Shure SR-109 Service manual

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Page 1

SR109

Professional Mixer

OPERATION AND SERVICE MANUAL

Manufactured

SHURE BROTHERS

222

Hartrey Avenue

Evanston, Illinois

60204

INC.

U.S.A.

WARNING

To reduce the risk of fire or electric shock, do not

expose this appliance to rain or extreme moisture.

Printed in

U.S.A.

Page 2

SR109

Professional Mixer

SPECIFICATIONS

Equipment Type

Number of

lnput Channels Power Output Voltage Gain

Program

Headphones

Link

Accessory

Frequency Response

lnput Sensitivity

Distortion

Noise

(300 Hz-20 kHz)

Hum and Noise

(20 Hz-20 kHz)

'Measurement

kilohms

LINK INPUT

600

oh&,

up; all

PROGRAM

ohms:

other

nated

full

. . . . . . .

. .

. . . . . . .

. .

. . . . .. .

. . . . .

. . . . . .

. . . . . . . . . .

. . .

conditions:

through

MIC

MASTER

controls

All silicon transistor mixer/pre-

amplifier

. .

+19 dBm (program line level)

. .

.87 -13 dB MIC input to LlNE

LEVEL out

-+3 dB LlNE input to LlNE

LEVEL out

-13 dB MIC input to MIC

LEVEL out

. .

.69 -13 dB MIC input to PHONES

out

. .

.54.5 k3 dB MIC input to LlNK

OUTPUT (with 600-ohm termination)

k2 dB LlNK INPUT to LlNE

LEVEL output

.59 t3 dB MIC input to ACCES-

SORY output (via pins PUTS)

54.5

k3 dB MIC input to ACCESSORY output (via pin 9/PROGRAM) (terminated with 600 ohms)

. .

k3 dB, 20 Hz-20 kHz (150-ohm

source; 600-ohm load)

.0.1 mV max. for

output

.THD less than 1% at +12 dBm,

30 Hz-20 kHz; IM distortion less than

1% at +12 dBm

. .

128 dBV (equivalent input noise at full gain)

dBm output noise (MAS-

TER Volume Control down)

dBm output noise (MASTER and one channel Volume Control up)

125 dBV (equivalent input hum and noise at full gain)

dBm output noise (MASTER Volume Control down)

dBm output noise (MASTER and one channel Volume

Control up)

through

ohms

PROGRAM

terrhinated

Channel

out.

. .

MIC

LEVEL Volume,

and

-72.8

-38.8

-61.8

-34.8

input

600

switches

150

Volume

ohms,

LlNE

150

dBm program

LINE

input

LEVEL

ohms,

PHONES

and

PHONES

1-8/IN-

through

terminated

termi-

Controls

Signal to Noise

(20 Hz-20 kHz)

lnput Attenuation lnput Clipping Level

at 1 kHz:

MIC lnput

LlNE lnput

lnput Common

Mode Rejection

Low-Frequency

Equalization

High-Frequency

Equalization

Tone Oscillator

lnput Impedance at

1 kHz:

Microphone Line (channels

and 8) Link lnput

Output Impedance:

Program

. . .

. . . .

. . . . . . .

. . . . . .

. . .

. . . . . . .

. .

. . . . .

. . .

. . . .

. . .

. . . . .

.Typically 83 dB at maximum out-

put with one channel Volume Control and MASTER Volume Control set at 8 (approximately 58 dB gain)

0, 15 dB (switch-selected)

100 mV (ATTENUATOR out; Ch.

Volume at 2)

4.5

mV (ATTENUATOR out; Ch.

Volume at 12)

0.56V (ATTENUATOR in; Ch. Volume at 2)

mV (ATTENUATOR in; Ch. Vol-

ume at 12)

.33V (ATTENUATOR out; Ch. Vol-

ume at 2)

1.35V (ATTENUATOR out; Ch. Volume at 12)

90V (ATTENUATOR in; Ch. Vol-

ume at 2)

8.OV (ATTENUATOR in; Ch. Vol-

ume at 12)

.I00 dB at 100 Hz

213 dB at 100 Hz with respect to

0 (flat) setting

212 dB at 10 kHz with respect

0 (flat) setting

1 kHz; less than 1% distortion;

variable level

. .

.2.1 kilohms balanced (for use with

25- to 600-ohm microphones)

. . .

66 kilohms balanced bridging

.35 kilohms unbalanced

Balanced line level: 120 ohms ac-

tual (for use with 25- to

ohm inputs)

Microphone level: 0.5 ohms ac-

tual (for use with 25- to ohm inputs)

600-

Page 3

SR109

Professional Mixer

SPECIFICATIONS

Headphones

..........

Link Accessory

Limiter

Threshold

(adjustable)

Range

Link Jack System

VU Meter Calibration

Phasing (polarity) .Pin 3 of INPUT connectors in

............

...

.3.5 ohms actual (for use with 4- to

16-ohm headphones)

.600 ohms (actual)

......

Unbalanced aux level: 33 ohms

actual (for use with 4K or higher loads)

.....

.Typically -20 to +20 dBm (at

LlNE LEVEL output)

.Approximately 30 dB

......

External signal conditioning out-

put/input; high-level auxiliary amplifier and tape recorder signal output; multiple Mixer con-

nection (common mix); remote master volume control

...

0, f4, +8 dBm, switch-select-

able (0.775, 1.23, 1.95 Vrms) at 1 kHz to 600-ohm load. [VU

RANGE Switch in provides (0.775 Vrms) to 600-ohm load1

0 VU reading of 0 dBm

....

phase with pin 9 of ACCESSORY OUTPUT, tips of OUTPUT and PROGRAM LlNE LEVEL OUTPUTS, and pin 3 of

PROGRAM

MIC LEVEL OUTPUTS (PHASE Switch in of ACCESSORY OUTPUT out of phase with the above.

LlNE LEVEL and

0" position). Pins 1-8

0 position

LINK

Phase Switch Output polarity-reversing switch

30 Vdc Bus .Pin 10 on ACCESSORY OUTPUT

Operating Voltage

Power Consumption

Temperature Range:

Operating Storage

Dimensions..

Installation

Weight 7.7 kg (17 Ib) Finish

Certifications Listed by Underwriters' Labora-

...............

................

.........

.90-132 Vac, 50/60 Hz (SR109)

....

90-132, 180-250 Vac, 50/60 Hz

...

20 watts max. (Mixer only). 500

-7O to 54OC (20' to 130°F)

......

.......

.........

...........

.........

.-29O to 71°C (-20' to 160°F)

133 mm H

Equipped for standard 19 in. (483

Matte black, with beige write-on

(0°, 180') (reverses phase of all program outputs)

connector is regulated +30

k3.5 Vdc supply; pin 11 is ground (earth). May be used to power accessories up to 50

mA.

(SR109-2E)

watts max. (SWITCHED AC re-

ceptacle)

mm D (See Page 4.)

(51/4 in. x 19 in. x 9% in.)

mm) rack mounting; (133 mm) height; may be oper-

ated in accessory

rying Case or in custom control center.

trim strip

tories, Inc.; listed by Canadian

Standards Association as cer-

tified

(SR109 only)

483 mm W X 232

(SR109 only)

5% in.

A105A Car-

Page 4

SR109

Professional Mixer

TABLE OF CONTENTS

Section

SPECIFICATIONS

DESCRIPTION OPERATING INSTRUCTIONS

Functional Identification General Operating Instructions 3 Mounting and Ventilation 4 Power Supply 5 Functional Circuit Description Inputchannels Monitor Mixer System Program Mix Amplifier 7 Link Jacks Program Output

VU Meter Circuit 7

Limiter Tone Oscillator Basic Operating Hints

SPECIAL OPERATING INSTRUCTIONS

High-Impedance Microphones Musical Instruments Tape Recording 9 Record Playback Tape Playback Additional Mixer Inputs Additional Mixer Inputs (Two SRlO9s) Redundant Mixer Set-up (Two Stereo Operation Remote Volume Control Telephone Line Surge Protection

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SRIO9s)

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Page

ii.

Section

iii

SERVICE INSTRUCTIONS

1 Mixer Service 14

Replacement Parts Fuse Replacement

Knob Replacement Service Access Lamp Replacement Board Removal

Limiter Internal Adjustment

Overload Indicator Check

VU Meter Removal VU Meter Calibration

Parts Removal

Transistor and Diode Removal Active Component Checking

Service Illustrations

Optional Accessories

REPLACEMENT PARTS LIST 19 NOTES TO CIRCUIT DIAGRAM

General 29

Troubleshooting 10 11 11 12 12 12 13 14

Ac Voltage Measurements

Dc Voltage Measurements

Resistance Measurements

CONDENSED OPERATING INSTRUCTIONS 35

ARCHITECTS' AND ENGINEERS' SPECIFICATIONS GUARANTEE 35 SHIPPING INSTRUCTIONS 35

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Page

14 14 14 14 14 15 16 16 16 16 17 17 17 18 18

29 29 30 30

. .

SR109

Professional Mixer

LlST OF ILLUSTRATIONS

Figure Page

1 SR109 Professional Mixer Front Panel 2 2 SR109 Professional Mixer Rear Panel 2

3 Overall Dimensions 4 Block Diagram 5 SR110 Monitor Mixer Applications 7

Tone Oscillator Applications 7 Preamplifier-Mixer Connections 8 Tape Recording 9 Record Playback

10 Tape Playback 11 Additional Mixer Inputs 12 Additional Inputs: Two

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SRIO9s

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9 10 10 11 11 12

Figure Page

13 Redundant Mixers 13 14 Stereo Tape Recording 13 15 Remote Volume Control

16 Printed Circuit Board and Parts Location 16

17 Opto-Isolator Test 18 Board

19 Board 2: Channel Equalizer 20 Board 3: Main Board 21 Board 9: Power Supply 22 Board 23 Lead Codes 24 SR109-2E Power Supply Circuit Diagram 30 25 SR109 Professional Mixer Circuit Diagram .3 2-33

1: Preamplifier

0: Program Mute

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13 17

24 25 26 27 27 29

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Page 5

SR109

Professional

DESCRIPTION

Mixer

The Shure Model SR109 Professional Mixer is a solidstate, eight-channel microphone mixer-preamplifier that enables the operator to mix as many as eight microphones with individual control over input attenuation, volume and high- and low-frequency equalization. The Mixer has three outputs: a program output, an accessory output and a headphone output. In addition, channels

switch-selectable inputs for use with either low-impedance microphones or line level sources. A master volume control regulates program output.

The program output has both a 600-ohm, balanced line

level output and a low-impedance, balanced, microphone output. The with separate volume control. A pair of link jacks facilitate connection to an additional mixer, or external equipment such as compressors, limiters or equalizers.

The

to one or more Shure The mixer designed to provide a separate stage monitor mix that follows the program mix levels. In addition, it may be used in multi-track recording as a submaster mix panel or mixdown panel.

The

put limiter with an in-out switch and an indicator lamp

that flashes when the limiter is operating. The front panel

also contains an overload indicator lamp that signals when

headphqne output is an &ohm balanced output

SR109 rear panel contains provisions for connection

SR110 Professional Monitor Mixers.

SR110 is a self-contained, eight-channel, line level

SR109 contains a peak-responding, adjustable out-

and 8 contain

the output is clipping in the non-limiting mode.

The Mixer contains a switch to adjust sensitivity to indicate program output level. A built-in 1 kHz tone oscillator facilitates synchronization of all meters in a system. space for pencilled notations.

The regulated power supply is designed to operate over a wide range of ac line voltages, permitting the use of extremely long ac extension cables without performance degradation. Accessory equipment drawing up to 500 watts may be connected to the rear-panel switched ac receptacle

The solid-state components in the Mixer are protected against damage as a possible result of open-circuit or short-circuit conditions on the inputs or outputs. All components are conservatively rated and are operated well within their respective ratings to assure long life and trouble-free performance.

