for the ideal sound.  Another amazing Hendrix wah moment is the talking wah from Still Raining, Still Dreaming off of Electric Ladyland.  Genius.

[Paul Perry (Frostwave)]

On the table, I see the Crybaby has Cout and Cef at .001u while all the others are .2u or more. I'm not sayng that's wrong, but....... it looks a bit suspicious.
I must say, it's great to see a table like that.. reminds me of literary analysis where one is trying to recreate the "original" Canterbury Tales from the various copies. Guess we'll have a family tree next.

[tcobretti]

Paul, you may be right.  I based the table on this schem:



But after your post I started digging and I found this:



So, I looked at my Crybaby from the late 80s/early 90s (pre-input buffer) and it has .22u caps in it.  So, I think I'm gonna change it on the table.

Nice catch!

[Paul Marossy]

Every CryBaby/Vox wah pedal that I have seen has 0.22uF caps in it. With 0.001uF caps in those positions, it would sound horrible - probably like a mosquito! 

[Seljer]

if you can look past all the bypass circuity and buffers, the Steve Vai Bad Horsie and Mark Tremonti wahs from Morley also use the same classic circuit:
http://morleypedals.com/downloads.html

[Seljer]

there are also schematics for an Electroharmonix one and a Dallas Arbiter one, as well as some others with the same type of circuit on http://www.schematicheaven.com/effects.htm

[tcobretti]

Thanks, Seljer.  When I get home from visiting my family for Christmas I'll add those to the chart.

[Barcode80]

looking at this, i wonder about my bad horsie. i searched for a schem and only found the bad horsie 2. here it is:

http://www.morleypedals.com/vai-2es.pdf

now my question is this. i have been wanting to mod the sweep and range of this for a while. so can someone tell me:

1) do you guys know what differences there are component-wise between 1 and 2? is the schematic essentially the same with a few tweaked values?

2) which part of the above schematic would contain the parts i would tweak to increase the wah range and smooth the sweep from toe-down to toe-up? when toe-down (but on), the travel from there to about halfway doesn't do much, then a small space in the middle does a LOT, then the top towards toe down changes in the same fashion as the bottom.

basically it seems like the bulk of the effect is bunched in the middle. any thoughts?

anyone know the huge difference between this schem and the "average" wah schem (besides opto-electric switching)?

[Seljer]

heres the first bad horsie - http://morleypedals.com/vai-1es.pdf

C9 would be the capacitor that controls the sweep range

I believe changing the value of R13 to something slightly larger (2k to 3k) would smooth out the transistion from bass->treble. Though to really adjust the sweep you'd have to do something with that moving semi opaque cover they have between the LEDs and LDRs

(the part names are the same on both schematics)


and as far as I can tell, the wah section is identical on both the bad horsie 1 and 2. The 2 only has some power filtering/protection added as well as the contour modecoming after the wah (which is just a fixed position opamp based twin-t type wah after the regular wah circuit)

[Paul Perry (Frostwave)]

http://www.geocities.com/j4_student/NewWayWah.gif

some dunlop variants

[RLBJR65]

[tcobretti]

Wow, I have never heard of the Clav Wah.  I guess it's designed for Clavinet, which might explain the very high value for the feedback cap.

Thanks Paul!

[tcobretti]

I added a couple more wahs.

[joegagan]

this is  an old thread but i like it!

Paul, thanks for publicizing how cool this circuit is. i have a broken boomerang circa 72 at my house. with the elrad inductor but the 25k pot was long gone, replaced by  a common 100k. looks like a good bet to get it started and done right. i will post results.
BTW, I despise the dearmond casing, the gear always feels like it has a glitchy 'drag' on it due to the spring at the back of the straight gear. i have owned several of the dearmond vol peds as well, never like them!

Tremblay (heyB!) , i like the clips you posted. the low end emphasis in the sweep is cool , the overall tone of the wah is sweet.

Re: the Philpott '97 crybaby shem. - i think there are two versions of that schem floating around , i could swear i had the same schem printed out 6 yrs ago that had .01 caps where the .001s are in the schem in question.

Re: the morley sweep on the opto circ - has anyone anylized the sweep of those wahs to see how they compare to the crybaby sweep?

On a related note:
I had total success with a new invention using dual LED/LDRs in a small plastic case. the throw was the same length as the straight gear  on the crybaby.  ( two separate chambers with two 'shutters' moving on a common shaft)
By using two LDRs, the two legs can be tied together to simulate a pot. One closes while the other opens

By altering the shape of the 'shutter', various ramps or tapers can be obtained. all of this tested out beautifully, was able to simulate all kinds of tapers by changing the shape of the shutter triangles ( see diagram).
It worked perfectly in my wah and also in a volume pedal.

if anyone knows of this being done before please let me know
I didn't feel it was worth patenting (if it hasn't been patented already) since the application is fairly limited. As a retrofit for existing wahs or volume pedals it would require a power hookup and add battery drain. I guess a wider application would be audio circuits where custom tapers would be cost prohibitive. very easy to change taper by altering the shutter shape.

The upshot would be that users could easily try different tapers by swapping out different shutter inserts.+ no pot to wear out

[B Tremblay]

BTW, I despise the dearmond casing, the gear always feels like it has a glitchy 'drag' on it due to the spring at the back of the straight gear. i have owned several of the dearmond vol peds as well, never like them!

I'm not a fan of the DeArmond shell either.  While the long rack is nice, the lack of adjustable tension makes for an odd feel.  Also, the pot mounting is reversed from the Vox/Crybaby shell, so the taper is reversed as well.  You could wire the pot for heel-down being the treble position to have the correct taper, but that's pretty counter-intuitive to play.  The only decent option is to use a linear pot.

Tremblay (heyB!) , i like the clips you posted. the low end emphasis in the sweep is cool , the overall tone of the wah is sweet.

Thanks, I'm glad they sound good to you.  The overall tone is close to my modded Vox, but with a fuller sound.