Super compact and lightweight 4-channel power amplifiers in a 1U rack-mountable housing. Fully digital architecture provides high power output and efficiency with inbuilt protection circuitry. Configured as 2 pairs of channels, the amplifier can be operated as quad output, 2.1 system or stereo output by selecting bridge mode. Signal inputs are balanced XLR connectors and speaker outputs are provided on 4mm binding posts. Minimal weight and rack height make these amplifiers a viable option for portable rigs as well as convenient and unobtrusive for installations.