Let me echo Mr. Broadmoore's comments about the importance of properly
adjusting the limiter rail in the Ampico grand action. These thin L-shaped
strips of wood with padded lower edges, mounted on the back edge of
the main action rail have a somewhat flimsy design. They are adjusted
vertically by loosening 2 or 3 screws which fasten them to the main
rail through vertically slotted holes in the strips.

Larger washers, and new (and larger if necessary) screws may be needed
to make this difficult adjustment easier. Gluing very fine sandpaper to
the back of these strips, an old piano builder's trick, will make the
adjustment hold after the screws are tightened.

Ampico grand actions have no other stop to limit the closing of the
pneumatics. Not only does this adjustment cure regulation problems like
over-lifting of the dampers, but it also prevents the pneumatic from
closing beyond the amount required to play the note. If not limited,
this over-closing causes more volume of airflow per note than was allowed
for in the roll's dynamic coding, distorting the complex balances of flow
and pressure which occur in a Reproducing piano's playing.

Once I understood the significance of making this adjustment correctly,
doing so produced a very noticeable improvement in my piano's performance.

Richard Vance