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MMD > Archives > June 2008 > 2008.06.03 > 02Prev  Next

Pedal Duo-Art (Half Duo-Art) Tubing Diagram
By John A. Tuttle

Hi All,  First, I'd like to thank Alan Turner, Hans Schweizer, and
Rollie Chisnell for the information they sent to me.  I've already
heard from Robbie Rhodes, and know that Alan's tubing schematics of
the 'Half' Duo-Art are going to be placed in the Technical section
of the MMDigest Archives.

 [ Visible at
 [ -- Robbie

Secondly, during this investigation into the tubing layout of the
'Half' Duo-Art, little bits of information have come forth which showed
the need for something a bit more comprehensive than the schematics,
so I created a series of web pages that present all of the information
I've gathered to date.  They are all related to the 88-note version of
the Half Duo-Art.  Presently, there are five pages of data (text,
diagrams, and pictures), but I hope more will be added.

There is still one mystery that I have been unable to solve, and
hopefully someone has the answer.  In two cases that have been brought
to my attention, I have seen a pallet valve that doesn't appear in
Alan's schematic.  In the schematic drawn by Rollie, he describes two
pallet valves but doesn't mention where they are physically located
or how they would be activated.  In the pictures sent to me by Hans,
a pallet valve is located on the expression device, but no explanation
is given as to its purpose.

Also, on the unit that I dismantled years ago, there is a pallet valve
located on the Soft pneumatic that gets activated every time the bellow
collapses.  Unfortunately, the tubing in the lower portion of the piano
was destroyed before I got to it, so I don't know how it was connected
into the system.

Armed with Alan's schematic, Rollie's written explanation, and articles
written by other MMDigest authors, a fairly clear picture begins to
emerge of exactly how the Half Duo-Art operated.  As far as I can tell,
the only missing piece of the puzzle is the function, location, and
tubing of the two pallet valves.  (The information might be in one of
the postings that are already in the Archives, but if it is, I missed
it.)  The main web page about the Half Duo-Art is located at

Hopefully, the editors of the MMDigest and the authors who have already
written accurate descriptions of the Half D-A system will allow me to
add another page to the series.  It will contain links to all of the
pertinent postings in the Archives.  My reasoning for doing this is
that I am one of those people who has somewhat of a difficult time
conceptualizing written descriptions.  On the other hand, if I can
look at a diagram or a schematic, then the written words become crystal
clear.  So, I conclude that what makes perfect sense to one person,
might sound or look like 'Greek' to someone else.  Therefore, having
the widest variety of information, on the topic, available to everyone,
should help make it clear to anyone who desires to learn about the

Again, 'thank you' to all who have helped me to this date.

John A Tuttle
Brick, New Jersey, USA

(Message sent Wed 4 Jun 2008, 02:07:22 GMT, from time zone GMT-0400.)

Key Words in Subject:  Diagram, Duo-Art, Half, Pedal, Tubing

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