McCartney and his family returned to London shortly before Christmas 1969, and he started work on the album at his home in Cavendish Avenue, St John's Wood. The recordings were carried out on a recently delivered Studer four-track tape recorder, without a mixing desk, and therefore without VU displays as a guide for recording levels. McCartney described his home-recording set-up as "Studer, one mike, and nerve". He played all the musical instruments on the album – from acoustic and electric guitars and bass to keyboards, drums and various percussion instruments – with Linda supplying backing vocals on some songs.