[ Randolph Herr wrote in 080207 MMDigest:

> Clarence Hickman had a brilliant idea in using the vacuum that closes
> a bellows and plays a note to also exhaust the air that is under the
> pouch and in the tubing leading to the tracker bar.  His "ball bleed"
> valve, used in the Model B Ampico, is the result.
>
> Speaking of this "ball bleed," I want to ask a question: it seems
> to me that it was not necessary to make this entire ball-bleed gizmo,
> when all you need is a tiny flap valve, perhaps a quarter inch on
> each side, made of pouch leather and put over the top of the hole
> where the ball bleed went.  I would appreciate hearing from other
> readers on their ideas as to whether this would work.

Would the life of the leather outlast the life of the ball bleed in
the Ampico B unit valve?  Leather pouches last a long time but I wonder
how long a tiny leather flap valve would last, especially in today's
pollution laden air.

Your question about the bleed also exhausting the tracker bar tube is
interesting; I think it does because there is a certain length on the
roll before the note will repeat.  (The first consideration is that the
roll will tear if too short a space between the holes.)

I thought it had to do with the speed of the roll across the tracker
bar rather than the bleed and also that a human can not make a note on
a piano repeat faster than a player piano can.  So the bleed works --
no need to improve it(?).

Richard Moody