Pro Digital HIFI Pre Amplifier 1. High performance 2. Easy to cooperate Pro Digital HIFI Pre Amplifier DSP-99 Features:1.Has 99 digital echo effector.2. Build in Sub-bass output can be adjusted by music, echo and mic tone;3.Crossover is adjustable;4.High ,MID and bass of mic can adjusted. Pro Digital HIFI Pre Amplifier DSP-99