The RDB-400 is four independent Direct Boxes in one 2U Rack Space with features and performance that set it in a class by itself. It boasts a totally active transformerless audio path. Its line level output mode allows direct insertion into tape decks, bypassing mic pre-amps and mixing consoles completely. With the variable line and attenuation trim, you can convert -10dB signals to +4dB and vice-versa. It can also be used as a pre-amp, buffer, Its rugged construction and superb performance also make it great for stage use as well.