John Humbird Duffey, Jr. (March 4, 1934 – December 10, 1996) was a Washington D.C. based bluegrass musician.Duffey was born in Washington, D.C., and lived nearly all his life in the Washington D.C. area. He graduated from Bethesda-Chevy Chase High School in suburban Maryland. Duffy learned to play the mandolin, dobro, and guitar, in addition to his tenor singing voice.