Hello all and Happy New Year,  I would like to appeal to any MMD reader
who may be able to provide me with information on the operation of the
pneumatic stack vacuum regulator used by Pierre Eich in the Solophone.

I have two back-to-back pneumatics and valve mounted on a wood block
that in turn mounts on the vacuum/pressure pump.  It would seem that
somewhere, as part of this device, there should be a spring.  I would
like to communicate with any reader that may be able to provide a photo
or other information that may be helpful.

Thank you,
Howard Kohlbrenner
Broomall, Pennsylvania