Dear Mr. Chesters,

Since this is an issue I've dealt with as well (having a similar, upright
Ampico instrument) thought I would offer what little advice I can.

As I understand it, the Ampico was designed to play normally at the first
intensity, or softest volume, which generally speaking is a bit weak for
standard roll playing.  In playing 88-note (non-expression) rolls, the
system was designed such that the Ampico on/off switch (second from bottom
on left side of tracker compartment) should be switched "off."  Then,
the bass and treble buttons are used to provide a rapid volume increase
as desired to add expression to the performance, via the left and right
side intensity pneumatics.

But of course when the buttons are released the piano settles back to
"first intensity."  I've found that (at least on my piano) it's possible
to lock the intensity at maximum simply by turning the _Ampico_ on/off
switch to "on" before playing the roll, and then depressing both treble
and bass buttons after turning on the electric power to the piano.  For
88-note play I usually keep the volume (uppermost) switch at the "low"
setting, and locking the expression pneumatics then gives sufficient
volume.

Good luck -- I hope this works with your piano.

Frank Himpsl