Open Kalarm, create a new command alarm, check Enter a script box and paste this in:
qdbus org.kde.amarok /Player org.freedesktop.MediaPlayer.VolumeSet 100
amixer sset Master 100
Bam! Amarok alarm.
Don’t forget to leave Kalarm turned on for the night.
You may turn off your sound system, given that you have some unnecessarily intricate contraption to turn it on in time, or a programmable time switch.
Also, thanks to the guys at #amarok for pointing me to D-Bus.