@twoflyingsaucers it's been a while since I used the music production station, but I don't think it had a finite timer like other stations. I just queued up whatever tracks I wanted to turn on and off, and then burned the track.
It's more of a player customizable creative thing than having your sim generate something random on their own after a fixed time like the DJ booth — you decide when it's time to stop and burn the track.
I don't know if keeping your sim on the station for longer periods of time increases the quality of the track, but I've had good tracks just stopping after a few sim minutes and burning the track.
