TOA U-61S unbalanced line in module for unbalanced, line level sources such as AM/FM tuners, casette decks, CD players, computer sound cards, jukeboxes, mixers and satellite receivers. Use For Adjacent Sources (less than 15 feet from the hos unit). Compressor Function Helps Prevent Overload And Distortion, activates when the module's input signal exceeds a preset, adjustable threshold.