John O'Callaghan (born 1982, Navan, Ireland) is an Irish trance DJ and producer who has been a fixture of the genre for over two decades. He broke through in 2007 with 'Big Sky' (feat. Audrey Gallagher), whose Agnelli & Nelson remix was voted 'Tune of the Year' by listeners of Armin van Buuren's A State of Trance. As founder of the Subculture label and under aliases including Joint Operations Centre and Key4050 (with Bryan Kearney), he has left a lasting mark on the international trance scene.
Key4050 (O'Callaghan & Kearney) sloot Luminosity Beach Festival 2026 af en kondigde aan dat de eerste 45 minuten van hun set de basis vormen voor een nieuw Key4050-album.
Key4050 bracht samen met Bo Bruce de langverwachte samenwerking 'Empty Space' uit op Armind/Armada.
O'Callaghan speelde op 25 Years of Goodgreef in Belfast.
Bryan Kearney en John O'Callaghan kondigden aan het Key4050-alias in 2026 te reactiveren met een lange reeks geplande releases.
Luminosity and Amsterdam Dance Event bring This Is Trance By Night with Bryan Kearney, Darren Porter, John O'Callaghan, Mauro Picotto, Modea and Re-Solve to Panama.
Luminosity brings This Is Trance · Day with a strong line-up of international trance producers and DJs to Q-Factory Amsterdam.