Shure Sr101 series Operation manual

SRlOl

Series

Audio Console

OPERATION AND SERVICE MANUAL

Manufactured

SHURE BROTHERS INC.

222

Hartrey Avenue

Evanston, Illinois

60204

U.S.A.

27A1171

(SD)

(95E652) Printed

U.S.A.

SR101 Series

Audio Console

SPECIFICATIONS

Equipment Type

Number of

lnput Channels

Power Output

. . .

Voltage Gain*

Program

. . . .

. .. ..

All silicon transistor mixerlpre- Hum and Noise

amplifier (20Hz-20 kHz)

.....

+19

dBm (program line level)

.73 k3dB MIC input to LlNE

LEVELout

. . . ..

125 dBV (equivalent input hum

and noise at full gain)

68 dBm output noise (MASTER

Volume Control down)

50 dBm output noise (one

channel Volume Control and

MASTER Volume Control up)

50 k3dB AUX input to LlNE

LEVELout Signal to Noise Ratio

23 t3d~

MIC

input

MIC

LEVEL

(20 Hz-20 kHz)

. .

.Typically 81 dB at maximum out-

out put with one channel Volume

Control and MASTER Volume

Monitor

. .

.78 13dB MIC input via PRO- Control at 10 (approximately

GRAM MONITOR to LlNE 60 dB gain)

LEVEL out

65 k3dB MIC input via PRO- lnput Attenuation

. . . .

GRAM MONITOR to PHONES

out Input Clipping Level

87 23dBMIC input via one chan-

kHz:

nel MONITOR to LINE LEVEL MIC Input

. .

out

Link

. . .

. .

.38 _t3 dB MIC input to LlNK OUT

(with 600-ohm termination)

dB LlNK INto LlNE LEVEL

out

Accessory

. .

...

.48 t2dB MIC input to ACCES-

SORY output (via pins 1-8lIN-

PUTS) AUX Input

. . . .

. .

43 i.3 dB MIC inputs to ACCES-

SORY output (via pin 91PRO-

GRAM)

Frequency Response

. .

13dB, 20 Hz-20 kHz (150-ohm

source; 600-ohm load)

lnput Sensitivity

. .

...

0.4 mV max.for

4 dBm program

output

Distortion

. . .... .

Noise

THD less than

at +12 dBm, Input Common

30 Hz -20 kHz; IM distortion

Mode

Rejection

less than 1% at t12dBm

.O-30 dB (10 dB steps)

,315 mV (INPUT ATTEN at 0; Ch.

Volume at 2)

17.5 mV (INPUT ATTEN at 0; Ch.

Volume at 14)

10V (INPUT ATTEN at -30; Ch.

Volume at 2)

0.56V (INPUTATTEN at -30; Ch.

Volume at 14)

.3.15V (INPUT ATTEN at 0; Ch.

Volume at 2)

0.18V (INPUT ATTEN at 0; Ch.

Volume at 14)

IOOV (INPUT ATTEN at -30; Ch.

Volume at 2)

5.6V (INPUT ATTEN at -30; Ch.

Volume at 14)

(300 Hz-20 kHz)

. .

128dBV(equiva1ent input noise LOW-~requency

at full gain) Equalization

78 dBm output noise (MASTER

Volume Control down)

53 dBm output noise (one High-Frequency

channel Volume Control and Equalization

. . .

MASTER Volume Control up)

100 dB min. at 100 Hz (balanced

inputs)

-;I3 dB at 100 Hz with respect to

0 (flat) setting

k12dB at 10 kHz with respect to

0 (flat) setting

'Measurement conditions: MIC input through

150

ohms, AUX input through

kilohms LlNK IN through

600

ohms PROGRAM LlNE LEVEL and MONITOR

LlNE

LEVEL

terminated In

600

O~~~.'PROGRAMMIC LEVEL terminated in

150

ohms. MONITOR PHONES terminated in

ohms: MASTER Volume. Channel

~olur;leand MONITOR Controls full up; all other controls and switches

or off.

SR101 Series

Audio Console

SPECIFICATIONS

...

Feedback Filter VU Meter Calibration $4 dBm (1.23 Vrms) at 1 kHz to

.......

Frequencies .I30Hz; 800 Hz; 2 kHz; 5 kHz 600-ohm load (METER SENSI-

Tone Oscillator

........

1 kHz; less than 1% distortion;

variable level

lnput Impedance

at1 kHz:

Microphone

.....

.1.2 kilohms balanced (for use

with 25- to 600-ohm' micro-

Auxiliary

(Channels

phones)

........

and 8). .I70 kilohms unbalanced

.......

Link Input .35 kilohms unbalanced

Output Impedances:

Program

.........

Balanced line level: 120 ohms

actual (for use with 600-ohm

lines)

Microphonelevel:0.5 ohms actual

(for use with 25- to 600-ohm in-

puts)

Monitor

.........

.Unbalanced line level: 600 ohms

actual (for use with 600-ohm or

high-impedance phones, or

600-ohm lines)

Headphones: 3 ohms actual (for

use with 4- to 16-ohm head-

phones)

ACCESSORY AUX LEVEL (unbal-

anced) pins 1-811NPUTS: 33

ohms actual (for use with 3-

kilohmor greater loads); pin 91

PROGRAM: 600 ohms actual

Link Output

......

.600 ohms (actual)

Monitor System

.......

Headphone andlor 600-ohm line

output; individual and mixed

channel select or program;pre-

and post-link monitoring

Reverberation

System

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

Spring type with individual chan-

nel intensity controls and high-

and low-frequency equalization

LinkJack System

......

External signal conditioning out-

putlinput; high-level auxiliary

amplifier and tape recorder

signal output; multiple Console

connection (mix bus); remote

master volume control

TlVlTY~ontrol'in

CAL position)

[22 dB-range METER SENSI-

TIVITY Controlinfull clockwise

position provides 0 VU reading

of -18 dBm (0.1 Vrms) on 600-

ohm load]

....

Phasing (polarity). .AUX LEVEL input and LINK IN

tips and pin 3 of INPUT con-

nectors in phase with pin 9 of

ACCESSORY OUTPUT; tips of

LlNK OUT, PROGRAM LlNE

LEVEL, and MONITOR LlNE

LEVEL outputs; tip of PHONES

jack; and pin 3 of PROGRAM

LlNE and MIC LEVEL outputs.

(PHASE Switch in 0" position.)

Pins 1-8 of ACCESSORY OUT-

PUT out of phase with the

above.

.........

Phase Switch Output polarity-reversing switch

(0°, 180°) (reverses phaseof all

program outputs)

30 Vdc Bus

..........

.Pin 10 on ACCESSORY

AUX

LEVEL connector is regulated

+30 ~3.5Vdc supply; pin 11is

ground (earth). May be used to

power accessories with up to

50 mA.

Operating Voltage

....

.90-132Vac, 50160 Hz (SR101)

90-132, 180-250 Vac, 50160 Hz

(SR101-2E)

Power Consumption

...

20 watts max. (Console only). 500

watts max. (SWITCHED A.

receptacle)

Temperature Range:

Operating

..........

-7' to 54OC (20' to 130°F)

Storage

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

-29' to 71°C (-20' to 160°F)

Dimensions

..........

.311 mm

483 mm x 162 mm

(121/'"

19" W

6%''

Installation

...........

Equipped for standard 19" rack

mounting (12%" height); may

be operated in accessory

AlOlA Carrying Case or incus-

tom control center

Weight

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

.22 Ib (10 kg)

Finish

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

Matte black, with beige write-on

trim strip

Certifications

.........

Listed by Underwriters' Labora-

tories, Inc.; listed by Canadian

Standards Association as certi-

fied (SRIOI only)

iii

SR101 Series

Audio Console

TABLE OF CONTENTS

Section Page

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

SPECIFICATIONS ii

DESCRIPTION

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

OPERATING INSTRUCTIONS

Functional Identification

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

General Operating Instructions

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

Mounting and Ventilation

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

Power Supply

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

Functional Circuit Description

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

Input Channels

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

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

Source Cuing 7

Reverberation

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

Monitor System

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

Monitor Mixer System

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

Program Mix Amplifier

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

Link Jacks

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

Feedback Filters

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

Program Output

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

VU Meter Circuit

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

Tone Oscillator

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

Basic Operating Hints

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

SPECIAL OPERATING INSTRUCTIONS

High-Impedance Microphones

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

Musical Instruments

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

Tape Recording

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

Record Playback

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

Tape Playback

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

Talkback Circuit

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

Additional Mixer Inputs

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

Section Page

........

Additional Console Inputs (Two Consoles) 14

.......

