This is the song that sent people checking the sleeve for a DJ credit. There isn't one. Every scratch on the lead single from Evil Empire came from Tom Morello's guitar and feet, and the January 1996 release reached No. 27 in the UK and No. 7 on the US Mainstream Rock chart.
What makes the tone. Underneath it all is a cranked Marshall JCM800 delivering a plain, honest crunch. The riff goes through a Cry Baby wah rocked in time, a DigiTech Whammy adds an octave-up siren, and the kill-switch toggle on his 'Arm the Homeless' guitar chops the signal like a fader. The magic is in the feet and the switch, not in exotic amp tone.
The analogue recipe. Guitar with a kill switch, then wah, then a Whammy-style pitch shifter on its octave-up setting, into a JCM800 with enough gain to crunch but not fizz, and a small room. Keep any compression light. The amp should sound almost boring on its own, because the pedals are the voice.
How to play it. It sits in F minor territory, played in drop D with no capo, at 105 BPM and rated advanced. The main hook is a single-note riff with the wah rocked rhythmically, so practise foot and picking hand together until the pedal moves on the beat. The famous scratch section comes from rapid flicking of the pickup selector, with no fixed notes at all.
On a Boss GT-1000 / GX-100 / GT-100. Pick the Brit Stack preamp with a V30 cab, then compressor, chorus bypassed, Pedal Wah in FX3, no delay and a room reverb, with the expression pedal assigned to the Whammy-style octave sweep. Spend most of your practice on the expression pedal itself; the patch is simple, the performance isn't.
On a Kemper. A JCM800 profile does the heavy lifting, with Wah Pedal in Stomp A, the Pitch Shifter in Whammy mode in Stomp B and a compressor in Stomp C, then room reverb. Assign an expression pedal to morph both sweeps, and calibrate it so heel and toe hit the extremes exactly.
Skip the guesswork. Every block and every value for “Bulls on Parade” is laid out in the Soulster Tonebook for fans of Rage Against the Machine →, along with the key, the capo and the chord shapes.
All Along the Watchtower Guitar Tone: Hendrix's Four-Part Solo
Heart-Shaped Box Guitar Tone: Cobain's Flanged Verse, SansAmp Roar