Karl Heinz Weimar started fresh in 1947. He had financing. His original shop was a small concern , in an air raid shelter. From 1949 to 1956 he was in a modest small factory renovated from burned out premises. In 1956, the year Trixon moved into stage 3 of production they moved to a new factory. They simply weren't copying Sonor, from the late 50's on. In fact Trixon ,clearly were the innovators from 1947 on and due to the unfortunate circumstances of the war, Sonor had to play catchup.
The other 3 major German drum companies, in the picture were Lefima, Tromsa and Deri.
Lefima is probably the second oldest drum company ,in the world, dating to 1863. Like Sonor, it was a family owned company and like Sonor it has a long tradition of innovation and development and like Sonor the owners were forced to leave for West Germany and had to start again. Lefima ,never redeveloped their kit drum manufacturing, effectively. They now concentrate on marching drums and orchestral drums but under state ownership in East Germany, there were some pretty interesting Lefima drums made.Lefima was merged with Trowa(TROmellfabrik Weiesenfells A.g.) eventually, yielding the Tacton brand ( transl. time-beat or possibly tempo-rhythm). That's about when the family left for the west and reestablished( approx. 1963).
Tromsa( TROMellfabrik SAttler). The Sattler family had been in the leather and I believe barrel business . Fusing the two, meant drums. I do not know, when they made their first drums but a safe assumption would be , pre-war. They already were in production of quite nice kits in the early 50's, with parallel strainer snare drums and made their own hardware. Sonor was able to purchase hardware from them , to get up and running. The early 53-54 Sonor catalogues show a nice Tromsa double spring pedal and hi-hat with cast aluminum footboards and the hoops look suspiciously like the Tromsa hoops , that persisted for decades.
Deri( Max DEibel and Karl RImmel). Deri, dates from the 30's and even in 1947( I have seen a kit dated as such) had nice modern kits with perloid finishes L-arm mounts with nickel on cast aluminum lugs and hoops.This company was also a source of metal parts for Sonor, during the rebuilding. Karl Rimmel won a huge lottery and built a state of the art foundry, where he produced hardware for several drum companies, including his own. Deri was a bit unique because they used Birch for shells,mostly, whereas the common choice in Germany was Beech.