Redundant Console Set-up (Two Consoles) 15

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

Stereo Operation 16

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

Remote Volume Control 17

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

Telephone Line Surge Protection 17

SERVICE INSTRUCTIONS

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

Console Service 18

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

ReplacementParts 18

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

Fuse Replacement 18

Knob Replacement

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

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

ServiceAccess 18

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

Lamp Replacement 18

Reverberation Assembly .......................18

Board Removal

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

VU Meter Removal

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

VU Meter Calibration

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

Volume Control Assembly

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

Parts Removal

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

Transistor and Diode Removal

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

Transistor and Diode Checking

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

Service Illustrations

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

Optional Accessories

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

Guarantee

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

Shipping Instructions

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

PARTS LIST

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

CONDENSED OPERATING INSTRUCTIONS

........

ARCHITECTS' AND ENGINEERS'

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

SPECIFICATIONS 47

SR101

Series

Audio Console

LlST

ILLUSTRATIONS

Figure Page

1 SR101 Audio Console Front Panel ........... 2

2 SR101 Audio Console Rear Panel

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

3 SRlO1 Audio Console Dimensional

Outline Drawing

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

4 SR101 Audio Console Block Diagram

........

5 Monitor Mixer Applications

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

6 Tone Oscillator Applications

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

7 Preamplifier-Console Connnections

.........

8 Tape Recording

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

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

9 Record Playback 13

10 Talkbackcircuit

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

11 Carbon Microphone Power Supply

..........

12 Additional Mixer Inputs

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

13 Additional Inputs: Two Consoles

..........

14 Redundant Consoles

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

15 Stereo Tape Recording

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

Figure Page

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

16 Remote Volume Control 17

.....

17 Printed Circuit Board and Parts Location 19

18 Volume Control Assembly

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

19 Board 1: Preamplifier

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

20 Board 2A: Channel Equalizer

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

21 Board 28: Reverb Equalizer

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

22 Board 3: Program Mix Amplifier

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

23 Board4: Reverb Mix Amplifier

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

24 Board 5: Program Output

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

Board 6: Feedback Filters

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

26 Board 7: Reverb Spring Amplifier

...........

27 Board 8: Monitor

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

28 Board9: Power Supply

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

29 Board0: ProgramMute

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

30 Transistor Lead Codes

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

31 SR101-2E Power Supply

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

32 Circuit Diagram

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

.44-45

SRIOI Series

Audio Console

DESCRIPTION

(Shown

AIOIA

Carrying Case

with

AlOlB

Panel Lamp)

The Shure Model SR101 series

Audio Console is a

solid-state, eight-channel microphone mixer-preamplifier

that enables the operator to mix as many as eight micro-

phones with individual control over volume, reverberation,

and high- and low-frequency equalization. The Series 2

Consoles have rear-panel provisions for connection to up

to eight Shure SR110 Professional Monitor Mixers. The

SR110 is a self-contained, eight-channel, line level 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 recording mix panel.The Con-

sole has two outputs: a program output and a monitor out-

put. Inaddition,channels

and

contain switch-selectable

input connectors for .use with auxiliary high-level sources

or high-impedance microphones. Master volume controls

regulate program and monitor outputs. Program and mon-

itor switches permit the operator to select the input signals

to be routed toeachof the two outputs.

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

level output and a low-impedance, balanced, microphone

output. The monitor has two outputs: a 600-ohm unbal-

anced output and an 8-ohm balanced headphone output.

Four switch-selectable feedback filters are included in the

program output, and a pair of link jacks facilitate connec-

tion to an additional audio console, mixer, or external

equipmentsuch as compressors, limiters or equalizers.

The Console contains a VU meter with adjustable sensi-

tivity to indicate program output level. A built-in 1 kHz

tone oscillator facilitates synchronization of all meters in

the system. An optional panel lamp accessory may be con-

nected to the front panel lamp connector for illumination

of controls. Accessory equipment drawing up to 500 watts

may be connectedto the rear-panel switchedac receptacle.

A front-panel trim strip provides space for pencilled nota-

tions.

The regulated power supply is designed to operate over

a wide range of input voltages, permitting the use of ex-

tremely long ac extension cables without performance

degradation.

The solid-state components in the SR101 Audio Con-

sole 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 Console is supplied with rack-mounting screws and

spare fuses (the SRlOI-2E comes with a detachable line

cord).

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

and is listed by the Canadian Standards Association as

certified (SRI01 only).

The following accessories are specifically designed for

usewith the SRlOl Series 2 Audio Console:

AlOlA Carrying Case

A101

Panel LampAccessory

SR110 Professional Monitor Mixer

FIGURE 1. SRlOl SERIES

AUDIO CONSOLE FRONT PANEL

(SR101

Only)

(SR101

Only)

FIGURE

SRlOl SERIES

AUDIO CONSOLE REAR PANEL

SR101

Series

Audio Console

OPERATING INSTRUCTIONS

FUNCTIONAL IDENTIFICATION (Refer to Figures 1 and

2, Page 2.)

NOTE: All push-button switches are "on" when in (de-

pressed) and "off" when out (released). Input attenuator

switches are calibrated in decibels; all other front panel

controls are numbered for reference only.

1. lndividual Channel Volume Slide Controls (Eight)

Control volume and input clipping level of each chan-

nel separately.

2. REVERB INTENSITY Rotary Controls (Eight)

Con-

trol reverb level for each channel.

3. Master REVERB Push-Button Switch -Turns on (or

off) amount of reverb preset by channel REVERB IN-

TENSITY controls.

4. REVERB FREQuency EQualizer-LOWRotary Control

Adjusts low-frequency reverb signal equalization.

5. lndividual Channel FREQuency EQualizer-LOWRotary

Controls (Eight)

Adjust low-frequency signal equal-

ization for each channel.

6. REVERB FREQuency EQualizer-Hlgh Rotary Control

Adjusts high-frequency reverb signal equalization.

7. lndividual Channel FREQuency EQualization-Hlgh Ro-

tary Control (Eight)

Adjusts high-frequency signal

equalization for each channel.

8. PHONES Output Jack

Provides for connection of

stereo or monophonic headphones for monitoring.

9. Panel LAMP Accessory Connector

Provides con-

nection for optional panel lamp accessory to illumi-

nate front panel.

10. MONITOR Level Rotary Control

Controls volume

level to PHONES Jack (8) and MONITOR OUTPUT/

LlNE LEVEL Jack (30).

11. PROGRAM MONITOR Push-Button Switch

Con-

nects total program output (all channels and reverb)

to PHONES Jack (8) and MONITOR OUTPUT/LINE

LEVEL Jack (30).

12. lndividual Channel MONITOR Push-Button Switches

(Eight)

Connect individual channel outputs (with-

out reverb) to PHONES Jack (8) and MONITOR OUT-

PUT/LINE LEVEL Jack (30) when PROGRAM MON-

ITOR Switch (11) is off.

13. lndividual Channel PROGRAM Push-Button Switches

(Eight)

Connect individual channel inputs to pro-

gram output.

14. lndividual Channel INPUT ATTENuator Rotary

Switches (Eight)

Provide choice of input signal at-

tenuation for each channel. Dual switches on chan-

nels

and 8 also select low-impedance (MIC) or high-

impedance (AUX) input connections.

15. FEEDBACK FILTERS Push-Button Switches (Four)

Provide for elimination of acoustic feedback in four

most probable audio frequency ranges.

16. TONE Oscillator LEVEL SwitchIRotary Control

Turns on and adjusts level of 1

kHz

tone generated

internally for set-up purposes.

17. True VU Meter

Indicates volume level of program

output. (Meets all current standards for VU Meters).

18. METER SENSITIVITY Rotary Control

Adjusts VU

meter sensitivity for wide ranges of program level

indication.

19.

POWER ON-OFF Toggle Switch

Applies ac power

to power supply and SWITCHED A.C. Receptacle (23).

20. MASTER Volume Slide Control

Adjusts level of total

program output.

21. Ac Grounded Line Cord

Connects ac power source

to Console power supply (SRlO1only).

22. 3AG-3/16A SLO-BLO Ac Fuse

Protects Console ac

input line against overload (SRlOl only).

23. SWITCHED A. C. Grounded Receptacle

Provides up

to 500 watts of switched ac power to accessory equip-

ment iSR101 only).

24.

PROGRAM OUTPUTSIMICrophone LEVEL 3-Pin Con-

nector

Provides low-impedance microphone-level

program output.

25. PROGRAM OUTPUTS/LINE LEVEL Phone Jacks

(Two)

Provide balanced or unbalanced output con-

nections to power amplifier.

