To the technician working on a Marshall and Wendell Ampico, these
instruments actually came several versions.  Most did not have what we
refer to as full B hence the span of the pneumatic is not adjustable.

Most had the expression system away from the stack, not part of the
stack.  I say most as I have only heard of one Marshall with the note
compensation pneumatics.

The B usually does not play louder than an A on loud passages in the
music but it also does not play the softest passages softer.

Don Teach
Shreveport, Louisiana