Datablues,

Which Roland expression pedal do you have?

Boss FV-300L (product from Roland) with 2 ins and 2 outs can handle any keyboards. Just connect the L and R outs of your keyboard to FV-300L's ins and connect FV-300L's outs to your mixer. There is no need for modification on this product to work with PSR2000 or PSR9000. For other Roland expression pedals like Boss EV-5, and FV-50L etc. since I have not used them before, I cannot answer. I only know that the polarity of sustain pedals for Roland and Yamaha are the same. Yamaha MFC10 MIDI foot controller also has a built in expression pedal that works really well with Yamaha keyboards.

Paul Ip
from Texas