The S1M Preamp Module features the standard-setting sound characteristics that have driven the international success of our top-selling Little Mark II and SA 450 amplifiers. It's a solid-state preamp with a warm and natural sound that faithfully reproduces the tone of whatever instrument you play through it, without adding coloration. The S1 preamp features an unbalanced input (usable for both passive and active basses), gain control, clip LED, and a mute switch. This last function is useful for when you need to change instruments during a performance, or tune in silence when using a tuner connected to the tuner output.