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MMD > Archives > July 2005 > 2005.07.21 > 06Prev  Next

Tubing Diagrams for Player Pianos
By John A. Tuttle

Hi All,  The following relates only to 88-note player pianos made in
the early 1900's.

Some years ago I created a general tubing diagram of a Standard player
action because so many people kept asking about such a diagram and
I had never seen one.  The diagram is located at 

I've always found it somewhat surprising that so few of the player
system manufacturers (regular 88-note) created a simple diagram of the
tubing layout in their player piano.  My feeling is that the basic
layout was considered so simple that a diagram wasn't needed.

Generally speaking, the tubing layout is fairly simple.  The vast
majority of manufacturers followed a few simple rules: Point the vacuum
fitting towards the point where it will connect, use the least amount
of tubing possible, and use the same size fitting at both ends.

The stark exceptions to those rules have to do with the 'push buttons'
and the peripheral devices (bass soft, treble soft, and auto-sustain).
Almost without exception, every manufacturer seemed to go out of their
way to make the tubing layout esthetically pleasing instead of
efficient.  Instead of taking the shortest route, they generally
'squared' the corners (or ran the tubing in a straight line from turn
to turn).

For those who know that the Bass Soft push button operates the Bass
Soft device and the Treble Soft push button operates the Treble Soft
device, connecting the signal tubes doesn't present a problem.
However, I don't believe the manufacturers ever considered that people
without some formal training in player piano repair would ever attempt
to work on their own player piano.  So, information about how these
devices are suppose to be tubed was generally not included in a service

The Auto-Sustain device can also be very confusing to someone without
a general understand of how player pianos are tubed.  In almost all
cases, the Auto-Sustain is operated by either the Loud push button or
by the Auto-Sustain perforation on the music roll.  And, in most
cases, there is only one signal nipple on the Auto-Sustain device.  To
accommodate the 'either-or' scenario just mentioned, a "T" fitting was
used to couple the signal tube from the push button and the signal tube
from the trackerbar to the nipple on the sustain device.

Complicating things a bit further, the signal tube from the trackerbar
was typically connected to an "On-Off" air switch which was mounted on
the left side wall of the spool box.  That switch was normally labeled
"Loud" or just "On-Off".

While the above seems very simple to someone with a working knowledge
of player pianos, it can be intimidating to someone who has no knowledge
of the mechanism.  And, it can be even more confusing if all of the
tubing and the "T" fitting are lying in the bottom of the piano in
small pieces.

Another confusion factor is the pneumatic tracking system.  Fortunately,
because the tubing lengths are relatively short, this tubing is usually
intact even if it's as hard as a rock.  (In fact, some people think
that it's metal tubing because it's so hard.) However, most manufacturers
did include a tubing diagram of their tracking system in their service
manual.  So, once you have the manual, connecting the device up
properly is generally not a problem.

Next we come to the trackerbar.  While the tubing looks extremely
complicated, it's actually the easiest to figure out because it's so
direct and very uniform.  In all cases, the first note hole on the
trackerbar relates to the first note valve on the stack, and the
pattern progresses from left to right in numeric order, i.e.,
1-2-3-4-5, etc., to hole/note 88.

Lastly, there are the mechanisms that employed pneumatic switching for
the Stack Cut-Out and the Fast Reroll cycles.  Even after 30+ years in
the business, I still encounter systems that cause me create a simple
diagram and rationalize what the manufacturer was thinking.  In some
cases, the manufacturer modified (or made improvements to) their own
system/s after producing their service manual.  So, even if you have
the manual, it might not contain a diagram that correctly depicts the
air switch/es in the piano.

Here again, a seasoned veteran can usually figure out what the
manufacturer intended by process of elimination and/or trial-and-error.
On the other hand, trying to explain the primary function and desired
outcome of such switching devices to someone without a working
knowledge of player pianos is next to impossible.  It is for this
reason that I continue to add new information to my web site
( and submit postings to the MMDigest.

By the way, "Colby" has just been added to the list of Player Piano Makes.
It is currently marked as "unknown" because I don't know which player
system is in the piano.  Hopefully, Mike Dostert will work with me to
figure out which system is in the piano, so I can add that information
to the database.  See: 

John A Tuttle
Brick, New Jersey, USA

(Message sent Thu 21 Jul 2005, 12:36:54 GMT, from time zone GMT-0400.)

Key Words in Subject:  Diagrams, Pianos, Player, Tubing

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