Marveltone was a brand name of Targ & Dinner a wholesale instrument distributer from Chicago, used from 1926 until the early 1990s. Up to the 1960s Marveltone acoustic guitars would have been made by the big Chicago factories such as Kay, Harmony and Regal, whereas later Marveltones would have been made in Japan or Korea.
Source: Guitar Stories: The Histories of Cool Guitars. Michael Wright. 2000. Hal Leonard,
Source: Marveltone catalog 1960
Source: Targ and Dinner catalog 1950