The blueprint of desert/stoner rock: Josh Homme's molten riff from Kyuss's Blues for the Red Sun (1992). Produced by Chris Goss at Sound City, the tone is a down-tuned guitar (Ovation Ultra GP, DiMarzio Super 2s) driven hard through a Marshall JCM900 4100 into an Ampeg 8x10 BASS cabinet -- the famous 'guitar through a bass rig' move that gives the riff its woolly, earth-moving low end. The dirt is amp gain plus wah, not a fuzz pedal.