Gary,  suction units were made by the Lee Music Mfg. Co, PO Box 308,
Culver OR 97734.  A Google search pulls them up with a phone number
of 503-546-3306.  However, I don't know how old the site is.

I recently picked up one of these units, new in the box, from an estate
sale.  It controls the amount of vacuum not by changing the motor speed
but with a small regulator.  I don't know how well it regulates, but it
does draw a great vacuum.

I used it to check out a band organ whose vacuum bellows leaked.  It
worked fine.  I have a standard vacuum pump on a custom orchestrion
which is controlled by varying the speed of the motor.  This isn't the
best way to do it as the motor can overheat with insufficient air flow.
I may put this unit on that instrument.

Jim Quashnock