The 4100 is a valve powered JCM900 Hi-Gain Dual Reverb head featuring twin footswitchable channels and reverb. It has become "industry standard," as one of the world's best selling 100-watt valve amp heads. If offers great tone and reliability, along with the Marshall sound guitarists demand.

Channel A is voiced for clean on lower settings, building up to a raw crunch from the days of yore when driven hard. Channel B picks up where Channel A left off, covering everthing from smooth distortion to over-the-top saturation. As well as having separate Gain controls, each channel has its own controls for the Master Volume and Reverb. Add an internal spring Reverb and a 4-band EQ (Treble, Middle, Bass and Presence) and you've got a winner!