Hi there.  Okay, Aeolian linked the hammer rail pneumatic with the
number 2 Accompaniment accordion valve.  The manuals say that this was
done to compensate for 'lost motion'.

This is true in a way because the contact between the wippen and hammer
is lost when the hammers are raised, but then again, it is this lost
motion that actually makes the piano play softer.  So am not completely
sure why they would want to compensate for it.

Logically, when you shift the hammers, there would be no extra 'lost
motion' and this leads me to the conclusion that your soft lever must
raise the hammer rail and operate the no. 2 Acc. accordion.  This would
then have the same effect as the upright piano version, but there they
used a pallet valve on the hammer rail pneumatic to activate the no. 2
Acc. accordion.

On the other hand, some pianos activate the no. 1 Acc. and others don't
have this facility at all.  Like the saying goes, no two Duo-Arts are
exactly the same...

Regards,

Bernt Damm
Cape Town