The Mixer is supplied with rack-mounting screws and spare fuses.

The Mixer is Underwriters' Laboratories, Inc., listed,

and is listed by the Canadian Standards Association as

certified

The following are designed for use with the

fessional Mixer:

(SR109 only).

SR110 Professional Monitor Mixer

A1 05A Carrying Case

meter and a meter sensitivity

front-panel trim strip provides

SR109 Professional

SR109 Pro-

Page 6

FIGURE 1. SR109 PROFESSIONAL MIXER FRONT PANEL

15 16 17 18

FIGURE

(SR109-2E

SR109 PROFESSIONAL MIXER REAR PANEL

Only)

Page 7

SR109

Professional Mixer

FUNCTIONAL IDENTIFICATION (Refer to Figures 1 and 2,

Page 2.) NOTE: All front panel controls are numbered for ref-

erence only.

Individual Channel Volume Controls (Eight) trol volume and input clipping level of each channel separately. Channel 1 contains TONE

push-pull Switch - Pulling switch outward turns oscillator on, and rotating control adjusts level of 1 kHz tone generated internally for set-up purposes.

Individual Channel tary Controls (Eight) -Adjust low-frequency signal equalization for each channel.

Individual Channel Rotary Controls (Eight) -Adjust high-frequency sig-

nal equalization for each channel. LIMITER Indicator Lamp

when LIMITER Switch (11) is turned on (IN).

OVERLOAD Indicator Lamp load condition (output clipping) when LIMITER Switch (11) is turned off (OUT).

True VU Meter

output. (Meets all current standards for VU Meters.) PHONES Rotary Control PHONES Jack (8). PHONES Output Jack- Provides for connection of

stereo or monophonic headphones for monitoring.

9. MASTER Volume Rotary control and POWER

-Adjusts level of totai program output, and applies ac power to power supply and SWITCHED AC Receptacle. THRESHOLD

Control -Sets threshold level of limiter function. LIMITER IN-OUT Slide Switch -Turns program output limiter on and off. Ac Grounded Line Cord to Mixer power supply 3AG-3/16A SLO-BLO Ac Fuse - Protects Mixer ac input line against overload

SWITCHED AC Grounded Receptacle to 500 watts of unfused switched ac power to accessory equipment

PROGRAM

verses phase (polarity) of

PHONE LEVEL program outputs with respect to

inputs. VU METER RANGE Slide Switch

(6) sensitivity for three ranges of program level indication in ACCESSORY OUTPUT/AUX LEVEL 1 1-Pin Connector

Monitor Mixer. 15

dB ATTENUATORS/IN-OUT Slide Switches (Eight)

Provide choice of input signal attenuation for each

channel.

INPUTS/MICROPHONE LEVEL LOW IMPEDANCE Three-Pin Jacks (Eight) nection of low-impedance sources to channels 1

OUTPUTS/PHASE Slide Switch - Re-

dBm.

Provides output connection to Shure SR110

FREQuency EQualizer-LOW Ro-

FREQuency EQualization-Hlgh

lndicates limiting action

lndicates Mixer over-

lndicates volume level of program

Controls volume level to

ADJustment Screwdriver-Adjustable

Connects ac power source

(SR109 only).

Provides up

(SR109 only).

LINE LEVEL and MICRO-

Selects VU meter

Provide for balanced con-

Con-

OSCillator

switch

through 8 inputs, or line level sources to channels and 8.

MIC/LINE Slide Switches (Two) -Select low-impedance (MIC) or line level (LINE) input connections for channels LlNK OUTPUT Phone Jack - Provides output connection to external equipment or common mix bus to combine two or more Mixers.

LlNK INPUT Phone Jack - Provides input connection from external equipment (compressor, limiter, equal-

izer, etc.). PROGRAM

nector power amplifier. PROGRAM (Two) nection to power amplifier. PROGRAM Pin Connector phone-level program output. VOLTAGE SELECTOR Slide Switch -Selects operating voltage range of 90 to 132 or 180 to 250 50/60 Hz (SR109-2E only). AC (MAINS) POWER 3-Pin Connector line cord to Mixer power supply 180-250V 0.1 Protects Mixer ac input line against overload (SR109-2E only).

GENERAL OPERATING INSTRUCTIONS

and 8.

OUTPUTS/LINE LEVEL Three-Pin Con-

Provides balanced output connection to

OUTPUTS/LINE LEVEL Phone Jacks

Provide balanced or unbalanced output con-

OUTPUTS/MICROPHONE LEVEL Three-

provides low-impedance micro-

Connects ac

(SR109-2E only).

AT/90-132V 0.2AT SLO-BLO Ac Fuse

Vac,

WARNING

Voltages in this equipment are Make all input and output connections before ac power is connected. Refer servicing to qualified

service personnel.

Using hardware provided, install Mixer securely in standard 19 in. (483 mm) rack or optional rying Case prior to making electrical connections.

Set front-panel switches to off or OUT and all controls to

Set rear-panel PHASE Switch (15) to

3. Connect desired PROGRAM OUTPUT/LINE LEVEL Connector (23, 24) to

ing cable. (NOTE: Shure

supplied with audio connecting cables.) If Mixer out-

put is to be fed to another mixer or tape recorder microphone input, use PROGRAM PHONE LEVEL Connector (25). If desired, connect monophonic or stereo headphones to front-panel PHONES Jack (8). Connect speakers to power ampli-

fier.

Connect one or more low-impedance microphones to rear-panel PEDANCE Connectors (19). Any high-quality dynamic,

INPUTS/MICROPHONE LEVEL LOW IM-

power amplifier input connect-

hazardous to life.

A105A Car-

OO.

SR105 Power Amplifiers are

OUTPUT/MICRO-

Page 8

ribbon or condenser low-impedance microphone may be used. Connect line level sources to channel 7 or 8 connectors only. If line level inputs are used, set

corresponding

If external signal-processing equipment such as an

MICILINE Switch (20) to LINE.

equalizer, compressor or limiter is to be used, con-

nect Mixer

equipment input and external equipment output. (See 7, for detailed information.) If a Shure

LlNK OUTPUT Connector (21) to external

LlNK INPUT Connector (22) to

Link

Jacks,

Page

SR110

Monitor Mixer is to be used with the SR109, connect multi-pin plug of Connector (17) of

SR110 to ACCESSORY OUTPUT

SR109.

6. SR109: Connect ac line cord (12) to grounded 90- to 132-volt, 50160 Hz ac source. Line cord is a

2.4m

(8 ft), 3-conductor cord with 3-pin grounding plug.

If extension cords are required, use high-quality, rubber-jacketed cable with 18 gauge (0.8 mm2) or heavier wire.

SR109-2E: Obtain suitable &pin male ac connector

and attach to line cord: brown lead to "hot" or "live"

terminal, blue lead to neutral terminal, and

green1 yellow lead to ground or earth terminal. (Connector should be installed by qualified service personnel.) Select proper operating voltage (90-132V or

180250V) using VOLTAGE SELECTOR Switch (26). Note that switch positions are marked 115 and 220 volts. Make certain proper fuse is installed in fuseholder (28):

O.1AT with switch set to 220, or 0.2AT with

switch set to 115. Insert female end of line cord into

chassis power connector (27) and connect male plug

to 3-wire grounded ac power receptacle providing

proper operating voltage.

7. Turn on front-panel MASTER Volume

ControllPOW-

ER Switch (9) and allow one to two minutes warmup time. This warmup time allows the supply voltages to stabilize and capacitors to charge to provide opti-

mum performance. Set 15 dB ATTENUATOR Switch

(18) initially to OUT for normal PA use, to IN for

"hard" rock music. For nels 7 and 8), set

LINE INPUT sources (chan-

MICILINE switch (20) to LINE.

8. Set Master Volume Control (9) to 6. Set VU METER RANGE Switch (16) to (when using a Western Electric

0 for PA or telephone line use

308 Voice Coupler), +4 for recording, or +8 for broadcast use. Have someone sing or talk into microphone and raise channel Volume Control (1) to achieve desired sound level. If meter reads low at proper sound level, reduce power amplifier volume level and increase channel volume level. For single microphone set-up, if meter

indicates excessively high level ("pinning" or "pegging" needle), decrease MASTER Volume Control to obtain good meter reading and increase power amplifier volume level or input sensitivity to obtain proper sound level. In multiple microphone set-up, it may be necessary to decrease MASTER Volume Control in order to maintain channel Volume Control setting. Ideally, set the channel Volume Controls as high as possible (consistent with an adequate mixing range), and increase the MASTER Volume Control to obtain a

0 VU Meter reading. Then increase the power amplifier level control to the desired level. Using the 15 dB ATTENUATORS (18) may aid in maintaining this setting if the channel Volume Control is consistently set low.

9. Set

HI and LO FREQ EQ Controls use. Vertical position response. Clockwise

(0) indicates "flat" frequency

(+)

(3,

2) for channel in

settings increase highfrequency (treble) or low-frequency (bass) level and counterclockwise

(-)

settings decrease the high- or

low-frequency level.

10. With LIMITER Switch (11) in OUT position, OVERLOAD Indicator Lamp (5) will flash when Mixer output clipping level is exceeded. If limiting is desired,

adjust limiter as follows: Operate Mixer with program

material and adjust the channel and MASTER Volume

Controls (1, 9) for desired sound level. With small screwdriver, turn THRESHOLD ADJ Control (10) full counterclockwise. Set LIMITER

INIOUT Switch to

IN. Slowly increase (clockwise) THRESHOLD ADJ

Control until LIMITER Lamp

(4)

flashes intermittently,

indicating limiting action on program peaks. A con-

tinuous glow indicates an undesirable excess of lim-

iting: MASTER

andlor channel Volume Controls should be reduced. Increasing channel or MASTER Volume Controls will not increase mixer output above the level just set. Should higher or lower maximum output level be desired, increase or decrease THRESHOLD ADJustment. (An alternate set-up pro-

cedure uses the TONE

OSCillator to produce a maximum desired VU level. The THRESHOLD ADJustment is slowly increased (clockwise) until the VU Meter reading just set is reduced by 1 dB. Note that with this set-up, the program material level displayed on the VU Meter will be lower because of the difference between peak and average levels. However, limiting action will take place at the same peak level. This effect will be more evident on speech than on music.)

11. Monitor output is available at front-panel PHONES Jack (8). Adjust PHONES Control (7) for comfortable

listening level.

12. NOTE: During temporary shutdown (break, intermission), do not turn off Mixer power. It is designed to operate continuously, and optimum performance is

maintained after internal voltages are allowed to stabilize. Also, do not turn down all microphones. Leave the master or announcer's microphone on so that if

the Mixer is left unattended, announcements may be

made, and the operator will be alerted that the next performance is about

to begin.

MOUNTING AND VENTILATION

The Shure

SR109 Professional Mixer may be operated

in a standard 19 in. (483 mm) audio equipment rack (see

Figure 3, Page

5),

or in a Shure A105A Carrying Case.

Four rack-mounting screws are provided with the Mixer.

The Shure rack-mounting space. When the case, an additional rack-mounted unit such as the

A105A Carrying Case has a 7 in. (178 mm)

SR109 is mounted in this

SR110 Monitor Mixer may be mounted in the remaining 1% in. (44.4 mm) space.

In rack-mounted installations, consider rear-panel ac-

cess before installation is made. Although most installa-

tions will not require frequent access, it should be re-

membered that input and output changes, and some switch movements, will necessitate rear-panel access.

