Thanks to Mike Walter for correctly identifying the early Ampico
system.  I had written privately to Giovanni with comments, much
in line with what Mike said.

I also told Giovanni it has been my understanding for some time
that Welte held patents on the concept of changing vacuum levels to
impart expression to piano roll music.  Under those patents it made
no difference how the vacuum was manipulated.  Ampico had to pay
royalties to Welte and perhaps had to display the Welte name.  This
"display" concept is speculation on my part.

But there was something else that Mike Walter commented on that
illustrates my current campaign: I am trying to educate everyone on
the importance of the Ampico A amplifier.

Mike's statement, "... a reservoir mounted on top of the pump with
an excess vacuum escape port on the top of the reservoir."  is typical
of how most collectors regard the pump amplifier.  Yet it is the
amplifier that gives the Ampico dynamic system its full breadth.  The
concept started with the earliest Stoddard system and continued through
the Ampico B era, but rarely is it fully explained.  The only Ampico
that does not use this system is the Baby Ampico Spinet.

I am preparing an article on the amplifier.  The concept is simple, but
relating it is not so easy.   Most collectors have no knowledge of the
three-stage Ampico A amplifier as a significant element of expression,
or of the additional stage added to the concert grand piano.  Yet, the
coding on almost all A rolls precisely controls these functions with
spectacular results.

Bob Taylor
Missouri