The HD-PA35 is a single input audio amplifier for systems demanding high energy efficiency. It may be used as a single zone amplifier fed from a variety of RDL or OEM mixers. It is ideal for providing one or more additional zones to a mix originating from another RDL HD series mixer amplifier. The 35W power amplifier output is driven from a high-efficiency Class D amplifier stage. The amplifier output level may be VCA controlled using various optional RDL remote controls, or by industry standard 0 to 10V DC or 0 to 10k ohms controls. The output drives 4 ohms or 8 ohms speakers. The output impedance is switch-selectable on the rear panel. The HD-PA35A has all the features of the HD-PA35 except its 35 W amplifier provides a constant voltage output (25V, 70V or 100V) instead of a low impedance speaker output. The HD-PA35 is engineered and manufactured in the U.S.A.