Analysis of information sources in references of the Wikipedia article "Stradella bass system" in English language version.
His understanding of how the left-hand mechanisms worked caused him to merely open up the instrument, cut off the offending 5th of the dominant and diminished seventh stradella chord buttons.
The diminished seventh chord row is shifted, so that the diminished seventh G chord is where one would expect the diminished seventh C chord in the Stradella bass system.
