Responding to Tim Gautreaux's question about the difference between
Green Welte and Welte-Mignon Licensee pianos:

At some point in the 1920's Welte in Germany figured it would be
economically advantageous to also make a piano that used 11&1/4" paper
for the rolls, using standard flanges, a more standard 9-holes-to-the-
inch tracker bar, and a roll which unwound from the top down to the
take-up spool, exactly like all their competitors and unlike their Red
rolls (or T-100 scale, 100 hole), which used wider paper with different
hole spacing, pin-end flanges, and unwound from the bottom with the
take-up spool at the top.

This change alone made their reproducing pianos capable of playing
standard piano rolls, just like most other reproducing pianos on the
market.

The new Green-roll tracker bar had 98 holes, just like the Welte
Licensee in America.  It looks almost the same but for a very slight
amount of staggering in the first five and last five holes in the
tracker bar.

As is well known, the first ten holes in the Red scale are not for note
playing.  There are lock and cancel functions requiring lock-and-cancel
valves on holes 1-2, 3-4, 7-8, and 9-10.  Holes 5 (FZ off) and 6 (FZ
on) are not really lock and cancel, but two separate functions.  Holes
9-10 are unique to Red Welte, providing a lock-cancel speed-change
function for the pump motor.

On the treble side of the tracker bar from right to left, lock and
cancel functions are on holes 1-2, 3-4, and 7-8.  Holes 5 and 6 are
again FZ off and FZ on.  Hole 9 is not used, and 10 is the rewind.

The Licensee system is set up the same except there is no pump-speed
change ever, hence only 8 holes are needed in the bass. So 100 minus 2
equals 98.

In Red and Licensee pianos the expression functions which require lock
and cancel (Mezzo Forte, Slow Crescendo) and the Sustain and Soft pedal
functions are controlled by small single punches in the roll: a punch
to turn it on, and a punch to turn it off.  The Forzando on, and
Forzando off, are not  operated by lock-and-cancel, but by perforations
of varying length. This is easier to understand if one thinks of the
Forzando-on as being like a fast crescendo or quick increase of stack
vacuum, and Forzando-off as a fast decrease of  stack vacuum.

The Green system eliminates all the lock and cancel functions.  In the
Green system the expression functions which were previously controlled
by lock-cancel valves and single punch perforations are now controlled
by perforations of varying length in the music roll.  For example, the
Slow Crescendo will be "on" only for the length of its corresponding
perforation.  When the perforation ends, that is the same as canceling
the Slow Crescendo. But no cancel hole is required in the tracker bar.

Since the Green system eliminates the cancel holes, this frees up three
more holes on each side of the tracker bar.  And since hole 9 in the
treble is never used,  the number of holes needed is further reduced.
Finally, in the Green system the rewind hole is eliminated (more about
this later).  That leaves only five holes on each side of the tracker
bar required for expression or pedal functions.  Consequently 98 minus
5, minus 5, leaves an amazing 88 notes in the middle of the tracker bar
for music, making the Green system one of the few 88-note reproducing
pianos.  I cannot answer the question "Which came first, the Licensee
or the Green?".

In the bass section the holes and functions are:

    1 - FZ off (quickly drains off stack vacuum in bass and vacuum in
        bass crescendo pneumatic); also initiates time-delay rewind.
    2 - MF (or hook)
    3 - Sustain pedal.  Having the sustain pedal in this position is
        compatible with 88-note rolls.
    4 - Slow Crescendo (bass crescendo pneumatic slowly collapses)
    5 - FZ on (closes bass crescendo pneumatic quickly)

In the treble (right to left)

    1 - FZ off (quickly drains off stack vacuum in treble and vacuum in
        treble crescendo pneumatic)
    2 - MF (or hook)
    3 - Soft pedal
    4 - Slow Crescendo (treble crescendo pneumatic slowly collapses)
    5 - FZ on (closes treble crescendo pneumatic quickly)

To solve the problem of the eliminated rewind hole, bass hole number 1
also activates a slow collapsing pneumatic.  When almost fully
collapsed, it triggers a separate rewind valve and pneumatic.  Since FZ
off perforations are usually short, the rewind is not tripped during
normal playing until a very long (3-4") perforation occurs at hole 1
at the end of the roll.

The term Green refers to the color of the paper.  Many of the rolls are
sort of nickelodeon roll green.  They are much more common in Germany;
however some Green rolls were punched in the U.S.  All of the rolls are
made up from the Red Welte masters with varying success, with only a
few new titles mixed in.  To take advantage of the full scale
capabilities, the Green rolls were sometimes edited to take advantage
of the previously unplayable notes: A, A#, B in the bass and G#, A, A#,
B, C in the treble.  Surprisingly though, most of the Green Welte
pianos have only 80-note stacks, leaving eight unused holes in the
tracker bar.

German Welte did not give up on the speed change feature when making
this new system.  When the crescendo pneumatic on either the bass or
treble side reaches a certain (adjustable) point, usually above medium
loud,  a pallet valve opens, tripping a glass-encased mercury switch to
make an electrical contact which lowers the resistance that is in
series with the motor and its very large rotary pump.  This boosts the
motor speed and vacuum to correspond with the louder playing.  In
normal playing the motor is controlled by another variable resistor
such that motor speed, supply vacuum, (and corresponding pump noise)
are reduced to only the minimum required to play the piano.  Don't try
this at home; these were not induction motors.

Perhaps the sweetest and most overlooked feature of these pianos is
that Welte used an external pouch to "pull up" on the secondary valves
(rather than enclosing the push-up type pouches in the valve chest).
This is true of Red Welte with Welte-built stacks also.  The Green
system goes further by making the primary-valve vacuum and resulting
pull-up-pouch vacuum independently adjustable from the stack vacuum.
Thus the secondary valve will rise even with zero stack vacuum!
Therefore a minimum stack vacuum can be set with no fear of notes
failing to play due to valve tipping.  This precedes the Ampico B valve
by several years, achieving similar, if not superior, results.

These were beautifully engineered pianos, immaculately constructed, and
featuring aluminum tubing.  I believe it is unfortunate that the better
Welte Licensee music rolls from the same period were not remastered for
this system.

Kirk Russell
Wakefield, R.I.