I am looking to buy an SY-1 this weekend. I also would like to purchase the Boss FV-500 to use as an expression/volume pedal. I play both passive & active guitars & basses. The FV-500 comes in either a high or low impedance version. Does anyone have any experience with this combination, SY-1+ FV-500, or a recommendation regarding which impedance would best suit both passive/active types of instruments into the SY-1. Thanks