Billy Corgan

• Big Muff Volume knob above noon — the fuzz cuts mids dramatically. Push the output to compensate and maintain presence in the mix
• Maximum Sustain on the Big Muff for Siamese Dream leads — Corgan used a near-infinite sustain setting for soaring lead tones
• The amp is slightly overdriven into the Big Muff — a clean amp makes the Muff too fizzy; a slightly-dirty amp rounds off the harsh top end
• Stratocaster neck pickup for solos — despite the high gain, Corgan often used the neck pickup for its warmer, more vocal character
• Studio technique: in "Siamese Dream" the guitars were quadruple-tracked with slight pitch and tone variations to create the massive layered sound
• Use a ProCo RAT in place of the Big Muff for the distortion-without-fuzz-character — more mid-forward and better for rhythm parts
• Tune down to Eb standard for the characteristic Pumpkins "heaviness" — most of the band's recordings are in Eb
• The chord voicings are often power chords with an added major third — the "Corgan chord" is not just a bare fifth
• Feedback and noise are used structurally — at the end of "Soma," the noise IS the composition, not an accident

Billy Corgan's Smashing Pumpkins tone is the sound of shoegaze meeting hard rock — walls of layered distortion, Big Muff fuzz cranked to maximum sustain, and a melodic sensibility that cuts through the noise.