Hello Jim,  I don't know just where you saw the article, but I have
MIDI decoders that will work your valves nicely. I have these as 64
note decoders in 120 MA per valve drivers up to 10 Amps per valve
driver.

This is in addition to my other MIDI products. I can be found at
http://www.foothill.net/~soundres.

I have MIDI Orchestra Bells as a standard offering, maybe a MIDI band
organ next...

Hope you find your information and the site.

Musically yours,

Vern Jones, Sound Research