I completely agree that it is not acceptable to modify a rare or
unique antique, nor is it good practice to modify even a common one in
non-reversible ways if you intend to maintain its value.  I have mixed
feelings about instruments that are not rare and which would likely be
modified or disposed of anyway.

It was a difficult decision for me to remove the Duo-Art player from
my Weber and install an LX player system.  If I didn't buy the piano
it would most likely have been gutted and the player parts disposed of.
The owner had no concerns about doing this.  Now I have a piano that
cost me very little to acquire and that gives me a lot of enjoyment.

I still have my original Duo-Art which I can play with MIDI and I will
never change that.  The MIDI interface is installed in rubber tubing
only and can be removed at any time with no evidence of it ever being
installed.  This is certainly not the case with lead or brass tubing.

Another possibility for someone wanting to add MIDI control without
modifying the original instrument at all is to use a tracker bar
interface.  This will not result in as good performance as a direct
tubing connection but in some cases, it is the only option.  Performance
is likely to suffer with instruments that have very low tracker bar
suctions levels such as single valve reproducing pianos.  For other
instruments with fixed higher suction levels at the tracker bar, there
may be no degradation of performance.

Making a universal interface such as the largely unsuccessful
"PowerRoll" is very difficult as there is enough variation from one
tracker bar to another that one unit is not likely to fit all very
well.

For demonstration purposes, I made a tracker bar interfaced unit for
the Duo-Art piano.  I still have this and it works quite well.  There
are a few features that make it work much better than a PowerRoll such
as registration pins and a better gasket material.

I no longer have a need for this unit and would consider selling it
to a serious buyer.  It would be possible to convert it to play other
9-to-the-inch 88 note players with minor modification and it would be
possible to make a custom tracker bar interface for other systems such
as a player organ with 96 or fewer tracker bar ducts.

Best regards, Spencer Chase
Garberville, California
http://www.spencerserolls.com/