The previous owner of my Aeolian 7-rank pipe organ purchased it about
six years ago.  What was disappointing was that the player system in
the console and the jack switch box found in the chamber was missing.

Being that these parts were hard to find, a Z-tronics electronic
switching system was added to the organ.  The cost for parts came to
$3,600 (labor and assembly not included).  The organ now can be played
manually or through a MIDI port.  You can even record MIDI files from
the keyboard.  The stops and shades can also be recorded.

It seems that Paul Morris has a Duo-Art Player Organ and wants to add a
MIDI interface to his unit.  This shouldn't be any real problem if the
organ key and coupler relay switches are in good working order.  This
modification can be done without changing the current operation of the
organ and without disturbing the majority of the wiring.

I should say that there are many ways to add MIDI to a pipe organ.
Each has its good and bad points.  What you want to find is a board
that will convert the MIDI channel data into 64 separate outputs that
will drive the relays currently found in the organ.  You can use four
of these boards to control the entire organ.  This is far less than the
specialized 25 Z-tronics boards needed for my Aeolian.

In testing the old relay coupler that was once installed on my Duo-Art
organ, the coils for driving the keys and stops are all 140 ohms.  Most
driver boards can drive 90 ohms or greater.  You should be able to
parallel the output lines of the MIDI converter boards directly to the
organ logic.  When the organ is first powered on, the jack switches
that control the stops are all turned off (relays open) so the organ
can be played by the newly installed MIDI logic.

At this point I should start talking about where your music is going
to come from.  Standard MIDI for a synthesizer is not standard for pipe
organs.  It would be nice to take music from the Internet and play it
unchanged on the organ but don't expect this to happen. I believe this
is feasible but I don't know of any pipe organ MIDI switch that can do
this.  If one were out there, it would be extremely expensive.

You must expect to get MIDI files that are specifically made to drive
your pipe organ logic.  You can also change MIDI files using Cakewalk
or another MIDI editor to modify these files.  This all depends on how
you wire up your MIDI controller boards to the organ.  The Kegg Organ
Company may be able to help you in some music if you wire the organ for
the proper format.

The simplest way to wire your system is by using 4 MIDI control boards.
Board #1 = 31 Pedal notes, #2 = 61 Great notes, #3 = 61 Swell notes,
#4 = 64 control lines for the Stops and Shades.

You should assign a MIDI channel number to each of these boards.
Connecting the Pedal, Great, and Swell boards is fairly straightforward
and logical.  These wires parallel the key switches in the console
which operates the note relays in the coupler chest.

The stops and shade lines take a bit of thinking: Which MIDI note
controls which pipe stop?  What about the wires to control the shades?

Because of a lack of a standard in this area, my pipe organ was wired
to a Kegg stop list that he generated many years ago.  I call this the
Kegg Standard but I haven't found others using it.  He sells some MIDI
files that will play music on my pipe organ.  He created these music
files by connecting four MIDI input boards to a working Duo-Art pipe
organ and recording the Duo-Art roll.  The control lines for the stop
and shades were connected directly to the rank coupler relays found
after the jack-switches.  If you connect them in a similar fashion, you
should also be able to use his MIDI files.  You can write me and I can
get you this stop list.  Wire up the last MIDI board according to this
stop list, add a power supply and computer, and you should be in
business.

Now the big problem is finding the right music.

Pete Knobloch (Tempe Arizona, USA)