The Rickenbacker Model B went through a few "post-war" changes in the mid-1940s, with a metal insert appearing in the neck, the width of the pickup magnet going from 1 1/2" to 1 1/4", as well as the pickup adjustable with Phillips head screws. The "T-Shape" logo on the headstock is also introduced here in 1946 but is gone by 1950.
