SFTMC had begun as an electronic studio established by the improvisation group Sonics at the San Francisco Conservatory. Sonics was formed in 1961 by Oliveros and other members of one of Robert Erickson's composition seminars.
In 1967 the group accepted a $15,000 grant to join the Mills Center for Contemporary Music, with Oliveros as director, though the last of the original composers left the group that year. When Robert Ashley became the director in 1969 no equipment was left. San Francisco Tape Music Center moved to Mills College that same year and became the Mills Tape Music Center.