The new site will offer DRM-free downloads from the two largest classical labels – Universal Music and EMI Classics – as well as key independent labels including Naxos and Chandos.
The site offers music in formats up to 320kbps DRM-free MP3 and lossless FLAC, and downloads can be transferred to users' portable devices or other media, or burned to CD.
Also on offer is the free Passionato Player, which enables users to organise existing CD collections alongside music bought and downloaded from the Passionato Store.
Passionato has been developed by James Glic ker, the former President of the Baltimore Symphony Orchestra; he also ran MusicNow, one of the first subscription download services.
Users registering now can download 10 free tracks, and a typical album costs £7.99 for an MP3 download, with 'daily deals' available for £1.99.