hey dom,
the volume knob is not a volume knob as it is on a amp or so. it's to set how high you have to lift the volume arm to get the full volume.
double and triple check your soldering. i followed these instructions : etherwave tuning. wich brings the unit into a playable state. not perfect, but playable. for ultimate fine tuning: go to colmar for the summer academy and meet thierry. he tames every whacked theremin.
do you live near my place?
@christopher: it's walpurgisnacht!!