[ Ref. 130613 MMDigest, Bleeds for Secondary Valves --

The "bleeds" of which Don Barton speaks are not actually bleeds but
rather constrictions to slow the passage of air between the primary
valves and secondary pouches.  This is done to quiet the valve action,
which is otherwise especially noticeable when playing treble passages
unaccompanied by bass notes.

Aeolian pouches were presumably sealed with egg white, a substance
which apparently evaporates over the years, leaving both sets of
pouches quite porous.  If the pouches cannot be made perfectly
airtight, the primary bleeds must be replaced with smaller ones and
the constrictions enlarged to achieve acceptable performance.

Bear in mind that 88-note rolls made by Aeolian and others during the
early period were double-punched to make them more compatible with the
65/88-note instruments [with a tracker bar] designed to play both
types.  Otherwise, small single punches found on later 88-note rolls
will often cause missed notes and require precise tracking to register
at all.

Bear in mind that these valves were designed for actions playing only
65-note rolls, and some modification is required for high performance
when playing 88-note rolls.

If the primary bleeds are #65 drill size, I would recommend replacing
them with #67 or #68.  I have never rubberized a set of primary pouches
in one of these actions, and I worry that if rubberizing stiffens the
pouches somewhat, they may be less responsive because of the extremely
low suction level at which these actions with their oversize pneumatics
operate.

I would enlarge the constrictions somewhat, using a small round file
with the tip ground or broken off.  Absolute uniformity of size will
overcome any normal variations in primary valve travel.

Secondary valve travel was set to 1/16" at the factory (Aeolian was
hung up on fractions!) and tends to increase somewhat on heavily used
notes.  A more realistic travel would involve subtracting at least
0.010" from the 1/16" (0.063") measurement.  This requires getting
card stock and paper punchings which to my knowledge are presently
unobtainable anywhere.  I could perhaps be talked into making some
extras here in my own shop.  Reduction in secondary valve travel will
not only improve repetition, but also have a quieting effect on the
valves.

A single cover board on the front of the stack has an amplifying effect
on valve noise.  Some Aeolian actions have individual cover boards for
each tier, separated by heavy (red) felt.  Changing to the latter type
will also quiet the valves by eliminating the "soundboard" effect.

Presently I have two Steinways with this type of player action that are
performing unacceptably.  Hopefully I will soon gain experience which
should result in more specific recommendations.

Jeffrey R. Wood