Eighteen years ago, appearing within the pages of the MMD, there was
much interesting and useful discussion [Ref. 1] regarding the small
damper pedal compensation pneumatic that Dr. Clarence Hickman had
developed and caused to be attached to Ampico "A" expression devices,
these as ostensibly produced up-until the appearance of the Ampico "B."

The exchanges were begun with style by reader/contributor Bruce Clark
with his post of 2002.07.10 MMD, wherein he described succinctly and
completely it's operation and purpose, the course of the debating
ending with reader/contributor Craig Brougher's fine final rejoinder
of 2002.02.17 MMD.  In all there were to be and are 16 parts to the
wide-ranging talk, as carried-on by various others of the interested
in-between.  All are recommended for rereading, for a quick brushing-up
for sake of background context, as regarding our present subject.

Some fifty-plus years ago, now, Clare Spencer -- he of the unique Sam
Thompson Steinway Ampico creation [Ref. 2, 3] -- explained to me in
those tender, know-little years of mine, just what it's purpose was
and, how and why it worked.  [Ref. 3 offers many views of the Southern
California player restoration scene complete with portraits of "the
usual suspects," who had carried it forth, all being of the mid-Sixties
and Seventies, an era of greatest delight of living to this writer.
Clare Spencer is to be seen in the sixth photo down.]

Having become entranced more than usual by the idea and explanation,
at nearly that moment a "brilliant" idea popped into my youthful head
similar to this: "Well, if good enough for the Ampico, it should as
well be applied to the Welte-Mignon!" And so the infant Mignon Pedal
Compensator was born after conceived, to then be designed and applied
but only twice, thus far.

It is this subject, as coming from that early day to ours, that the
article of-present seeks to address.  As prelude I will present the
newer case summarily:

As most know who are familiar with piano actions, dampers and their
lifting mechanisms comprise some varying quantities of mass as pulled
downward by the action of gravity.  (I do not know that some might not
also include some spring-force as well? I suggest this as an additive
possibility.) When lifted by the Sustain Pedal, all of this previously
opposing force is thus removed.

Since hand-playing involves combinations of applied force plus
transfers of momentum from said hand to mechanism, these in addition
to a pianist's talent to whatever the degree of fineness, the effect
of the disappearance of gravitational opposition is that it is to be
compensated-for by the playing artist's hand more-or-less automatically,
so as to maintain smoothness during dynamical transitioning.

Absolutely this is not the case in any instance of our mechanical
pianists when at work -- which benefits by nothing like the advantage
of a compensating/considering human brain -- results being jarring
increases of strike velocity at terminus, when presented no longer with
the opposition that in-place dampers had before applied.

Assuming easily because obvious, that it is deleterious to the
achievement and sustenance of pianissimo play (and, to the greatly
desired pianississimo or finer, even), then said resulting differences
with and without dampers MUST be addressed and ameliorated!

It is all this that Ampico's Dr. Clarence Hickman of then, had observed
and solved to perfection, that vital trick done most simply with his
1-inch-square applied rider pneumatic, pushing downward alternately and
compensationally, as according with and to pedal signaling.

The expression pneumatics of all Welte-Mignon versions, of course,
operate differently than do Ampico Spring pneumatics, and so a different
approach had to be found and was.  In the new case, the compensating
'dodge' required was to be but a minute lessening of the originally
pianissimo, it just enough so as to achieve terminal velocity parity
for dampers up-or-down.  Specifically/rigorously: So that identical
parcels of energy are input to all strings in all cases of single-strike
pianissimo play.

However, still there are additional complexities, in that dwell-time
exists between dampers fully-risen and down.  (What pesky matters
might be 'doing' in that quarter-second between?)  I suppose that
a "Part 3" could address this, or not.  Though not exactly 'gilding
Mona Lisa's face,' such additional compensation admittedly would be
an improvement most subtle, that is excepting for in the finest and
most perfected instance, of created-marvelous instrumentation.
(This more than likely to be attained _only_ as-new?)

My solution was direct, and as a fix, even more obvious than was
Dr. Hickman's brilliant stroke of creative simplicity, although it's
having lead eventually many decades hence (as can be read in the
aforereferenced MMDigest postings) to misapprehensions, in which
subjectivity mostly was used for nominal, actual guidance -- this
where objectivity might have been more successful in an achieving of
desired, positive consensus?

Now sans apologies in waxing as subjective myself: The only two
instances in which my Compensator was ever applied, were to be the
No. 1 and No. 3 Tushinsky Vorsetzers [Ref. 4], the first being the
instrument used for the recording of Mignon-sourced Keyboard Immortals
broadcasts, and the other, the later "Tri-Plex" which I had designed
and built from rote.

(In both cases it might be noted for a clarified record, that the
additions of the two compensator pairs were made well after all
recording activity for KBI episodes had ceased.  Excepting for one
new finger-set I'd built and added to Vorsetzer No. 1, no results of
my work done on any of the Tushinsky instruments, were ever to be
heard as broadcast.)

Concerning the No.1 Tushinsky Welte Red-Roll Vorsetzer, I applied
a pair to it first as part of a new build [Ref. 5].  When done, it
worked just as designed and advertised.  However, true magic of play
was to manifest only after Note Compensation as well had been added
-- yet-more of that bountiful harvest that had come to fruition, due
to Dr. Hickman's keen observing thought and correcting, of insufficient
early design work.  The summed subjective effect as experienced proved
marvelous! It is the only case I know of, where Welte-Mignon T-100 scale
and Licensee instruments have ever be heard re-performing complete with
Sustain Pedal compensation, and, that same of note.

(However, as true as that might have been and was, the ever-present
problem of 'reflected energy', with it's pernicious, uniformly
subtractive effect both temporally and dynamically from closely-
succeeding strikes, was not to be conquered, for it could not have
been.  For an advent of such a striven-for miraculous, a better
inventive and constructive future holds-out-still, I am sure.)

In Part 2, I will present to the MMD readership for it's consideration,
a complete drawing, along with instructions and tips, as to how any
interested Mignon Connoisseurs might fabricate their own set and
finally, applying it for quite gainful use to their Welte-Mignon
(Licensee) instruments.

Jim Miller, Las Vegas, NV

References:
1. https://www.mmdigest.com/Archives/Digests/200207/2002.07.10.09.html 
    The rest being accessible here as alphabetically listed: -
    https://www.mmdigest.com/Archives/KWIC/A/ampico.html 
2. https://www.mmdigest.com/Archives/Digests/201706/2017.06.06.01.html 
3. http://www.jfeenstra.com/CartyPiano4.html 
4. https://www.mmdigest.com/Archives/Digests/201712/2017.12.22.04.html 
5. See attached photo linked below.

 [ Jim Miller Struggles To Meet The Fast-Approaching Delivery Deadline
 [ http://www.mmdigest.com/Attachments/20/01/15/200115_153800_J_M_deadline.JPG