[ David Dewey wrote in 200325 MMDigest --

> Violano rolls are sometimes, perhaps eventually always, "eaten"
> by the player due to electrical arcing. Hmm; I just thought,
> has anyone added anti-flyback diodes to them to prevent or reduce
> the arcing, as is done in pipe organs? 

The difficulty about diodes would be that the original DC
motor-generator could start up in either polarity, so that the
magnets would not get permanently magnetised.

At least in theory, the paper roll quenches the spark as it cuts
off the current flow at the end of the note hole.  Our Violano
rolls seem to have deteriorated just due to the paper drying out.
Have not so far has a conflagration!

Regards,
David Evans
British Columbia, Canada

 [ For consistent polarity and safety, a bridge rectifier and a
 [ 1-to-1 motor isolation transformer can be installed.  -- Robbie