[ Ref. Solenoid Player Piano Systems

I have no experience with PianoDisc systems, but I have plenty with the
QRS system.

I installed a QRS system in the suggested manner in an upright Foster
piano.  It didn't work correctly; on loud playing, the solenoids tended
to push the keys off the center rail.  Before I realized what was going
on, I had a piano full of "pulley keys".  On soft playing the forward
bank of solenoids did not have enough power to propel the action all the
way through it's cycle, due to the different engagement ratio.  I boxed
up the keys, and sent them to Rochester for refurbishing.

I removed the solenoid rails and studied the problem.  I was expecting
even playing; the problems were twofold.  The main problem was that,
due to the design of the rail, one in front of the other, there was
two different engagement ratios (points) on the bottom of the keys.
The other problem was that the solenoids didn't have quite enough
power: if the soft level was brought up to compensate for this, then
the back row of solenoids was too loud.

I then constructed a "stack" from a set of junk upright stickers,
and installed the unit in the location of the original pneumatic stack,
driving the wippens.  This worked far better, however the point where
the solenoids engaged the lifting levers was very critical (reminds
me of finding the hammer striking point).  So I simply bent all the
plunger wires to form a straight line (like bending a damper wire) to
line up with my "ideal" point.

On the top of each solenoid wire, I installed an upright hammer flange
with a hole drilled in the bottom to accept the plunger wires.  In the
notch of the flange a piece of action cloth was glued in.  The flanges
were not pinned to the levers, however -- the levers simply rested in
them.

The levers were made from old upright stickers and positioned so that
the free ends would fit under the action wippens.  A capstan screw was
installed in each one.  The solenoid rail was regulated on the bench so
that all the lifting levers would assume a straight line, and the fine
regulation was done with the capstans while installed in the piano.

This mechanism worked flawlessly, and would play and express perfectly
any MIDI file you threw at it.  I know it sounds like more trouble than
it's worth, but to me it was well worth the time.  Sadly, this piano
was destroyed in the house fire.  If I had to install another Pianomation
in an upright, I'd do it the same way.

I'm not at all inferring that the Pianomation system is a bad product.
I had many hours of pleasure from listening to the piano, and the system
itself is very reliable.  The folks at QRS are very helpful and do
exactly what they say.  I plan to purchase another one soon.  I simply
prefer to install them a different way.  Also, the QRS music is far
better than anything from PianoDisc.

In no instance I can think of, no original player system used two
different engagement ratios.  All the pushrods were in a straight line,
and for a good reason: even playing.

The next time you observe an upright with a solenoid system, pay
attention to what the action is doing on soft playing, then you will
understand what I'm talking about.  However I have no experience with
grand pianos, but it would be reasonable to expect that the principles
are the same.

Andy Taylor - Tempola Music Rolls

 [ See Andy's earlier article on this topic at
 [ http://mmd.foxtail.com/Archives/Digests/199901/1999.01.03.10.html
 [ -- Robbie