[ In reply to query by John D. Rutoskey, 040812 MMDigest ]

To date I have probably installed somewhere close to 250 PianoDisc
systems for the largest piano dealer in Las Vegas.  I've installed them
in older cheap pianos and in new ones ranging in price up to $100,000.
I've also gutted quite a few old systems for upgrading.  I still have
some of the early system parts I save for demo purposes.

As you mentioned, the kits that you have are very old and obsolete
and PianoDisc no longer provides parts or technical support for those.
Truthfully, seeing how they are still in the original unopened box,
they may be worth more as they are if you are willing to keep them
stored for another 25 years until a collector makes you an offer.

The expression on those early PianoDisc units was horrible.  Partly
due to patents owned by Yamaha, PianoDisc was unable to perfect their
system until the "silent drive" system was introduced.  PianoDisc
systems work by using a pulse modulation system.  That is to say, the
solenoids are powered by a 40-volt DC power supply that varies the key
velocity by increasing or decreasing a number of pulses of power per
second.  Thus a solenoid receiving 75 DC pulses per second will have
twice the power and likewise the volume if it receives 150 pulses per
second.

The early systems were very crude, with a 35-volt DC power supply and a
maximum scale of 40 pulses available.  The later "silent drive" systems
use 40 volts and up to around 300 much shorter pulses available, thus
far more control and vastly superior and impressive expression.  My
general description of the early systems is that they had two volume
levels: loud and off.

The early systems did have MIDI inputs just as today's modern systems.
If you do a lot of installs, as I do, sometimes you can have a little
fun if you have completed several units and the dealer hasn't picked
them up yet.  Once we chained five PianoDisc units together via MIDI
cables and had them playing together at the same time.  We even tried
connecting a digital piano to the first one so that you could manually
play all of them at once!

Rob Goodale, RPT
Las Vegas, Nevada

 [ Well, John, if your old PianoDisc systems have the familiar 5-pin
 [ DIN connector to receive MIDI wireline signals, then I guess you
 [ could equip a few nickelodeons!  -- Robbie