The Dopyera family emigrated from the Austro-Hungary area to Southern Califonia in 1908 and in the early 1920s, John and Rudy Dopyera began producing banjos. They were approached by guitarist George Beauchamp to help solve his volume (or lack thereof) problem with other instruments in the vaudeville orchestra. In the course of their conversation, the idea of placing aluminum resonators in a guitar body for amplification purposes was developed. John Dopyera and his four brothers (plus some associates, like George Beauchamp) formed National in 1925. The initial partnership between Dopyera and Beauchamp lasted for about two years, and then John Dopyera left National to form the Dobro company. The Dobro name was chosen as a contraction of the Dopyera Brothers (and it also means good in Slavic languages).
The Dobro and National companies were later remerged by Louis Dopyera in 1931 or 1932. The company moved to Chicago, IL in 1936, and a year later granted Regal the rights to manufacture Dobros. The revised company changed its name to Valco in 1943, and worked on war materials during World War II. In 1959, Valco transferred the Dobro name and tools to Emil Dopyera. Between 1966 and 1967, the Dobro trademark was sold to Semie Moseley, of Mosrite fame. Moseley constructed the first Dobros out of parts from Emil's California plant, and later built his own necks and bodies. Moseley also built Mobros, a Mosrite-inspired Dobro design. In 1970, Mosrite fell into bankruptcy and Moseley lost the Dobro trademark, however after he started producing Mosrites again he also produced Dobro-inspired guitars under the Mobro brand. In the late 1960s, Emil's company produced resonator guitars under the tradename of Hound Dog and Dopera (note the missing "y") Originals. When the Dobro name finally became available again, Emil and new associates founded the Original Musical Instruments Company, Inc. (OMI) in 1970. In 1985, Chester and Mary Lizak purchased OMI from Gabriela and Ron Lazar; and eight years later in 1993, OMI was purchased by the Gibson Guitar Corporation, and production continued to be centered in California. Gibson changed the name to OAI (Original Acoustic Instruments), and the production of Dobro instruments was moved to Nashville, TN in the Spring of 1997. Gibson continues to produced Dobro resonators under the OAI trademark. Although Dobro has produced acoustic resonators off and on since the late 1920s, mandolins were mainly produced between the late 1920s and the early 1940s. After the company was changed to Valco, they only introduced one mandolin resonator - The Ampliphonic Mandolin/Model 15(D). Early company history courtesy Bob Brozman, The History and Artistry of National Resonator Instruments.
Mandolins previously produced in Huntington Beach, CA and Chicago, IL between the late 1920s and early 1940s. The Dobro trademark is currently owned by Gibson and they produce resnoator guitars under the Original Acosutic Instrument (OAI) trademark in Nashville, TN.