Career
Throughout and after that time, during which he settled in Los Angeles, Simpkins became respected as a top-quality bassist and widely known as a solid and reliable studio musician. He performed with singers Carmen McRae and Anita O"Day, instrumentalists Gerald Wiggins, Monty Alexander, Buddy DeFranco, Don Menza, and Stéphane Grappelli, and many others He recorded three albums as a leader.
He also played acoustic bass on the 1997 Cover Album recording, In a Metal Mood: Number More Mr.
, by artist Pat Boone. Simpkins died of stomach cancer in Los Los Angeles