For a long time, I thought all resonator guitars were a “National Resonator Guitar“. It soon became apparent that several other manufacturers produce resonator guitars, but I believe the first ones were produced by National.
National Dobro, Hound Dog, and Gibson
After much legal action, the Dopyera brothers gained control of both National and Dobro in 1932, and subsequently merged them to form the National Dobro Corporation. However all production of resonator guitars by this company ceased following the US entry into World War II in 1941.
Emile Dopyera (also known as Ed Dopera) manufactured Dobros from 1959, before selling the company and trademark to Semie Moseley, who merged it with his Mosrite guitar company and manufactured Dobros for a time.
In 1967, Rudy and Emile Dopyera formed the Original Musical Instrument Company (OMI) to manufacture resonator guitars, first branded Hound Dog. In 1970 they again acquired the Dobro trademark, Mosrite having gone into temporary liquidation.
OMI was acquired by the Gibson Guitar Corporation in 1993, which announced it would defend its right to exclusive use of the Dobro trademark, which had come to be commonly used for any resonator guitar. As of 2006, Gibson produces several round sound hole models under the Dobro name, and cheaper f-hole models both under the Hound Dog name and also its Epiphone brand. All have a single resonator, and many are available in either round or square neck.
Other National instruments
After the formation of the National Dobro Corporation, the term ‘National’ was often used to mean an instrument with a non-inverted cone, to distinguish these designs from the inverted-cone ‘Dobro’. Makers particularly used it for single-cone biscuit designs, as the relatively elaborate and expensive tricone was for some time out of production. Players and collectors also used the term for the older tricone instruments, which despite their softer volume and rarity were still preferred by some players.
In 1942, the National Dobro Corporation, which no longer produced Dobros or any other resonator instruments, was reorganized and renamed Valco. Valco produced a large volume and variety of fretted instruments under many names, with National as its premium brand. By the early 1960s, Valco was again producing resonator guitars for mail order under the National brand name. These instruments had biscuit resonators and bodies of wood and fiberglass.
In the late 1980s, the National brand and trademark reappeared with the formation of National Reso-Phonic Guitars. As of 2006, it produces six-string resonator guitars of all three traditional resonator types, focusing on reproducing the feel and sound of old instruments. Its other resonator instruments include a 12-string guitar, ukuleles and mandolins.
In the late 90’s Amistar, a Czech Republic manufacturer, began marketing tricone resonator guitars.
Wayne Acoustic Guitars produced a spider bridge resonator guitar in the ’40s and ’50s in Australia. They were crudely made out of what was at the time cheap Australian timber using a tone ring rather than a tone well but their biggest problems were no neck reinforcement and a very different pressed (rather than spun) cone. This is often called a pillow cone due to the shapes pressed into the face to strengthen the cone. Many examples exist today and if the neck is straight and a good cone is used can give a reasonable sound. As of 2010 Don Morrison is producing highly regarded resonators under the Donmo brand name.
Many Asian brands such as Johnson, Recording King, Republic Guitars and Rogue also produce or import a wide variety of comparatively inexpensive resonator guitars. Johnson has also produced resonator ukuleles and mandolins.
A company called Gallotone in South Africa is also known to have produced resonator guitars in the 1950s and ’60s.
(courtesy of http://en.wikipedia.org/wiki/Resonator_guitar
So as you can see, there are several resonator guitar makers. Hard to beat an old vintage National Resonator Guitar for it’s unique “steel” sound. But as far as I’m concerned they all sound pretty darn good it the right hands.