Cub Model Bisonoric Accordion
The Club layout is both modified and extended. The modification makes the tonic or root note of the Major key of the outer row available on the draw on the middle row in the low and middle octaves, creating a unisonoric button, or "gleichton" in German, near the middle of the row. In the upper octave the tonic note is found on the draw but on the last button of the outer row!
Depending on the model the first button of the outer row may have accidental or "helper" notes but notice also that the draw note of the second button of the outer row is not part of the regular diatonic system. In the C/F system this button would normally have E/A, but the Club replaces the A with a G.
On the whole the treble arrangement is rather irregular and highly idiosyncratic and the unisonoric button or "gleichton" in the middle of the instrument will force experienced players of regular diatonic accordions to relearn fingering patterns.
Although the system favours a very limited number of musical keys, in theory, you can play in any key. However, the further the key is removed from the home key, the more difficult it is to play. Some keys will be easier in predominantly one direction of the bellows and others will require a lot of bellows reversals. In any case, the 8 basses found on the Club model accordion are simply inadecuate for playing in a variety of different keys, and are probably the major weakness of the set-up.
If you like bisonoric accordions but want to play any kind of music in any key with similar ease, much better chording, much smoother, easier bellows work with less reversals, and you are willing to learn new fingering patterns, you should think about getting an Atzarin instrument!
Club accordion keyboard layouts