Wah Component Comparison Chart

[tcobretti]

I built this for myself, but thought some of you might find it interesting.  The only other wah schem I have handy is for the Clyde McCoy, and I'm thinking about adding it on.  Come to think of it, I might have a Shinei wah somewhere; I'll check it out.  If anybody has any unusual wah schems, pm them to me and I'll add them on.

Thanks to RG for allowing me to use his schem.  I like it very much because the names he gave the components are illustrative of their purpose.

[tcobretti]

I added the Shinei.

Anybody know anything about the Roger Mayer wah?

[jimbob]

Great list.

[Paul Marossy]

That's a good idea. I don't know if would put the Boomerang on that list as it's considerably different than the schematic shown...

[tcobretti]

Paul, I tried to describe the differences at the bottom.  Did I miss anything?

[Paul Marossy]

Paul, I tried to describe the differences at the bottom.  Did I miss anything?

Well, if you compare schematics, how the inductor is incorporated into the circuit on the Boomerang is much different.  It's so different that I do not think you can really put it on the list above because it really needs its own schematic with a description of what each part does.

[tcobretti]

Paul, looking at this schem I can't see the difference.  Can you explain it so I can understand what I am missing?  Thanks for the help.

[Paul Marossy]

There I go trying to work and surf again. Sorry about that. One version of the schematic that I drew got me confused. 

It gets confusing when you look at the Vox patent document the way it is drawn and the way the Boomerang schematic is drawn. The main differences that I see in the Boomerang are:

1. 820K (not 620K) feedback resistor on Q2
2. 1uF caps at hot and wiper of 100K pot
3. 1.5M resistor from collector of Q1 to inductor

I think these are then main factors in what makes the Boomerang sound different.

Here is the BG-2 schematic, similar to the BG-1:


This is a schematic and PCB that I drew based on my own original Boomerang: http://www.diyguitarist.com/PDF_Files/BoomerangBG2PCB.pdf

[B Tremblay]

This seems like as good of a thread as any to discuss some of my work with the Boomerang, so here goes:

I've always wanted to build a wah and the one I've wanted to tackle is the Maestro Boomerang. Since Paul Marossy had recently shared a confirmed schematic and I had the wah shell from the Phozer 2 development, I decided to finally do so.

I started by using the Radio Shack transformer that RG mentions in his wah tech article. I needed to tweak the component values a bit for a good sound, but I held off sharing my work until I had a proper inductor. Then I finally got a yellow Fasel and over two days I modified the circuit to my liking.

In its stock form, there was some distortion present in the bass section of the sweep as well as an abundance of midrange. I reduced the mids, gain, and bass to my liking, then added an adjustable Q control.

The result is a smoother, fuller sounding wah than my modded Vox V847.

I used a Dunlop Hot Potz II in parallel with a 33k resistor as Paul did to create the 25k pot of the Maestro.



Here are two clips of the circuit.  There's a little bit of my strumming picked up by the mike, but it doesn't detract too much.

Setup: Tele bridge pup - wah - Ampeg Rocket II (reverb on) close-miked - mixer - sound card.

http://runoffgroove.com/dry-vox-noo.mp3 has the same passage played dry, then through my modded Vox wah, then the Noomerang.

http://runoffgroove.com/noo.mp3 features the Noomerang only.

[Paul Marossy]

Cool Mr. Tremblay. The Boomerang is definitely one worth messin' with. The funny thing is that my original has no distortion, but my clones have a little bit. The transistors that you use seem to make a big difference in this circuit. 

[tcobretti]

It's very interesting to see the "ROG" version of the Boomerang; thanks for posting it.

[Paul Marossy]

I'll have to take my extra Boomerang PCB and try these ROG mods! 

[jonathan perez]

within the next month, im going to build one.

i still have the giant shell...so...yeah...

[alderbody]

very interesting thread!

just wanted to follow the updates.

great job fellas! 

[Paul Marossy]

Quick question for the ROG team: that 1.5M resistor to ground on the input, why did you add that? I'm just curious...

[Dai H.]

cool stuff! 

[B Tremblay]

Quick question for the ROG team: that 1.5M resistor to ground on the input, why did you add that? I'm just curious...

As a better-safe-than-sorry switch pop pulldown.

[Paul Marossy]

As a better-safe-than-sorry switch pop pulldown

That's what I thought. I haven't had any problems with popping, but it doesn't hurt to add one in...

[PenPen]

So, first is that Vox the Clyde McCoy? If so, then the Crybaby is nearly identical?

[Paul Marossy]

So, first is that Vox the Clyde McCoy? If so, then the Crybaby is nearly identical?

Yes, and yes.