Assessments - 2, GPA: 4
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Hazardous voltaee may be eti-CAUTION: . , „ . , r . . countered wt/hiit me chassis. Installation and Service information within this document is for use only by ALTEC sound contractors, faeton/ authorized warranty stations and qualified service personnel. Il est enjoint à l'utilisateur de ne pas réparer lui-même les pièces IMPORTANT: . . ' , , . , £ i , , , ■ . internes de l appareil, des courants a haute tension pouvant passera ¡'intérieur du châssis. Les renseignements inclus dans ce document sont destinés uniquement à l'usage des installateurs agréés des systèmes acoustiques ALTEC, des centres de réparation sous garantie autorisés, ainsi que du personnel d'entretien qualifié. INTRODUCTION The ALTEC LANSING Model 1270 Power Amplifier provides continuous high power demand where uninterrupted operation is requisite. Designed to protect itself and the acoustic elements it drives, the Model 1270 represents 800 + watts of controlled power. Two channels may be operated independently, in parallel or in bridged configuration to deliver up to 400 watts per channel at less than 0.05% THD from 20 Hz to 20 kHz. Peak Error Computer The amplifier is provided with a peak/error computer that compares channel input and output signals and detects any output errors. Detection of any peak/error causes the appropriate peak/error indicator to illuminate. Output anomalies detected include excessive voltage, excessive current (load), excessive slew rate, and any other significant difference between the channel input and output signal. Load Protection The load is protected from transients during startup and shutdown of the amplifier. During startup, the load remains disconnected through a relay during a three- FRONT PANEL CONTROLS AND FEATURES second delay period. During shutdown or loss of power, the load is instantaneously disconnected by the relay. The load is similarly protected against amplifier failure, such as dc voltage at the output. Amplifier Protection The amplifier output is continuously monitored to guard against excessive current drain. An instantaneous VI limiter restricts output to 400 VA ±45° phase shift. The amplifier is additionally protected against excessive operating temperature; logic circuitry automatical^ overrides low-speed fan operation and locks to the high fan speed mode. If operating temperature remains excessive, the load is disconnected by a relay and the protection indicator iliummates. When temperature falls to safe operating conditions, the amplifier automatically resumes operation. ALTTEIO Specifications and components subject to change without notice. Overall performance will be maintained or improved. LANSING I 1515 S. Manchester Ave., Anaheim, Calif. 92803 42-02-045589-01 LITHO IN U.S.A. 681-1M Item 1 2 3 4 5 Name Peak/Error Indicators Protection Indicator POWER Indicator POWER Switch CHANNEL Volume Controls Function/Description Illuminate when excessive voltage, current or slew rate appears at the output terminals. Illuminates when protection circuitry operates to prevent damage to the amplifier or load. Illuminated when primary ac power is applied to the amplifier. Applies primary ac power to the amplifier. Adjust gain of LEFT and RIGHT channels. Rotate clockwise to increase gain. INSTALLATION Rack Mounting The 1270 may be installed in a standard 19-inch equipment rack, or in the 42526 Shelf Mount Cover Accessory for shelf use. Vertical space required is 5Vt Rack installation is accomplished by using the appropriate four mounting screws supplied. Ventilation The 1270 must be adequately ventilated to prevent excessive temperature rise. Maximum rated ambient operating temperature is 55°C (131 °F). - CAUTION - Do not block the side ventilation aperatures on either side of the main frame. Allow at least 2" on each side of the main frame to assure adequate ventilation. Do not operate within a completely closed, unventilated housing. ELECTRICAL 120 Volt, 50/60 Hz Power Connections Equipment supplied for domestic use is provided with the power transformer primary strapped for 120 volts. Specified voltage rating is located on the chassis, adjacent to the power cord. Verify that line voltage is in accordance with specified voltage before connecting the 1270 to ac line power. 100V, 200V, 220V, 240V, 50/60 Hz Power Connections Refer to Authorized Altec Service Representative. Input Connections Unbalanced input connections to the INPUT jacks are made with shielded singleconductor cables terminated with standard %-inch phone jacks. In preparing the cable, the conductor Is soldered to the tip of the jack, and the shield Is soldered to the sleeve. Balanced input connections are made with the optional 1270TM Dual Balanced Transformer Input Module. Plug the 1270TM into the INPUT receptacles of the 1270 and secure the retaining screw. See Figure 1. Cables terminated with XLR3-type connectors are used to make input connections to the 1270 TM module; wirin...