Conn 12J/13J Professional Front Action Eb Bass
Date: 1920's. Owner unknown
The "Professional" family includes the 12J and 13J (pictured here) which are 3-valve, front action Eb basses and the 10J and 11J which are 3-valve, top action Eb basses.
What Conn said in 1926:
The "Professional" Model or medium size Eb bass of the New Wonder family has taken its place among the professional musicians of the world as the most practicable and desirable Eb bass manufactured. Particularly is this true among bass players whose engagements require both concert and parade work, for the models listed here are not too heavy for a marching purpose and yet give a broader tone than the "Standard" model.
The introduction of this "Professional" Model some years ago met with almost instantaneous favor, and in a short time this bass had become on of the leading models of the Conn line. It is perfectly balanced, possesses a rich, full quality of tone, and is credited with producing a greater volume than that produced by many basses of larger dimensions.
For its adaptability to either marching or concert engagements, coupled with its Conn action and tone, the "Professional" model cannot fail to please the most discriminating bass player.