Thank you, Eli Shahar, and the others who have sent emails about my
restoration guide to the Ampico A, at

  http://antiquemechanicalrestorations.com/Ampico_A.html 

This week I shared some information with a hobbyist who was adjusting
his pump so I thought I'd send the information along to MMD.

Here's a tip for regulating the amplifier pneumatic on your Ampico "A"
pump.  Set the Modify switch to Brilliant and play a heavy classical
piece with lots of loud crescendos in the music and watch the behavior
of the amplifier pneumatic.  Of course your piano will have to have a
good rebuild with plenty of power to do this.

As the music gets loud the amplifier should start to collapse.  The
pneumatic should not close all the way (limited by the bolt adjustment)
before the music climaxes in volume.  If your amplifier pneumatic
closes before the music reaches its peak, strengthen the coil spring
at the very end of the amplifier lever.

There are two springs on the amplifier lever.  Don't adjust the spring
for the spill to make this adjustment, [but] increase tension to the
spring at the very end of the lever.  This will give the widest range
of amplification.

The pneumatic should 'float' while the music increases in volume,
closing only at the loudest point.

Paul Manganaro