Legend has it there are few guitarists who are more demanding to design signature gear for than Steve Vai (see my interview with DiMarzio pickup designer Steve Blucher for more on this). You don’t rise to such technical and compositional levels of excellence without being extremely driven, and Vai’s demands on gear companies are the thing of legend. So when he turned to Morley to design a signature wah pedal, I’m sure a few white hairs sprung up on the heads of Morley engineers.
The first cool thing about the Bad Horsie’s design is that it features switchless activation. There’s no chunky switch at the top of the pedal’s travel to stamp down on to start wah-ing. You simply put your foot on the pedal, and the effect engages. Take your foot off, and the wah effect tails off over a period of 1.5 seconds. Or you can pop the bottom off the pedal and adjust a tiny internal trim pot for your preferred off time, from instantaneously all the way up to 3.5 seconds.
The next design twist is the pedal’s operation itself. Instead of using an assembly to rotate a potentiometer when the pedal is moved like other wahs, Morley pedals use an Electro-Optical design which uses an LED light array and a light-sensitive sensor to control the wah sweep. What this means is that instead of stepping on the pedal to rotate a pot, stepping on the pedal brings the LEDs closer to the sensor, and the nearer it gets, the higher the wah tone sweep gets. The benefits are twofold: extremely smooth linear wah sweep, and best of all no pots to wear out and become scratchy and noisy. Some higher end tremolo and compressor pedals use similar technology to regulate the effect dependent on internal settings or the strength of the input signal, but it’s a logical fit for expression pedal effects.
The original Bad Horsie wah pedal – named after the opening track from Vai’s 1995 “Alien Love Secrets” EP – was a pretty big success, but because it was customised for Vai’s particular needs and rig, players wanted a little more flexibility. So the Bad Horsie 2 takes the exact sound of the original, and adds a foot switchable second mode, Contour mode, which enables the user to adjust Q and wah level.
More practical but by no means less exciting features are a Clear-Tone buffer circuit, which maintains a pure guitar tone and signal level whether in wah or bypass mode, and an easy access battery compartment which is simple to operate and extremely durable. It’s also a very heavy, robust unit, and its spring loaded design, while preventing traditional “set in one place as a tone modifier” techniques, is well suited to aggressive “stomp the bejabbers out of the pedal” styles.
By way of reference, the original Bad Horsie mode seems to be replicatable by setting the Contour control to 10 and Level to 0. Cranking up the level while on this setting thickens the tone considerably, which you can use either as a gain boost or just to compensate for thinner sounding pickups.