John O'Callaghan

John O'Callaghan is an Irish musician and DJ, who mainly produces trance music. He also produces music under the aliases of Joint Operations Centre, Mannix, Henrik Zuberstein, and Stenna. He has collaborated with fellow Discover artists such as Bryan Kearney, Neal Scarborough, Thomas Bronzwaer, and Greg Downey as well as, more recently, trance hero Leon Bolier.