Rapper Yung Joc (born Jasiel Robinson) learned about running his own business from his father, who owned a hair-care products company. It was also his father who gave a teenage Yung Joc his first break, writing a jingle for the Revlon company. Joc decided right then that the hip-hop business was for him, but he needed time to find his own style. Watching the various hip-hop crews that grew out of his native Atlanta, Yung Joc didn’t feel a kinship to any movement until the hard-edged T.I. came on the scene, although he was a big OutKast fan. Like T.I., Joc had begun rapping with the street in mind. To release this music, he formed his own company, Mastermind. He later hooked up with Russell “Block” Spencer and his Block Enterprises label and released the hard club track “It’s Goin’ Down” in early 2006. The track became an Atlanta favorite …