I am building a MIDI version of a Wurlitzer 104 band organ.  I have
purchased a 128-note MIDI decoder but now I realize that it may not
be able to drive multiple Peterson magnet valves.

The decoder outputs for each note are rated at 35 volts (or less) at
500 milliamperes.  I plan to use 12 VDC to power the magnets, and at
that voltage each magnet draws from 300 to 400 milliamps each.  Four
Peterson magnets in parallel would draw too much current since several
groups of pipes in the melody section play at the same time, i.e.,
Stopped Flutes, Violins, Piccolos and Flageolets.

Do any of you have any suggestions for additional drivers, etc.?
(I hope there is some scheme so that I will not have to make additional
transistor drivers for each note.)  The groups of pipes will have their
own ground returns so that ranks may be turned off and on with a switch
in the ground return line.  Any ideas will be appreciated.

Burl Updyke

 [ Although each output is rated to control 500 milliamps, some makes
 [ of output driver ICs carry an additional limitation upon the total
 [ current the package can safely control.  Check the specs.  -- Robbie