Main Source has been played over 30 times on NTS, first on 31 May 2014. Main Source's music has been featured on 29 episodes.

Main Source is an innovative, acclaimed Toronto and New York-based hip hop group comprised of Toronto natives Sir Scratch, K-Cut, and New York native Large Professor. Later on after Large Professor's departure, came along Mikey D to replace him as the new lead lyricist.

Their first album, Breaking Atoms, featured conscious MC tracks such as "Looking at the Front Door", "A Friendly Game of Baseball" and "Watch Roger Do His Thing". The album also has the first on-record appearance of Nas on "Live at the Barbeque", which also featured Joe Fatal and Akinyele. The group broke up before their second album, tentatively entitled The Science, could be released. However, Sir Scratch and K-Cut released a second album under the Main Source name, entitled Fuck What You Think, with new recruit Mikey D on vocals. However, the album was shelved due to inner conflicts between the record label and group management, which caused Mikey D to leave.

Ironically, both Mikey D and Large Professor left Main Source for the same reasons. Which was exploitative business practices by members K-Cut and Sir Scratch. Both MCs faced attempts to take their publishing royalties, leading to similar departures.

Large Professor has gone on to be an instrumental producer for hip-hop stars such as Eric B. & Rakim, Pete Rock & C.L. Smooth, Nas, and Diamond D. He has released a Solo LP entitled First Class, and his shelved The LP has been widely bootlegged.