The Last Hurrah for the
Coinola Midget Duplex Coin Piano
also known as the Thirty Tunes Coinola

(Photograph courtesy of Dana Johnson.)

Coinola Portfolio photograph of the Coinola Midget Duplex coin piano. This attractive cabinet piano was introduced in 1927, too late in the declining coin piano market to attract much attention, and so, consequently, few were sold and even fewer survive in collections today. It could play the standardized style "A" music roll, but Capitol cut special extended 15-tune music rolls for this instrument, which was alternately advertised as the "Thirty Tune Coinola." Soon after the introduction of the Midget Duplex all Operators Piano Company advertising disappeared from trade magazines, and sadly the Coinola line of coin pianos gradually faded away into the dustbin of history.

(Photograph courtesy of Don Teach.)

Coinola Midget Duplex coin piano #9829. The case is oak with a silver-fox finish (a black stain finish with white glazing rubbed into the wood pores), providing a pleasant contrast against the colorful art glass. Notice that there are two music program card holders, one is to the left of the left-side art glass panel, and another to the right of the right-side art glass panel. The oval shaped bevel glass in the center of each art glass panel allows the patron to view the large tune number that is rubber-stamped on the music roll. Then by correlating the tune number with the appropriate tune program card it is possible to know which tune will play next on either the left or right side roll mechanism. At center, between the two roll frames, is a small placard that reads: "Select Right or Left Roll Before Droping Coin" (sic). Thus the customer moves the little lever below the placard to whichever tune is desired, and then inserts a nickel into the coin slot to hear the selected tune.

(Photograph courtesy of Don Teach.)

Interior of Coinola Midget Duplex coin piano #9829. The Midget Duplex was built in a unique case that employed a 66-note piano. However, to accommodate the A-roll scale the piano was tuned differently than were the typical late-style 66-note O-roll Midget pianos. The lowest note on the Midget Duplex piano (B) and the seven highest notes (A# to E) are not played by the stack. That leaves the normal 58 notes of the “A” roll, C through A, that are played automatically.

Below the roll frame shelf and at center is the roll selection lever (left or right side) and "foolproof" lockout device, which prevents any tampering with the roll selection until the machine shuts down. At the bottom of the case is the vacuum pump and reservoir. Above the pump and at left is the electric motor that powers (by means of leather belts) both the pump and the duplex roll system.

The gleaming little device with a dome shaped cap and thumbscrew clamp, and centered on top of the pump, is a music-roll cleaner. It is basically nothing more than a small capped easy to clean out vessel with a filter in it to catch any lint sucked into the unit. Operators filed a patent application for its music-roll cleaner in December of 1925, and a patent was finally granted in February of 1929. This device came on board late in the coin piano era, and so it is only encountered in circa 1925 or later Coinola pianos and Reproduco organs.

(Photograph courtesy of Don Teach.)

Duplex roll mechanisms in Midget Duplex coin piano #9829. The great advantage of a duplex roll system is that when one roll reaches its end and goes into rewind mode the other interconnected roll frame begins playing from the start of its roll, so that there is no long term interruption in the music program. But that kind of setup is not what Operators installed in the Midget Duplex. There is no transfer chest to switch from one tracker bar to the other. Both tracker bars are hole-for-hole teed together. This requires that there must be a paper music roll sealing off the holes in both tracker bars whenever the instrument is in operation, with the roll frame at idle stopped dead between tunes where no control or note perforation exist. This is why there is a "Left - Right" selection lever and a lockout mechanism to prevent any changes during play that might adversely affect the idle roll frame. It works, but possibly not the most advantageous use of a duplex roll system. It does, however, allow the patron to select between two tunes, which is better than no selection at all.


(Photograph courtesy of Don Teach.)

Coinola Midget Duplex coin piano instructional placard. The small celluloid placard on the front of the case clearly instructs the patron to select either the left side or the right side roll mechanism, and then drop the coin in the slot. Below the placard is a slot in the case front to accommodate a metal lever that can be moved from side to side to make a selection as desired. Once the motor starts and a vacuum begins to build the selection lever cannot be moved again, until the motor stops and the vacuum level bleeds off.