Page 9

FIGURE

OVERALL DIMENSIONS

POWER

SUPPLY

SR109: The Mixer regulated power supply is designed

to operate from 90 to 132 volts ac,

50/60

without adjustments, allowing the Mixer to meet all specifications over this wide range of ac input voltages.

three-conductor, grounded line cord (12) supplies ac power to the Mixer through the front-panel POWER Switch (9). The Mixer consumes 20 watts maximum (0.2 amperes) and the

ac line input is protected by a

(13) and a wired-in

3/10-ampere slow-blow fuse in series.

3/16-ampere slow-blow fuse

'(TYPICAL

-50 DB -1100 XFMR

ATTENUATOR ATTENUATOR

NOTE I

600A

RESISTOR

CHXNELS

23DB CHANNEL

200x~:HGH VOLUME CHANNEL

1-8)

PHONES

LEVEL

FIGURE

METER

SR109 BLOCK DIAGRAM

NOTES I MIC-LINE SWITCHES ON CHANNELS

2 TONE GENERATOR ON CHANNEL I ONLY

AND 8 ONLY

Page 10

These fuses should not be replaced with

CAUTION

any other size or type of fuse.

Accessory equipment may be connected to the panel SWITCHED AC Receptacle (14). The accessory equipment may consume up to 500 watts maximum, which provides for use with high-power amplifiers such as the

SR105. Note that the receptacle is switched but not

Shure fused; all accessory equipment used with the Mixer should contain its own fuse.

SR109-2E: The SR109-2E regulated power supply is designed to operate from either 90 to 132 volts ac or 180 to 250 volts ac, VOLTAGE SELECTOR Switch (26). A three-conductor, grounded line cord supplies ac power to the Mixer through the front-panel POWER ON-OFF Switch (9). The

SR109-2E line cord does not have a connector on the

power source end of the cord. Obtain a suitable male ac connector and install it on the line cord: brown to "hot" or "live" terminal, blue lear to neutral terminal,

green/yellow lead to ground or earth terminal. (Con-

and nector should be installed by qualified service personnel.) The ac line is protected by a 0.1-ampere Slo-Blo fuse (for 180- to 250-volt operation) or a 0.2-ampere Slo-Blo fuse (for 90- to 132-volt operation. A wired-in fuse also protects the ac line.

FUNCTIONAL CIRCUIT DESCRIPTION (See Figure 4, Page 5)

Each three-pin professional audio input MICROPHONE LEVEL Connector (19) feeds its own low-impedance bal-

anced lnput Transformer, which provides gain of 23 dB.

Channels 7 and 8 also contain

which switch in a 50 dB bridging line-to-microphone

level Attenuator to accept line-level inputs. The lnput Transformers (and, on channels 7 and 8, the Switch) are fed to 15 dB ATTENUATOR Switches (18) and then to the Preamplifier, which provides gain. The amount of voltage gain provided by the Preamplifier (7 to 42 dB) is controlled by the Channel Volume Control as gain is reduced. The Preamplifier circuits contain the individual Channel Volume Controls and feed the individual Channel Equalizer (HI and LO FREQ EQ) Controls (3,2) which decrease the signal approximately 3 dB when set to the 0, or "flat," setting.

fier and the ACCESSORY OUTPUT Connector (17) for interconnection with Mix Amplifier feeds through a 560-ohm resistor to the LlNK jacks (21, 22). When accessory equipment is not connected to the the program signal is fed to the MASTER Volume Control (9) and back to the ACCESSORY OUTPUT Connector.

a The attenuated signal feeds a limiter, which is connected to a Lamp Driver (for driving the LIMITER and OVERLOAD lamps) and a Limiter THRESHOLD ADJ Control (10) for setting the threshold of Limiter operation. Note that when the LIMITER Switch (11) is turned off (OUT), the LIMITER Lamp (4) will not light, but the OVERLOAD Lamp flash whenever the output clipping level is exceeded. The Limiter Attenuator also feeds a Amplifier, also controlled by the MASTER Volume Control.

(I), providing an increase in input clipping level

The Equalizer outputs are fed to the Program Mix Ampli-

The output of the MASTER Volume Control, after feeding

0 dB gain Amplifier, is sent to a Limiter Attenuator circuit.

50/60 Hz, as selected by the rear-panel

3/10-ampere

MIC/LINE Switches (20)

+7 to +42 dB

SR110 Monitor Mixers. The Program

LlNK jacks, the jacks are bypassed and

+7 to +35 dB output

rear-

three-'pin

MIC/LINE

(5)

will

The signal then goes through a

and into the Program Output Transformer. The Trans-

former feeds three

24) and a MIC LEVEL Output Connector 50 dB below line level. The

fier also feeds the VU METER RANGE Switch

goes to a +22 dB Meter Amplifier and then to the VU

(6), and a PHONES Level Control (7), Headphones

Meter

Transformer and PHONES Output Jack (8).

The Mixer also contains a in set-up and check-out. The Generator is activated and controlled by the channel 1 Volume Switch

and their uses is provided in the following paragraphs of this section.

INPUT CHANNELS LEVEL lnput Connectors (19) are provided on the rear

panel of the Mixer. The Mixer is designed to operate with high-quality, low-impedance dynamic, ribbon or condenser microphones. Each low impedance microphone input connected to a low-impedance, balanced-input transformer through a 15 dB input ATTENUATOR (18). Two Slide Switches (20) are provided for channels 7 and 8. These switches allow the user to select between either low-impedance MICROPHONE or additional line level inputs are required, Shure lnput Adapters may be used in each microphone level input.

vides input attenuations of the user to compensate for the differences in levels due to

different sources, such as close talking or distant microphone placement, and to compensate for high output levels from condenser microphones.

section, in a feedback circuit, sets the gain of the preamplifier; the second section is a preamplifier output tenuator. This circuit configuration increases the preamplifier input clipping level as the Volume Control is reduced to lower settings. Ideally, the control should operate in the middle range, between 4 and be accomplished by proper 15 dB ATTENUATOR Switch

(18) setting.

equalizer circuit. Individual HI and LO FREQ EQ controls

(3,2) allow the user to shape the sound of each input channel without affecting the other channels of the Mixer. The HI FREQ controls provide up to 13 dB of boost or cut at 10 kHz with a 1 kHz hinge point. The LO FREQ controls provide up to 13 dB of boost or cut at 100 Hz with a 1 kHz

bin-ge

cate boost, and minus (-) markings denote cut. A ting provides a normal or "flat" frequency response.

PUT/AUX LEVEL Connector (17) and the Program Mix Amplifier.

MONITOR MIXER SYSTEM nector (17) of the

one or more Shure The output of each individual channel after all channel controls (volume, equalization and attenuation) appears

(I), and the Control output is fed to the Preamplifier.

A detailed description of the Mixer circuits and controls

Eight professional, three-pin, audio MICROPHONE

The 15 dB ATTENUATOR (18) two-position switch pro-

The Channel Volume Control

The output of the Channel Volume Control (1) feeds the

point. Control settings with plus

The output of the equalizer feeds the ACCESSORY

The rear-panel ACCESSORY

LlNE LEVEL Output Connectors (23,

SR109 provides for interconnection to

SRl10 Professional Monitor Mixers.

0'-180' PHASE Switch (15),

(25), which is at

+7 to +35 dB output Ampli-

(16), which

1 kHz Tone Generator for use

Control/TONE OSC

MIC/LIINE

LlNE LEVEL inputs. If

0 or 15 dB. This switch allows

(1) is a dual control: one

(+)

OUTPUT/AUX LEVEL Con-

A15LA Line

This can often

markings indi-

at-

0 set-

OUT-

Page 11

on this connector as do the LlNK INPUT total mix signal and the power supply connections. The

SR110 is a selfcontained, eight-channel, line level mixer designed for use with the

SR109 or similar equipment. The SR110 can provide a separate stage monitor "mix" that follows the program "mix" levels coming from the eight channels of

SR109. In addition, it may be used in multi-track re-

the cording as a submaster mix panel or as a "mixdown" panel.

SR110 provides eight high-impedance, unbalanced,

The line level inputs to its mixing circuity, one high-impedance, unbalanced, line level input to its Output Selector Switch for monitoring the program mix, and one line level,

600ohm, balanced output. Individual channel and master volume controls are provided, as is a switch to choose between monitoring the channels in use (Mixed Inputs) and the total program mix (Program Input). The Mixed Inputs position takes the signal from each channel frequency equalization circuit, and the Program

Input position obtains

the mixed signal at the LlNK INPUT Jack (22).

SR110 has parallel accessory input/output male and

The

female connectors. These connectors permit the connec-

tion of addition tandem or "stacked"

SRllOs. A typical

application is shown in Figure 5, Page 7. PROGRAM MIX AMPLIFIER

The program mix amplifier is an active mixing amplifier in which gain remains constant independent of the individual channel volume control settings. The output of the program mix amplifier is connected through a 560-ohm mixing resistor to the LlNK Jacks (21, 22).

SR1w LINE MIXER LEVEL

ACC

OUT

SRl I0

MONITOR

MIXER

SRllO

MONITOR

MlXER

SRllO

MONITOR

MIXER

FIGURE

POWER

AMPLIFIER

POWER

AMPLIFIER

STEREO

TAPE

RECORDER

SRllO MONITOR MlXER APPLICATIONS

SPEAKERS

STAGE

MONITOR

SPEAKER

LlNK JACKS

The LlNK Jacks

(21,22) on the rear panel of the Mixer enable the user to interconnect more Mixers for additional inputs or add external equipment, such as equalizers, compressors, or limiters. When connecting two or more SR109 Professional Mixers together to provide many channel inputs, connect the LlNK OUTPUT Jacks (21) of all the units together. It should be noted that the LlNK OUTPUT Jack is actually a two-way jack; the impedance at this point is actually 600 ohms, and any number of units may be tied together at this point. The LlNK INPUT Jack

(22) is an input-only jack and has switching contacts that

disconnect the LlNK OUTPUT signal from the MASTER Vol-

ume Control (9). Note that the

SR109 and the Shure SR101

Audio Console may be interconnected in the same manner.

If an equalizer, limiter or compressor is connected to the Mixer, the LlNK OUTPUT Jack (21) is connected to the input of the external unit and the output of the external unit is connected to the LlNK INPUT Jack (22).

The signals at the LlNK Jacks are typically at a level 10 dB below line level. These jacks will accommodate signal levels in the range between LlNK INPUT impedance is greater than 20

30 to +10 dBm. The

kilohms and

may be considered a bridging impedance. The output of

the LlNK Jacks feeds the MASTER Volume Control (9)

which is a two-section control similar to those used in the individual channels. The LlNK INPUT Jack is connected to the ACCESSORY

OUTPUT/AUX LEVEL Connector (17).

PROGRAM OUTPUT

The signal from the LlNK Jacks (22, 21) drives the program output amplifier. The gain of this amplifier is controlled by one-half of the MASTER Volume Control (9) (the other half is an input attenuator for the output amplifier). In addition to the limiter circuitry, the program output amplifier also contains the front-panel OVERLOAD Indicator Lamp (5). This indicator will flash when the output clipping level is exceeded, and only when the LIMITER Switch (11) is in the OUT position. The output of the program amplifier is sent to the PHASE Switch (15) mounted on the rear panel of the Mixer. This switch allows the user to change the phase of the program output, which may be helpful in eliminating or reducing low-frequency acoustic feedback. Generally, this switch is adjusted to the position which either gives the most gain before feedback or, if both positions give the same gain before feedback, use the position that produces the highest pitch feedback. The program signal, after leaving the PHASE Switch, is routed to the output transformer which provides both LlNE LEVEL and MICROPHONE LEVEL outputs. The LlNE LEVEL output is connected to one professional three-pin, male, audio output connector (23) and two three-circuit phone jacks (24). The MICROPHONE LEVEL output is a low-impedance, balanced output, 50 dB below the LlNE LEVEL output, and is connected to a professional three-pin, male, audio output connector (25).

