Larry Claus wrote in 010226 MMDigest, "I'm still stuck on deciding
about valves and solenoids.  Money is a factor here ..."

In 010107 MMDigest I posted about "MIDIfying a Raffin 20-key Organ".
I bought the valves from Peterson Electro-Musical Products in the U.S.
-- they were USD 4 apiece for the smallest ones.  They have quite
large valves also, I think up to about 2 inches pallet diameter.
See http://www.petersonemp.com/

In my organ, the air pressure tries to *open* the valves, which is
probably wrong for a calliope with its high pressure; there, you would
have to put them inside a wind chest, so that the pressure tries to
close them.  If the pressure on the pallet is so high that the magnet
cannot open it, maybe you can put a second, small-pallet valve in
parallel which opens first and thus equalizes the pressure on both
sides of the big valve (similar designs are used in church organs).

Re the MIDI connection: my laptop PC also has no MIDI output.  I
purchased a BiPort [connects to the parallel port] from Midiman.  If
you use Win95 or Win98 or Win2000, a Midiman Portman/S ("S" for serial
port) also works and is less than half the price of the BiPort.  The
BiPort feeds the MIDI signal into an MTP-3 by John Wale in England.  A
parallel interface (with enough outputs) is, as far as I know, not much
cheaper than using real MIDI, and using MIDI has the advantage that you
can hook up your instrument to anything MIDI in this big world.

Hope that helps a bit.

Harald M. Mueller

 [ A Tangley calliope may operate at pressure 2 pounds(force) per
 [ square inch, or more.  If the valve area is 0.25 sq. in. then the
 [ solenoid must overcome 0.5 pound force, or 8 ounces force.  The
 [ valve travel is only 0.25 inch or maybe less.  Paul Freiling made
 [ small magnet valves to operate the pneumatic player action of his
 [ calliope.  See http://mmd.foxtail.com/Calliope/freiling.html
 [ -- Robbie