Condensed Operating Instructions

SR105 Power Amplifier

CONDENSED OPERATING INSTRUCTIONS

DIRECT SPEAKER OUTPUT (MODELS SRlOSA and SRlOSBI

I.'with line cord unplugged, install Amplifier in rack or carrying case, allowing adequate ventilation.

2.Connect speakers to DIRECT OUTPUT Jacks and/or Terminal S t r i ~ .

3.Connect con'soleor mixer output to UNBALANCED PARALLELED HIGH IMPEDANCE Input Jack. For cable length greater than 15m (50 ft), use 600-ohm bat- anced line into BALANCED BRIDGING Input Jack (three-pin).

4.connect additional power amplifiers or auxiliary equip- ment as required.

5.Connect line cord to ac source.

6.Turn on POWER ON-OFF Switch and adjust VOLUME Control to desired level.

CONSTANT VOLTAGE 70-VOLT SPEAKER OUTPUT

(MODEL SRlOSA ONLY)

l. Amplifier and connect auxiliary equipment as

for Direct Speaker Output operation.

2.Connect speakers to 70V OUTPUT Terminal Strip.

3.Connect console or mixer output to UNBALANCED PARALLELED HIGH IMPEDANCE Input Jack. For cable length greater than 15rn (50 ft), use 600-ohm bal- anced line into BALANCED BRIDGING Input Jack (three-pin). ..

4.fur, 70V-OFFSwitch to 70".

5.Connect line cord to ac source.

6.Turn POWER ON-OFF Switch on and adjust VOLUME Control.

SR105 Power Amplifier

ARCHITECTS' ANDENGINEERS' SPECIFICATIONS

SRlOSA POWER AMPLIFIER

The Amplifier shall be a rack-mounted, 120-volt, 50/60 Hz line-operated, all silicon transistor, 200-watt power amplifier.

The Amplifier shall deliver 200 watts rms continuous out- put power at 1 kHz into a 4-ohm load with less than 2% distortion (DIRECT OUTPUT), and 150 watts rms continuous output power with less than 3% distortion to a 33-ohm load (70-VOLT OUTPUT). Typical frequency response shall be 20 to 20,000 Hz t 1 . 5 dB with a 4-ohm load (DIRECT OUT- PUT) and 50 to 15,000 Hz 2 db with a 33-ohm load (70-

VOLT OUTPUT).

The Amplifier shall have four phone jacks and one ter- minal strip speaker output for 25-volt output, plus one ter- minal strip for 70-volt output.

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, POWER ON-OFF Switch and 70-VOLTIOFF Switch to activate the 70-volt output transformer.

The Amplifier shall be enclosed in a metal, rack-mount- ing 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 lO5/8 inches in depth). The weight shall be no more than 15.66 kg (34 pounds 8 ounces).

The Amplifier shall have a maximum voltage gain of 27 -+2 dB at 1 kHz, and a nominal input sensitivity of

1.2volts for 200 watts rms output power to a 4-ohm load. Seventy-volt circuitry voltage gain shall be 35 %3.5 dB at 1 kHz, and a 1.2-volt nominal input sensitivity for 150 watts rms output power to a 33-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, 13 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 SR105A.

SRlOSB POWER AMPLIFIER

The Amplifier shall be a rack-mountable, 120-volt, 50/60 Hz line-operated, all silicon transistor, 200-watt powar amplifier.

The Amplifier shall deliver 200 watts rms continuous power at 1 kHz into a 4-ohm load with less than 2% dis- tortion. Typical frequency response shall be 20 to 20,DOO Hz 2 1 . 5 dB with a 4-ohm load.

The Amplifier shall have four phone jacks and one ter- minal strip speaker output for 25-volt output.