Note that all of the program outputs are balanced with respect to ground. If a two-circuit type phone plug is used to connect the mixer line level output to an amplifier or tape recorder, the line outputs will automatically become unbalanced. If the three-pin unbalanced output is used and a phone jack output is also to be used, obtain a stereo phone plug and

corrnect the tip and ring of the plug only.

(The sleeve is a shield and would cause a ground loop.)

If it becomes necessary to use the MICROPHONE LEVEL Output Connector (25) to feed a high-impedance microphone input, use a line matching transformer such as one of the Shure A95 Series at the high-impedance microphone input.

The output of the program output amplifier is also fed

to the VU Meter (6) circuit. VU METER CIRCUIT

To allow a wide range of signals to be handled by the

VU Meter

(6), a VU Meter amplifier is provided. The output of the program amplifier is fed to the VU METER RANGE Switch (16) which in turn feeds the VU Meter amplifier and the Meter. The VU METER RANGE Switch provides a

Page 12

choice of 0, +4 or The

0 setting is usually used for PA applications, +4 is the

standard for recording use, and

dBm output levels for the VU Meter.

+8 is preferred for use

by broadcasters. The calibration of the VU METER RANGE

Switch is internally adjusted at the factory for a 600-ohm load on the program output in the

VU across

+4 dBm switch position. The VU Meter amplifier provides the proper impedance and signal level for correct VU Meter ballistics and calibration. This amplifier also isolates the Meter from the program output and eliminates the distortion normally caused by the nonlinearities of VU meters.

LIMITER

The program output amplifier also contains a

peakresponding, rapid-acting, limiter circuit. When the LIMITER Switch (11) is turned on (IN), and the THRESHOLD

ADJ Control (10) is properly adjusted, the LIMITER Indicator Lamp (4) will flash whenever the limit threshold is exceeded and the limiter is functioning. The dynamic range

of the limiter is approximately 30 dB.

Set the limiter THRESHOLD ADJ Control (10) as fol-

lows. Operate the Mixer with program material, and adjust

the individual channel and MASTER Volume Controls (1, 9) for the desired level. With a small screwdriver, turn

the THRESHOLD ADJ Control full counterclockwise. Set the LIMITER IN-OUT Switch (11) to IN. Slowly increase (turn clockwise) the THRESHOLD ADJ Control until the

LIMITER Indicator Lamp (4) flashes, indicating limiting ac-

tion on program peaks. Note that increasing the channel

or MASTER Volume Controls will not increase the mixed

output above the level just set. Should a higher or lower maximum output level be desired, increase or decrease the THRESHOLD ADJ Control.

An alternate method of limiter threshold adjustment is

to turn on the TONE

Oscillator (1) to produce a maximum reference level on the VU Meter (6). Adjust the THRESHOLD ADJ Control (10) clockwise until the VU Meter reading

just set is reduced by 1 dB. The program material dis-

played on the VU Meter will be lower because of the difference between peak and average levels, but limiting action will take place at the same peak level. This effect

will be more evident on speech than music.

TONE OSCILLATOR

The Mixer contains a built-in 1 kHz tone oscillator for

set-up and check-out purposes. The TONE OSC Control

and On-Off Switch

(1)

injects the 1 kHz tone into the channel 1 preamplifier. The tone is processed through the program channel in the same manner as microphone or line input signals.

The tone oscillator may be used as follows: With the VU METER RANGE Switch (16) set to MASTER Volume Control

until a

VU reading is obtained on the VU Meter. A tone

(9)

and TONE OSC Control (1)

+4,

increase the

reference level has now been established. The Mixer LlNE

LEVEL Output (23,

24)

is now

4-4

dBm (1.23 volts across a 600-ohm load) and the MICROPHONE LEVEL Output (25) is approximately 4 millivolts. These reference signals may be used to set up power amplifiers, tape recorders, or other equipment connected to these outputs (Figure

6A, Page

8). By adjusting the input level (or volume) controls on

the associated equipment, all meters in the audio system

can be made to "track." This allows the Mixer operator to observe only the Mixer VU Meter.

The tone oscillator may also be used to provide a check of cables and equipment connected to the link output. With the

LlNK OUTPUT Jack (21) connected to the input

MIC

LINE LINE

TAPE

RECORDER

GATED

COMPRESSOR

MIXER

6B,

Page 8). Set

(23)

(15)

SLO-BLO

has not

is not be-

SR 109 MIXER

POWER AMPL

109

MIXER

FIGURE

TONE OSCILLATOR APPLICATIONS

POWER

AMPLIFIER

MIC

AUX LEVEL

INPUT JACK

of external equipment, such as a Shure SE30 Gated Compressor/Mixer which in turn feeds a broadcast line, disconnect the Mixer output, either at the back of the Mixer,

power amplifier or speakers (Figure

the MASTER Volume Control

(9)

to 6 or the normal operating position, and increase the TONE OSC Control (1) for a

0 VU reading on the VU Meter (6). Set the MASTER

Volume Control to

Under this set-up condition, the external equipment may now be calibrated or checked out without affecting the Mixer output. After calibrating the external equipment, turn off the tone oscillator, and return the MASTER to the previous setting. Reconnect the power amplifier or speakers.

BASIC OPERATING HINTS

Should any difficulty be encountered in Mixer operation, the problem may often be traced to some simple source such as an error in interconnection. The following is offered as a basic guide to problems of this sort.

Symptom: Mixer is "dead" (no output, VU METER lamps

out)

Check: 1. Check that ac power source is "live" and

that Mixer is plugged in.

2. Check that POWER OFF Switch (9) is on.

3. Check to see that rear-panel Fuse (13, 28) is good.

Symptom:

Mixer is "dead" (no output, VU Meter lamps lit)

Check: 1. Check that cable from PROGRAM OUT

PUT/LINE LEVEL Connector accidentally been connected to PROGRAM

OUTPUT/MICROPHONE LEVEL

Connector (25).

2. Check that PHASE Switch tween positions.

3. If external equipment is connected to LlNK Jacks (21, 22), disconnect external equipment to determine whether fault is in external equipment.

Symptom: One channel is "dead" (other channels oper-

ating properly)

Check:

Check for defective input cable or source. Check that

2. nels

MIC/LINE Switch (20) (chan-

and 8 only) is not between positions

or in the wrong position.

Page 13

SR109

Professional Mixer

SPECIAL OPERATING INSTRUCTIONS

The previous section described normal interconnection nel 7 or 8 jack with MIC/LINE Switch in LlNE position). If and operation of the provides information on special set-ups to more fully uti- 1 and the hot conductor to pin 3 of the input jack. As an lize the capabilities of the Mixer.

HIGH-IMPEDANCE MICROPHONES

High-impedance phones (crystal

mended) MICROPHONE LEVEL Input Jacks (191, providing a line matching transformer (Shure A95 Series) is used. NOTE:

The

sate microphones.

The high-impedance cable should be limited to 6m (20 ft). of high-impedance, single-conductor, shielded cable (Bel-

den #8401, #8410, or #8411) between the microphone Output the speaker jack; damage and line matching transformer, and add as much low-im- may may be

pedance, two-conductor,

Mixer

frequency

and noise.

MUSICAL INSTRUMENTS

Musical tical-electrical, or electrified, may be amplified through the Mixer. For acoustical instruments, place a microphone close to the instrument strings, sounding board, or mouth. Adjust equalization and volume controls as necessary.

For acoustical-electrified instruments such as classic or folk guitars with pickups and preamplifier outputs, or pianos with pickups and preamplifier outputs, either place the microphone as described above, or connect the pickup to a line matching transformer as described under

High-Impedance Microphones (Page 9). Adjust the 15 dB ATTENUATOR Switch (8) for the channel the desired sound level with the channel Volume

(1) set at about mid-scale.

To use a preamplifier auxiliary output (instrument or impedance auxiliary tape recorder input, connect a cable

tape recorder preamplifier, or hi-fi amplifier tape monitor from one LlNE LEVEL Jack to the tape recorder input (see

output jack, or headphone jack; not the speaker jacks- Figure 8, Page 10). If the LlNE LEVEL Output is being amplifier damage may result) with the Mixer, connect the used and a two-circuit phone jack is used to connect the preamplifier auxiliary output to a LlNE LEVEL input (chan- Mixer to the tape recorder, this will unbalance the LlNE

the

If a long

#8422)

input

can

ATTENUAToR Switch

very high Output produced

cable

jack.

signal loss and reduce the possibility of hum

instr~ments, aco~stical (n0n-electrified), acous-

SR109 Professional Mixer; this section the source is unbalanced, connect the cable shield to pin

alternate connection, connect the preamplifier auxiliary output through up to 3m (10 ft) of cable to the high-impe-

dynamic, ribbon or condenser micro-

ceramic

used

with

One

length

necessary between

These

required,

shielded

precautions

may

are recorn-

the

1°w-im~edance

used

use

cable

(Belden

the

transformer

will

help

avoid

in use to provide nection, the operator should decide whether he wants the

'Ompen-

#8412

high-

Control tape level to follow the MASTER Control and LIMITER.

dance side of a line matching transformer (Shure A95 series)

impedance side of the transformer through a low-imped-

ante

MICROPHONE LEVEL Input Jack (19). Adjust Mixer

equalization controls

15 dB ATTENUATOR Switch (18) for the channel in use to provide the desired sound level with the channel Volume Control (1) set at about mid-scale.

ft)

scribed above. It is important to note that the tonal quality of fully electrified instruments is primarily formed by the

and

instrument amplifier and speaker; an external microphone

picking up

provide a more desirable sound than that obtained by di-

rect connections.

microphones also apply to most musical instruments (see High-Impedance Microphones, Page 9).

TAPE RECORDING

from either the LINE LEVEL Output (23,241, MICROPHONE

LEVEL Output (25) or LINK OUTPUT (21) Jacks. The Mixer

Program Outputs are after the MASTER Volume Control (9) and LIMITER Switch (11); the LINK OUTPUT Jack is

before these features. In planning a tape recorder con-

shown

microphone cable (up to 300m-1000 ft) to a Mixer

Fully electrified instruments may also be amplified using

the

The cable length restrictions applying to high-impedance

The Mixer output may be recorded on a tape recorder

To use a

LINE LEVEL Output Jack (23,24) feeding a high-

front of

fed

instrument

~i~~~~

for

Page

connect the

optimum sound. ~dj~~t the Mixer

the

instrument speaker,

to an jack as de-

Output may very

the

low-

in-

AUX OR HEADPHONE OUT

PREAMPLIFIER

(10')

MAX.-

HIGH IMPEDANCE

FIGURE

p=-UP

A95 LINE

MATCHING

TRANSFORMER

LOW IMPEDANCE

MICROPHONE

PREAMPLIFIER-MIXER CONNECTIONS

LOW IMPEDANCE

CABLE

300

(1000')

MIC LEVEL

INPUT

109

MIXER

Page 14

LEVEL Output (refer to Program Output, Page

7).

If the MICROPHONE LEVEL Output Jack (25) is to be

used, connect a cable from it to the tape recorder

low-

impedance microphone input. If the microphone input on

the tape recorder is designed to be used with

high-imped-

ance microphones (greater than 1000 ohms), insert a

line matching transformer (Shure A95 Series with proper connectors) between the MICROPHONE LEVEL Output

Jack and the tape recorder input (refer to Program Output, Page

7).

To use the LlNK OUTPUT Jack (21), use a two-circuit phone plug on the cable to the tape recorder auxiliary or line input. The input impedance of the tape recorder should

be 600 ohms minimum.

The output impedance of the

LlNK OUTPUT Jack (21) is low; this provides for unlimited cable length between the Mixer output and tape recorder input. Low-capacitance, single-conductor, shielded cable (Belden

#8401, #8410, or #8411) is recommended to reduce the possibility of hum and noise pickup.

For operation with a stereo tape recorder, refer to Stereo

Operation, Page

12.

