California Jam (also known as Cal Jam) was a rock music festival co-headlined by Deep Purple and Emerson, Lake & Palmer, held at the Ontario Motor Speedway in Ontario, California, on April 6, 1974. It was produced by ABC Entertainment, Sandy Feldman and Leonard Stogel. Pacific Presentations, a Los Angeles-based concert company headed by and , coordinated the event, booked all the musical talent and ran the advertising campaign. Don Branker worked for Leonard Stogel and was responsible for concert site facilitation, toilets, fencing and medical. The California Jam attracted 300,000–400,000 paying music fans. The festival set what were then records for the loudest amplification system ever installed, the highest paid attendance, and highest gross in history. It was one of the last of the or