Festival Series guitar. The design also lent itself well to acoustic basses, and Washburn's AB Series quickly became popular both for its look and its tone, whether amplified or unplugged. In recent years, Washburn licensed several guitar construction features: the Buzz Feiten Tuning System — a corrected temperation tuning formula, using a compensated nut and saddle to minimize the inherent intonation problems of the Western tuning formula. The BFTS was first used by Washburn in 1995 on a very few models, then increasingly with the introduction of the WI-64 (1999), and was entirely phased out after the 2010 production year. At its peak, this system came standard on U.S.-made Washburn guitars and basses and the better imports. Stephen's Extended Cutaway — a unique bolt-on neck joint invented by luthier Stephen Davies to allow greater unrestricted access for a guitarist's fretting hand. Used primarily with the Nuno Bettencourt signature models, the SEC has also been employed with acoustic guitars, and remains on some current (2017) models of the Parallaxe line. Voice Contour Control (VCC) — a special potentiometer and wiring, intended to allow access to the entire range of tones "between" the one-coil ("single-coil" mode) and two-coil sounds of a humbucking pickup, rather than one or the other. VCC is similar to coil splitting, in that it changes the tone of a humbucking pick-up to that of a single coil, but it does it by turning the tone knob … without the hum normally associated with single coils. Designed by Trevor Wilkinson, the VCC is no longer in use by Washburn, but is available in various models of Vintage (UK) guitar as the "Roll Control" knob. Model number suffixes Over the past 40 years, Washburn has accreted a system of identifying some of the most pertinent features in many of its acoustic instruments and some of the electric. Additional letters may be used to indicate the instrument's finish. While imperfectly applied, and sometimes awkwardly long, this can often be useful in identifying a given guitar. suffix — C - cutaway DL - deluxe (generally, a standard model with a few upgraded features) E - electric (i.e., built-in pickup) K - kit (i.e., includes case or gig bag) LH - left-handed M - mahogany top Q - quilt maple top R - rosewood S - solid-wood top (rather than laminate) SP - spalt maple top SW - solid wood used throughout V