Radio Design Labs HD-MA35 35 Watt Mixer Amplifier with Power Supply - Low Impedance Output 4 Ohm or 8 OhmThe HD-MA35 is a three input audio mixer amplifier for systems demanding a broad range of features and high energy efficiency. Two output power amplifier zones are provided, 35 W (Zone 1) and 2 W (Zone 2). The Zone 1 output is driven from a high-efficiency Class D amplifier stage. The Zone 1 amplifier output level may be VCA controlled using various optional RDL remote controls, or by industry standard 0 to 10 Vdc or 0 to 10 kΩ controls. This output drives 4 Ω or 8 Ω speakers. The output impedance is switch-selectable on the rear panel. The Zone 2 amplifier output drives an 8 Ω speaker and/or 600 Ω telephone equipment. The HD-MA35A has all the features of the HD-MA35 except its 35 W (Zone 1) amplifier provides a constant voltage output (25 V, 70 V or 100 V) instead of a low impedance speaker output. The HD-MA35 is engineered and manufactured in the U.S.A.The HD-MA35 features two mixers. The Zone 1 mixer is located on the front-panel providing user level and tone controls for the 35 W amplifier output. The tone controls adjust the equalization at the Zone 1 amplifier output. The Zone 2 mixer on the rear panel provides level trimmers normally set by the installer to provide music-on-hold and/or for background music in a small zone equipped with an 8Ω speaker. The Zone 2 section includes a 2 W amplifier and a 600 Ω transformer-balanced MOH output.The HD-MA35 has three inputs that are common to both mixers. Input 1 accepts a balanced mic or line level source. Inputs 2 and 3 accept unbalanced mono or stereo line-level sources. Input 1 is switch-selectable MIC or LINE. Phantom voltage (IEC standard 24 Vdc) is switch-selectable for the microphone input. The line input is transformer isolated and accepts balanced or unbalanced, high or low impedance audio sources.; A paging source is normally connected to Input 1. This input is