On May 13, 1963, the station first signed on using the call sign WDVR, which stood for Delaware Valley Radio. It was one of several Philadelphia stations airing a beautiful music format, including WPBS (98.9 FM) and WWSH (106.1 FM). In 1981, it switched call signs to WEAZ, which stood for easy listening. It began using the slogan "EAZY 101" with actor Patrick O'Neal and later with actor Robert Urich as its TV commercial spokesperson. By 1984, EAZY 101 had become the #1 rated station in Philadelphia.