[ Mark Reed wrote in 220914 MMDigest:

> I am working on some MIDI conversions and am looking for options that
> people have been using for the electric valves used to open and close
> the tracker bar lines. Options that are fast to respond, compact and
> economical are encouraged. Please share sources too.

Robbie remarked:

>[ Probably the most economical electric valves for orchestrions and
>[ organs are at eBay; search for "Reisner organ valve magnets".

To which I reply:

I share Mark's interest, and I want to add MIDI to some paper roll
devices, with a tiny electromagnet teed to each tracker bar tube.

Typical pipe organ magnets, and especially direct-electric valve
magnets are _way_ too big for this application. I keep checking the
web for project posts, hoping to find a cheap, fast, and small magnet
for the purpose. Big Reisner magnets are certainly not what is needed.

This question comes up often, seldom with a workable answer. There must
be hundreds of folks on-line who have done this, and at least a few must
have a part number that is still available.

Optimistically,
Greg Graham