The standard wah pedal. Hendrix made it famous. Used on Voodoo Child, White Room, and thousands of other recordings.
A direct comparison of the Big Muff and Fuzz Face circuits: how they work, how they respond to guitar volume and picking dynamics, and which one belongs in your signal chain.
Tom Morello's tone broken down: the JCM800 gain structure, wah-as-filter technique, Whammy settings, and how to approximate it on a modeler or pedalboard.