26. PROGRAM OUTPUTS/PHASE Slide Switch

Re-

verses phase (polarity)of LlNE LEVEL and MIC LEVEL

program outputs with respect to inputs.

27. PROGRAM OUTPUTSILINE LEVEL 3-Pin Connector

Provides balanced output connection to power

amplifier.

28. LlNK IN Phone Jack- Provides input connection for

external equipment (compressor, limiter, equalizer,

etc.).

29. MONITOR OUTPUTIPOST LINK-PRE LlNK Slide

Switch

Selects program monitoring either before or

after external equipment connection to LlNK Jacks (28,

31).

30. MONITOR OUTPUTILINE LEVEL Phone Jack

Pro-

vides monitor output connection to power amplifier.

31. LlNK OUT Phone Jack

Provides output connection

for external equipment, or mix bus to add Consoles.

32. INPUTS/AUX. LEVEL Phone Jacks (Two)

Provide

for connection of high-impedance sources to channel

or 8 inputs.

33. INPUTS/MICROPHONE LEVEL 3-Pin Jacks (Eight)

Provide for balanced connection of low-impedance

sources to channels 1 through 8 inputs.

34. ACCESSORY AUX LEVEL 1I-PinConnector-Provides

output connectionto Shure SR110 Monitor Mixer.

35. AC (MAINS) POWER 3-Pin Connector-Connects ac

power cable to Console power supply (SRlOl-2Eonly).

36. VOLTAGE SELECTOR Slide Switch-Selects oper-

ating voltage range of 90 to 132 or 180 to 250 Vac,

50/60 Hz (SRIOI-2E only).

37. 180-250V 0.1

AT/90-132V 0.2AT Ac Fuse-Protects

Console ac input line against overload (SR101-2E

only).

GENERAL OPERATING INSTRUCTIONS

WARNING

Voltages inthis equipment are hazardousto life. Make

all input and output connections with ac power dis-

connected. Refer servicing to qualified service per-

sonnel.

1. Using hardware provided, install Console securely in

standard 19" (483 mm) rack or optional AlOIA Carry-

ing Case prior to making electrical connections. For

custom installations, see mounting template supplied

with Console. If desired, connect AlOlB Panel Lamp

Accessory to LAMP Connector (9).

2. Set all front-panel switches to off (out) and all con-

trols to 0. Set rear-panel PHASE Switch (26) to 0'.

3. Connect desired PROGRAM OUTPUT/LINE LEVEL

Connector (25,27) to power amplifier input connect-

ing cable. (NOTE: Shure SR105 Power Amplifiers

are suppliedwith audio connecting cables.) If Console

output is to be fed to another mixer or tape recorder

microphone input, use PROGRAM OUTPUT/MIC

LEVEL Connector (24). If desired, connect mono-

phonic or stereo headphones to front-panel PHONES

Jack (8). Connect speakers to power amplifier.

4. Connect one or more low-impedance microphones to

rear-panel INPUTS/MICROPHONE LEVEL Connector

(33). Any high-quality dynamic, ribbon or condenser

low-impedance microphone may be used. Connect

high-impedance microphones or auxiliary high-level

sources to INPUTS/AUX. LEVEL Connectors (32) in

channels 7 or 8 only. If AUX. LEVEL Connectors are

used, set corresponding front-panel MIC/AUX (INPUT

ATTEN) Switch (14) to AUX.

5. If external signal-processing equipment such as an

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

nect Console LlNK OUT Connector (31) to external

equipment input and Console LlNK IN Connector (28)

to external equipment output. (See Link Jacks, Page

for detailed information.)

6. SR101: Connect ac line cord (21) to grounded 90- to

132-volt, 50/60 Hz ac source.

Line cord

a 2.44m (8-ft.), 3-conductor cord with

3-pin grounding plug. If extension cords are required,

use high-quality, rubber-jacketed cable with 18 gauge

or larger wire.

SRlOl-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 green/

yellow lead to ground or earth terminal. (Connector

should be installed by qualified service personnel.)

Select proper operating voltage (90-132V or 180-

250V) using VOLTAGE SELECTOR Switch (36). Note

that switch positions are marked 115 and 220 volts.

Make certain proper fuse is installed in fuseholder

(37): 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 (35) and connect male plug

to 3-wire grounded ac power receptacle providing

proper operating voltage.

7. Turn on front-panel POWER Switch (19) and allow

one to two minutes warmup time. This warmup time

allows the supply voltages to stabilize and capacitors

to charge to provide optimum performance. Depress

PROGRAM Switch (13) for channel to be used. (IM-

PORTANT: No program output will result if this switch

is not depressed!) Set INPUT ATTEN Control (14) for

that channel initially to 0 for normal or PA use, to -10

for instrumental music, or to -20 or -30 for "hard"

rock music. For AUX. INPUT sources (channels 7 and

8), set INPUT ATTEN Control initially to -20 or -30.

Set MASTER Volume Control (20) to 7. Set METER

SENSITIVITY Control (18) to CAL position. Havesome-

one sing or talk into microphone and raise channel

Volume Control (1) to achieve desired sound level. If

VU Meter (17) reads too low at proper sound level, in-

crease METER SENSITIVITY Control until normal me-

ter movement

operation in black area of scale with

occasional peak excursions into red area

is ob-

tained. If meter still reads low, reduce power amplifier

volume level and increase channel volume level. For

single microphone set-up, if meter indicates exces-

sively high level ("pinning" or "pegging" needle),

decrease channel 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 main-

tain channel Volume Control setting. Ideally, channel

Volume Control should remain approximately at mid-

range (7-9) to facilitate increases or decreases in con-

trol setting due to program change; INPUT ATTEN

Control (14) adjustment will aid in maintaining this set-

ting. If feedback occurs below desired sound level,

consult section on Feedback

Filters

(Page 8).

9. Set HI and LO FREQ EQ Controls (7,5) for channel in

use. Vertical position (0) indicates "flat" frequency re-

sponse. Clockwise

(+)

settings increase high-fre-

quency (treble) or low-frequency (bass) equalization

and counterclockwise

(-)

settings decrease fre-

quency equalization. Note that these controls also

affect feedback; readjustment of Feedback Filters (15)

may be necessary.

10. If reverberation is desired, depress REVERB Switch

(3) and adjust REVERB INTENSITY Control (2) to

desired level for channel in use. Recommended set-

tings are: speech

0, vocals

3-6, instruments

5-10. Adjust HI and LO REVERB FREQ EQ Controls

(6,4) for desired frequency equalization.

11. To monitor channel in use, depress MONITOR Switch

(12) for that channel. Monitor output is available at

front-panel PHONES Jack (8) and rear-panel MONI-

TOR OUTPUT/LINE LEVEL Jack (30). Adjust MONI-

TOR Control (10) for comfortable listening level. Note

that any or all channels may be monitored whether or

not PROGRAM Switch (13) for that channel is de-

pressed; merely depress MONITOR Switch for desired

channel. When total program output monitoring is de-

sired,depress PROGRAM MONITOR Switch (11).Note

too that only those channels with PROGRAM Switch

(13) depressed will be heard while monitoring with

PROGRAM MONITOR Switch depressed.

12. NOTE: During temporary shutdown (break, intermis-

sion), it is not necessary to turn off Console power. It

isdesigned to operate continuously, and optimum per-

formance is maintained after internal voltages are al-

lowedto stabilize. Also, donot turn off all microphones.

Leavethe master or announcer's microphoneon (PRO-

GRAM Switch depressed) so that

the Console is left

unattended, announcements may be made, and the

Console operator will be alerted that the next perform-

ance isabout to begin.

MOUNTING AND VENTILATION

The Shure SR101 Audio Console may be operated in a

standard 19" (483 mm) audio equipment rack, in a Shure

AlOlA Carrying Case, or custom-mounted in a table- or

desk-type control center. Four rack-mounting screws are

providedwith the Console. These screws may also be used

if the Console is to be custom-mounted in a metal-top con-

trol center.

A custom-mounting template is supplied with the Con-

sole. Cutting dimensions and drill hole locations are given,

as are clearances for insertion and ventilation. The dimen-

sions given should be followed to provide adequate cable

clearance (see Figure 3, Page 5).

Ineither rack- or custom-mounted installations, consider

rear-panel access before installation is made. Although

most installations will not requirefrequent access, itshould

be remembered that input and output changes, and some

switch movements, will necessitate rear-panel access. Rear

panels are most easily reached in standard audio racks or

in custom installations having bottom access, such as an

open desk or a lower control center access panel.

NOTE: CLEARANCE DIMENSIONS

SHOWN. SEE MOUNTING

TEMPLATE.

