Yo. A new rap sheet is hittin' the street. The Source, a monthly magazine of hip-hop music and style, began its national rollout this spring. Publisher David Mays started it with $75 when he was a college student. After graduation he moved the publication to New York City and expanded it with $80,000 worth of advances on advertising revenues. He hopes to pump up circulation from 30,000 to 75,000 this year. The major record labels are lining up to advertise, and Mays predicts The Source, sold through record stores and newsstands, will be the Rolling Stone of the '90s. -- Anne Murphy

* * *