I have a new FBV Shortboard MKII with a new spider valve MKII 112 amp. When I switch channels on the foot controller, A to B etc, I hear a loud pop regularly. It does not happen everytime, but most times. This is with the volume @ 100%. I don't hear it if the volume pedal is @ 0%, but I can't imagine the design is such that changing channels requires using the volume pedal to cycle the volume off and on in between each channel change with the volume pedal.

Wondering if I need to take this up the chain for repair/replacement. Thanks.

Mark