I think Andy LaTorre had a good suggestion asking if somebody built
electric air valves.  So far I have heard of the magnet valves used in
pipe organ work (which are huge) and the smaller cousins developed by
Ragtime Automatic Music, of which I have heard nothing about (good or
bad).  While this would be a wonderfully profitable product for somebody
to design RIGHT, building a regular vacuum valve operated by a magnet
will create a player stack with tremendous speed and power.  Let air
pressure do all the work, and you greatly simplify the electronics.

The only really big hang-up after that will be the centrifugal pump noise.
"Only" did I say?  Unless somebody designs one from scratch, forget using
one of these cheapie vacuum units you presently find in sweepers.  Ampico
did finally get a vacuum unit quiet enough to work.  I think it was a ten
stage pump.  And of course, the very late Welte Mignons had them under
their baby grands, and they were very quiet.  But they appear to have
been made out of cast zinc or something, balanced, suspended inside a
muffler box, and their exhaust dissipated through felt and sawdust, etc.

I suggest, then, that before we get too carried away with valves, we first
get carried away, just a little bit, at least, with a suitable vacuum
source that is able to pump quietly without overheating.  To my mind,
presently, that's where the real money is in the new products and
after-market buildups.

Craig Brougher

 [ I purchased a cast-aluminum two-stage regenerative blower for my lab
 [ at work.  It's flow at 2-inches water gage equaled that of a 10,000
 [ rpm squirrel-cage blower, and it was *much* quieter.  It cost about
 [ $500, and the tag said "Made in Japan for Spencer Turbine Co."  Could
 [ that be the famous "Spencer Orgel-Blo" company which supplied blowers
 [ for many pipe organs?  -- Robbie