Craig Brougher wrote:

> For instance, a tiny unit small enough to put in-line with trackerbar
> tubing would probably not be an answer to a reproducer or player
> requiring vacuum pressures changing from 5" or less, all the way to
> beyond 100."  And a tiny valve like that would constrict the airflow
> to a pneumatic valve at low tension to the degree that performance at
> those levels would be non-existent.  All this regardless of reliability,
> which definitely would become a problem with an inline unit covered
> with rubber, and required to open and close rapidly under high tension.

Craig's points are valid, but my understanding of the inline valve by
Ragtime Automated Music is that it looks like a one-inch piece of
straight nipple to the tubing, and would not add (much) constriction to
the normal roll operation.  And the valve body itself is not covered
with the rubber, being maybe 0.5" (at least 1 cm) in diameter.

The valves would have to be installed in a less congested area than
right behind the tracker bar, to let each valve "breath" when opened.
I'd put them at the stack end, or at the right-angle distribution and
bleeds bar in a Duo-Art grand.

> For low pressures and short tubing runs in a hurdy-gurdy, I'd say they
> are probably okay.  That might work out, if they are reliable.

Pipe organs have the advantage of running on one fixed pressure (or
suction, in a Wurlitzer).  In a piano, a valve designed against the
maximum suction (40 or 50") should work at the lowest values also, so
long as the designer did not rely on the air pressure to help close the
valve when released.

Reliability is paramount!  The first few days (hours?) with a new
instrument, failures are another invitation to get inside and tinker
with one's new toy.  After that brief honeymoon, ciphers and missing
notes lose their charm entirely.

A possible disadvantage of the Ragtime valves is that the user may be
tempted to install them in a cramped, hard-to-reach space, then to be
frustrated if one acts up.  Think ahead; install them where you can
easily get at them.

Mike Knudsen

 [ If you plan to spend the money for a set of 100 valves you'll surely
 [ want to deal with a firm who will refund your money if you're not
 [ satisfied.  I recall only one or two MMD authors who have actually
 [ worked with and attempted repairs to products sold by Ragtime Automated
 [ Music, and the writers became quite unhappy dealing with the firm.
 [ -- Robbie