Adastra RS121 High power class-D 100V line slave amplifier in a rack-mountable housing. Slave inputs accept standard line level audio from a mixer. Slave outputs can be cascaded onto further RS slaves to build larger systems. All line level inputs are connectible via RCA sockets or hard-wired via removable screw terminals. A further removable screw terminal is provided for 100V input, which enables the RS series slave amplifier to extend an existing 100V installation by connecting directly to the 100V speaker feed, or indeed from a long distance 100V feed using standard double-insulated cable. A 24V terminal is provided for connection to a security or alert panel to mute the output if required during alarm triggering. Speaker outputs are either 100V or low impedance which is stable down to 2 Ohms, enabling multiple low impedance speakers to be connected if preferred. Designed to power medium to large installations from a mixer output or to expand existing systems.