In July 1961 he took over from
Dick Hawdon as lead trumpeter for the John Dankworth Orchestra. He can be heard on many Ken Moule and Dankworth recordings of this period, his style influenced by the early work of
Miles Davis. He was featured on
Johnny Scott's
London Swings in 1966. Calvert began operating a jazz label at
Lansdowne Studios in the 1960s with drummer Barry Morgan, Monty Babson and Jerry Allen. In 1967 the group founded
Morgan Sound Studios at 169–171 High Road,
Willesden. The studio was the location for recordings by notable artists and bands, including
Joan Armatrading,
Black Sabbath,
The Cure,
Donovan,
Jethro Tull,
the Kinks,
Paul McCartney,
Cat Stevens,
Rod Stewart,
UFO,
Yes and many more. As a session musician he played for
The Beatles in the brass section on
Penny Lane, and trumpet and flugelhorn on
Martha My Dear. ==1970s==