RECORD PLAYBACK

To play records through the Mixer using a turntable or record changer with a stereo magnetic cartridge and no preamplifier, the most expedient method is to join the left and right channel leads from the turntable in a

"Y"

adapter and connect the joined output through an A95 Series Line Matching Transformer to a MICROPHONE LEVEL lnput Connector (19) on the Mixer (see Figure

9A, Page 10). Note that the total lead length between the turntable and the A95 should not exceed

1.5m (5 ft). To approximate the

RlAA equalization curve, set the Mixer FREQ EQ-LO Con-

trol (2) to +4, the FREQ EQ-HI Control 15

ATTENUATOR Switch (18) to 0 for the channel being

(3)

to -6, and the

used. Adjust the channel Volume Control (1) as necessary.

LOW

IMPEDANCE

MIC

BALANCED

LEVEL

OUTPUT

FIGURE

LINE

TAPE

RECORDING

A better method of performing this interconnection in-

volves the use of a phono preamplifier such as the Shure

M64 Stereo Preamplifier (see Figure

96, Page 10). In this set-up, RlAA equalization will be achieved at the preamplifier, before the signal enters the Mixer. In this manner, the Mixer equalization controls may be used to optimize the room sound, rather than compensating for the input signal. The joined turntable leads enter the channel 1 input of the preamplifier, and the output is taken from the channel 1 low level output and fed to a MICROPHONE LEVEL lnput Jack (19) of the Mixer. Set the Mixer 15 dB

ATTENU-

ATOR Switch (18) to 0 with this set-up.

Note also that this set-up removes the cable restriction

between turntable and Mixer described above; although

TURNTABLE

A95

MIC

INPUT

109

MIXER

1.5

(5')

MAX.-=

CHAN.1

INPUT

ONLY

FIGURE

ONE

M64

PREAMPLIFIER

CHANNEL

RECORD

STEREO

p-UP

CHAN.

LOW LEVEL

OUTPUT

USED

FOR

PLAYBACK

FREQ. EQ-L0:+4

(

FREQ.

THIS

APPLICATION.

EP-HI:

300

-6

(1000')

)

MIC

SRlOS

MIXER

INPUT

Page 15

a maximum of 1.5m (5 ft) between turntable and preamplifier is mandatory, the cable length between the preamplifier and Mixer is virtually unlimited.

TAPE PLAYBACK

To play tape-recorded material through the Mixer, con-

nect output to the channel 7 or 8 For unbalanced tape recorder outputs, connect a conductor, shielded cable as shown in Figure 10, Page 11. Connect the tape recorder output cable shield to pin and the "hot" conductor to pin lnput Jack.

or 8 (whichever is being used) to LINE. Set the 15 dB

TENUATOR Switch (18) to 0, and the channel Volume

Control (1) as required.

cable from the tape recorder auxiliary or line level

LlNE LEVEL lnput Jack (19).

of the SR109 LlNE LEVEL

Set the rear-panel

TAPE RECORDER

AUX OUTPUT

MIC/LINE Switch (20) on channel 7

c-------

-------

SR109 MlXER

(CHANNEL 7 OR

single-

AT-

ure 11B, Page 11). Set the SR109 15 dB ATTENUATOR Switch (18) to this set-up with other mixers, essentially the same procedure is followed. The Shure M67 mixer, for instance, may be connected to the mixer line out connector (binding posts) or headphone output (phone jack) (Figure 11 C, Page 11).

If a mixer is to be used with the

to maintain as many

can be connected to the

IlD, Page 11). However, this requires sacrificing the

channel equalization functions for the sources entering through the mixer. The only

erating on the mixer sources in this set-up are the MASTER Volume Control

PHASE Switch (15). In addition, any mixer used in this setup requires a output to provide an attenuator bridging connection; the

resulting signal level will be down -10 dB (see Figure Page 11). The M67 Mixer headphone jack has suitable built-in resistors and may be connected directly to the SR109 LlNK OUTPUT Jack. Only mixers with 600-ohm line outputs may be used in the configuration. Note that the

M68FC mixer cannot be used this way.

Shure

mixer-to-link out jack connection can also be used

The

with several

0 and the MIC/LINE switch to LINE. To use

SR109 LlNE INPUT Jack through the

SR109 but it is desirable

SR109 channels as possible, the mixer

LlNK OUTPUT Jack (21) (Figure

SR109 control functions op-

(9), LIMITER Switch (11) and rear-panel

2.2-kilohm resistor in series with the mixer

mjxers. Each mixer output must contain its

11E,

FIGURE

ADDITIONAL MlXER INPUTS

Additional microphone or other source inputs may be obtained using a high gain, low noise, microphone mixer such as the Shure PHONE LEVEL provide a total of 11 inputs (see Figure (Note that adding a mixer at an channel to a submaster control; the total number of inputs

will thus be the mixer total plus the

minus 1 for the submaster.)

A common practice when adding a mixer in this manner

is to connect similar-use microphones (for instance, all

drum, string or horn microphones) to a single mixer which

is fed into the

ume Control (1) then controls an entire section, facilitating adjustment of that section during a performance. With this set-up, set the channel 15 dB ATTENUATOR Switch (18)

0 and adjust the mixer channel volume controls in the

to mid-to-high range. Adjust the mixer master volume control as required to keep the the desirable middle range.

M68FC mixer has a switch-selectable low- or high-

The impedance microphone output. When using an M68FCtype mixer into an SR109 MICROPHONE LEVEL lnput Jack (19), set the mixer MIC OUT switch to low impedance, and make necessary adjustments as described above. It is sometimes desirable to use the auxiliary output from the mixer into the (Refer to this set-up.)

To use this set-up with an between the mixer auxiliary output (phono pin jack) and

SR109 LINE INPUT Jack (19) on channel 7 (or 8) (Fig-

the

lnput Jack (19), the M68FC and SR109 will

SR109. The SR109 individual channel Vol-

SRl09 channel 7 (or 8) LlNE INPUT (19).

Tape

Playback,

10.

TAPE PLAYBACK

M68FC. When connected to a MICRO-

11A, Page 11).

lnput Jack converts that

SR109 total

SR109 channel volume control in

Page 11, for a description of

M68FC mixer, connect a cable

---8

LOW IMPEDANCE

MIC LEVEL

M68FC SR109 MIXER MIXER

AUX LEVEL

MIXER MIXER TOTALaII CWNNELS

LlNE OUT OR

PHONES OUT

MIXER MIXER

PHONES

MIXER MIXER ON

M6"Tv

600Ll

LlNE OUT

MIXER

FIGURE

11.

MIC

LEVEL

TOTAL.11 CHAP:NELS

LlNE LEVEL

SR109

LlNE LEVEL

SRlOS

SRlOS (NO EWALlZATlON

SRIO,

MlXE R

ADDITIONAL MIXER INPUTS

TOTAL: I

TOTAL I2 CHANNELS

M67

TOTAC. I2 CHANNELS

(NO EOUAUZATI ON ON MlXER

CHANNELS

INPUTS)

INPUTS1

Page 16

Page 17

LlNK

OUT

SR1Os

MIXER

LINK

OUT

SR1Os

MIXER

LlNE LEVEL

FIGURE

LINE

LEVEL

LlNE

LEVEL

RESISTORS ARE CARBON COMP., 1/2 W.5%

13.

RESISTIVE

NETWORK

1 I I I

I I I

BALANCED

I BRIDGING

-- - - - -

-J

REDUNDANT MIXERS

AMPLIFIER

POWER

AMPL

INPUT

POWER

D D

SR109

MlXER

FIGURE

SRllO

MONITOR

MlXER

ACC OUT

AUX LEVEL

14.

STEREO TAPE RECORDING

SRllO

MONITOR

MlXER

STEREO

RECORDER

TAPE

REMOTE VOLUME CONTROL

A remote volume control may be constructed for adjusting the output level at a considerable distance from the Mixer. For remote control up to

15m (50 ft), obtain a lineartaper potentiometer with knob (any value from 1000 to 2500 ohms), a standard phone plug, and a length of

single-

conductor, shielded microphone cable (such as Belden

#8401, #8410, or #8411). Connect the potentiometer and plug as shown in Figure

15A, Page

13,

and connect the

phone plug to the Mixer LlNK OUTPUT Jack (21).

If hum or noise is encountered with the above set-up, it

may be necessary to provide a two-wire control. Using the

same potentiometer, obtain two standard phone plugs and

twice the desired length of single-conductor, shielded microphone cable. Connect the potentiometer and plugs

ing tape channel input; an omnidirectional unit suspended from the ceiling will pick up the full acoustic output of the instruments.

An ideal method of recording the is to use two method allows the

SR110 Professional Monitor Mixers. This

SR109 output to be used for the PA

SR109 output in stereo

system. Connect the SRllOs as shown in Figure 14, Page 13, with the output of one of the tape recorder and the other

SR110 feeding the left input

SR110 feeding the right.

Note that the controls of the SRllOs permit spatial po-

sitioning ("panning" from left to right) and also allow different level settings to be used on the recording as opposed to the PA level. Spatial channel assignment or positioning is accomplished as follows: If the

SR109 channel 1 input is to be recorded on the left tape channel, set the left level and leave the right at (both left and right), adjust both

SR110 channel 1 volume control for the proper

SR110 channel 1 volume control

0. If the second tape input is to be recorded "centered" SR110 channel 2 volume

controls to the same setting. Note that these two controls combine the functions of record level and panning or

positioning.

SR109 instrumental channels that are set at a low level for PA use with respect to vocal channels should be set higher on the SRllOs to provide a proper recording balance. Once the

SR110 levels are set, the SR109 provides

the "mix" for both PA and tape recording.

An expansion of the above method may be used to re-

cord 4-channel (quadriphonic) sound. In this-method, four

SRllOs are connected to the four tape recorder inputs, and adjustments are made as described above.

SRlOS

MIXER

SRIOS

MIXER IN

LlNK

OUT

FIGURE

LlNK

15.

WHITE

BLACK

REMOTE VOLUME CONTROL

r-------7

---------

I I

Page 18

as shown in Figure 158, Page 13, and plug the control assembly into the

(22) Jacks.

For distances over 15m (50 ft) or for permanent installations where hum or noise may be encountered, use low-capacitance, two-conductor, shielded cable

den #8412 or #8422). Connect as shown in Figure 15C,

Page 13, and use a metal box to contain the potenti-

ometer. The cable shield must be connected to the metal

box containing the potentiometer, to the common conductor (black), and not to the sleeve connections of the

LlNK OUTPUT (21) and LlNK INPUT

(Bel-

phone plugs. IMPORTANT: To avoid hum caused by a ground loop, do not ground the metal box to any metal such as electrical conduit, water pipes, heating ducts, or

structural steel.

TELEPHONE LINE SURGE PROTECTION

When using the Mixer to feed a telephone line that may

be subject to lightning-induced voltage surges, the follow-

ing part should be installed across the telephone line to

provide additional protection for output circuit components: Thyrector, General Electric Part No.

6RS20SPlBl.

SR109

Professional Mixer

SERVICE INSTRUCTIONS

MIXER SERVICE (SEE GUARANTEE, Page

The SR109 Professional Mixer uses components of the highest quality, operating well within their respective ratings to assure long life.

WARNING

Voltages in this equipment are hazardous to life. Make all input and output connections before ac power is connected. Refer servicing to qualified

service personnel.

REPLACEMENT PARTS

Parts that are readily available through local electronics parts distributors are not shown on the accompanying Parts List. Their values are shown on the Circuit Diagram (Figure 25, Pages 32-33). Commercial parts not readily available and unique parts are shown on the Parts List and may be ordered directly from the factory.

