The San Francisco Conservatory of Music announced Tuesday that it had purchased Opus 3 Artists, which represents about 250 musicians and attractions, a group that include conductors Barenboim, Conlon, Eschenbach and cellist Yo-Yo Ma. The San Francisco Conservatory of Music announced Tuesday that it had purchased Opus 3 Artists, which represents about 250 musicians and attractions, a group that includes conductors Daniel Barenboim, James Conlon, Christoph Eschenbach and cellist Yo-Yo Ma. David Stull, president of the San Francisco Conservatory of Music, would not reveal the monetary details of purchasing the management agency. Foster said the agency would have an arms-length relationship with students at the San Francisco conservatory and will continue to recruit clients from Juilliard, Curtis, Eastman and elsewhere. The conservatory, which serves about 500 students, broke ground two years ago and is in the process of opening the Bowes Center building in San Francisco.