In the city of Kharkov, I bought an incomplete drum set Trowa with an unusual interesting pattern of drum perloid. As for the details of mounting the rims, mounting the viola and the big drum, the installation was made in the 50s of the last century. The fact is that the diameter of the big drum is 22 ", not 20", as it was in those years.
I have never met the big drums of Trowa with a diameter of 22 ". The German producer of drums of Trowa began to release the big drums of such a diameter only after renaming the factory to Tacton and with the beginning of the production of second-generation drums of Tacton from the 80s