The Radio Products Corporation manufactured ''Superflex'' broadcast radio receivers. The corporation was founded in 1925 by inventor Ernest W. House with W. T. Estes and Jelk Cabiness. The company manufactured its radio sets in a facility at 3814 28th Street North in Birmingham, Alabama. This is the only known radio manufacturing faculty in the deep south, during this time period.
In 1925, the most common radio sets, with the highest sales, were three dial receivers which offered the greatest sensitivity and selectivity. These types of receiver were, however difficult to tune, so most manufacturers opting for a single dial. Improvements in this area were generally mechanical, in nature, employing techniques such as connecting all three tuners together with belts, mounting them on a single shaft or using a rack and pinion system.
The radio design envisioned by Ernest House took a different approach. His design accomplished the tuning electrically. The Superflex radio used a basic regenerative circuit, except House's design used a capacitor to provide feedback from the detector to the RF stage. The effect of this innovative feedback technique was the operator did not need to tune the front end of the RF circuit...it automatically tuned itself. The result of his efforts was a radio that used only one dial to tune for desired radio stations. In its day, this circuitry was, unique and unprecedented.
The corporations’ organizers empowered House to move forward with his ideas regarding the Superflex circuitry. On September 20, 1927, almost two and out-half year after the corporation was organized in Birmingham, the patent was awarded by the U.S. Patent Office. Radio Products Corporation proceeded to manufacture the Superflex. Each Superflex radio receiver was individually made. Coils were hand-wound in the factory and many parts were riveted to a chassis made of a non-conductive material like Bakelite. The set uses one '12A output tube and three 01A tubes. Circuitry consisted of four stages: an RF amplifier, a detector plus two stages of audio amplification. It used two tubes in the front-end with output fed into a standard transformer-coupled audio system.
The Superflex also distinguished itself from other radios by the unique "theatrical stage curtain" design on the front panel. Also, painted in each lower corner was an outline of a decorative plant which you might see on the sides of a real stage. The cabinet of the Superflex was polished wood with a somewhat standard rectangle box shape and form.
According to Ernest House, Jr., a selling point used by his father was “You haven't got all them blamed tubes to have to buy!" This was an apparent reference to the large number of tubes found in many sets manufactured by competitors. Initially Superflex sets sold for $80.
All Superflex radios were made in a small factory located at 3814 N. 28th Street in north Birmingham. After the initial building was constructed, a speaker system was mounted on the roof which was used to entertain the neighbors and anyone else who gathered to listen. One special event was the famous Dempsey-Tunney boxing match in September 1927, when hundreds of people gathered outside the factory to hear the live coverage.
No sales records for the Superflex are known to exist, however it is known sales were negatively impacted by the economic conditions caused by the Great Depression and later by technologically advanced superheterodyne sets. Efforts to locate some of the early experimental models have been unsuccessful.
The only two existing examples of a Superflex radio are in the collection of the Alabama Historical Radio Society and displayed in their museum in the Alabama Power Building Atrium at 600 18th Street North in Birmingham, Alabama.
The first Superflex owned by the Society was in poor condition when located in the 1980’s. The receiver was restored to museum standards by members Don Kresge and Marvin Sheppard. (Don Kresge was an Electrical Engineer with General Electric, worked with Edwin Armstrong and was the founder of the Alabama Historical Radio Society)
The second receiver was recently purchased from the Haynes family. The unit was original purchased by the patriarch of the family in the late 1920’s. The find included the original Manhattan speaker sold with the radio.
The Society also has photographs, documents and recorded oral histories relating to the Superflex and Radio Products Corporation. This radio is now the official logo of the Alabama Historical Radio Society.