NOT INCLUDING CONNECTOR/CABLE CLEARANCE

DEPTH.

FIGURE

SRlOl AUDIO CONSOLE

DIMENSIONAL OUTLINE DRAWING

POWER SUPPLY

SR101:The SR101regulatedpower supply isdesigned to

operate from 90 to 132 volts ac, 50/60 Hz without adjust-

ments, allowing the Console to meet all specifications over

this wide range of ac input voltages. A three-conductor,

grounded line cord (21) supplies ac power to the Console

through the front-panel POWER ON-OFF Switch (19). The

Console consumes 20 watts maximum (0.2 amperes) and

the ac line input is protected by a 3/16-ampere slo-blo fuse

(22) and a wired-in 3/10-ampere slo-blo fuse in series. A

wired-in 1-ampereslo-blofuse protectsthe 5.6-volt second-

ary winding (indicator lamp) of the power transformer.

CAUTION

These fuses should not be replaced with any

other size or type of fuse.

Accessory equipment may be connected to the rear-

panel SWITCHED A.C. Receptacle (23). The accessory

equipment may consume up to 500 watts maximum, which

provides for use with high-power amplifiers such as the

Shure SR105. Note that the receptacle is switched but not

fused; all accessory equipment used with the Console

should contain itsownfuse.

SR101-2E: The SR101-2E regulated power supply is de-

signed to operate from either 90 to 132 volts ac or 180 to

250 volts ac,50/60 Hz, as selected by the rear-panel VOLT-

AGE SELECTOR Switch (36).A three-conductor, grounded

line cord supplies ac power to the Console through the

front-panel POWER ON-OFF Switch (19). The SR101-2E

line cord does not have a connector on the power source

end of the cord. Obtain a suitable three-pin male ac con-

nector and install it on the line cord: brown to "hot" or

"live" terminal, blue lead to neutral terminal, and green/

yellow lead to ground or earth terminal. (Connector 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). Wired-in 3/10- and 1-ampere fuses protect the

ac line and power transformer 5.6-volt secondary winding,

respectively.

FUNCTIONAL CIRCUIT DESCRIPTION

(SeeFigure4, Page 6)

Each 3-pin professional audio input Microphone Con-

nector (33)feeds itsown low-impedance lnputTransformer,

which provides a gain increase of 23 dB. Channels

and 8

also contain switchableAUX LEVEL phone jacks (32) which

accept high-impedance microphones or other inputs. The

lnput Transformers (and, on channels

and 8, the AUX-

MIC Switch) are fed to 0-30 dB INPUT ATTEN Controls (14)

and then to the Preamplifier, which provides a A6to $30

dB gain increase. The amount of gain provided by the Pre-

amplifier (6 to 30 dB) is controlled by the Channel Volume

Control (I),providing an increase in input clipping level as

gain is reduced. The Preamplifier circuits contain the in-

dividual Channel Volume Controls and feed the individual

Channel Equalizer (HI and LO FREQ EQ) Controls (73)

which decrease the signal approximately

dB when set to

the 0, or "flat," setting.

The Equalizer outputs go to the Program and Monitor

circuits, and to the ACCESSORY AUX LEVEL Connector

(34) for interconnection with SR110 Monitor Mixers. The

Channel Equalizer outputs going to the Program circuits

go first to the individual channel PROGRAM Switch (13),

and subsequently to the Reverb circuits and individual

channel REVERB INTENSITY Controls (2). When reverb is

not used, the REVERB INTENSITY Control is set to 0, and

the channel output is sent directly to the Program Mix

Amplifier. When reverb is employed

REVERB Switch (3)

depressed

the REVERB INTENSITY Control feeds the

Reverb Intensity Mix Amplifier, Reverb Equalizer, Reverb

Driver and DifferentialAmplifiers, Reverb Output Mix Amp-

lifier, andthen into the Program Mix Amplifier. Note that as

the control is increased the amount of non-reverb ("dry")

signal sent to the Program Mix Amplifier is reduced, while

the signal sent to the Reverb lntensity Mix Amplifier is

increased.

The Channel Equalizer output to the Monitor input, con-

trolled for each channel by a MONITOR Switch (12), is fed

to the Monitor Mix Amplifier, which changes the input by

+3 to -13 dB. The Amplifier output goes to the PROGRAM

MONITORSwitch (1

I),where itmay beselected tocontinue

through the MONITOR Level Control (lo),+40 dB Monitor

Amplifier, and to the rear-panel MONITOR OUTPUT/LINE

LEVEL jack (30) and front-panel PHONES jack (8).

The Program Mix Amplifier goes to both the PRE LlNK

side of the POST LINK/PRE LlNK Switch (29) for routing to

the Monitor circuits, and through a 560-ohm resistor to the

LlNK jacks (28,31).When accessory equipment is not con-

nected to the LlNK jacks, the jacks are bypassed and the

program signal is fed to the POST LlNK side of the POST

LINK/PRE LINK Switch for monitoring, and to the MASTER

Volume Control (20). Note that the PRE LINK/POST LlNK

Switch output to the Monitor circuits is also routed to the

ACCESSORY AUX LEVEL Connector (34).

The output of the MASTER Volume Control,after feeding

a 0 dBgain Amplifier, is sent through a bank of four select-

able FEEDBACK FILTERS (15), which provide attenuation

at 130, 800, 2000 and 5000 Hz for feedback control. The

FEEDBACK FILTERS output goes to a +6 to +31 dB

Amplifier, also controlled by the MASTER Volume Control,

through a 180' PHASE Switch (26), and into the Program

(

TYPICAL OF CHANNELS 1-8

NOTE

lMlCROPHONE LEVEL

pimq

200

OUT

HIGH

0-30 dB CHANNEL

-2

dB REVERB

X~~~

INPUT

VOLUME

CHANNEL

(SECTION

EWALIZER

INTENSITY

1+23 dB1

ITTEN

IN (SECTION 0)

CHANNEL REVERB

VOLUME

INTENSITY

(SECTION 0) (SECTIONA)

TONE

OSC

LEVEL

FEEDBACK

FILTERS]

RESISTOR

[PHASE]

PROGRAM OUTPUTS

MASTER

VOLUME

LEVEL

(SECTION

MON

LEVEL

NOTES: I. AUX. LEVEL INPUT AND AUX-MIC SWITCH

ON CHANNELS

AND

ONLY. 1-10 dB1

FlGUR,E

SRlOl SERIES

CONSOLE BLOCK DIAGRAM

Output Transformer. The Transformer feeds three LlNE

LEVEL Output Connectors (25,27) and a MIC LEVEL Out-

put Connector (24), which is at

dB below line level. The

to $-31 dB Amplifier also feeds the METER SENSITIV-

ITY Control (18),which goes to a +22 dB Meter Amplifier,

and then to the VU Meter (17).

The Console also contains a 1 kHz Tone Generator for

use inset-up and checkout. The Generator is activated and

controlled by the TONE OSC LEVEL SwitchIControl (16),

and the control output is fed to the Program Mix Amplifier.

A detailed description of the Console circuits and con-

trols and their uses is provided in the following paragraphs

of this section.

INPUT CHANNELS

Eight professional, three-pin, audio MICROPHONE

LEVEL lnput Connectors (33) are provided on the upper

rear panel of the Console.The Console isdesigned to oper-

ate with high-quality, low-impedance dynamic, ribbon or

condenser microphones. Two additional AUX. LEVEL In-

put Connectors (32) are provided for channels

and

These standard quarter-inch phone jacks allow connection

to auxiliary high-level sources or high-impedance micro-

phones. Switches on the channels 7 and

INPUT ATTEN

Control (14) allow the user to select between either the

low-impedance microphone input (MIC), or the high-im-

pedance auxiliary input (AUX).Each low-impedance micro-

phone input is connected to a low-impedance, balanced-

input transformer, the output of which is connected to a

0-30 dB input attenuator. On channels 7 and

the outputs

of the low-impedance microphone transformer and the

AUX. LEVEL lnput Jack (32) terminate in the AUX-MIC

Switch. The output of this switchgoes to the 0-30 dB INPUT

ATTEN Switch (14). Note that the AUX-MIC Switch has

two detented positions; no output will be obtained when

the switch is between detent positions. The MIC-AUX

Switch grounds the unselected input to reduce crosstalk.

This should be considered when connecting inputs to this

channel. A I-kilohm isolation resistor is provided in the

AUX input circuit. When the AUX input is not selected, this

resistor is grounded, placing the I-kilohm load on the AUX

input. If the source connected to this input is also bridged

to feed other inputs, an additional isolation resistor may be

required.

