Tag Archives: robin trower

Building a “static wah” pedal on veroboard

What is a wah pedal?

A normal “wah pedal” is a device that you drive with your foot. When you waggle it back and forth it makes your guitar sound like a human literally going “wah wah”. It was built (possibly by accident) to emulate the way a trumpet player might use a hand-held mute, but it doesn’t really sound much like that on a guitar. It is definitely its own sound. To understand the ‘traditional’ circuit here’s just about the best explanation ever written about them. Indeed, within weeks of the first useful device appearing on the market, Eric Clapton was using it on the Cream track “Tales of Brave Ulysses” to great effect. Then it became de riguer, and the likes of Hendrix, Beck and even George Harrison took it to great heights themselves. And for us amateurs, a pedal board is not complete without one. I currently have a Boss V-Wah, which does a passable simulation of a standard Cry Baby wah, as well as others.

Jimi doing the wah thing

Jimi doing the wah thing

What is a “static” wah pedal?

Sometimes when you’re playing with a wah pedal you end up leaving it turned on without your foot on the pedal. And sometimes it will even sound good. Legend has it that Mark Knopfler played the Money For Nothing intro using a wah pedal left in a certain fortuitous position. After reading various interviews about those mythical sessions, it’s not so clear. It seems the tone was achieved accidentally with some unorthodox positioning of the mics, which implies their locations created odd phase relationships, which in turn may have sounded as if someone used a notch filter (kind of like a wah). But then this one talks about Knopfler himself describing the concept of a static wah. I read a third interview once (can’t find it now) that supports both. i.e. the studio recording was the accidental mic positioning, whereas when MK tried to recreate the tone elsewhere he tried using a wah pedal (in a static position). Either way, I want to build a static wah for a second, and perhaps more important reason: Robin Trower uses a static wah for solos. Here’s Mike Fuller, from Fulltone:

11 years ago I made a couple of fixed wah wah effects I called the Wahfull®… they were simply the guts from a wah wah stuffed inside a box with a knob so you could find that perfect Mid-Boost sound every time you kicked it on. Nice effect, sold a few, moved on. Last year Robin Trower called me and said he was doing some gigs with Jack Bruce and asked “Would it be possible to have a wah wah in a regular box so that one could get that “fixed wah” sound by clicking on the pedal?” So I made one up and he’s been using it ever since.

Here it is in all its glory on Trower’s stage rig:

Trower's rig - including the Wahfull

Trower’s rig – including the Wahfull

* Note how Trower doesn’t use a power supply, or even a pedal board. Rock ‘n’ Roll!

Bringing it to fruition

So, all I had to do was find a decent circuit, and make the damned thing. I didn’t have to worry about buying either a broken wah or buying a new empty enclosure as this will fit in a standard pedal enclosure, such as the 125B I had laying around. I found a circuit on Sabrotone’s site: Static Wah circuit Here are the useful features over and above a normal wah circuit:

  • A ‘gain’ control to add a bit of grit/boost. I am a big fan of using a booster to give you a bit of “ooomph” when entering a solo.
  • a ‘Q’ control to change the width of the notch. This offers flexibility for little cost.
  • A ‘volume’ control to help match levels, especially when you’ve cranked the Gain a bit.
  • A multi-position rotary switch to adjust the main filter’s capacitor. Again, flexibility is good if it doesn’t degrade tone.

The mods are such that it still retains its bog-standard Vox circuit, but it becomes a little more useful for modern times.

The layout

The Sabrotone "WahWithMods" layout

The Sabrotone “WahWithMods” layout

Almost there

Almost there

I forgot to drill the hole for the capacitor switch. Doh!

I forgot to drill the hole for the capacitor switch. Doh!

The finished article

The finished article

Demo

Here’s a demo clip. It’s with the usual setup: my Tokai Les Paul, the one with the 1961 hum bucker in the neck. It’s going into the static wah, then my Box of Rock clone. Then into my AX84 amp, into a 2×12 cab.

I start off with the clean signal, then I turn on the way. Then I turn off the wah, and turn on the Box of Rock for a second. Then the wah goes back on. Each time the wah goes on I begin with the frequency knob anti-clockwise and work my way around to maximum. This is the same as ricking a wah pedal from back to front. You can hear that happening especially in the overdriven section.

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