The commercial alternates shown on the Parts List are not necessarily equivalents, but may be used in the event that direct factory replacements are not immediately available. To maintain the highest possible performance and reliability, Shure factory replacement parts should be

used. When ordering replacement parts, specify the Shure Replacement Kit Number (RKC), description, product model number, and serial number.

FUSE REPLACEMENT

To replace line fuse F1 (with no apparent problems in

the Mixer), disconnect the line cord from the ac source

and remove the rear-panel fuseholder cap. Replace the defective fuse only with a (SR109 only; SR109-2E contains a 0.1A Slo-Blo fuse for

180- to 250-volt operation, or a to 132-volt operation).

3AG-3/16A Slo-Blo fuse

0.2A Slo-Blo fuse for 90-

35.)

CAUTION

If trouble symptoms -overheating, erratic eration, etc. -were apparent before the fuse blew, or if the replacement fuse blows, a qualified serviceman should troubleshoot the Mixer carefully to find the source of the trouble. Do not continue to replace fuses until the trouble has been corrected.

The Mixer also contains a wired-in fuse in series with

rear-panel line fuse

becomes necessary, replace only with an identical fuse.

KNOB REPLACEMENT

All front-panel control knobs are pull-off types and are interchangeable with others of the same function. When ordering replacement knobs, be sure to order the proper color-coded type for the desired control.

SERVICE ACCESS

To open the Mixer for servicing, remove the eight Phillips head screws securing the top cover and remove the top cover. Rear-panel-mounted parts and the preamplifier assembly may be reached by removing the eight Phillips head screws securing the rear panel, and carefully moving

the rear panel assembly out and downward. Front-panelmounted parts may be reached by removing the two screws at the top of the cover channels and the four screws at the bottom of the chassis, and carefully moving the front panel assembly out and downward.

LAMP REPLACEMENT

To replace either of the two luminating the VU Meter (MI), carefully raise the metal cli~ assemblv holdina the of; the power suppry printed circuit board biacket. Lift the lamp socket upward, taking care not to crimp or break any associated wiring. Replace the defective lamp and carefully return the lamp assembly to its original position.

To replace either of the two light-emitting diodes (DI,D2) mounted on the front panel, remove the outer

insulating tubing and mounting ring from the rear of the LED. Press against the front-panel portion of the LED envelope to force it out the back through the mounting clip.

F1 (F2, 3/10A, Slo-Blo). If replacement

#47

lamps (PLl,PL2)

lam^

to be re~laced uoward and

op-

il-

(LED'S)

Page 19

Unsolder both LED gray leads from the Power Supply assembly. Remove the Power Supply assembly and (see

Meter Removal, Page 16). Unsolder the LED orange lead from the LIMITER OUT-IN Switch THRESHOLD ADJ Control be replaced). Insert the replacement LED in the front panel and place the mounting ring and insulating tubing over the leads. Solder the orange lead in place, loosely coiling the two LED orange leads together. Replace the VU Meter and Power Supply assembly. Loosely coil the

two LED gray leads together and re-solder them to the

Power Supply ground terminal.

The above is the recommended procedure for LED re-

placement. In an emergency, the LED wires may be spliced

and insulated (with tape or tubing) without removing the VU Meter or Power Supply.

BOARD REMOVAL

The various printed circuit boards are mounted in different manners. The following paragraphs describe the best method of removing these boards after wires and cable assemblies have been removed. IMPORTANT: When disconnecting push-on terminals or soldered board connections, make sure each wire is identified for proper reconnection. This may be done by affixing a piece of masking tape marked with the connection or terminal letter to each wire.

Wire colors are given in the following table.

Similar wire colors are used in different circuits; make sure proper re-connections can be made. Take care not to bend or break the push-on terminals. Remove or replace terminals by grasping the terminal itself; do not pull on the associated

wire.

Letter Wire Color Letter

Brown G/Ch. 6 Orange

Yellow Green

Red

Black Brown White/Red

Orange

White Gray Blue Green Yellow Orange

White/Red Brown Black

A B C,D/Ch. 1 C,D/Ch. 2 C,D/Ch.

B C D E F

(R10) (depending on which is to

CAUTION

Preamplifier Board

G/Ch.

Equalizer Boards

C,D/Ch. 4

C,D/Ch. C,D/Ch. 6 C,D/Ch. C,D/Ch. 8

Main Board

S T V

Meter

(S12) or

Wire Color

White Black

Yellow Green

Blue Gray White

Blue White/Purple Gray White/Green Yellow/Red Yellow Purple Orange

Green

Main Board (Cont'd.)

Black White/Red

A A Black AG Red AB White

G Black (7)

NOTE:

Refer to Figure 16, Page 16, for the location of each board. The function of each board assembly is defined in the table below.

Board No. Component Numbering

When removing front-panel control retaining nuts with a

Y2"

nutdriver or wrench, be careful not to damage the

black plastic surface.

Remove boards from nylon fasteners by squeezing the upper protruding tab on the circuit board side inward and sliding the board outward and off the fastener. The fasteners may be removed from the support bracket by squeezing both tabs securing the fastener to the bracket and pushing the fastener through the bracket hole. NOTE: When replacing nylon fasteners, be sure the protruding

tab on the circuit board side is oriented towards the top of the chassis. Failure to do so will make future board

removal difficult.

Preamplifier (Board 1): Remove the board from the

seven nylon fasteners (see procedure above) securing the

board to the vertical bracket, disconnect the eight

coded channel output leads, and lift the board up for service access.

Channel Equalizer (Board 2):

boards may be removed by removing the two front-panel

equalizer control knobs and retaining nuts associated with

that channel. The Channel Equalizer Boards are identical and may be interchanged without modification.

Main Board (Board nylon fasteners (see procedure above) securing the board to the vertical bracket, remove the 41 push-on leads, and lift the board upward.

Power Supply (Board 9): Remove the four screws securing the board and lift straight up.

White Red White/Green AF

Power Supply Board

Red (5) Green Black

Yellow Gray

Program Mute Board

Green/White E

Red

Production variations may result in wire colors differing from those in the table.

Preamplifier Board 100's Equalizer Boards (8) 200's Main Board 300's Power Supply Board 900's Program Mute Board 90's

3):

1:;

Each of these eight

Remove the board from the six

Green

Brown Black

Black

Yellow

White Green

color-

Page 20

FIGURE 16. PRINTED CIRCUIT BOARD AND PARTS LOCATION

Program Mute (Board 0): Remove the board from the four nylon fasteners securing the board to the vertical bracket and lift upward.

LIMITER INTERNAL ADJUSTMENT

To adjust the limiter function following replacement of

circuit components, set the MASTER Volume Control

(R9) to full clockwise. With the LIMITER Switch (S12) in the OUT position, turn on the TONE

OSCillator (Rl) (with all other microphone inputs full counterclockwise) and adjust channel 1 Volume Control to produce a VU Meter

(MI)

reading of 0 VU with the VU RANGE Switch (S13) set to

+4. This provides Output Connector adjust the THRESHOLD ADJ Control output by 1 dB on the VU Meter (to

internal LED potentiometer

+4 dBm (f1.8 dBV) at the LlNE LEVEL (Jl). Set the LIMITER Switch to IN and

(R10) to reduce the

+0.8 dBV). Adjust the

(R379) so that the LIMITER In-

dicator Lamp (Dl) just begins to light.

OVERLOAD INDICATOR CHECK

Set up as for Limiter Internal Adjustment and set the

LIMITER Switch

PHONES Jack, listen to the tone with a 600-ohm

(S12) to OUT. Connect headphones to the

LlNE OUTPUT load, and increase the channel 1 volume. The OVERLOAD Lamp

(D2) should light 2 dB before distortion can

be heard on the headphones.

VU METER REMOVAL

If the VU Meter (MI) requires replacement, remove it as follows. Remove the top cover. Remove the two screws at the top of the cover channels and the four screws at the bottom of the chassis, and move the front panel out and downward. Remove the hex nuts, wire leads and washers

from both meter terminals. Loosen the 1-inch screws in the meter retaining brackets at either side of the meter

until the brackets slip off the screws in the sides of the meter. Carefully pass the meter assembly out through the

front panel. To replace the meter, reverse the above steps, taking care to engage the slots in the meter retaining brackets with the screws in the sides of the meter. Tighten the 1-inch screws as necessary to retain the meter against the front panel. Reattach the meter leads, and close and secure the front panel. Replace the top cover.

CAUTION

Do not overtighten screws so as to deform meter retaining brackets.

METER CALIBRATION

With the Mixer turned off, the front-panel VU Meter (MI) should read 0 on the lower of the two meter scales. If it does not, adjust the screw below the meter face to obtain the correct reading.

To calibrate the meter, set the VU RANGE Switch

(S13)

Page 21

to +4 and connect a 600-ohm load and an ac voltmeter across the Mixer and adjust the TONE OSC Control MASTER Volume Control (1.228V across 600 ohms) is obtained on the voltmeter.

Adjust potentiometer R355 (VU Calibrate) on the Main

Board until the VU Meter reads

scales.

Note that the VU Calibrate potentiometer range allows the VU Meter to be adjusted to 0 dBm and +8 dBm.

PARTS REMOVAL

Access to certain parts in the Mixer is not always apparent due to the large number of parts and assemblies, and the requirements for their placement. The following

information is given to help locate and gain access to these

parts (see Figure 16, Page 16).

Parts mounted on the rear panel may be replaced by removing the eight screws securing the rear panel to the chassis and moving the rear panel out and downward.

Parts mounted on the front panel may be replaced by

removing the two screws at the top of the cover channels and the four screws at the bottom of the chassis, and moving the front panel out and downward.

To remove transformers the bottom of the chassis holding the three-board bracket assembly to the chassis. Carefully lift the entire assembly upward, and remove the nut and washer securing the desired transformer.

Front panel controls located below the VU Meter (LIMITER Switch S12, THRESHOLD ADJ Control R10, MASTER Volume Control R9, PHONES Level Control R14

and PHONES Jack J15) may be reached by lowering the front panel as described above.

Headphones transformer

removing the Power Supply board and bracket as de-

scribed under Board Removal.

To gain access to channel Volume Control potentiom-

eters

TRANSISTOR AND DIODE REMOVAL

Most transistors and all diodes used in the Mixer are

mechanically supported by their leads. When replacing

these devices, proper lead configurations must be fol-

lowed. Minimum soldering heat (preferably with a low-

wattage soldering iron) should be used to avoid damage

to the device. Be sure to place heat-shrinkable tubing or

"spaghetti" on leads where the original device contained

such tubing. Transistor lead codes are included in the Notes to Circuit Diagram (Figure 23, Page 29). IMPORTANT: Be sure to replace ferrite bead rings on those transistor leads where they were removed.

LINE LEVEL OUTPUT (J12-J14). Turn on the

(Rl) and the

(R9) until a reading of +4 dBm

0 on the upper of the two

0 for any output between

TI-T8, remove the five screws at

(MI)

TI0 may be reached by first

R1-R8, lower the front panel.

ohmmeter "plus" probe on the anode end of a diode, and the "minus" probe on the cathode end, the ohmmeter should read approximately 2000 ohms or less. With the meter probes reversed, a reading of about 10,000 ohms or

more should be obtained. If either of these conditions is not

met, the diode should be replaced.

To check transistors, the ohmmeter should be set to the 100- or 1,000-ohm scale. Transistors and diodes must be removed from the circuit before testing. conditions in the following table are met, the transistor may be considered free of any major defect; if any of the following conditions are not met, the transistor should be replaced. See Notes to Circuit Diagram, Figure 23, Page 29, for transistor lead codes.

OHMMETER CONNECTIONS

"Plus" Lead "Minus" Lead Collector Emitter

Emitter Collector Collector Base Emitter Base Base Collector Base Emitter

*Not a significant measurement.