The INPUT ATTEN (14) four-position switch provides

input attenuations of 0, 10,20, or 30 dB. This switch allows

the user to compensate for the differences in levels due to

different sources, such as close talking or distant micro-

phoneplacement, and to compensate for high output levels

from condenser microphones.

The Channel Volume Control (1) is a dual control: one

section, ina feedback circuit, sets the gain of the preampli-

fier, and the second section isa preamplifier output attenu-

ator. 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 7 and

This can generally be ac-

complished by proper INPUT ATTEN Control (14) setting.

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

equalizer circuit. Individual HI and LO FREQ EQ controls

(7,5)

allow the user to shape the sound of each input

channel without affecting the other channels on the Con-

sole. 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 13dB of boost or cut at 100 Hz with

a 1kHz hinge point.Control settings with plus

(+)

markings

indicate boost, and minus

(-)

markings denote cut. A 0

setting provides a normal or "flat" frequency response.

The output of the equalizer feeds the channel PROGRAM

and MONITOR Switches (13,12). The PROGRAM Switch

selects the channels to be connected to the program out-

put.The MONITOR switches select the channels to be con-

nected to the monitor output. The two switches are inde-

pendent and have no effect on each other.

SOURCE CUING

Microphones, tape recorders, or other sources may be

preset, or cued, during a performance in the following

manner. With headphones connected to the front-panel

PHONES Jack (8) or rear-panel MONITOR LlNE LEVEL

Jack (30) (high-impedance headphones only), depress the

PROGRAM MONITOR Switch (11) and a PROGRAMSwitch

(13) for a channel that has program material at the proper

level on it. Adjust the MONITOR Level Control (10) until an

adequate audio level is heard in the headphones. Release

the PROGRAM MONITOR Switch and PROGRAM Switch

for that channel, and depress the MONITOR Switch (12) for

the channel being cued. With the MONITOR Level Control

previously set, raise the channel Volume Control (1) until

the same audio level heard in the other PROGRAM channel

has been reached.

With the channel PROGRAM Switch (13) released and

the channel MONITOR Switch (12) depressed, the source

will be heard on the headphones and not on the program

channel. This allows the Console operator to cue up tapes,

check out microphones, etc., without interfering with the

program. When the channel is to be activated, depress the

channel PROGRAM Switch.

It is most important to have a good knowledge of micro-

phone placement and the performer's microphone tech-

nique when cuing a microphone. Always begin cuing in the

new microphone at the lowest estimated volume setting. If

volume level correction is necessary, slowly raise the Vol-

ume Control

(1)

level. If a change in the INPUT ATTEN

(14) setting is required, wait until the vocalist takes a

breath or the instrumentalist takes a restto balance out the

volume and attenuation levels to the required degree. Note

that minor changes in volume during a performance per-

ceptible to the Console operator are rarely noticed by the

audience. However,if the channel level issettoo highwhen

the channel is turned on, the sound may "blast" the audi-

ence, or cause acoustic feedback, or both. Either condition

will prove embarrassing to the Console operator.

REVERBERATION

The SR101 Audio Console contains a built-in electro-

mechanical spring-type reverberation device utilizing four

coil springs in two transmission paths. Reverberation isac-

complished by driving the input ends of the springs in a

torsional mode and transferring the torsional movement

back into an electrical signal which exhibits time delay with

a long decay time at the opposite ends of the springs. Since

the reverberation device is electromechanical in nature, it

issensitive to mechanical shock.

The Console isdesignedto provideafoundation of "dry,"

or non-reverb, signal on the total output, no matter howthe

channel REVERB INTENSITY Controls (2) are set. Of great

importance, too, is the fact that reverb intensity can be

increased without increasing overall gain. In most units

which employ artificial reverberation, the total gain in-

creases as the intensity of the reverberant signal is in-

creased. This generally leads to acoustic feedback. How-

ever, the SR101 Audio Console reverb mixing system

reduces the "dry" signal as the reverb signal is increased;

this provides an almost constant gain and reduces the

possibility of feedback as reverb is added.

The following controls are pertinent to reverb operation.

The output of the PROGRAM Switch (13) feeds the channel

REVERB INTENSITY Controls (2).These are dual controls:

one section controls the amount of "dry" signal fed to the

program mix amplifier, and the other controls the amount

of signal fed to the reverb mix amplifier. As each REVERB

INTENSITY Control is increased, the amount of signal to

the program mix amplifier is reduced and the amount of

signal to the reverb mix amplifier is increased. As stated

above, this action keeps the same approximate overall

volume level to avoid feedback problems. The REVERB

INTENSITY Control is generally used at settings of 0 for

speech,3-6for vocals, and 5-10 for instruments.

The reverb mix amplifier combines the output of all chan-

nel REVERB INTENSITY Controls (2),mixing the signal and

sending it to the REVERB FREQ EQ Controls (6,4). The

output of the reverb equalizer circuit drives the reverbation

system. The separate REVERB FREQ EQ-HI and -LO Con-

trols affect the reverb signal only. These reverb controls

modify the reverberant signals in essentially the same way

the channel equalization controls modify both "dry" and

reverb signals. The REVERB FREQ EQ Controls allow the

user to change the reverberant sound to compensate for

the reverberation in each room in which the Console is

used. In a "boomy" (low-frequency resonant) room, de-

crease the REVERB FREQ EQ-LO Control or increase the

REVERB FREQ-HI Control, or do both until the proper

equalized reverb sound is achieved.

The output of the reverberation spring is fed to a dif-

ferential amplifier whose output is connected to the RE-

VERB Switch (3).This switch turnsthe reverb system on (in)

and off (out) without affecting the overall level or the RE-

VERB INTENSITY Controls (2). In this manner, the RE-

VERB INTENSITY Controls may be preset, and when the

REVERB Switch is depressed, the reverb level is predeter-

mined. The reverb signal, after passing through the RE-

VERB Switch, is routed to the program mix amplifier and

combined with the "dry" signals from the program

channels.

MONITOR SYSTEM

The output of the individual channel MONITOR Switches

(12) are combined in the monitor mix amplifier. The chan-

nels that appear on the monitor system are independent of

the setting of the PROGRAM Switches (13). This feature

allows the signals that do not appear on the program out-

put to be fed to the monitor output. This may be useful for

providing a talkback or for a "click track" signal feed.

The monitor mix amplifier is a passive mix amplifier; its

gain depends on the number of channels selected to be

monitored.This type of mixing means that as channels are

added to the monitor system, the overall apparent level

remains constant while each individual channel contribu-

tion is reduced. The output of the monitor mix amplifier

feeds the PROGRAM MONITOR Switch (11). When this

switch is released,the monitor system carries the channels

selected by the individual channel MONITOR Switches

(12).When the PROGRAM MONITOR Switch is depressed,

the monitor system monitors the output of the program mix

amplifier.

It should be noted that the individual channel MONITOR

Switches (12) monitor the channels ahead of the reverb,

and the PROGRAM MONITOR Switch (11) monitors the

entire program after reverb. The output signal from the

PROGRAM MONITOR Switch is fed to the MONITOR Level

Control (lo),which provides an output signal to drive the

monitor output amplifier. The signal from this amplifier

appears on the MONITOR OUTPUT/LINE LEVEL Jack (30)

on the rear panel, and also through a headphone matching

transformer to the PHONES Jack

(8)

on the front panel.

These two outputs may be used simultaneously.

Note that the front-panel PHONES Jack

(8)

permits the

use of either monophonic or stereo headphones (4-16ohms

impedance) without rewiring. High-impedance mono-

phonic headphones may be connected to the rear-panel

MONITOR OUTPUTILINE LEVEL Jack (30).

The purposeof the monitorsystem isto allow an operator

to use headphonesto monitor the program if the PROGRAM

MONITOR Switch (11) is depressed, or to monitor the in-

dividual channels. Monitoring the individual channels

allows the operator to determine which microphones are

in use, which are turned off, or which may be malfunction-

ing. Notethat itisalso possible to use the monitor output to

listen to a microphone or cue a tape that is driving a chan-

nel

AUX. LEVEL lnput Jack (32) without having the

signal on the program output.

The second major use of the monitor system is to pro-

vide on-stage monitoring, or foldback, which allows the

performers to hear themselves, but only gives them a

partial mix. This is useful in a system where all the instru-

ments have microphonesbutthe vocalists only want-to hear

themselves and one or two instruments, such as the piano,

to be able to keep in tune. When used in this manner, the

MONITOR OUTPUT/LINE LEVEL Jack (30) is connected

to the inputof anauxiliary power amplifier that is connected

in turn to monitor speakers located on stage.

