Being you have a Yamaha, get a Yamaha Expression pedal. I have a Yamaha FC7 that I got for my Motif ES, and it works great. It has a nice amount of travel which does vary the volume level, and it has an "off" postion. I just plugged it in and worked correctly right out of the box. Sweetwater has them for $42 bucks and change. Free shipping. That's a great deal.