ARCHITECT'S AND ENGINEER'S SPECIFICATION

The power amplifier shall be capable of operating from a 100/120/220/240V ac line or from a 24/28V dc battery. The power supply shall automatically transfer the power to dc operation if ac power fails. An octal socket shall be provided on the rear panel for installation of an accessory line transformer. The front panel shall be hinged to permit access to the chassis interior without removing the amplifier from the equipment rack.
The power amplifier shall meet the following performance criteria. Gain, 61 dB. Input sensitivity, 0.8V rms for rated output. Power output, 50 watts at less than 1% THD from 50 Hz to 12 kHz. Frequency response at 1 watt output, ± 1_ dB from 20 Hz to 20 kHz and ± 1 dB 50 Hz to 12 kHz at ratedoutput. Input impedance: 15,000 ohms (potentiometer), 600 ohms balanced with 15095A plug-in transformer, 15,000 ohms balanced with 15335A transformer. Load impedance; 4, 8, 16 and 100 ohms. Load voltage; 14, 20, 28 (25V, 40-watt), and 70 volts. Output impedance, less than 10% of nominal load impedance. Noise level, -38 dBm or 85 dB below rated output. Operating temperature range up to 55°C (131°F) ambient. Dimensions, 51/4" H x 19" W x 7;/e" D. Weight, 23 pounds. Color, black.
The power amplifier shall be Underwriters Laboratories listed for use in commercial audio systems and fire protection signaling systems.