[ Adam Aceto wrote in 120810 MMDigest:

> I have a late Ampico A (1928) Symphonique Grand. ...  There is
> a tiny squeak coming from the stack.

I had a mint version of this piano at one time.  My first thought was
the lost motion pneumatics but you indicate it does this on full power.
A wild guess would be that the piano action is a hair too far in or
out.  Or, the pneumatic stack is perhaps the same, although that seems
unlikely as it is in a relatively fixed position unlike the piano
action.

Another problem is the pneumatics on a single affected board have been
glued back on out of position.  If it is confined to a single board,
check its relation to the other two to see if the three were put back
together so they are plumb.  As in, that section is too far in or out.

Tightening the valve clamps should have no effect.  You will have to
take the cover boards off and take a good look things while it is
squeaking; a friend would come in handy here.  Press the bottom of the
stack carefully to the front then to the rear of the piano while it
squeaks.

It's also possible something is wrong with the flange fingers
themselves though chances are small.  Does humidity have any effect?
Good luck.

Bruce Mercer