I'm presently trying to put together a 1917 upright Stoddard Ampico
action.  The parts are all rebuilt, but I don't have a tubing guide
for the expression mechanism.

The unit has a dual sliding spool valve that has direct control to
amplifier or subdue pneumatics.  It also has the finger expression
buttons, but they are not the normal one-tube variety: there are three
tubes for each button.  I assume it somehow overrides the sliding valve
controller.  I also do not know if there are any bleeds involved.

I have posted pictures on my web site:
http://webs.lanset.com/rslemon/ampico_expression_system.html

I'd appreciate any help you can give me.

Bob Lemon - Lemon's Player Piano Service
Sacramento, CA