AUDIO INTERFACES Redbox - Microphone Amplifiers & Limiters MICROPHONE AMPLIFIERS & LIMITERS RB-DMA2 Dual Digital Microphone Amplifier “ The unit can either be used as two independent microphone amplifiers, or one mic input can be copied to both channels of the digital output. The RB-DMA2 consists of two independent low-noise microphone pre-amplifiers for converting microphone level signals to a digital AES/EBU or S/PDIF output.