How Dave Jerden's AMS Digital Delay Gave Keith Richards' 'Mixed Emotions' Riff Its Pulsing Drive

During the Steel Wheels sessions at Air Studios in London, engineer Dave Jerden wanted to capture the band’s raw live energy without relying on the cavernous echo chambers that had defined earlier Stones records. For the opening riff of “Mixed Emotions,” Jerden patched Keith Richards’ guitar through an AMS DMX 15-80S digital delay, set to a rhythmic eighth-note repeat that locked tightly with the track’s tempo.

The benefit was two-fold: the delay gave Richards’ signature phrasing a percussive, almost pneumatic push that cut through the mix without needing excessive reverb or overd