Hi all,  Just a thought concerning the upright Marshall & Wendell
Pedal-Electric Ampico; perhaps the pedals were included to compensate
for the fact that there were no crescendo pneumatics in this mechanism.
This would presume that the pianolist knew the capabilities of the
Ampico A system and that there were no crescendos visible.

One question which might support this presumption: could the pedals
alone provide a sufficient amount of vacuum to drive the roll plus
provide a sufficient amount of vacuum for the complete stack?  It
appears that there is no reservoir for the pedals.

Good Luck!

Mike Walter

 [ More about the foot-powered Ampico in the MMD articles indexed
 [ at https://www.mmdigest.com/archives/KWIC/M/marque-ampico.html 
 [ and https://www.mmdigest.com/archives/KWIC/M/marque.html 
 [ -- Robbie