To check LEDs (OVERLOAD or LIMITER), disconnect

the orange LED lead and connect a

resistor between the +30 Vdc supply and the orange LED lead (gray lead is still grounded). The LED should light

with power applied. Replace any LED that does not light.

NOTE: Do not check LEDs with an ohmmeter; the ohmmeter may damage the LED or give erroneous readings.

To check the

impedance ohmmeter (VOM or VTVM), a 1 V2V battery and a 100-ohm resistor. Disconnect the leads to as follows.

1. Connect the ohmmeter across the light-dependent resistor side of greater than 10 megohms.

With ohmmeter connected as above, connect battery and resistor as shown in Figure 17, Page 17. (IMPORTANT: Connect only as shown to avoid damage

to the LED.) The resistance reading should drop to less than are not met.

opto-isolator (UI) on Board 3, obtain a high-

U1. Resistance reading should be

1000 ohms. Replace

I00

OHMMETER READING

NPN PNP Transistor Transistor

High High High High High Low

Low Low High Low

I-,

1.5-, or 2.2-kilohm

U1 and check

if these conditions

If all

ACTIVE COMPONENT CHECKING

Defective transistors and diodes may be located by use of a standard ohmmeter such as a of the ohmmeter must be verified before these checks are

made.

With a known diode orientation, measure the diode re-

sistance in the forward and reverse directions. The lowest

meter reading will establish the probe at the cathode end (schematic symbol arrow points to cathode) as the "minus" probe while the other probe will be "plus." Some ohmmeters "volts plus probe" and "volts minus probe." With the

Ere not polarized in this manner with relation to

Simpson 260. Polarity

1.5V

FIGURE

CATHODE END

(CODED DOT)

17.

OPTO-ISOLATOR TEST

Page 22

SERVICE ILLUSTRATIONS

Immediately following the parts list on the pages that fol-

low are parts location drawings (Figures

24-27),

25,

and an overall Circuit Diagram (Figures

Pages

and

32-33).

Once a board has been located

through the parts location photo (Figure

16,

22,

Page

Pages

16),

and

the components on that board may be located from the corresponding parts location drawing. Foil circuit paths are shown as shaded areas on the drawings. The overall Circuit Diagram (Figures

and

25,

Pages

and

32-33)

shows all board circuits and chassis-mounted parts.

OPTIONAL ACCESSORIES

The following optional companion unit and accessory

are designed for use with the Shure

SR109

Professional

Mixer:

SRI 10

Professional Monitor Mixer

A1 05A

Carrying Case

SR109

The

and an

mount in a single

SR110

A105A

Monitor Mixer will conveniently

case.

Page 23

NOTE:

SR109

Professional

Mixer

REPLACEMENT PARTS LIST

The commercial alternates shown in the following lists are not necessarily equivalent parts, but are electrically and mechanically similar, and may be used if direct factory replacements are not immediately available.

maintain highest possible performance and reliability, Shure Factory Replacement Parts should be used. insure low noise figure, order transistors from Shure Brothers Inc.

Reference

Designation

CHASSIS-MOUNTED PARTS AND ASSEMBLIES

Bd.

Bd. 2

Bd. 3

Bd. 9

Bd. 0

~e;i;gmfnt

~ty.

Replacement Kit Consists Of:

part

NO.

Printed Circuit-Assembly,

Preamplifier Printed Circuit Assembly, Channel

Equalizer, with HI and LO controls

Printed Circuit Assembly,

Main Board Printed Circuit Assembly,

Power Supply

Printed Circuit Assembly,

Program Mute

Capacitor, Dual

Electrolytic, 1000 Diode Assembly, Light-Emitting Fuse, Ac,

Slo-Blo (SR109)

0.1A for 220V operation,

0.2A for 115V operation, Fuse, Ac, Slo-Blo, 250V

Fuse, Ac, Pigtail, 3/10A, Slo-Blo

Description

pF, 70V

3AG-3/16A, 125V,

(SR109-2E)

None

Monsanto Littelfuse 313.187

Bussman MDL3116

Littelfuse 21 300 Series

Littelfuse 31 5.300

MV5023

Parts listed as RKC

RKC

quantities.

Connector, Female, 3-pin Audio,

MICROPHONE LEVEL Connector, Phone Jack, 2-Conductor

Single Closed Circuit, INPUT

Connector, Phone Jack, Conductor, Open Circuit, LlNK OUTPUT

Connector, Male, 3-Pin Audio, MIC LEVEL and

Connector, Phone Jack, Open Circuit, LlNE LEVEL Output

Connector, Phone Jack,

3-Conductor, Open Circuit,

PHONES

ts should be ordered by that kit number. Any orders received for piece parts where

95A655

958552

Connector, Female, 11-pin, MONITOR OUTPUT

Connector, Female, SWITCHED AC, 500 WATTS MAX.

LlNE LEVEL Output

(SR109 only)

Switchcraft D3F

Input

Switchcraft 12A

LlNK

3-Conducto~

RKC

Kit number is shown will be shipped

Switchcraft 11

Switchcraft D3M

Switchcraft

Switchcraft 1128

Amphenol 126-805

None

128

Page 24

REPLACEMENT PARTS LIST FOR SR109 PROFESSIONAL MIXER

Reference

Designation

J18

L2-L4

MP1

MP2

MP3

MP4

MP5 MP6 PL1 -PL2 Q1 R1

R2-R8

R10

R14

S1-S10

S11 S12 S13 S14 S15

S16

T1 -T8

"eg~mfnt

RKC7 RKC55

Qty.

4 1

Replacement Kit Consists

Part

No.

95A689

80A250

95A615

90D2085

90C2085

9082119

90A1786

39A384 39A345

95A466 86A338

46A051

46A052

46A050

46A074

46A048

46A049

55A119

55A120 55B62 55C119

55A116

90J2150

51A235

Connector, Spin, AC (MAINS) POWER

Ferrite Bead Ring

Meter Assembly, VU

Knob Assembly, Orange,

HI FREQ EQ Knob Assembly, Red,

LO FREQ EQ Knob Assembly, Grey,

PHONES

Knob Assembly, Black, Individual Channel and MASTER Volume

Nameplate, Write-on Nameplate, Shure Lamp, Indicator, Transistor, Silicon, NPN

Potentiometer, Modified Log, Tandem, Switch, Channel 1 Volume

Potentiometer, Tandem, Channels 2-8 Volume

Potentiometer, Tandem,

with On-Off Switch,

MASTER Volume Potentiometer, Tandem, 50k,

with On-Off Switch, MASTER Volume

Potentiometer, Screwdriver Adjust, 50k, THRESHOLD ADJ

Potentiometer, Linear, 2k, PHONES

Switch, Slide, DPDT, 15 dB ATTENUATOR and

Part of R1 Switch, Slide, TPDT, LIMITER Switch, Slide, DPTT, VU RANGE Switch, Slide, DPDT, PHASE Part of Switch, Slide, DPDT, VOLTAGE

SELECTOR Transformer and Shield Assembly,

Mic Input

Transformer, Line Level

Output

Of:

Description

(SR109-2E only)

6.3V

50k, with TONE OSC

(SR109)

(SR109-2E)

MIC/LINE

(SR109-2E only)

50k,

Commercial

Alternate

None

Stackpole 57-0181 Ferronics 21-031

API Instruments 361 -2, A-Scale

None

GE 47

2N3441

RCA

None

None None None

None

;

Parts listed as RKC

in RKC quantities.

Kits should be ordered

by that kit

number. Any orders

received for piece parts where RKC Kit number

is shown will be shipped

Page 25

Reference

Designation

PREAMPLIFIER (BOARD

C130, C140, C150, C160, C170, C180, C190, C191

Replacement

Kit No.

Qty.

Replacement Kit Consists

Part No.

51 D228

51A262 51A265 95A632

90A1888

95A429

95A604

95A657

50KB104 I Capacitor, Film, 0.1

868629 Capacitor, Electrolytic,

Transformer, Headphone Output

Transformer, Ac Power (SR109) Transformer, Ac Power (SR109-2E) Line Cord, Ac, Grounded,

2.7m (9 ft) (SR109) Line Cord, Ac, Grounded, %Foot,

Single Connector (SR109-2E) Fuseholder, Miniature,

Panel-Mounting Fuseholder, Miniature, Panel-

Mounting (SR109-2E) Lampholder and Bracket

Assembly

22pF, 35V

Capacitor, Electrolytic,

4.7 or 5

pF, 35V

Description

(SR109)

Of:

NF,

Commercial

Alternate

None

None None Belden 17408

None

Littelfuse 342014

None

Sprague CDE DMF-1 PI-10

Sprague 502D226G050CE10;

Mallory MTV-25CB35

Sprague 30D-TE1303; CDE NLW-5-50

225P10491;

Capacitor, Electrolytic,

p.F, 35V

Capacitor, Electrolytic,

250

pF,

40V

Silicon Rectifier,

Ferrite Bead Ring

Transistor, Silicon, Low Power, NPN

Transistor, Silicon, Low Power, PNP

Transistor, Silicon, NPN

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.

100V,

Y2A

Sprague CDE NLW-50-50

None

Motorola Stackpole 57-01 80;

Ferronics 21

Motorola 2N5210

Motorola or Fairchild

Motorola 2N5088; TI 2N3711

30D-TE1307;

N4002

-0305

2N5087

Page 26

REPLACEMENT PARTS LIST FOR SR109 PROFESSIONAL MIXER

Reference

Designation

Replacement

Kit No.

~ty. I part

Replacement Kit Consists

NO.

Of:

Description

EQUALIZER (BOARD

C200, C201, C205. C208

Q200, (2201, (2202 TI 2N3711

R204, R208

MAIN BOARD (BOARD

RKC9

86A630 Capacitor, Electrolytic,

1-1

(

86A349

46A034

4.7 or 5 ,F, 35V

Transistor, Silicon, NPN Motorola 2N5088;

Potentiometer, 50k, HI

and LO FREQ EQ

Capacitor, Electrolytic, 22,F, 35V

Capacitor, Electrolytic,

F, 35V

Capacitor, Electrolytic,

250

,F, 40V

Capacitor, Electrolytic, 1

,F, 25V

Capacitor, Electrolytic,

.1 ,F, 1oov

Capacitor, Electrolytic,

,F, 25V

Capacitor, Electrolytic, 100

,F, 25V

Capacitor, Electrolytic,

,F,

16V

Silicon Rectifier,

50V, 112A

Sprague 30D-TE1303; CDE NLW-5-50

None

spGgue CDE NLW-5-50

Sprague 226G050CE10; Mallory MTV-25CD35

Sprague 30D-TE1307;

CDE N LW-50-50 None

Sprague CDE NLW-1-25

Sprague CDE DMF-lP1-10

None

Sprague Mallory MTA-100F35; CDE NLW-100-25

Sprague 476G016;

Mallory MTV-35CB25 Motorola 1 N4001

Commercial

Alternate

GD-TEI~O~;

502D-

30D-TE1200;

225P10491;

30D-TE1211;

503D-

Diode, Silicon, Computer, 75v

Silicon Zener Diode,

Ferrite Bead Ring

Transistor, Silicon, NPN

Transistor, Silicon, PNP

Parts listed as RKC Kits should be ordered by that kit number. Any orders received for piece parts where in

RKC

quantities.

22V, 5%

Motorola 1 N4748A

Stackpole 57-0180; Ferronics 21-031

Motorola 2N5210

RKC

Kit number is shown will be shipped

Page 27

REPLACEMENT PARTS LIST FOR SR109 PROFESSIONAL MIXER

Reference

Designation

POWER

SUPPLY

Replacemtent

Kit No.

Qty.

RKC65 86A334 Transistor, Silicon, NPN

111

86A348 Transistor, Silicon, Low

1-1

RKC9

RKC12

1-1

86A329 Transistor, Silicon,

86A349

86A336

46D033 Potentiometer, look,

1-1

(BOARD

1 - 1

86A901

Replacement Kit Consists

Part No.