MONITOR MIXER SYSTEM

The rear-panel ACCESSORY OUTPUT/AUX LEVEL Con-

nector (34) of the SR101 providesfor interconnection to up

toeight Shure SR110 Professional Monitor Mixers. The out-

put of each individual channel after the volume, equal-

ization and attenuation channel controls appears on this

connector as do the LlNK INPUTIOUTPUT total mix signal

and the power supply connections. The SRI10 is a self-

contained, eight-channel, line level mixer designed for use

with the SRlOl Series 2 or similar equipment. The SR110

can provide a separate stage monitor "mix" that follows

the program "mix" levels coming from the eight channels

of the SR101. In addition, it may be used in making multi-

track recordings: use two SRllOs for stereo and four for

quadriphonic.

The SR110 provides eight high-impedance, unbalanced,

line level inputsto its mixing circuitry, one high-impedance,

unbalanced, line level input to its Output Selector Switch

for monitoring the program mix, and one line level, 600-

ohm, balanced output. Individual channel and master vol-

ume controls are provided, as is a switch to choose be-

tween 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 lnput position ob-

tains the mixed signal at the PRE LINK/POST LlNK Switch

(29).

The SR110 has parallel accessory inputloutput male and

female connectors. These connectors permit the connect-

ion of additional tandem or "stacked" SRllOs. A typical

application is shown in Figure

Page 9.

POWER PA

AMPLIFIER SPEAKERS

LEVEL

SRllO STAGE

MONITOR POWER MONITOR

MIXER AMPLIFIER SPEAKER

SRllO

MONITOR

MIXER

STEREO

RECORDER

MONITOR

FIGURE

SR110 MONITOR MIXER APPLICATIONS

PROGRAM

MIX

AMPLIFIER

The program mix amplifier is an active mixing amplifier

in which gain remains constant independent of the num-

ber of individual channel PROGRAM Switches (13) that are

activated. The output of the program mix amplifier is con-

nected through a 560-ohm mixing resistor to the LlNK

Jacks (28,31).

LlNK JACKS

The LlNK Jacks (28,31) on the rear panel of the Console

enable the user to interconnect more Consoles for addi-

tional inputs or add external equipment, such as equalizers,

compressors, or limiters. When connecting two or more

SR101 Audio Consoles together to provide many channel

inputs, connect the LlNK OUT Jacks (31) of all the units

together. It should be noted that the LlNK OUT 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 INJack (28) is an input-only

jack and has switching contacts that disconnect the output

of the program mix amplifier from the MASTER Volume

Control (20).

If an equalizer, limiter or compressor is connected to the

Console, the LlNK OUT Jack (31) is connected to the input

of the external unit and the output of the external unit is

connected to the LlNK IN Jack (28).

The signals at the LlNK JACKS are typically at a level 10

dB below line level. These jacks will accommodate signal

levelsinthe range between -30 to +I0 dBm.The LlNK IN

input impedance is greater than 20 kilohms and may be

considered a bridging impedance. The output of the LlNK

Jacks feeds the MASTER Volume Control (20) which is a

two-section control similar to those used in the individual

channels. The POST LINK/PRE LlNK Switch (29) on the

rear panel, in the monitor circuit, allows the operator to

monitor the program before (PRE)or after (POST) the LlNK

Jacks.

FEEDBACK FILTERS

The output signal from the MASTER Volume Control

(20)

attenuator section is sent to the feedback filter circuit at

this point. The FEEDBACK FILTERS (15) are four notch

filters whose center frequencies are 130

Hz,

800

Hz,

kHz,

and

kHz.

These jil'lers are designed

minimize

the

acousticfeedback (speaker howl or squeal) that may occur

through some combination of room acoustics, microphone

and speaker placement, volume increase, or equalization

control boost. Each filter modifies the frequency response

of the program output, with the lowest (130 Hz) filter af-

fecting the lowest feedback pitch (howl) and the highest (5

kHz) filter affecting the highest feedback pitch (squeal).

The two center frequency filters affect feedback modes in

the middle ranges of the audio frequency spectrum.

The three upper frequency filters have little effect on

voice tonal qualities. The 130 Hz filter, generally used to

eliminate low-frequency room reverberations, causes some

decrease in bass tones. This may be compensated for by

increasing the FREQ EQ-LO Controls (5) slightly for the

individual channels in use.

Iffeedback is present,locate the one FEEDBACK FILTER

Switch (15) which eliminates it. Then increasethe VOLUME

(1)or FREQ EQ Controls (5,7)as desired until another feed-

back pitch occurs. Then locate the filter to eliminate the

new feedback mode. IMPORTANT: Up to two FEEDBACK

FILTERS may be used at one time; more than two filters

will reduceoverallgain and significantly affect system tonal

quality.

Note that the PHASE Switch (26), which allows the Con-

sole operator to change the output phase, functions to

reduce or eliminate acoustic feedback, too. It is normally

used to obtain maximum gain before feedback, or to obtain

the highest pitched feedback for elimination by the feed-

backfilters.

PROGRAM OUTPUT

The output signal from the feedback filters drives the

program output amplifier. The gain of this amplifier is con-

trolled by one-half ofthe MASTER Volume Control (20) (the

other half isa preamplifieroutput attenuator). The output of

the program amplifier is sent to the PHASE Switch (26)

mounted on the rear panel of the Console. This switch

allows the user to change the phase of the program output,

which may be helpful in eliminating or reducing low-fre-

quency acoustic feedback. Generally, this switch is ad-

justed to the position which either gives the most gain

before feedback or, if both positions give the same gain

beforefeedback, use the positionthat producesthe highest

pitch feedback. The program signal, after leaving the

PHASE Switch, is routed to the output transformer which

provides both LlNE LEVEL and MIC LEVEL outputs. The

LlNE LEVELoutput is connected to one professional three-

pin,male, audio output connector (27) and two three-circuit

phone jacks (25). The MIC LEVEL output is a low-im-

pedanceoutput,50 dB belowthe LlNE LEVELoutput, and is

connected to a professional three-pin male, audio output

connector (24).

Note that all of the program outputs are balanced with

respect to ground. If a phone plug is used to connect the

mixer line level output to an amplifier or tape recorder and

the phone plug is a two-circuit type, the line outputs will

automatically become unbalanced. If the 3-pin unbalanced

output is used and a phone jack output is

also

to be used,

obtain a stereo phone plug and connect 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 MIC LEVEL Output

Connector (24) to feed a high-impedance input, use a

matching transformer such as one of the Shure A95 Series

at the high-impedance input.

The output of the program output amplifier is also fed to

the VU Meter (17) circuit.

VU METER CIRCUIT

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

VU Meter (17),a 22 dB VU Meter amplifier is provided. The

output of the program amplifier is fed to the METER SENSI-

TIVITY Control (18) which inturn feeds the VU Meter ampli-

fier and the Meter. The METER SENSITIVITY Control is

calibrated in its maximum counterclockwise position only.

The calibration of this position is internally adjusted at the

factory for +4 dBm at 0 VU across a 600-ohm load on the

program output. The VU Meter amplifier provides the

proper signal, impedance, and level for proper 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.

TONE OSCILLATOR

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

set-up and checkout purposes.TheTONE OSC LEVELCon-

trol a-ndON-OFF Switch (16) injects the 1 kHz tone into the

program mix amplifier. The tone is processed through the

program channel in the same manner as microphone or

auxiliary input signals, except that the reverb system is

bypassed.

When using the tone oscillator, calibrate the Console VU

Meter (17) and proceed as follows: With the METER SEN-

SITIVITY Control (18) set to CAL, increase the MASTER

Volume Control (20) and TONE OSC LEVEL Control (16)

until a 0 VU reading is obtained on the VU Meter. A tone

reference level has now been established. The Console

LlNE LEVEL Output (25,27) isnow +4 dBm (1.23 volts) and

the MIC LEVEL Output (24) is approximately 4 millivolts.

These reference signals may be used to set uppower ampli-

fiers, tape recorders, or other equipment connected to

these outputs (Figure 6A, Page 10). By adjusting the input

level (or volume) controls on the associated equipment, all

the meters in the audio system can be made to "track."

This allows the Console operator to observe the Console

VU Meter (17) to see if all the equipment is in its proper

operating range. This reference tone may also be used to

check out cables and equipment for proper operation.

To check a microphone cable, connect the cable be-

tween the Console MIC INPUT Jack (33) (any channel) and

the MIC LEVEL Output Jack (24) (refer to Figure 6B, Page

10).Connect headphones to the PHONESJack (8).Release

the PROGRAM MONITOR Switch (ll),and for the channel

being used,depress the MONITOR Switch (12), release the

PROGRAM Switch (13),and set the FREQEQ Controls (5,7)

to 0, the channel Volume Control (1) to mid-range, and IN-

PUT ATTEN Switch (14) to 0. An audible tone should be

heard through the headphones as the MONITOR Level

Control (10) is increased.

