Regarding the shredding of rolls, the model B Ampico is no worse than
any other roll drive with one correctable exception.

The springs that pull the sensing fingers inward are too stiff for
ancient paper and may tend to curl the edges.  They were fine for the
rolls when they were new.  These can be weakened by bending them so
they have less pre-load, or replaced with thinner spring stock for
the same effect.  The actual operation of the model B tracker valve
assembly requires very little force, so the tracker finger springs
don't have to exert much force to keep the fingers in contact with the
roll edges.

The snubber brake on the take-up spool which is operated intermittently
by a cam and pallet valve on the roll drive motor assembly must be
properly adjusted so it will instantly "snub" (stop) the rotation of
the take-up spool, not just slow it down.  In this manner, the intended
purpose of providing a firm pack reroll can be achieved without edge
damage from high tension in the paper while the roll is being rewound
onto the supply spool.  Paper motion ceases when the snubber brake
comes on and the loose wind is taken up as the rewind spool continues
to turn.  Excessively tightened rolls are prevented by a slip clutch in
the rewind spindle drive.  This should be set to be just tight enough
to prevent slippage when the snubber is off.

Regarding A rolls on a model B, the piano may need to have the subdued
function enabled in order to avoid playing too loudly on some rolls.
The B has a maximum suction level of 45 inches.  B rolls only rarely
call up this level.  A rolls reach this level on the B under conditions
where an A piano would only reach 20 -22 inches in "normal" and maybe
30 inches in "brilliant".

I have a model B which doesn't eat rolls and plays A rolls agreeably.
It does not have bricks for hammers (reproducers should not have hard
hammers) When restored carefully and voiced appropriately, a model B
is a superb instrument even when playing A rolls.

Bob Hunt
Kennebunk, Maine

 [ Master player tech Iver Becklund, of Lakewood, Calif., showed me
 [ how the tracking mechanism in some late production 'B' models can
 [ be adjusted so that the thin tracker rod oscillates at 100 Hz or so
 [ during normal tracking.  This proportional control mode uses more
 [ air flow than the typical "bang-bang" mode, so the factory installed
 [ an extra suction hose connected to the pedal regulator suction
 [ supply.  To oscillate reliably, the valve faces on the tracker rod
 [ must seal properly against the brass nipples and the leaf spring
 [ tensions should be equal and rather forceful.  As Bob cautions,
 [ however, the stiff springs may damage old and weak paper.
 [ -- Robbie