In this video I compare a Marshall and a Fender, which both have had the S.I.R. #39 high gain mod installed by Daniel Forsberg. I'm playing both amps through a 1960B cab with 2 G12-65 speakers in it using a Gibson Les Paul 1959 Standard reissue. The amps are:
1976 Fender Bassman 100
1977 Marshall Superbass