Richards uses a fuzz pedal for the iconic guitar riff in this song. The sitar-like sound comes from the fuzz on a Strat.
Signal Chain
Maestro Fuzz-Tone FZ-1→Vox AC30→Output
PedalMaestro Fuzz-Tone FZ-1
gain
8
level
7
AmpVox AC30
bass
4
gain
5
treble
7
presence
6
Notes
The descending riff mimics a sitar. Use the bridge pickup and dial in maximum treble.