The RU-PA518 features two modes of operation: stereo and bridged mono. Depending on the mode of operation, the RU-PA518 can deliver from 5 to more than 18 watts of RMS power at the output. In stereo mode, each of the two inputs feeds its respective left or right output. Front-panel level controls set the gain for both left and right channels. When the rear-panel switch is set to the bridge mode, the two inputs (A and B) are mixed together and fed to the output. In either the stereo or mono mode, an internal audio peak limiter may be turned on using a rear panel switch.