A short time ago, while looking through my "boneyard" of reproducer
parts, something strange about an Ampico stack caught my eye.  At first
glance it looked to be a Type 5 or 6, as defined in the Howe/Morgan
article, "The Evolution of the Ampico", originally published in the
1991 AMICA Bulletin and subsequently updated by Morgan:

http://www.amica.org/Live/Publications/Past-Bulletin-Articles/EvolutionOfTheAmpico.pdf 

It is a push-rod style stack with two hammer breaks.  (I am currently
away on vacation and did not record where the breaks occur, but I can
provide that information later if will aid in the analysis.)  I am used
to seeing the troublesome upside-down unit valves with wooden covers in
these stacks, but suddenly I realized I was looking at valves that
still had wooden covers but were right-side up!  This would appear then
to be an earlier use of a right-side up valve design, in contrast to
the Howe/Morgan Type 7 variant which states, "First right-side-up unit
valves in stack, metal top-seats flared, limiting adjustment."

This design must have been in production for a very short time as I have
seen no other examples of it.  I obtained it in a collection of similar
parts, so it was not associated with a specific piano brand, size or
vintage that I can identify.  Perhaps the breaks can help narrow down
the list of possible candidate brands and years of manufacture.  The
only other possibly helpful information is two sets of numbers stamped
into the bass-end wooden end of the stack reading "FA28" and "14271".

Evolutionarily, in keeping with the Howe/Morgan numbering scheme,
I suppose this variant could be considered either a Type 6B (accompanied
by a re-designation of the present Type 6 design as Type 6A) or a Type
7A (accompanied by a re-designation of the present Type 7 design as
Type 7B) depending on which attribute (wooden valve cover or right-side
up orientation) is considered its most defining feature.

The stack is missing one of these secondary valves, so on the outside
chance I find a stripped piano with compatible hammer breaks which
qualifies for restoration, or someone out there can use the stack (call
me!), a replacement valve will need to be found or fabricated.  It _may_
be possible to substitute a normal right-side up, metal top-seat valve,
but I have not yet tried the "fit" of such a substitution.  Modifying
an existing upside-down valve to work _may_ also be feasible, but tricky.

Has anyone else seen one of these variants and can you provide more
information about its employment?

John Grant

 [ John sent photos which I'll place at the MMD Pictures site,
 [ http://www.mmdigest.com/Gallery/Pictures/index.html  -- Robbie