It only applies to single notes/pads. Keep in mind it is not really effect, it is just changing the parameters on what it is assigned to (decay, attack, filter or tuning parameters). You could use the slider to record changes one track at a time and do every single one to do what you are talking about. Very tedious and probably isn't what you are looking for.
The FX card modifies the actual sound signal and would be required to effect multiple sounds at once. On the 2ks, you usually would not want to apply effects to the whole mix as they really aren't designed for that (like the ones on 1k and 2500), but it would be possible if you set all pads to the same effect group and level.
