The Klangfilm company was founded in 1928 with two major shareholders (Beteiligungsgesellschaft): Siemens and AEG (owner of Telefunken). In February 1929 Klangfilm was coupled with Tobis (Tonbild Syndikat AG - with a swiss owner company). In Paris, in 1930, the new Tobis-Klangfilm company signed a very important contract with the General and Western Electric Company ("Pariser Tonfilmfrieden"). This contract reserved exclusive rights of distribution and licensing of recording and cinema equipment in Germany, Austria, Switzerland, The Netherlands and other Eurpean states.

  In 1941 Siemens acquired the part held by AEG and after WWII the former plant in Leipzig remained in East Germany, but the Siemens AG was located in West Germany (Munic). This way the production was restarted in the Siemens plant in Karlsruhe. Many products were sold with Siemens brand name as well as with Klangfilm logo (when distributed for cinemas). Most parts, chassis and speakers can be found in units with both labels.

  Significant differences appear on the design and units from the Austrian Siemens Klangfilm section. Beside the fact that they used different chassis (click for picture) and parts (made in Austria by WSW "Wiener Schwachstrom Werke) the amplifier designs were very different. Many of these used ultralinear circuits (click for schematic) and in several units the reserve amp was built into the main amp (as with a SE EL84 stage).