- solid state amplifiers
- tube amplifiers
QSC Audio began in 1968 when the Quilter Sound Company was founded by Patrick Howe Quilter. Quilter Sound Co. concentrated on guitar and bass amps initially but moved into professional power amplifiers, audio control systems and loudspeakers The company was renamed QSC, LLC in 2015. Patrick Quilter retired from QSC in 2011, and founded Quilter Labs to develop portable, solid-state, high-power guitar amplifiers.