Great to see Ed Gaida's Broadwood player with the unit valve
pneumatics.  From 1904 to 1907 Broadwoods made some of the first ever
Pianola pianos, but from 1907 to about 1912 (when they moved over
to Hupfeld Solophonola systems) they manufactured and fitted this
fascinating patented unit valve/pneumatic design of their own.

There are pretty startling grand installations using it too, with
forests of unit valve/pneumatics and push-rods underneath the soundboard!

Clearly Broadwoods erred on the side of making the components too big,
and the sheer bulk of the installations does soak up much of the
pianos' sound!  This despite the fact that both grands and uprights
were invariably the expensive Barless models, which as Ed may have
discovered have stunning power, tone and impressively even scaling.

The build quality of the pianos is superb and these player actions
are actually very cleverly designed and production-engineered.  I have
a unit valve/pneumatic in original condition in front of me now, and
it still works perfectly.

Note among other details the primary and secondary valves in the same
unit; the economy of machining; the fixed pneumatic board serving as
the top secondary valve seat; how easy it is to access the bleeds and
adjust the valves; and how the note pneumatics' span, travel and
pitman/key play are all easily adjusted at the same location just
in front of each unit.

In most installations the top action is quickly and easily removable
for tuning and regulation, with some 46 tubes from the tracker bar
going down to the stack via each end of the key-bed rather than between
the keys as in early Pianola pianos.

The note pneumatics incorporate an amazing design feature which few
notice and which I recommend.  The force characteristics of any normal
note pneumatic depend greatly on the flexibility of the hinge.  To
quickly manufacture a uniformly flexible, airtight hinge is in fact
very difficult with hot glue, and many of us have come across
reproducer and ordinary stacks where, because a previous rebuilder was
careless or inexperienced, the hinge tightness varies considerably,
and even, soft playing just isn't possible.  In the UK Aeolian's note
pneumatics were largely made by outworkers and a quality assurance and
grading system was apparently used to ensure consistency.  But Broadwoods'
designers realised a cunning method of virtually eliminating the
significance of hinge flexibility.

If you look at Ed's pictures, you'll see that the pneumatics are made
'square' with no internal hinge (like Duo-Art accordions) and with an
overlapped seam in the rubbercloth at one end.  The pneumatic is then
closed at the seam end, and a rubbercloth strip hinge stuck across from
board to board -- but without any glue in the crease.  This method
requires no more time, materials or technique but ensures that every
hinge is airtight and properly constrained yet has only the uniform,
negligible stiffness of the rubbercloth strip, so even, soft playing
is exemplary.

If anyone wants more information let me know.

Patrick Handscombe
Wivenhoe, Essex, UK