I just bought a Boss PS-5 super shifter pedal, and I want to buy an expression pedal to use with it. But there are a few things I'm wondering before I buy one. Firstly, is a volume pedal the same as an expression pedal? Could I use an Ernie Ball Volume pedal with the PS-5? If so, should I buy one designed for passive electronics or active? Or doesn't it really matter? Also, if it's possible, how would I plug it in? Would I just plug the output from the volume pedal into the PS-5's expression pedal input? Or is it more complicated than that?