The Amplifier shall have built-in circuitry to protect the Amplifier from open circuit, short circuit, or mismatched output loads, by using current-limiting, voltage-limiting, temperature-sensing diodes, and thermal-sensing switches.
The automatic thermal-sensing switches and temper- ature-sensing diodes shall be mounted on the output tran- sistor heat sinks to protect the Amplifier from overheating due to short circuits, mismatched output loads, or high ambient temperatures. The thermal switches shall auto- matically shut off the ac power in the event of overheating and shall automatically restore the ac power when the Amplifier has reached a safe operating temperature. When the Amplifier has thermally cycled off, a THERMAL OVER- LOAD indicator shall light.
The INPUTS shall accept signals from high impedance sources. The balanced bridging input shall be a profes- sional three-pin audio connector. The unbalanced input connectors shall be standard %-inch phone jacks.
The Amplifier shall have an independent VOLUME Con- trol and POWER ON-OFF Switch. The Amplifier shall be en- closed in a metal, rack-mounting cabinet, with a scuff- resistant vinyl-covered front panel. The dimensions shall be 178 mm x 483 mm x 270 mm (7 inches in height, 19 inches in width, and 105h inches in depth). The weight shall be no more than 12.23 kg (27 pounds).
The Amplifier shall have a maximum voltage gain of 27 k 2 dB at 1 kHz, and a nominal input sensitivity of 1.2 volts for 200 watts rms output power to a 4-ohm load.
The Amplifier hum and noise shall be at least 80 dB below 200 watts rms output with a 4-ohm resistive load.
The Amplifier shall contain 4 silicon output transistors, 10 other silicon transistors, and 1 Zener diode.
Any Amplifier not meeting all of the above specifications shall be deemed unacceptable under this specification. The Amplifier shall be a Shure Model SR105B.
