Function of the
Deca-Disc Changer
(Click on
picture above to see the Deca-Disc
in action)
The
Deca-Disc is a small upright
phonograph with a case made from plain
quartersawn oak and a glass top. A small grille in front
is the horn/ loudspeaker opening.
The five
10” records sit on three supports above the turntable. The
coin-op mechanism with an accumulator function allows prepaying
multiple records. The phonograph is powered via a belt by a
small electric motor, which drives both the turntable and the
mechanism via a clutch arrangement.
The turntable is made of lightweight aluminum to minimize
the load placed on the changer mechanism with a full stack of
records, allowing for use of a very small and inexpensive motor.
The low mass of the turntable and corresponding lack of
inertia necessitates an overly complex governor to maintain
speed.
The motor
is somewhat underpowered and is managed with a curious governor
arrangement: At start-up or when the resistance of activating
the changer mechanism lowers the speed, the governor activates a
switch which sends more current to the motor. To regulate
constant playing speed, the governor uses a second switch to
interrupt the motor circuit. The curious blue “mood lamp” at the
back of the phonograph assists the owner to regulate the
governor with the top-mounted speed control: Correct speed is
reached when the light flickers steadily during play. Despite
this somewhat cumbersome governor arrangement, the lightweight
turntable runs smoothly without wow and flutter.
When a coin
is inserted, the record starts spinning.
At the end
of the record, the sophisticated trip mechanism activates on any
kind of run-off groove: Victor elliptic,
This is the
most sophisticated automatic trip, which for the first time
solved the problem of working with all records regardless of
manufacture and run-off groove design. To my knowledge, only
some Swedish LUXOR changers of the
1940s ever employed a similar device.
The design
of the turntable lift mechanism is of simple elegance, but is
compromised by the weak electric motor: The whole lift cycle is
actuated by a large vertical cylinder, where a helical groove
moves the platter upwards and downwards with the help of a pin
on the central axle. Regardless of the cycle (pick-up vs.
replenish cycle), the turntable always moves the same way. In
the reload cycle, the platter goes all the way up and deposits
the stack of records above the catches. In a record drop cycle,
the separator knifes prevent the platter from rising above the
bottom of the stack forcing the turntable to slip a few threads
further down on its central threaded shaft. It uses a
multiply-threaded pawl that can ratchet easily to accomplish
this. A cam on the main cylinder also adjusts the playing
surface lower for each additional record.
This
underpowered motor is a major weakness of the
Deca Disc: It is unable to lift more
than the weight of 5 records. Had Deca-Disc
chosen a stronger spring and a larger motor, the changer could
have handled more than the limited selection of only 5 records.
The support
posts and drop mechanism are entirely activated by the rim of
the raising turntable:
The rising
turntable pushes the three main catches aside. A complex linkage
inserts three separator knifes between the bottom and the second
record. As the catches further retreat, the bottom record drops
on the turntable. Inside the support posts, a mechanical sensor
recognizes an empty magazine and retracts the separator knifes,
allowing the turntable to restack the magazine during the reload
cycle.
While the
Deca-Disc is a reliable mechanism
that will play and change records securely and with no damage,
the spring-balanced mechanism and weak single motor are
difficult to adjust. The limit to 5 records is a major
disadvantage.
MACHINE INFORMATION
|
Maker |
Deca-Disc
Phonograph Co.,
Modified by Ristau Atlas Sales
Co. |
|
Model |
N/A |
|
Year |
1924, probably sold 1928 |
|
Owner |
Mark Williams |
|
Repaired/Serviced by |
Mark Williams |
Timeline and Patents
1921 James.
E. Stout unassigned, first patent of automatic phonograph:
1,449,252
1922
trademark registration: Deca-Disc
Jan 1923 Deca-Disc Phonograph
Co, Paul D.
Bodwell President, capitalization
500K$
Oct 1924,
American Music Corporation, Paul D. Bodwell
President, capitalization $1,200,000 (most likely a new parent
company of Deca-Disc). Stock
certificate shows Deca-Disc
Phonograph
1925 Paul
D. Bodwell and Henry W. Bellows for
Deca Disc, patent for coin-op
phonograph with an advertising device 1,837,608
1925 Paul
D. Bodwell and Henry W. Bellows for
Deca-Disc, patent for record trays:
1,683,440 (reference to the 1923 Stout patent) &
1,653,541
1926 W. K.
Kaufman for Deca-Disc, patent for
Record Trays: 1,683,469
1928
Deca-Disc inventory bought by
Ristau Brothers, resold with
electronic amplifier. Possibly Deca-Disc
patents sold to Rock-Ola
1929 Last
patent filing by Deca Disc: second
patent for Electramuse: 1,875,641
I am always interested to hear
about other machines.
You can reach me at:
sgimips1 "at"
yahoo.com (replace "at" with @)
Again my great thanks to Chuck Azzalina
for his great help in creating these pages.
Pleases check out his
other web pages with even more
fascinating early audio and TV tube electronics. One level above
this page, you can find more
fascinating changers with video clips.
MORE LINKS
The
original Deca-Disc/ American Music
Corporation stock certificate:
http://www.scripophily.net/ammuscor.html
1921 James.
E. Stout patent of automatic phonograph:
http://www.google.com/patents?id=Q3lWAAAAEBAJ&dq=1,449,252
1925 Paul
D. Bodwell / Henry W. Bellows,
patent for coin-op phonograph with an advertising device:
http://www.google.com/patents?id=wTlhAAAAEBAJ&dq=1,837,608
History of
Holcomb & Hokes and the Butter-Kist popcorn maker:
http://www.antiquepopcornmuseum.com/history.php
On
JukeboxWorld.de:
Great site
of the Electramuse:
http://www.jukebox-world.de/Forum/Archiv/USA/Electramuse.htm
More early
jukeboxes and the Electramuse/
Auditorium Models:
http://www.jukebox-world.de/Forum/Archiv/USA/Sonstige_Modelle_USA.htm