Tape deck

A tape deck was a human device which was used to play recorded music. Ace carried one with her as she visited Shoreditch in November 1963 with the Seventh Doctor. Since such a device did not exist in the 1960s, the Doctor called it a "dangerous anachronism." Through using the device, Ace was able to pick up transmissions from the Daleks. Ultimately, Ace's tape deck was destroyed by gunstick fire from an Imperial Dalek. The Doctor was pleased by its fate, explaining to Ace that if someone had found it and discovered the principles of its function, the microchip revolution would begin twenty years too early, causing "incalculable damage" to the timeline. (TV: Remembrance of the Daleks)

Behind the scenes
Though not narratively specified, the tape deck Ace was carrying is a.