Answering Mr. Dodrill's question about converting a 65/88 Themodist
Steinway foot-powered grand to full Duo-Art capability: yes, this would
be theoretically possible.  In fact, Aeolian Company did such
conversions when the Duo-Art came out; a beautiful example of this was
shown at this year's AMICA convention in Sandusky.

But it would involve certain compromises, depending on how one went
about it.  The easiest way would be to get a tracker bar and the
various control logic components from a defunct Duo-Art, and install
them.  The existing divided stack itself could be reused.

If an electric pump were added, it would probably have to be a 'side
box' or 'basement pump' installation, since the angled bracing under
the piano might not accommodate the usual pump installation, compared to
the special square bracing fitted to an original electric grand.

If you wished to retain foot-power only, you must note that foot pumped
Duo-Arts are not completely automatic.  Only one 'track' of digitally
controlled regulation was provided, for the 'accompaniment' level.  The
pumper had to regulate the 'theme' level by pumping hard or soft
according to the 'melody line' printed on original rolls (but not on
recuts).  Full automatic Duo-Art action was not provided because the
user would have had to keep the whole system pumped-up to the maximum
pressure continuously, an impossibly exhausting task.

If one chose to keep the switching-pouch network required to retain the
ability to play both 65 and 88-note rolls, this could be expanded to
accommodate the conversion, but the first and last few notes in the
65-note mode would be distorted, since the vertical dimension of the
holes in the edge of the normal Duo-Art tracker bar do not match up
with the end holes in the 65-note array, which extend all the way to
the edge of the paper.

One could, I suppose have made or modified, a special tracker bar which
would properly register the end holes in the 65-note array, as well as
the Themodist holes for both 65 and 88-note rolls, but then the
sustaining and the soft pedal holes for Duo-Art service would be
wrongly placed, and result in a slight mis-timing of these functions.

Having said all this, I still would respectfully recommend that such a
conversion not be attempted.  Apart from the fact that all the special
work and adjustment required would be extraordinarily costly compared
with an ordinary reproducing piano rebuild, and probably end up less
than satisfactory, it would spoil something rare and special.

A really good grand piano with pedal playing capability is uncommon
outside the U.K.  Combined with full Themodist in both 65 and 88-note
format, the instrument would be a treasure for the Interpretive
Pianolist, especially one interested in late 19th and early 20th
century music.  (I wish I had the money and the space for such a thing,
and at my age I need the exercise!!)

Richard Vance