Shure service manual SR105 Power Amplifier, Description

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SR105 Power Amplifier

DESCRIPTION

(Shown in A105A

Carrying Case)

The Shure SR105 Power Amplifier is a high-power ampli- fier designed for sound reinforcement applications. It is capsble of delivering 200 watts rms to a 4-ohm load, and is available in two models, the SR105A and SR105B. The SRlO5A Power Amplifier provides both a direct-coupled speaker output and a transformer-coupled constant-volt- age, 70-volt output, while the SR105B Power Amplifier is equipped with a direct-coupled speaker output only. In this manual "Amplifier" refers to both SRI05A and SRlOSB models unless otherwise specified.

The Amplifier is of rugged construction and is conserva- tively designed to provide reliable operation at high power levels with minimum distortion and phase shift. Used in conjunction with a suitable mixer-preamplifier or audio console such as the Shure Model SR101, a versatile, high- quality, high-power, sound reinforcement system may be assembled for use with a variety of speaker systems. Sev- eral SR105 Power Amplifiers may be interconnected (de- scribed under Operating Instructions) to provide greater power output for large installations and redundant opera- tion. The basic direct-coupled speaker output capabilities of the Amplifier are well suited to the source-oriented speaker systems used in theatres, auditoriums, stadiums, ballrooms, and convention halls, in short, wherever maxi- mum coverage with reserve power is required. The addi-

tional 70-volt output feature of the SR105A Power Amplifier makes it equally adaptable to source-oriented or distrib- uted speaker systems such as those used for background music or announcements in industrial buildings, institutions or public places.

An Output Voltage Meter in the Amplifier facilitates ad- justment and output level monitoring.

Silicon transistors and similar solid-state devices are used throughout the Amplifier. Short-circuit and thermal overload protection are design features which eliminate the need for special installation or operation precautions. All components are of the highest quality and are operated well within their respective ratings to assure maximum reliability under normal use conditions.

The Shure SR105 Power Amplifier is supplied with one 1.8m (6 ft) audio input connecting cable and an acces- sory package consisting of four rack-mounting screws, one Volume Control Cover, one Power On-Off Switch Cover, and one spare 5-ampere fuse.

The SR105A and SRIO5B Power Amplifiers are listed by Underwriters'Laboratories, Inc., and are listed by Canadian Standards Association as certified.

The A105A Portable Carrying Case accessory is de- signed specifically for use with the SR105 Power Amplifier.

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Contents SR105 Power Amplifier Specifications Iii Page Table of Contents Page Description SR105 Power AmplifierSR105 Power Amplifier Front Panel General Operating Instructions Operating InstructionsInput Connections Power RequirementsMounting and Ventilation Thermal OverloadSR105 Power Amplifier Block Diagram Output Connections Direct Output only AMPLIFIER-TO-SPEAKER Distance Meters Recommended Wire Gauge VS. AMPLIFIER-TO-SPEAKER DistanceOutput Voltage Meter Volt OutputBasic Operating Hints Special Operating InstructionsAdding SR105A Amplifiers in a 70-VOLT System Cascaded Adding Headphone Jack to Speaker Connections Bridging ConnectionsCoil Service Instructions Printed Circuit Board Removal Driver Transistors Small Signal and Predriver TransistorsChecking Transistors and Diodes Output TransistorsDiodes Diode Bridge RectifierWHT GRN RED YEL BLKCOM GND Service IllustrationsJI J2 Page XF1 RKC37TB1 TB2IRC CEC-TO RKC53RKC9 Main Circuit Board Parts Location Diagram DC Voltage Measurements TroubleshootingGeneral AC Voltage MeasurementsPage SR105 Power Amplifier Circuit Diagram Page Condensed Operating Instructions Architects Andengineers SpecificationsConstant Voltage 70-VOLT Speaker Output