Thanks for the link, interesting! I didn't realise just how much Trowa were following/copying Sonor. I still love my Trowa, though (sounds great).
Not sure this is actually true. When Sonor left for West Germany in 1950----presumably, it was an option for staff to either leave or stay and i am sure many people stayed, due to family connections, the uncertainty of a good future etc. etc. I have quite a few examples of various German made drums, ranging in age from ----probably the 1920's to the 1980's and it could be said that they all copied each other, if any copying was done at all. Workers ,probably would go to other companies to seek better employment and many ideas would come out of that,not dissimilar to sharing of ideas in the American drum business.
The old Trowa drums, made about the time that the exodus of Sonor workers took place were far superior to the early West German Sonors. I have an early 50's Sonor floor tom and it is the crudest and crappiest made drum I have ever seen.There was a community of interest and expertise ,in the art of musical instrument making in and around Dresden ----there were literally 100's of factories making instruments of all kinds and the workmanship was 1st class. Trowa became connected to Dresdner Apparatebau(best concert snaredrums in the world), the remnants of Lefima(another drum exodus to the West----oldest drum makers in Germany) and other smaller lesser known makers. The narrow snare pictured here(made around 1960 + has the finest muffler design ever put on a drum-----it is both a snap on and an adjustable all in one. The foundry work and chroming is generally good and the shell is built with old world care and expertise, likely from European Beech. So, does that make it a copy of a Sonor? Some of the same people that made that drum probably made Sonors at one time.What German drum of the period,didn't have teardrop lugs(5 ,at least did)? What German drum company didn't use beech in their shells?(---well, actually, all did , Trowa, as well but about the time this drum was made, East Germany was beginning the long slide into serious materials shortages and the shells began to come out in a softwood of some kind and then later a pressboard). Sonor, hardly ever had parallel drop snaredrums but with Trowa/Tacton it was almost ubiquitous. Trowa has the slickest, smoothest parallel throwoff, I have ever used and I have used quite a few.Trowa,moved to square head t-rods in the 1950's, which was very un Sonor. As far as wraps go, there was only one supplier of Celluloid wrap during the 40's,50's and 60's in Germany, so you will see some of the same wrap on all of the German drums. The designers ,engineers and builders of East German drums were equally as capable---possibly more so ,in some ways than some of their Western counterparts. They had materials and beuarocratic limitations, that probably would have brought any American company to a grinding halt and yet they produced fabulous instruments, under quite adverse conditions.My early 60's Trowa is one of the most responsive and well crafted drums ,I have ever played and contains within it some of the cleverest innovations. Rather than being criticised as mere copiers, I think that these craftsmen should be lauded as true innovators. Necessity is the Mother of Invention.