It is indeed possible to play Welte-Mignon Licensee rolls on a T-100
(red paper) Welte-Mignon.  Of course, a 9-to-the-inch tracker bar is
necessary to play the rolls.

The only provision not accounted for in Licensee rolls in the
resistance change for the motor speed control.  Many red pianos are no
longer equipped to change the motor speed on the pump via resistance
(Wiederstand) change.  In this case the Licensee rolls should perform
well as they are.

If the piano still has provision for motor speed change, then it is
possible that during forte passages that the piano will not provide
sufficient vacuum.  Alternatively, a jumper may be placed across the
resistance switch running the pump in high pressure for the duration of
the Licensee roll.  The downside, naturally, is that the pump will
produce slightly more noise during pianissimo passages.

It is also possible to mount a switch to the underside of the expression
regulators to close when the music calls for forte passages.  It is in
this manner that the T-98 (green paper) Welte-Mignon provides motor
speed control without provision in the music roll.

Ron Sanchez in Monrovia, California has successfully added a licensee
tracker bar to Welte-Mignon Vorsetzers while leaving the T-100 red
tracker bar to play its own roll scale.  I also believe that Jim Miller
of Tarzana, California has likewise built instruments to play both roll
types.

I have seen the advertisements for the "Power Roll" system.  It appears
that this could well be applied to the T-100 (red paper) Welte-Mignon.
Once again the problem remains for the resistance control.  It would be
interesting to know how many red pianos still use the motor speed
control as I do.

Mark Reinhart
West Virginia
weltemgnon@aol.com