The Lucille, designed by the man himself, is a semi-hollowbody with no F-holes, and therefore a unique, unmistakable voice. It also features a TP-6 fine-tuning tailpiece, two Humbucker pickups, Vari-tone switch, and stereo outputs. Her name is inlaid on the headstock, just as B.B. King insists.
The Varitone control has 6 settings. Setting number 1 simply bypasses the Varitone completely. The Epiphone literature on the Varitone indicates that this control serves to reduce the harmonic frequencies, which in effect produces a greater loss of low frequency harmonics the higher up the 6-position dial you go.
