To Bill Koenigsberg [171220 MMDigest] et al,

A. I have spare parts to a metal stack Concertola.  Want 'em?

B. I have a half dozen or so fan expression boxes, several types.
I was hot to collect them -- for a while...  Want 'em??

Both the boxes (and the fans themselves, in some cases) vary from
each other.  One of them, that is completely interchangeable with the
standard grand model Duo-Art expression, I used for my two larger
grand pianos.

Some boxes have larger internal channels than others and so could
pass more wind; who knows why.  Almost all have pneumatically operated
spill valves.


I have three pianos with fan systems operating them:

(1) One piano has small size valves, the size usually found operating
expression accordions.  In this piano the valves are set to move .032".

This is far from the only piano using this size valves to run the notes
-- I have records of several 1930s Strouds that employed them.  They
are all aluminum, which doesn't seem to be given to warpage.  I like
aluminum valve plates.

Two of my pianos are operating on the what appears to be a very early
model fan system which is about the same size and shape as the standard
Duo-Art expression system, and is all but perfectly interchangeable
with the standard model.  Can we guess why?

Ah, but then why were some of the latest the long type?  And has anyone
seen a long one in a spinet?  (I haven't, but I'm sure they would fit).

Donald Wood (of Philadelphia) claimed he saw one in a full-sized upright.
It was he who years ago told me about the big square one in the junk
bin at Acme Piano.

(2) The second of my pianos uses standard size aluminum round valves
set to move .035".

(3) The third piano uses standard size aluminum cross valves moving
.038" to 040".

The pneumatic spill is contained inside them.  I prefer the kind with
the spill as a separate unit.

I have records of Duo-Art grands from the late 'teens where the whole
stack ran .045" and .050"; an earlier pedal grand was set originally
at .055".  I aim at .035" travel.

The differences in how the "big square ones" play (compared to the
standard system Duo-Art) was good enough that I put one in my Steinway
D.  I like it a lot.

The pneumatic spill is operated by tiny pneumatic slaves tripped by the
Theme signals only.  These can be tubed to skip any call for #1-T, and
use the extra tube to join #8-A to cause the crash.  This results in an
interesting floating crash -- depending on where you set it, it also
gives more than one value to the higher levels of Accompaniment.

Just for instance, if you were to add #A-12 with no Theme called for,
your piano couldn't get above the vacuum level for the lowest Theme
-- say, 30 inches.  That said, if you were to add the several Theme
values closing down the spill, which raise the vacuum available to that
#A-12, then the difference is apparent.  This especially so if there
are _no_ snake bite accents.  It can change depending on how many Theme
valves are open.

Some of the same variations can be achieved in the standard system
backing off the Accompaniment spill lever so that the only occasion
full closure of the spill is achieved is 16T.  How far to back it off
is up depends on the technician, the size of the room and the volume
desired for the crash.  If it's done on both spill levers, the top end
of the volume achieved can be backed off gently, and a piano too large
for a room can be made to more desirably fit its surroundings.

This isn't in the book but it was pointed out to me by the factory
tech who used to care for Mom's piano when I was still a kid.  The
manual was created more for home handy guys than factory trained
technicians.

There are some really late pianos out there that have Ampico-style
spills added to them.  I think this approach is kind of sloppy, but
at this point, who cares?  One thing seems clear about them: they were
not designed by Aeolian to be part of a Duo-Art system.

[from Tockhwockh, sending as]
Bruce Grimes

 [ Hear the Steinway D with the fan-accordion system at
 [ https://www.youtube.com/watch?v=4b486I4xbbQ 
 [
 [ MMDigest articles on this topic are indexed at
 [ http://www.mmdigest.com/Archives/KWIC/F/fan_accordion.html 
 [ and http://www.mmdigest.com/Archives/KWIC/F/fan.html 
 [
 [ -- Robbie