The first appearance on record of amplified harmonica was Little Walter 's performance on Muddy 's `` Country Boy '' ( Chess 1452 ) , recorded on July 11 , 1951 .
First he played acoustic , the first appearance on record of Little Walter 's amplified harmonica sound was on Muddy 's `` Country Boy '' \ / `` Too Young To Know '' ( Chess 1452 ) , recorded on July 11 , 1951 .