In the 1970s Ditmas played in the pit orchestra for the Broadway show Promises, Promises.[2] He was then with Joe Newman (1971), Jazz Interactions Orchestra (1971), Gil Evans (1971–77), Enrico Rava (from 1971), Stardrive, Atmospheres, and Future Shock (1972), New Wilderness Preservation Band (1972–73), Paul Bley, Lee Konitz, Chet Baker (1974–75), and Stan Getz (1975).[1] Later in the 1970s he concentrated on solo performance, including experiments with drum machines.[1] He returned to work with the Evans Orchestra from 1979 to 1985, and lived in Italy in 1986–87, where he played with Dino Saluzzi, Enrico Rava, Rita Marcotulli, and Pietro Tonolo.[1] He played with his own trio D3 with Jack DeSalvo and Tony DeCicco[3] from 1988, after returning to New York.[1] D3 recorded Spontaneous Combustion for the Tutu label.[3] In the 1990s he played with Pat Hall and Karl Berger among others.[1] He often played drum synthesizers in the same decade.[2] His 1995 album What If also featured saxophonist Sam Rivers, guitarist John Abercrombie, Bley on piano and synthesizers, and bassist Dominic Richards.[4]
In 1990, Ditmas orchestrated the music to an opera by Patricia Burgess, The Dream of Four Directions.[1] He has also composed prolifically for television and advertising; among his credits is the film Deathscape.[1]