Hi Len
I am one who has had a volume problem, but hope it was related only to a midi sequence I was using,however,I may not be so lucky.
I haven't utilized the parts expression as I am still learning the basics,but,if you are referring to the analog pedal that goes into the pedal and out to an external amp, it might work assuming external speakers are used instead of the internal speakers.
I,however,try to use just the board unless the venue is too large.
Bernie
_________________________
pa4X 76 ,SX900, Audya 76,Yamaha S970 , vArranger, Hammond SK1, Ketron SD40, Centerpoint Space Station, Bose compact