Special thanks to everyone who responded to me on this issue.
Taken together, I will likely buy the blower to play the Aeolian
harp from the Player Piano Co.  and not try to convert a vacuum unit.

I really appreciate everyone's counsel -- you saved me a lot of grief
and I am grateful.

Carl Dodrill - Pipe Organ Foundation
Mercer Island, Washington
http://www.pipeorganfoundation.org/

 [ Maybe you could swap the flap valves in a common box pump to make
 [ it a pressure pump, as long as the connecting rods and bearings
 [ will operate okay.  It wouldn't be as noisy as a small turbine
 [ blower.  -- Robbie