[ Bill Heverly wrote in 051004 MMDigest:

> I would be interested in details of this valve ... I'm sure that
> I'm not the only one interested.

I may take the time later to provide a fuller description, and even
attach some small GIF files of my drawings for it, but I'm happy to
reveal my valve design.

A problem with long solenoids is that they prefer to make a long stroke,
while to crack a valve a very short stroke is all that's needed.  Also,
solenoids pull hardest at the end of the stroke, not at the beginning
where we'd like it.  I got around this by putting a steel bracket around
the coil, to complete the magnetic circuit, and arranging the plunger
to not quite reach the top of the coil and bracket.  So there is a small
magnetic gap there, and that's what attracts the plunger (armature).

The coil is easy to wind yourself form #30 magnet wire, and is about
1.5" long.  You wind it on a brass tube from a hobby shop.  The plunger
fits nicely inside this tube, and is a piece of coat hanger wire!
This is threaded at the outside end and screwed into a wooden button
carrying the felt valve pad.   Return is by gravity, though a ball-point
pen spring could probably be used, after soaking it in acid to weaken it.
Somewhere I have the notes giving the Ohms resistance, estimated number
of turns, current drain, etc.

I'll provide these other data later.  Please remind me if it doesn't
appear within a week.

 [ Pete Knobloch wrote in 051004 MMDigest:

>> ... the Gerety-Chase valve blocks would be suitable, if they can be
>> purchased separate from their electronics.

> I think this would be your best bet but I don't think it would be
> very smart to remove the electronics from it.  The magnets are
> controlled by a "pick and hold" system that puts extra power to the
> magnets to get them to open, and then reduces the power so they will
> stay open and not overheat.  They would probably burn out if you just
> applied full voltage to them.

This is a good point that's been discussed before, and I should have
remembered it.  This intelligent current control is how Gerety-Chase
avoid the overheating problems said to have plagued the Power Bar and
Ragtime valves.

The Gerety-Chase valve blocks are sold in groups of 16.  Two blocks
would probably cover any non-cart-mounted barrel organ.

> As far as the problems with the valves being built to be chromatic
> and the music being played not nearly-diatonic, you could have a
> small electronic MIDI translator ("black box") placed between the
> player and the valves to transpose (translate) the notes as needed.
> In fact, you could translate the MIDI files on a computer before
> loading them into the organilleros' player system.

Yes, someone could write a computer program to translate the notes.

This would also help keep the arrangement files proprietary.  The
translated files -- if copied and played on a "normal" chromatic
instrument, or reverse-imported back onto a chromatic staff -- would
sound and look like a scrambled tracker bar tubing job!

Mike Knudsen