amps were sometimes repaired by Leo Fender, whose repair shop evolved into the Fender Electric Instrument Manufacturing Company. Early history George Beauchamp was a vaudeville performer, violinist, and steel guitarist who, like many acoustic guitarists in the pre-electric-guitar 1920s, was looking for some way to make his instrument cut through an orchestra. He first conceived of a guitar fitted with a phonograph-like amplifying horn. He approached inventor and violin-maker John Dopyera, who made a prototype that was, by all accounts, a failure. Their next collaboration involved experiments with mounting three conical aluminum resonators into the body of the guitar beneath the bridge. These efforts produced an instrument that so pleased Beauchamp that he told Dopyera that they should go into business to manufacture them. After further refinements, Dopyera applied for a patent on the so-called tri-cone guitar on April 9, 1927. Thereafter, Dopyera and his brothers made the tri-cone guitars in their Los Angeles shop, under the brand name National. On January 26, 1928, the National String Instrument Corporation opened, with a new factory located near a metal-stamping shop owned by Adolph Rickenbacher and staffed by experienced and competent craftsmen. The company made Spanish and Hawaiian style tri-cone guitars as well as four-string tenor guitars, mandolins, and ukuleles. Adolph Rickenbacher was born in Basel, Switzerland in 1887 and emigrated to the United States to live with relatives after the death of his parents. Sometime after moving to Los Angeles in 1918, he changed his surname to "Rickenbacker". In 1925, Rickenbacker and two partners formed the Rickenbacker Manufacturing Company and incorporated it in 1927. By the time he met George Beauchamp and began manufacturing metal bodies for the "Nationals" being produced by the National String Instruments Corporation, Rickenbacker was a highly skilled production engineer and machinist. Adolph Rickenbacker became a shareholder in National and, with the assistance of his Rickenbacker Manufacturing Company, National boosted production to fifty guitars a day. Unfortunately, National's line of instruments was not well diversified and, as demand for the expensive and hard-to-manufacture tri-cone guitars began to slip, the company realized that it would need to produce instruments with a lower production cost to remain competitive. Dissatisfaction with what John Dopyera felt was mismanagement led him to resign from National in January 1929. He subsequently formed the Dobro Manufacturing Corporation, later called Dobro Corporation, Ltd, and began to manufacture his own line of resonator-equipped instruments (dobros). Patent