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MMD > Archives > October 1997 > 1997.10.03 > 11Prev  Next

Solenoid vs. Pneumatic Pianos
By Craig Brougher

Scott Currier's really comprehensive list of interesting observations
regarding solenoid pianos was very helpful to me.  I have only heard
other people's electronic pianos so far.  I remember several times though
when a grand Yamaha was placed beside several pneumatic reproducers and
it played rings around them! They are very nice.  However, they will
still not play rings around a "factory spec ideal" pneumatic reproducer.

So many pneumatic reproducing pianos are not actually "fully" restored
as claimed, or restored correctly.  Scott's comments to that end were
sadly well-taken.  For example, there was a time when I was traveling
around the country repairing and restoring these  "fully restored"
instruments.  I would lay out an itinerary that would sometimes take six
months, living with the families I was working for, while making
(usually) extensive additional repairs to their "fully restored"
reproducer grands.  I repaired or rebuilt 49 players that way, and in
practically every single case, I began by rebuilding all the valves from

When you work under the scrutinizing eye of the owner who has been burned
once, you will find they don't miss a thing the second time.  And I
didn't want them to!  I would take components apart while they watched,
after having troubleshot a problem, and predicted what I'd find.  And
there it was.  (One owner owned 9 recently restored reproducing player
grands, and I had to work on every one of them!)

The purpose of this is to show how very few pneumatic reproducers live
up to the expectations of their original showroom performances.  A
comparison between a bright, brand new electronic player to what is left
of these original reproducers in many cases isn't quite proper, even
though the pneumatic instrument is still able to beat it.  And like Scott
was saying, some of them do a wiggly "hula dance" because one of the
feeders in the pump is leaking badly.

And speaking of pumps, I restored dozens of them "on the road." I even
ran into Duo-Art pumps still working that had never been touched in 50
years -- that also in "fully restored" expensive instruments!  Not to
mention valves whose original cloth strips still covered the valve
shelves.  (By the way, I have never and will never tell anybody whose
pianos these were.  So everybody -- your secret is safe with me.)

(One story involved a reproducer whose valves repeated with every hole in
the chain bridging on certain rolls.  The owner proudly told me that this
was proof of a superior valve restoration job! Only "good" valves can do
that! Since I wasn't going to do any work at this stopover anyway, I
didn't tell him the truth.  His rebuilder had already explained it,
apparently.  :-)

But when you consider the range of power available from pneumatic
reproducers versus that available from a commercial solenoid player, I
can understand why the solenoid player's forte is salon-style music which
is able to play on and on for an hour.  Very very nice, too.  But for
critical listeners who love the classics at full bore, you would really
need an instrument of the calibre which Wayne Stahnke designed and built.

I have also seen pneumatic reproducers whose valves had been fully
restored, and yet didn't play nearly as well as those whose valves had
been ignored.  The reason for that was gapping.  Years ago, somebody (and
I don't recall who) said the optimum valve gap was 1/32."  After that, we
had all these ideas as to how to achieve that result, plus or minus -- I
guess -- .0001."  The huge mistake here is that the "ideal gap" was
measured from old original valves from which they were careful not to
exert any positive pressure on the top valve seat while measuring the
travel.  (Now here I go off on a tangent, but a necessary one):

When old valve leather is played again after three decades of sitting
idle, it is partially dry-rotted.  Being glued to the poppet on the
bottom, it is sucked down to the inside valve seat, holding the poppet
with its glue.  When the pouch pushes the poppet away, it tends to "pull
that leather apart" while the leather is still sucked down to the seat.

Rebuild the pump and you can get the high pressures you once were able to
achieve, so now you are going to "fluff" or thicken this old leather by
repeated "delaminating" (for want of a better term) that old dry-rotted
leather.  When you have finally created enough combined leakage this way
that the piano stops playing altogether and measure the valve travel of
such a once-wonderful instrument, they are less than they once were.

So while the leather itself may look as though it has been "packed down,"
the fact is, it has internally been fluffed up, because piano vacuum
cannot compress the inside seat leather when the poppet is at rest on its
seat.  That's because it sucks on the leather surface, not the poppet
valve, so the leather is not compressed by piano vacuum.

This is one of the main reasons why pneumatic reproducers do not play up
to their factory potential!  And with a 1/32" valve gap, there is
positively no way they will ever do it again, either!

Now back to the original thought: A pneumatic reproducer, properly
restored, makes no noise with its pump and motor-- only its roll drive
air motor, and during play, you shouldn't be able to hear it.  The only
time you should be able to hear the mechanism is during reroll.  Never
does a reproducer do the hula, unless something is about ready to break.

And as far as the knee-knocker drawers, I would mention this story about
Matteo Napoli, a tall concert artist from Italy, who so loved a
particular collector's Ampico model B that he wants to give a recital on
it every year!

Many pianists learned to address the keyboard in a crouched position with
the bench too close.  In that case, the drawers are knee-knockers.  But
Ampico toured the country with two concert artists and two concert grands
equipped with Ampicos.  If their knees were ever up against those
drawers, the audience and the critics would have pointed it out, as to
how uncomfortable it looked.  So I have to raise a small, insignificant
objection to that particular characterization.

As to the extra length of Duo-Art keys, it doesn't really affect the
playing characteristics at all.  The key dip, letoff, leverage, touch,
weight, speed of key response, everything is still the same.  The only
thing it changes is the length of the piano, overall.

Craig Brougher

(Message sent Fri 3 Oct 1997, 13:20:08 GMT, from time zone GMT.)

Key Words in Subject:  Pianos, Pneumatic, Solenoid, vs

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