Power, PNP

N-Channel, Field Effect

Transistor, Silicon, NPN

Potentiometer, 10k, VU Cal

LIMITER Lamp Cal

Optical Isolator, LED Photoconductor

Capacitor, Electrolytic, 250

p.F,

60V

Of:

Description

Motorola or Fairchild

Motorola 2N5458

Motorola TI 2N3711

None

Commercial

Alternate

2N5087

2N5088;

PROGRAM

Parts listed as RKC Kits should be ordered by that kit number. Any orc in RKC quantities.

MUTE

(BOARD

I I

Capacitor, Electrolytic, 250

F, 40V

Capacitor, Film,

IOOV Silicon Rectifier, IOOV, 1 /2A

Silicon Zener Diode, 32V, 5%

Transistor, Silicon,

Power, NPN Resistor, Fixed, 2.0 ohms,

Capacitor, Film, 1 OOV

Capacitor, Electrolytic, 1000

p.F,

25V

Silicon Rectifier, Transistor, Silicon, NPN

Transistor, Silicon, NPN Relay, Reed, SPST,

24 Vdc

!rs received for piece parts where RKC Kit number is shown will be shipped

pF,

100V, 1/2A

CDE BR250-50

Sprague CDE DMF-I PI-10

Motorola 1 N4002 Motorola 1 N4752B RCA 40347

None

Sprague 225P10491; CDE DMF-1P1-I0

Sprague TVA-1211

Motorola 1 N4002

Motorola

TI 2N3711

TI TIS97

None

225P10491;

2N5088;

Page 28

Page 29

FIGURE

19.

BOARD

CHANNEL

EQUALIZER 2247-2/2246-3/587-4

Page 30

Page 31

FIGURE

21.

BOARD

POWER SUPPLY

2210-9/2251-3/591-4

FIGURE 22. BOARD

PROGRAM MUTE

2254415923

Page 32

Page 33

SR109

Professional Mixer

NOTES

GENERAL

Shure part numbers are not shown in the Parts List accompanying the Circuit Diagram (Figures 24 and 25, Pages 30 and 32-33) if parts are readily available through local electronics parts suppliers. In these instances, the Circuit Diagram shows only the reference designation and value of the standard parts.

All capacitor values are shown in microfarads unless

otherwise designated. All

100 working volts dc or more unless otherwise specified. Electrolytic capacitors are shown in microfarads x volts.

All resistor values are shown in ohms (k = 1000). Re-

sistors are 10% tolerance unless otherwise specified.

Resistors are

Transistor lead codes are shown in Figure 23. Accept-

able replacements are as shown in the Parts List.

The following ground symbols denote:

ChassisGround Circuit Ground Printed Circuit Board Ground

TROUBLESHOOTING

general troubleshooting process is as follows: If the

Mixer is completely "dead," check the ac power source,

%-watt unless otherwise specified.

non-electrolytic capacitors are

/$7

CIRCUIT DIAGRAM

fuses, and power supply output (30V between pins

G, Board 9). If the indicator lamps are on but the output is distorted, low or not present, apply an input signal as

described under

termine that the input and output voltage to each board assembly is correct. If an incorrect ac voltage is found at any board output, perform board as described below to isolate the problem area.

V~~~AGE

~h, numbers

circuit

the following test conditions:

diagram

1. Voltages measured with respect to chassis unless otherwise indicated.

2. Line voltage:

3. Test signal of 1 mV, 1 kHz applied between pins and 3 of connector J1.

Ac voltage measurements may vary 220% from values shown.

Measurements made with ac VTVM of 1 megohm or greater input impedance.

600-ohm load across LINE LEVEL Output Con-

nector J12 (pins 2 and 3).

Voltage Measurements below, and de-

Voltage Measurements on that

M~~~~REMENTS

denote

rectangular symbols

the

voltages

120V, 50/60 Hz (SR109)

120V or 240V, 50/60 Hz (SR109-2E)

that

point

and

de-

under

the

~Gii-GGq

.qJ

.aBa:a

Q90, Q112. 0122. 9132, Q142. Q152, 991, 0314 0110, 0120, Q302, Q3II, Q900 Q162,Q172, (2182, Q200-'2202, Q130, Q140. Q315.

0307,Q308,Q313, 9317, Q320. Q150, Ql60,

QIII, 0131, Q121. Q141, 0151, Q161, Q316, 0318,

0171, 9181. 9 319. Q32l.

0305.

.a;

0301, Q310, 9312, '2303,

00;

-1

GATwDRAIN

4306

SOURCE

9170, Q180, 9300,

0309.

.a:

a304

OPT0 - ISOLATOR

'(333

CATHODE

ANODE

do?!!)

ANODE

CATHODE

FIGURE

23.

LEAD CODES

Page 34

7. All Equalization Controls in 0 (flat) setting.

All Volume Controls set to maximum (12).

9. Tone oscillator circuit measurements on Main Board (Bd.

made with TONE OSC Switch on

(out). LIMITER Switch in IN position.

10.

4..

Dc voltage measurements may vary &20% from values shown.

5. Measurements made with VTVM of 11 megohms or greater input impedance.

6. Tone oscillator circuit measurements on Main Board

(Bd.

made with TONE OSC Switch on.

DC VOLTAGE MEASUREMENTS

The numbers within elliptical symbols

on the

circuit diagram denote the dc voltages at that point under

the following conditions:

1. Voltages measured with respect to chassis unless otherwise indicated.

Line voltage:

120V, 50/60

(SR109)

120V or 240V, 50/60 Hz (SR109-2E)

No input signal applied.

RESISTANCE MEASUREMENTS

With the ac line cord disconnected from the ac source and the POWER OFF Switch in the OFF position, the following ohmmeter measurements may be made:

1. Transformers may be checked for continuity of each winding.

2. To test transistors and diodes, see Page 17.

To check LEDs, see Page 17.

4. To check opto-isolator, see Page 17.

FIGURE 24. SR109-2E POWER SUPPLY CIRCUIT DIAGRAM

81227-11-1

Page 35

FIGURE

25.

SR109 PROFESSIONAL MIXER CIRCUIT DIAGRAM

Page 36

MAIN

BOARD

FIGURE 25. SR109 PROFESSIONAL MIXER CIRCUIT DIAGRAM

Page 37

SR109

Professional Mixer

CONDENSED OPERATING INSTRUCTIONS

1. Set all switches and controls to OFF or 0.

2. Connect PROGRAM OUTPUT (LINE or MICROPHONE LEVEL) to power amplifier, broadcast line

feed, etc. Connect speakers to power amplifier.

Connect headphones to PHONES Jack.

3. Connect sources (microphones, tape recorders, etc.) to INPUT Connectors. Set Channel 7 or 8 MIC/LINE Switches as necessary.

4. Connect external signal-processing equipment (compressor, equalizer, etc.) to LlNK Jacks. (To connect two Mixers, connect LlNK OUT Jacks together.) Connect ac line to ac source.

Turn on POWER Switch and allow one to two min-

warmup time.

utes

ARCHITECTS' AND ENGINEERS' SPECIFICATIONS

The Mixer shall be a self-contained 90- to 132-volt, 50 to 60 Hz, line-operated, all-silicon transistor mixing amplifier with preamplifiers and controls to mix eight independent low-impedance microphone input signals.

Each input channel in the Mixer shall have independent HIGH-FREQUENCY and LOW-FREQUENCY controls, position zero to 15 dB ATTENUATOR Switch and rotarymotion level control. The 7th and 8th input channels shall

each have an additional input switch to select the de-

sired input level (MIC or LINE).

The PROGRAM OUTPUT circuit shall have a 600-ohm balanced line level output rated at 1% distortion with a minimum clipping level of

and a low-impedance, balanced, microphone-level output at a level 50 dB below the LlNE LEVEL output. A PHASE switch shall be provided to reverse the phase of both the

LlNE and MICROPHONE LEVEL outputs.

The program channel shall have a rotary motion MAS-

TER LEVEL control, and a 76.2 mm (3 in.) illuminated

+4,

VU meter with a 0, Switch.

A pair of LlNK Jacks shall be provided in the program

circuit to allow connection to external equipment such as a compressor, limiter, equalizer, additional mixer or console, etc.

The Mixer shall have a PHONES level control and a

transformer-coupled headphone (PHONES) output.

The Mixer shall have a voltage gain of 87 maximum microphone input sensitivity of 0.1 millivolts for

+4 dBm program output.

The microphone input clipping level, with a zero

ator setting, shall be 4.5 millivolts minimum with the level

control at maximum and shall increase to 100 millivolts minimum with the level control near minimum.

All specifications apply to

180-250

volts; no switched

+8 dBm VU METER RANGE

SR109-2E

receptacle is provided.

+I2 dBm at less than

%3 dB and a

except: operating voltage is

two-

+I9 dBm

attenu-

90-132

7. Set 15 dB ATTENUATOR Switches to preliminary position for type of material to be used

speech or instrumental music, -15 for "hard" rock music).

8. Set VU METER RANGE Switch for present applica-

9. Set MASTER Volume Control to 6. With source in-

10. Adjust HI and LO

11. Turn on LIMITER and adjust-THRESHOLD ADJ

0 for PA, +4 for recording, or

tion:

cast. put, raise Channel Volume Control for desired

sound level. Readjust ATTENUATOR Switch if

necessary.

trols as necessary. Control if desired.

FREQuency EQualization Con-

for broad-

The Mixer shall contain a peak-responding adjustable output limiter with an in-out switch and an indicator lamp that flashes when the limiter threshold is exceeded. An overload lamp, which operates only when the limiter

is not activated, shall indicate when the output clipping level of the Mixer is exceeded.

An 11-pin accessory monitor output connector shall

provide for connection to one or more Shure fessional Monitor Mixers to provide separate monitor mixes for stage monitoring (foldback), multi-channel tape recording, or stereo broadcasting.

The Mixer shall be enclosed in a metal housing designed for rack-mounting in a standard 19-inch (483 mm) audio equipment rack, or mounting in an accessory vinyl-covered wood portable case.

The Mixer dimensions shall .be 133

height, 483

depth. The weight shall be not more than 7.7 kg (17 Ib).

The Mixer shall have a built-in tone oscillator and a level control built into the channel 1 program circuit. A POWER on/off switch shall also be located on the front panel. A switched ac receptacle rated for 500 watts maximum load shall be provided.

The MICROPHONE INPUT connectors shall be female professional audio type. The LlNK Jacks, and tho PROGRAM LlNE LEVEL OUTPUT Jacks shall be %-inch phone jacks. One PROGRAM LlNE LEVEL OUTPUT connector and the MIC LEVEL OUTPUT connector shall be three-pin male professional audio type. The headphone

(PHONES) connector shall be a three-circuit

jack to be used with either mono or stereo phones with an

impedance of 4 ohms or higher.

Any Mixer not meeting all of the above specifications shall be deemed unacceptable under this specification. The Mixer shall be a Shure Model

mm (19 in.) in width, and 232 mm (9% in.) in

SR109.

SR110 Pro-

mm (5Y4 in.) in

%-inch phone

(0 for

three- in

GUARANTEE

This Shure product is guaranteed in normal use to be free from electrical and mechanical defects for a period of one year from date of purchase. Please retain proof of purchase date. This guarantee includes all parts and labor. This guarantee is in lieu of any and all other guarantees or warranties, express or implied, and there shall be no recovery for any consequential or incidental damages.

SHIPPING INSTRUCTIONS

Carefully repack the unit and return it prepaid to:

Shure Brothers Incorporated

Attention: Service Department

1501 West Shure Drive

Arlington Heights, Illinois 60004

If outside the United States, return the unit to your dealer

or Authorized Shure Service Center for repair. The unit

will be returned to you prepaid.