The Doctor's recorder

From Tardis Wiki, the free Doctor Who reference

A recorder is a woodwind musical instrument played by blowing down a slit at the top and placing one's fingers and thumb on the airholes to produce notes.

The Second Doctor owned a recorder and often enjoyed playing it, usually as a source of self-amusement, but also to help him think, he used it on many occasions:

Although his memories of meeting his future self quickly faded, the Doctor did remember that he had lost his recorder, and went to a music shop on Amber Station to get a new one. (DWM: Briefly Noted)

Other

When the Second and Third Doctor were transported to Omega's realm, the recorder fell into the TARDIS' force field generator, and was therefore not converted into anti-matter during the trip there. When the Doctors discovered this, they offered it to Omega, and the resulting annihilation seemingly destroyed the renegade Time Lord and his world. (DW: The Three Doctors)

Sarah Jane Smith discovered the Doctor's recorder in the TARDIS' secondary control room. (DW: The Masque of Mandragora)

The newly regenerated Doctor tried playing the recorder, but realised it was just not him. (DW: Castrovalva)

The Doctor played the recorder in an alien marketplace to amuse Lilith. (NA: Timewyrm: Apocalypse)

According to one account, the Ninth Doctor threw the recorder away on a rubbish tip on Earth while having a clear out of some old things. In this case, however, the instrument was referred to as a flute. (whoisdoctorwho.co.uk)

The Doctor's recorder