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Summary of Contents for SR105

Page 1: ...factured by SHURE BROTHERS INC 222 Hartrey Avenue Evanston Illinois 60204 U S A WARNING To reduce the risk of fire or electric shock do not expose this appliance to rain or extreme moisture Copyright 1979 Shure Brothers Inc 27A888 SJ 95B652 Printed in U S A ...

Page 2: ...d output less than 2 8 mV at direct coupled speaker output with Volume Control at 0 Output Clipping Level 28 3 Vrms min at 1 kHz 4 ohm load Load lmpedance Direct Coupled Speaker Output 4 ohms or greater 4 ohms min 70 Volt Output I50 watts max 33 ohms min Load Regulation Direct Coupled Speaker Output Less than 1 dB from no load to 4 ohm load at 200 watts rms out put 70 Volt Output Less than 2 dB fr...

Page 3: ...TION TO 4 OHM LOAD DIRECT OUTPUT ONLY LOAD RESISTANCE OHMS OUTPUT POWER WATTS TOTAL HARMONIC DISTORTION VS OUTPUT POWER VAR IOUS LOADS AT 1 KHz AND CONSTANT 70 7V OUTPUT 70V OUTPUT ONLY FREQUENCY HJ OUTPUT POWER WATTS TOTAL HARMONIC DISTORTION VS OUTPUT POWER TO OUTPUT POWER VS FREQUENCY AT 1 2 TOTAL HAR 150 WATT 33 OHM LOAD AT 1KHz FOR INCREASING OUT MONlC DISTORTIONTO 33 OHM LOAD 70V OUTPUT ONLY...

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Page 5: ... 17 Guarantee 17 Shipping Instructions 17 PARTS LIST 19 CONDENSED OPERATING INSTRUCTIONS 27 ARCHITECTS AND ENGINEERS SPECIFICATIONS 27 SR105 Power Amplifier LlST OF ILLUSTRATIONS Figure Page 1 SR105 Power Amplifier Front Panel 2 2 SR105 Power Amplifier Rear Panel 2 3 SR105 Power Amplifier Dimensional Outline Drawing 4 4 SR105 Power Amplifier Block Diagram 5 5 Input Connections 6 6 Output Power vs ...

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Page 7: ...ier 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 i...

Page 8: ...FIGURE 1 SR105 POWER AMPLIFIER FRONT PANEL FIGURE 2 SR105 POWER AMPLIFIER REAR PANEL SR105A MODEL SHOWN ...

Page 9: ...lifier DIRECT OUT PUT jacks 8 andlor to terminal strip 9 using proper wire size and arranging speaker connections for total speaker load impedance as close to 4 ohms as possible Remove DIRECT OUTPUT Cover 14 and use right angle phone plugs to connect speakers to Amplifier When using DIRECT OUTPUT Terminal Strip 9 thread wires through Cover grommet Replace cover CAUTION In multiple speaker installa...

Page 10: ...wer Amplifier consist of two unbalanced grounded phone jacks 13 and one balanced bridging three pin female audio connector 5 The bal anced bridging input is wired in parallel to the phone jacks after passing through an isolation transformer The input signal then passes through the VOLUME Control 2 and if the Amplifier is an SR105A either passes through a Filter Assembly and 70V OFF Switch 10 to th...

Page 11: ...r auxiliary equipment see Figure 5C Page 6 VOLT METER 70 Additional SR105 Power Amplifiers may be added to the system for a fail safe type operation where complete re dundancy is required Refer to the section on Bridging Connections Page 11 Certain input equipment such as passive equalizers step attenuators and matching networks may require a 600 ohm termination for optimum performance This is not...

Page 12: ... is four ohms The output voltage under these conditions is 28 3 volts Speaker loads of less than four ohms should not be used with this Amplifier If less than four ohms is inadvertently used no damage to the speak ers or Amplifier will occur but a reduction in power output and an increase in distortion will be experienced Thermal shutoff of the Amplifier may also result BALANCED TAPE RECORDER INPU...

Page 13: ... this point is 80 watts This is the power available on the 70 volt output with a simultaneous 8 ohm direct output load CAUTION Parallel connection of the DIRECT OUTPUT Con nectors 8 9 or the speaker cables between two SR105 Power Amplifiers or the SR105 Amplifier and any other amplifier should not be attempted Bal ancing paralleled amplifiers is virtually impossible and the circuitry mismatch cann...

Page 14: ...tput and reduce distortion the total impedance of the speaker load should be as near to four ohms as practical under the existing circumstances see Figure 6 Page 7 If the speakers being used have a rated impedance of 16 ohms such as the Shure SR102 and SR103 then four such speakers connected in parallel present a total load impedance of four ohms to the direct speaker output of the Amplifier This ...

Page 15: ... watt tap produces 25 watts across the speaker The total load in watts presented by a 70 volt multiple speaker system is the sum of the individual speaker loads The value of each individual speaker load is indicated by the wattage rating of the transformer primary tap con nected to the 70 volt line For example assume only two speakers are connected to a 70 volt line the first using a 50 watt prima...

Page 16: ...o problems of this sort Symptom Amplifier is dead no output OUTPUT VOLTAGE Meter lamps out Symptom Check Symptom Check Symptom Check Symptom Check 1 Check that ac power source is live and that Amplifier is plugged in 2 Check that POWER ON OFF Switch 4 is on 3 Check to see that rear panel 3AG 5A Fuse 6 is good 4 Check that THERMAL OVERLOAD Lamp 3 is not lit Amplifier is dead no output OUTPUT VOLT A...

