Main Source was a Canadian/American hip hop group that was based from New York City/Toronto composed of Toronto's Sir Scratch and K-Cut, Queens' Large Professor. Later, Mikey D (also from Queens) replaced Large Professor. 　　The group's first album, Breaking Atoms, featured conscious tracks such as "Looking at the Front Door," "A Friendly Game of Baseball," and "Watch Roger Do His Thing," as well as the first on-record appearance of Nas on "Live at the Barbeque," which also featured Joe Fatal and Akinyele. Because of business differences, the group broke up before its second album, tentatively entitled The Science could be released. However, Sir Scratch and K-Cut released a second album under the Main Source name titled Fuck What You Think, with new recruit Mikey D on vocals & featured another first on-record appearance for The Dog Pack which would later become the legendary Yonkers rap group The LOX on "Set If Off"; however, the album was shelved due to inner conflicts between the record label and group management.[citation needed] Singer Madonna sampled the bassline from "What You Need" on Fuck What You Think in the song "Human Nature," which appeared on her 1994 album, Bedtime Stories. 　　 　　Large Professor went on to be an instrumental producer for hip hop stars such as Eric B. & Rakim, Pete Rock and CL Smooth, Nas, and Diamond D. He references his falling-out with Sir Scratch and K-Cut on A Tribe Called Quest's third album Midnight Marauders. On the track "Keep It Rollin'" he says, "I'm Uptown chillin', takin in this Grandmaster Vic blend/from the projects, the PJ's, fuck them two DJ's; Self mission." 　　 　　K-also produced for a wide range of hip hop artists including Big Pun, Maestro Fresh-Wes, Fu-Schnickens, Queen Latifah, and even NBA star Shaquille O'Neal. He also mentored another Toronto-based producer named Watts.