One of the first "rhythm and blues" radio stations in the United States, KSAN (AM), known later as KSOL (AM), was located in San Francisco, California. One star to come out of the station was DJ Sylvester Stewart, later known as Sly Stone of Sly and the Family Stone recording fame.
KSAN was a pioneer in broadcasting to the black audience in the San Francisco Bay Area, along with Oakland's KWBR, which later became KDIA. Until the mid-1950s, the relative handful of stations on the air locally devoted little time to "ethnic" programming of any kind, with the exception of KSAN and KWBR, which also broadcast programs intended for the Chinese, Italian, Portuguese, German and Japanese communities.
The original KSAN, (not KSAN (FM), KYLD or KSOL) , was born in June 1925 as KGTT. In 1929, it became KGGC and, in 1938, it became the first local station to use the KSAN call letters — again, (not KSAN (FM), KYLD or KSOL) . In 1958, KSAN switched to a full-time rhythm and blues music format, targeting black listeners in the Bay Area, the first station on the local dial to broadcast R&B around the clock. KSAN's transmitter was on top of the Merchandise Mart building on Market Street, where the studios were located.
On July 3, 1964, KSAN was sold to John F. (Les) Malloy and Delmor A. (Del) Courtney, two well-known San Francisco radio and television personalities; Les Malloy was for many years a star on local radio and had hosted a popular TV talk show on KGO in the 1950s, while Del Courtney found fame as a bandleader and personality on KSFO. With Malloy as president and general manager, KSAN became KSOL on its first day under new ownership, hoping to better emphasize its "Soul Radio" format, which it continued until September 1970. The station is currently known as KEST.[1]