The same process may be used to check out a Console

channel. With

good microphone cable, make the connec-

tions described above. The tone should be heard clearly

through the headphones. If a channel is suspected of poor

quality, it can be compared with another channel by con-

necting the microphone cable to the second channel with

all controls set in the same manner as the first. By care-

fully noting the level and quality of tone on each channel,

any significant differences can be established.

To check out an auxiliary channel, perform the process

described above, except connect a phone plug to phone

plug cable between the LlNE LEVEL Output Jack (25) and

the AUX. LEVEL Input Jack (32) for the channel

or 8)

being checked (Figure 6C, Page 10). Set the MIC/AUX

Switch (14)to AUX and INPUT ATTEN Switchto -30.

The tone oscillator may also be used to provide a check

of cables and equipment connected to the link output. With

the LINK OUT Jack (31) connected to the input of an ex-

ternal equipment, such as a Shure SE30 Gated Com-

pressor1Mixer which in turn feeds a broadcast line, dis-

connect the program output, either at the back of the Con-

sole, power amplifier or speakers (Figure 6D, Page 10).

Turn the METER SENSITIVITY Control (18) to CAL, set the

MASTER Volume Control (20) to 7, and increase the TONE

OSC LEVEL Control (16) for a 0

Meter (17) reading.

Slide the MASTER Volume Control down to 0. Under this

set-up condition, the external equipment may now be cali-

brated or checked out withoutaffecting the programoutput.

After calibrating the external equipment, turn off the tone

oscillator, and return the MASTER to 7. Reconnect the

power amplifier or speakers.

MIC~

ILINE,

LINE^

SR I01 POWER TAPE

AUDIO CONSOLE AMPLIFIER RECORDER

MIC LEVEL

INPUT JACK OUTPUT JACK

SR lOl

AUDIO CONSOLE

LlNE LEVEL

INPUT JACK

AUx.

LEVEL

OUTPUT JACK

101

AUDIO CONSOLE

PHONES JACK

POWER AWL

AUX LEVEL

INPUTJACK

SR lOl

AUDIO CONSOLE GATED

C0E;:SOR

MIXER

FIGURE

TON'E OSCILLATOR APPLICATIONS

BASIC OPERATING HINTS

Should any difficulty be encountered in Console opera-

tion, 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: Console is "dead" (no output, VU Meter lamps

out)

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

2. Check that cable from PROGRAM OUT-

PUT/LINE LEVEL Connector (27) has not

accidentally been connectedto PROGRAM

OUTPUT/MIC LEVEL Connector (24).

3. Check that PHASE Switch (26) is not be-

tween positions.

4. Check that external equipment is properly

connected to LINK Jacks (28,31).

that Console is plugged in. Symptom: One channel is "dead" (other channels oper-

Check that POWER ON-OFF Switch (19) is ating properly)

on.

3. Check to see that rear-panel 3AG-3116A Check: 1. Check for defective input cable or source.

SLO-BLO Fuse (22) is good. 2. Check that channel PROGRAM Switch (13)

Symptom: Console is "dead" (no output, VU Meter lamps is depressed.

lit) 3. Check that AUX-MIC Switch (14) (channels

Check: 1. Check that PROGRAM Switch or Switches

and

only) is not between positions or in

(13) are depressed. the wrong position.

SR101 Series

Audio Console

SPECIAL OPERATING INSTRUCTIONS

The previous section described normal interconnection The high-impedance cable should be limited to 6.lm

and operation of the SR101 Audio Console; this section (20 ft.). If a long cable length is required, use up to 3.05m

provides informationon special set-ups to more fully utilize (10 ft.) of high-impedance, single-conductor, shielded

the capabilitiesof the Console. cable (Belden #8401, #8410, or #8411) between the micro-

HIGH-IMPEDANCE MICROPHONES phone and line matching transformer, and add as much

low-impedance, two-conductor, shielded cable (Belden

UPto two high-impedance dynamic, ribbon or condenser #8412,' or #8422) as necessary between the transformer

microphones (crystal or ceramic microphones are not and Console input jack. These precautions will help avoid

recommended) can be used with the Console without the high-frequency signal loss and reduce the possibility of

need for line matching transformers simply by using the hum and noise.

AUX. INPUT Jacks (32) on channels

or 8 and moving the

corres~ondinclINPUT ATTEN Switch (14) to AUX. NOTE: INSTRUMENTS

The very highoutput produced by s0m.e dondenser micro- Musical instruments, acoustical (non-electrified),acous-

phones may be compensated for by proper setting of the tical-electrified, or electrified,may be amplifiedthrough the

INPUT ATTEN Control. Console. For acoustical instruments, place a microphone

If a high-impedance microphone isto be usedwith oneof close to the instrument strings, sounding board, or mouth.

the low-impedance MIC LEVEL Input Jacks (33), a line Adjust equalization, reverb and volume controls as neces-

matchingtransformer (ShureA95 Series) must be used. sary.

FIGURE

PREAMPLIFIER-CONSOLE CONNECTIONS

3.05

(10') MAX.

-I

PUP

305

(1000')

LOW IMPEDANCEHIGH IMPEDANCE

AUX OR HEADPHONE

r A95

LINE

MATCHING

TRANSFORMER

OUT MIC LEVEL

INPUT

PREAMPLIFIER

MICROPHONE

CABLE

LOW IMPEDANCE

SR lOl

AUDIO CONSOLE

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 an AUX. LEVEL lnput Jack (32) on the Console. If the

cable from the instrument to the Console is greater than

6.lm (20 ft.), use a line matching transformer as described

under High-Impedance Microphones (Page 11). This trans-

former also allows the instrument to be connected to chan-

nels 1-6. Adjust the Console INPUT ATTEN Control (14) for

the channel in use to provide the desired sound level with

the channel Volume Control (1) set at about mid-scale.

To use a preamplifier auxiliary output with the Console

(instrumentor tape recorder preamplifier, or hi-fi amplifier

tape monitoroutputjack, or headphonejack; never speaker

jacks), connect the preamplifier auxiliary output through

up to 3.05m (10 ft.) of cable to the high-impedance side of

a line matching transformer (Shure A95 Series) as shown

inFigure7, Page 11. Connect the low-impedance side of the

transformer through a low-impedance microphone cable

[up to 305m (1000 ft.)] to a Console MICROPHONE LEVEL

lnput Jack (33). Adjust Console equalization controls for

optimum sound. Adjust the Console INPUT ATTEN Control

(14) for the channel in use to provide the desired sound

level with the channel Volume Control (1) set at about mid-

scale.

Fully electrified instruments may also be amplified using

a microphone in front of the instrument speaker, or the in-

strument output (not the speaker jack) may be fed directly

to an input jack as described above. It is important to note

that the tonal quality of fully electrified instruments is pri-

marily formed by the instrument amplifier and speaker; an

external microphone picking up the instrument speaker

output may very well provide a more desirable sound than

that obtained by direct connections.

The cable length restrictionsapplying to high-impedance

microphones also apply to most musical instruments (see

High-Impedance Microphones, Page 11).

TAPE RECORDING

The Console output may be recorded on a tape recorder

from either the LlNE LEVEL Output (25,27), MIC LEVEL

Output (24) or LlNK OUT (31) Jacks.The Console Program

Outputs are after the FEEDBACK FILTERS (15) and MAS-

TER Volume Control (20); the LlNK OUT Jack is before

these circuits. In considering a tape recorder connection,

the operator should consider whether he wants the tape

levelto follow the MASTER Control.

To use a LlNE LEVEL Output Jack feeding a high-impe-

dance auxiliary tape recorder input, connect a cable from

one LlNE LEVEL Jack to the tape recorder input (see Fig-

ure8, Page 12). If the LINE LEVEL Output is being usedand

a two-circuit phone jack is used to connect the Console to

the tape recorder,this will unbalance the LlNE LEVEL Out-

put (refer to Program Output, Page 9).

If the MIC LEVEL Output Jack (24) is to be used, connect

a cable from itto the tape recorder low-impedance micro-

phone input. If the microphone input on the tape recorder

is designed to be used with high-impedance microphones

(greater than 1000 ohms), insert a line matching trans-

former (ShureA95 Series with proper connectors) between

the MIC LEVEL Output Jack and the tape recorder input

(refer to Program Output, Page 9).

To use the LlNK OUT Jack (31), use a two-circuit phone

plug onthe cable to thetape recorder auxiliary or lineinput.

