Dave Krall recently asked about increasing the DC voltage of his
Tel-Electric reproducing piano's generator.  I think a perhaps easier
way to accomplish the end result is to install a solid state power
supply to operate the player system.  Keep the motor-generator in
place, of course.

I recently installed an ordinary 12-15-volt power supply in my Telektra
88-note and it works beautifully.  Now there is absolute quiet as the
instrument plays, instead of the noise from the motor-generator.

My Telektra is now installed at a new, soon to be opened, museum in
Beijing, China, along with another dozen instruments we shipped in
Feb. 2020.  http://www.nickelodeonco.com/telektra-player-piano--piano-meacutecanique.html 

Food for thought.

Ron Schmuck - Nickelodeon Co.
Mount Forest, Ontario, Canada