The Crown 280MA is a high performance mixer-amplifiers for commercial and industrial audio. It provides 4-ohm and constant-voltage outputs for schools, hospitals, factories, restaurant/retail, houses of worship, fitness facilities, A/V boardrooms, prisons and small offices. Typical uses are paging, background music, security and evacuation instructions. Input routing allows each input to be assigned to any output. Other features include priority muting, phantom power, four-tone generator, and capability for remote volume control. Input Sensitivity - Balanced microphone inputs 3 mV, balanced line inputs 800 mV and RCA connectors 400 mV Nominal Input Impedance - microphone 400 ohms, Line 100 kilohms and RCA 50 kilohms Input Volume Controls - 8x Microphone/line Tone Controls - Bass and Treble non-detented recessed potentiometers on each input channel Auxiliary Power Input - 2-position terminal strip for 24 VDC backup power Amplifier Outputs Connectors - One per channel, 4-position terminal strip with COM (Common), 4-ohms, 70V and 100V terminals Output VCA Connector - 4-pin Phoenix-type connector for two VCA control lines of +10 VDC and ground Priority Connector - 3-pin Phoenix-type connector allows Input 1 or Input 5 (280MA only) to mute other input signals by contact closure Thermal Limit Protection - Over-temperature thermal cutout Dimensions - EIA Standard Rack Mount Width 19 x Height 3.5 x Depth 12.2 (48.3x8.9x31.0cm) Weight - 25.3 pounds (11.5 kg)