Radio-Onderneming Minimax has its origin in 1921. In that year Cor Thijssens, a radio telegraphist, built and sold his first radios. In 1923 he started his company "Radio Technisch Bureau C.R.M. Thijssens" in the house of his parents at the address Heuvel A44 in Beek en Donk.

In 1926 he changed the name of his company into "Radio-Onderneming Minimax." The company moved to Veghel by the end of 1928 and stopped production in 1934.

The founder of "Radio-Onderneming Minimax", Cor Thijssens, a radio telegraphist, built and sold radios already in 1921. He started his company "Radio Technisch Bureau C.R.M. Thijssens" in 1923, in the house of his parents at the address Heuvel A44 in Beek en Donk, a small village east of the city of Eindhoven. In 1926 he changed the name into "Radio-Onderneming Minimax".

Production grew and the factory moved to a larger building (a former brewery) in the nearby Veghel by the end of 1928. In order to finance the needs for the increased production facility, Bernard de Booij-Lieuwes, a local radio seller, took a 50% interest in the company. However, in 1931 he stepped out and Cor Thijssens regained a 100% participation. A few years later (1934) the factory stopped production because of the general crisis and the increasing competition by Philips in Eindhoven. Thereafter Cor Thijssens joined Philips.

Radio-Onderneming Minimax (and its predecessors) manufactured more than 20 different models, since 1925 under the brand name Minimax. The name Minimax was chosen to emphasize minimal size and maximum volume as well as minimal price and maximum quality in advertising.

Tubes were made by Telefunken and Philips, but coils and ebonite front plates were made in the factory. Cabinets were made by Meubelfabriek Beks in Helmond and loudspeakers were imported from Tefag in Germany.