David Peterson is a rare combination: a savvy independent recording artist and a bluegrass singer who cherishes tradition. His voice has that lofty quality that carries from mountain-top to mountain-top. It’s powerful, complete and saturated with Bill Monroe and Jimmy Martin’s blues. A Boston native, he’s not somebody who would have been issued a bluegrass license at birth. But Peterson learned the music from a deacon at his church and and as music writer Robert Oermann likes to say, there’s nobody as zealous as a convert. When he got serious about the mandolin, the guitar and bluegrass music in 1995, he left his track from becoming a minister to pursue music. Now Dave preaches bluegrass with a missionary zeal.