No sound on Build 1059

I like to keep up with the bleeding edge nightly versions of songbird. Have been using (windows) build 1053 perfectly for a few days. Just installed build 1059, and the player goes through the motions of playing a song whilst remaining strangely quiet. It appears to be playing - the volume is turned up and my normal playlists are all working mp3 files - but no sound comes from my speakers. To compare, 1053 still works, as do other media players on my system.
p.s. sorry I couldn't post this somewhere else, didn't know where to write it.
Nick