[ I mis-titled the article by Bruce Clark as "Ampico "A" Note Cut-out
 [ Block" whereas he was speaking of the set of small valves which
 [ disable the expression controls.  Similar valve blocks are often
 [ installed in other expression pianos to disable or cut out playing
 [ notes.  Virtually all music roll player systems also have a large
 [ action cutout valve which shuts off suction to the player mechanism
 [ while the music roll rewinds.  Bruce kindly sent me the explanation
 [ that follows.  -- Robbie

Hi Robbie,  The cutout block in the Ampico does not cut out any notes,
like some that are multiplexed in other makes of reproducing pianos.
It only disables the expression controls: it cuts out the crescendos,
the intensities, and soft pedal when the lever at the spool box is
moved to "Automatic Off".

Another way of looking at it: it cuts out the first seven expression
holes in the bass end of the tracker bar (excluding 3B, which is what
the factory calls "loud pedal") and cuts out the first seven holes
inward from the treble end of the tracker bar.  The tracker bar holes
are numbered, beginning at the edge: 1B 2B 3B 4B 5B 6B 7B (B=Bass).
The treble end is the same: 1T 2T 3T 4T 5T 6T 7T and 8T which is
rewind.

Needless to say, when the cutout block is activated the piano will not
reproduce, and it plays like a player piano at the lower intensity
which can be augmented by using the bass and treble finger buttons.

This to me is somewhat redundant because, if one were to play a
standard player roll, none of the expression holes would be activated
and there would be no need to cut out the Ampico expression.  Perhaps
the Ampico cutout block was designed for personal touches to Ampico
rolls, or so that other expressions rolls could be played and augmented
with the finger buttons?

If one is going to play only Ampico rolls, the automatic cutout block
can be bypassed entirely and piano will reproduce Ampico rolls very
nicely and the tracker bar pump will clean _all_ of the tracker bar
holes, instead of only the notes.

Bruce Clark