Multi-channel 100V slave amplifier with independent outputs for 100V or 4-16 Ohm speakers. Each amplifier channel has its own independent line input, which can be switched to a global auxiliary, providing the option of the same input to several of the amplifier channels if required. A paging microphone input is provided for voice alerts and a 24V mute terminal can be connected to an alarm panel for emergency evacuation override. Class D circuit design and efficient toroidal transformers have enabled a design which fits into a 1U rack-mount housing. The RMS-series amplifiers can be applied as high power slave units or equally as a fully independent zoning system for a multi-room installation.