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MMD > Archives > November 2004 > 2004.11.23 > 13Prev  Next

Primary Valves Bypassed in Double Valve Player
By John A. Tuttle

Hi All,  I too was somewhat amazed when I encountered my first
double-valve action that had been "modified".  I was even more amazed
when I found that there were no bleed cups in the system.  Like the
action that John Bushey spoke about, the only real "problem" seemed to
be repetition.  (It also seemed that some notes stayed 'on' a bit too

After mulling over the problem for a few minutes - trying to figure out
how the mechanism was working at all - I came to the conclusion that
there was sufficient leakage in the pouches (and perhaps elsewhere)
that they were, in essence, acting as a bleed.  (This happened years
before I worked on my first Baldwin Manualo player which has a pin hole
bleed in each pouch.)

What's rather odd about the "bypass trick" is that rebuilding the
primary valves in the Standard action is relatively easy.  And when
you considered the work that goes into changing the tubing and perhaps
changing the pouch-to-valve stem clearance in the secondaries to make
them more sensitive, the whole process seems like a terrible waste of
time, especially in light of the fact that the performance of the
system is degraded.

Although this recommendation flies in the face of acceptable technical
remedies, a quick fix to the repetition problem would be to take a
needle and put a tiny hole in the pouches of the notes that don't
repeat well.

Holding my breath and waiting for the fallout...

John A Tuttle
Brick, New Jersey, USA

(Message sent Tue 23 Nov 2004, 14:37:33 GMT, from time zone GMT-0500.)

Key Words in Subject:  Bypassed, Double, Player, Primary, Valve, Valves

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