I have an Ampico B piano that is missing the music roll brake control
valve assembly, mounted at the right rear corner of the spoolbox.
This is the device that "feels" the thickness of the top spool.  As
the paper diameter on the top spool gets smaller, a needle valve
gradually leaks more atmosphere counteracting the vacuum pull of the
friction brake, preventing large rolls from halting to tighten, since
the note sheet tension is constant.

I am wondering if anyone might have this part available from parting
out an Ampico B drawer.  Alternately, I'm wondering if anyone has made
a replacement and how they went about it.  The amount of bleed at
various positions seems tricky.

Thanks,
Craig Roothoff
Escondido, California