Mark bass S1 s1 Solid state preamp MOMARK MODULO S1 Product code: s1 Solid state preamp Ultra-linear frequency response Preamp inspired by Little Mark II and SA 450 The S1 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 that faithfully reproduces the tone of whatever instrument you play through it, without adding coloration. The S1 preamp features an unbalanced input (usable with bothpassive and active basses), gain control and clip LED.