In my "boneyard" of spare parts is an unusual Ampico "B" stack.
It's overall width is 47-1/4 inches, with 31 valve block spaces in
the usual three tiers.  The "split" positions are 48 valve spaces on
the bass end and 45 spaces on the treble.  Bass spaces include one
"A" space ("leaker"), two "L" spaces ("lifter"), and five "blanks",
leaving 40 spaces for notes.

Assuming the usual division between middle E and F, and working
backwards, the first bass playing note would be low C# instead of
low B.  The 45 treble spaces include one "A" space ("leaker"), three
"L" spaces ("lifter"), and one "blank", again leaving 40 spaces for
notes.  This makes the highest playing note high G# instead of high A.

Overall capstan distance is 44", first note to last note.  Distribution
is in four sections, 22 bass notes (C# - A#), 28 tenor notes (B - D),
17 alto notes (D# - G), 13 soprano notes (G# - G#).

I'm tempted to say this might have been intended for a smallish grand,
but the overall width, with 31 horizontal valve block spaces, is the
same as any normal 83 playing note "B" stack, the main difference being
the six blanks verses the usual three.

Anybody want to hazard a guess about this variant?  Are there other
examples of "B" stacks with note counts other than 83?

John Grant

 [ My guess is it was removed from a player piano advertised as "plays
 [ any reproducing piano roll" (without annoying tinkles)!  Or could it
 [ be from an Aeolian-American "B model" Duo-Art?  -- Robbie