Preserving the Phonograph

Included below is information regarding the mechanics of an Edison Diamond Disc Phonograph. This information is intended to shed light on how an Edison Diamond Disc Phonogaph functions, however the authors strongly urge seeking out professional assistance before attempting any sort of repair!

The information provided was found on the Edison Phonology Website, which offers a plethora of detailed mechanical insight and photographs. Another excellent resource is an online repair manual, courtesy of Volvic the Phonoguy. The following images are from that guide: Click on an image to browse pages from the manual.

                     

Composition of Phonograph

The Diamond Disc floating weight reproducer design was based on the old reliable Edison Diamond B reproducer that was designed to play vertical cut Blue Amberol cylinder records. The Diamond Disc diaphram is significantly larger and the floating weight faces in the opposite direction but the concept is the same. The Diamond Disc reproducer is secured to the horn with a knurled connector, allowing easy removal for servicing. The reproducer basically consists of a diamond stylus mounted to one end of a lever. The other end of the lever is attached to a diaphram by a thread. When the stylus bounces up and down in the record groove, the lever amplifies the movement and tugs on the diaphram to produce sound. The sound is further amplified as it travels through the horn.



Access to lubricating tubes is gained by lifting the turntable off of the spindle. Before doing this, one must remove the reproducer, turn the speed control knob fully clockwise, release the brake lever, and turn the control handle fully clockwise. Make sure the small oil tubes leading from the cups are not clogged and that the wicks are sticking out of the ends near the bearings before filling. Always lubricate the spindle bearing and put a few drops of light oil on the governor's felt friction pads. When replacing the turntable, make sure the slot lines up with the key on the spindle shaft and gently press down. Set the brake and turn the speed control knob almost fully counterclockwise. Use a strobe wheel to fine tune the speed to 80 rpm.



Removing the grill reveals the horn. The horn swivels about the vertical shaft seen in the front on the right side of the horn compartment. This shaft is rotated by a feed screw and sector gear to move the horn and reproducer in synch with the record groove. The round ball seen in the throat of the horn is the volume control. This is moved in and out of the horn throat with a choke cable connected to a lever on the top of the motor board. The wooden bracket to the left of the horn was for storing the reproducer when the phonograph was shipped.

Differences in Machines

With a few exceptions, all Edison disc phonograph mechanisms are basically the same. The only difference mechanically is the size of the horn and the number of springs used to drive the turntable and tone arm. Low-end machines used smaller horns and had one spring. Mid-range models had a slightly bigger horn and one spring. Top-end models had the largest horn and two springs. The two springs allowed you to play more records on one winding.

"Period Cabinets"

To help justify higher prices and gain a competitive edge, Edison commissioned furniture designers to develop attractive "period cabinets" to house his phonograph mechanisms. The result was a line of cabinets based on European designs from the 16th Century to the late 19th Century. These included Elizabethan, Queen Ann, Chippendale, Louis XIV, etc.

Important Things to Remember about Your Edison Disc Phonograph