Page 17: ...wo SR105A Amplifiers and connect the COM terminals together Use Class 1 wiring ADDING HEADPHONE JACK TO SPEAKER CONNECTIONS If it is desirable to monitor the Amplifier direct output through headphones a headphone output may be fabri cated as follows Obtain parts listed below or their equiva lent As def ned by U S Nat onal Electrical Code 70 VOLT LINE 3 PIN MALE Qty Part Recommended Type 1 Phone Ja...

Page 18: ...top of the chassis the protective cover grille MP7 must be removed This is done by removing one screw from the top two screws from each side and eight screws from the back surface To re move slide cover up and to the rear of the Amplifier LAMP REPLACEMENT Two bayonet base pilot lamps PL2 PL3 illuminate the scale of the OUTPUT VOLTAGE meter These lamps are mounted on the top surface of the chassis ...

Page 19: ...t Remove the bottom cover and Main Circuit Board remove all 15 interconnecting leads adjust the Meter Adjust resistor R27 METER ADJ located from the push on board terminals noting connections as on the Main Circuit Board under the chassis as shown in listed in the table below Figure 14 Page 14 for a 100 reading on the OUTPUT VOLTAGE Meter No further adjustment is necessary Re CAUTION place the bot...

Page 20: ...rmal joint compound to each side of the insulating wafer to provide good heat transfer from transistor to bracket After replacement and before connecting transis tor leads check the transistors between case and chassis with an ohmmeter there should be no continuity Be sure that these transistors are not interchanged in the circuit they are not identical devices Q7 is an NPN transistor and Q8 is a ...

Page 21: ...ion Diode Bridge Rectifier for instal lation instructions if replacement is required To check transistors the ohmmeter should be set to the 100 or 1 000 ohm scale Small signal transistors Q1 through Q6 Q13 214 Q201 through 2203 must be re moved from the circuit before testing Transistors mounted with screws Q7 through Q12 may be tested in place how ever the base and emitter leads to these transist...

Page 22: ...10 32 Machine Screws Phillips Round Head 4 40 x 3 16 Machine Screws Phillips Head 6 32 x Machine Screws Phillips Head 6 32 x 1 4 Wire Hookup 16Gauge AWG Stranded Copper Vinyl Insulation Wire Hookup 20 Gauge AWG Stranded Copper Vinyl Insulation Solder Rosin Core Shure Part No 51A244 55C131 56A204 90A2038 are presently securing IIScrewdriver Phil lips Head IISoldering Iron Low Wattage Wrench Open En...

Page 23: ...w preferred to the upper left viewed from terminal side terminal of switch S4 from pin T blue preferred to the bottom left viewed from terminal side terminal of switch S4 and from pin S red preferred to the positive red dot terminal of capacitor C14 Solder a length of 16 gauge hook up wire white pre ferred from the 28V terminal of the 28 volt terminal strip TS1 to the bottom right viewed from term...

Page 24: ...S4 OFF JI J2 e TS2 GROMMET x J e 3 d m WHT a FILTER CIRCUIT t BOARDTU 1 YEL BLK H RED aJ MAIN CIRCUIT BOARD R41 VOLUME FIGURE 17 70 VOLT CONVERSION INTERNAL WIRING ...

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Page 26: ... 2 Phone Plugs Fuseholder 3AG 5A Lampholder and Bracket Assembly Lampholder and Bracket Assembly Nylon Sleeve Qty 1 86K628 50KC224 86D630 86H628 86A409 86A404 1 4 C1 C2 C5 C6 D1 D2 D3 D6 Motorola 2N3741 Selected Part No 86A362 86A360 45EB439D 46A041 45CB758C 45CB308C 55A96 95A551 55C131 90K2150 51A256 51A244 56A211 56A204 95A632 90A1522 95A429 95A598 95A599 Capacitor Electrolytic 250 PF 16V Capaci...

Page 27: ...tor Silicon NPN Transistor Silicon Power NPN VI Limiting Transistor Silicon PNP VI Limiting 45F6818B 45F6498B Parts listed as RKC Kits should be ordered by that kit number Any orders received for piece parts where RKC Kit number is shown will be shipped in RKC quantities Use in emergency only Select for high gain May affect power output and reliability Capacitor Film 22 aF IOOV Capacitor Film I aF...

Page 28: ...FIGURE 18 MAIN CIRCUIT BOARD PARTS LOCATION DIAGRAM 2038 21525 2 FIGURE 19 FILTER CIRCUIT BOARD PARTS LOCATION DIAGRAM ...

Page 29: ... area AC VOLTAGE MEASUREMENTS The numbers within rectangular symbols 0on the Circuit Diagram denote the ac voltage at that point under the following test conditions 1 Voltage measured with respect to chassis unless other wise indicated 2 Line voltage 120V 50 60 Hz 3 Test signal of 0 3V 1 kHz applied across connector J1 4 Ac voltage measurements may vary t 2 0 from values shown 5 Measurements made ...

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Page 31: ...OSA AND SR105B STRAIGHT THROUGH WIRING SHOWS SRlOSB CIRCUITS SRIOSA CIRCUITS INCLUDE ASSEMBLY A2 SWITCH S4 TRANSFORMER T3 AND TERMINAL STRIP TS2 SRIOSB REFERENCE NO DESCRIPTION R I R 9 WERE 12kb C13 ADDED C17 CIB ADDED FIGURE 21 SR105 POWER AMPLIFIER CIRCUIT DIAGRAM ...

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Page 33: ...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...

Page 34: ...ced 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 OFFSwitch 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 1...

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