Dexter Wansel, the keyboardist, songwriter, arranger, and producer whose work helped define the Sound of Philadelphia, has died at 75.

His son, producer Andrew Pop Wansel, announced the news in a social media post, saying his father died May 31 after a long illness. He said Wansel had battled health issues for 17 years.

Wansel became a key creative force at Philadelphia International Records, where his arrangements and production helped shape the sound of soul and R&B in the 1970s. His work appeared alongside music by Teddy Pendergrass, Patti LaBelle, Lou Rawls, The Stylistics, and The Jones Girls.

He was also known for bringing synthesizers into soul, funk, and jazz in a way that felt bold but musical. His 1976 track Theme from the Planets became one of his most recognized recordings and later found new life through sampling in hip-hop, R&B, and pop.

Wansel leaves behind a deep musical legacy tied to Philadelphia, studio craft, and generations of producers who followed his sound.