Warm Audio WA-412 4-CHANNEL Microphone Pre-Amp With DIThe WA 412 from Warm Audio is a four channel preamp for microphones and Hi Z inputs housed in a 1 RU chassis. It's fashioned in the American console preamp style, providing a punchy bottom end and smooth trebles. Each channel gives you 65 dB of gain, polarity switching, a 20 dB pad, 48V phantom power, a switchable impedance selector for tonal shaping, and knobs for both input gain and output; this allows for both precise and creative gain structuring