(This was posted in Facebook Player Piano Talk also, but posted here
for those interested but not in that forum.)

Bob Taylor's YouTube video of his Ampico A roll compatibility device
for the B is quite interesting.

 [ https://www.youtube.com/watch?v=ZyFrUQz6KM4
 
 [ At time 1:55, "Same except with logic device attached to piano."

Bob, could you explain the theory of its operation?  We know basic
B coding (which you identified at Type 1) only uses a single crescendo
and causes the dual crescendos of an A to work in tandem.

This brings us to asking why the factory didn't have such a device
installed from the outset.  My guess is that from 1929 on the factory
planned to only issue B rolls and most owners would not be using old
A rolls unless they traded in A pianos for the New Ampico.  I doubt
this was common.  If you look at the 1933 and 1937 catalogues there was
still quite a library that was available to those who could afford it.
Now how many of these titles were re-coded in B format?

Early in the development of the Ampico B, Dr. Hickman entertained the
notion of new incompatible coding rendering A rolls unplayable on the
B system.  The management nixed this idea but is there any documentation
that shows what his ideal new system would have done differently?  He
would have still had only 100 holes to use, with 17 available for
expression and drawer functions.

Lee Lanier
Atlanta, Georgia