The station was known as WCAS from 1967 to the early 1980s. The call letters referred to "Watertown, Cambridge, Arlington and Somerville and Belmont" (where the B was said to be "silent"). It became a local favorite during the 1970s for its eclectic mix of music (L.A. folk-rock, jazz, bluegrass, country and western were only part of the playlist) and its support of local issues and musicians, notably through special live concerts and the Live at Passim's series of broadcasts. WCAS evolved to this unique format in 1973, after dabbling in soft rock, in 1972, and in Oldies, prior to that. In 1976, the Harvard Crimson wrote: "The least pretentious station around is WCAS at 740 AM, which mixes country, soft rock, and folk nicely, and goes easy on the ads."