Date: 1926. (Drawing)
The "Standard" family includes the 2J and 3J (pictured here) which are 3-valve, top action Eb basses; the 4J and 5J which are 3-valve, front action Eb basses and the 46J and 47J which are front action Bb basses (note: not BBb).
What Conn said in 1926:
The New Wonder Model standard size basses, generally known as the "Standard", are the smallest of the Conn basses. The Bb model weighs but seven pounds, and the Eb, being larger, weighs twelve. These comparatively light instruments are very easy to carry, and yet the reall Bass tone is in no way sacrificed.
Like all Conn instruments, these basses have quick and reliable valve actions, which, coupled with the wide curves of the valve slides and the smoothness of bore - due to the hydraulic expansion process - makes for instant response. The hydraulic process of manufacture also insures absolute accuracy in the proportions of the instrument, which is a guarantee of tone.
It should be remembered that these basses are the product of long years of experience in the construction of this type of instrument. Conn Basses have been the choice of leading artists in both orchestra and band work for years, and have earned a reputation for perfection in tone and appearance as well as in mechanical design and reliability which has never been equalled.
For a light weight, easy blowing, rich toned Bass one cannot find an instrument equal to the "Standard."