The input impedance of the tape recorder should be

600

ohms minimum.

The low output impedance of the Console provides for

unlimited cable length between the Console output and

tape recorder input. Low-capacitance, single-conductor,

shielded cable (Belden #8401, #8410, or #8411) is recom-

mended to reduce the possibility of hum and noise pickup.

Foroperation with a stereo tape recorder, refer to Stereo

Operation, Page 16.

LOW IMPEDANCE

BALANCED LlNE

SHIELD

MIC LEVEL OUTPUT

TRANSFORMER

SRlOl

AUDIO CONSOLE RECORDER

FIGURE

TAPE

RECORDING

RECORD PLAYBACK

To play records through the Console using a turntable

or record changer with a stereo magnetic cartridge and no

preamplifier, the most expedient method is to join the left

and rightchannel leads from the turntable in a

"Y"

adapter

and connect the joined output to a channel 7 (or 8) AUX.

LEVEL lnput Connector (32) on the Console (see Figure 9A,

Page 13). Note that the total lead length between turntable

and Console should not exceed five feet. To approximate

the RlAA equalization curve, set the Console FREQ EQ-LO

Control (5) to +4, the FREQ EQ-HI Control (7) to -6, and

the INPUT ATTEN Control (14) to

for the channel (7 or 8)

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

necessary.

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 13). In this

set-up, RlAA equalization will be achieved at the preampli-

fier, before the signal enters the Console. In this manner,

the Console equalization controls may be used to optimize

the room sound, rather than compensating for the input

signal. Thejoined turntable leads enter the channel 1 input

of the preamplifier, and the output istaken from the channel

1 low level output and fed to the channel 7 (or 8) AUX.

LEVEL lnput Jack (32) of the Console. Set the Console

INPUTATTEN Control (14)to

with this set-up.

Note also that this set-up removes the cable restriction

between turntable and Console described above: although

a maximum of 1.5m

ft.) between turntable and pre-

amplifier is mandatory, the cable length between the pre-

amplifier andConsole isvirtually unlimited.

TAPE PLAYBACK

To play tape-recorded material through the Console,

connect a cable from the tape recorder auxiliary or line

level output to the channel

or 8 AUX. LEVEL lnput Jack

(32). Turn the front-panel AUX-MIC Switch (14) on Channel

7 or 8 (whichever is being used) to AUX. Set the INPUT

ATTEN Switch (14) to -20 to start, and adjust it and the

channel Volume Control (1)as required.

FIGURE

RECORD PLAYBACK

lTl.5~~~m~y

CHANNEL

AUX

LEVEL

INPUT

TURNTABLE

lOl

FREQ.

EQ-LO:

AUDIO

CONSOLE

(

FREQ.

EQ-HI:

-6

)

1.5

(5') MAX.

PUP

305

(1000')

TALKBACK CIRCUIT

It is often necessary to provide a "talkback" circuit (or

"intercom," or "com line") to enable the Console operator

to instruct or cue performers, lighting control, announcers,

etc. It also enables the operator to avoid hand or light sig-

nals which may not be visible during a performance. The

talkback circuit requires the use of one input channel, re-

movingthat channel from use by performers. Note too that

the monitor circuit is being used, preventing its use for

other purposes.

To use low-impedance (not carbon) microphones, con-

nect the microphone of a single headset-microphone to a

Console MIC LEVEL lnput Jack (33) (see Figure 10, Page

13). Connectthe headset to the front-panel PHONES Jacks

(8). For high-impedance headphones, connect to the rear-

panel MONITOR LlNE LEVEL Jack (30). Additional head-

sets may be connected through

"Y"

adapters to the

PHONES or MONITOR LlNE LEVEL Jack. If additional

microphones are to be connected,

"Y"

adapters (Switch-

craft 391Q13,391Q53 or equivalent) should be usedto con-

nect these to the MIC LEVEL lnput Jack. Depress the

MONITOR Switch (12) for the talkback channel and adjust

the MONITOR LevelControl (10) as desired. Do notdepress

the PROGRAM Switch (13).

CHAN.

INPUT

MIC

LEVEL

lOl

AUDIO CONSOLE

PHONES

If this set-up does not work, and the microphone type

being used is unknown, it is possible that it is a carbon

microphone.To use carbon microphones such as found in

Western Electric-typeoperator's headsets,a battery power

supply is requiredto power the microphone (see Figure 11,

Page 13). A common battery may be used for powering a

number of carbon microphones, though each microphone

requires its own 100-ohm resistor and Shure A95 Series

line matching transformer.

Should a large number of headphones be required, a

power amplifier or headphone distribution amplifier should

be inserted in the headphone circuit between the MONI-

TOR LlNE LEVEL Output (30) and the distribution amplifier

input.

M64

STEREO

PREAMPLIFIER

CHAN.

LOW

LEVEL

OUTPUT

AUX

LEVEL

INPUT

TURNTABLE

FIGURE

11.

CARBON MICROPHONE POWER SUPPLY

ADDITIONAL MIXER INPUTS

Additional microphone or other source inputs may be

obtained using a high gain, low noise, microphone mixer

such as the Shure M68FC. When connected to a MIC

LEVEL lnput Jack (33), the M68FC and SR101 Audio Con-

sole will provide a total of 11 inputs (see Figure 12A, Page

14). (Note that adding a mixer at an lnput Jack converts

that channel to a submaster control; the total number of

inputs will thus be the mixer total plus the Console total

FIGURE

10.

TALKBACK CIRCUIT

minus 1 for the submaster.)

lOl

AUDIO

CONSOLE

LOW

IMPEDANCE

100

OHMS

1/2

ONLY

ONE

CHANNEL

USED

FOR

THIS

APPLICATION.

3-6V

CARBON

LANTERN

MICROPHONE

BATTERY

NEDA

915

,908

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 Console. The Console individual channel

Volume Control (1) then controls an entire section, fa-

cilitating adjustment of that section during a performance.

Withthis set-up, set the channel INPUTATTEN (14)to0 and

adjust the mixer volume controls inthe mid-to-high range;

adjust the mixer master volume control as required to keep

the Console volume control in the desirable middle range.

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

impedancemicrophone output. When using an M68FC-type

mixer into a Console MIC LEVEL lnput Jack (33), set the

mixer MIC OUT switch to low impedance, and make neces-

sary adjustments as described above. It is sometimes de-

sirable to use the auxiliary output from the mixer into the

Console channel 7 (or 8) AUX. INPUT Jacks (32) if the mixer

output is derived from a source which is not required con-

stantly (such as an orchestra); the same channel

(or 8)

MIC LEVEL lnputJack can beusedas a regular microphone

input, with the front-panel AUX-MIC Switch (14) selecting

one or the other for the program. (Refer to lnput Channels,

Page 5, for a description of the AUX-MIC Switch function.)

To usethis set-up with an M68FC mixer, connect a cable

between the mixer auxiliaryoutput (phonopinjack) and the

Console AUX. INPUT Jack (32) on channel 7 (or 8) (phone

jack) (Figure128, Page 14).Set the Console INPUT ATTEN

Control (14) to -20. To use this set-up with other mixers,

LOW IMPEDANCE

MIC LEVEL MIC LEVEL

AUX LEVEL AUX LEVEL

MlXER

LINE OUT OR AUX LEVEL

PHONES OUT

MIXER

PHONES

TOTAL:

CHANNELS

SRlOl

IN0

EQUALIZATION OR

MIXER

REVERB

~67INPUTS)

600n

;IP;

LINE OUT

MIXER SRlOl

AUDIO CONSOLE

FIGURE

12.

ADDITIONAL MIXER INPUTS

essenfially the same procedure is followed. The Shure M67

mixer,for instance, may be connected to the Console AUX:

INPUT Jack through the mixer line out connector (binding

posts) or headphone output (phonejack) (Figure 12C,Page

14). Because of the difference in outputs between 'the

M68FC and M67,the Console INPUT ATTEN Control, when

used with the M67, should be set at -30. Note that the

M67 microphone output should not be used into the Con-

sole AUX. INPUT without a line matching transformer.

If a mixer isto beused with the Console but itisdesirable

to maintain as many Console channels as possible, the

mixer can beconnectedto the Console LlNK OUT Jack (31)

(Figure 12D, Page 14). However, this requires sacrificing

the channel reverb, equalization and monitor functions for

the sources entering through the mixer (monitoring of the

total program can still be accomplished with the POST

LINKIPRE LlNK Switch (29) set to POST LINK). The only

Console control functions operating on the mixer sources

inthis set-up are the MASTER Volume Control (20), FEED-

BACK FILTERS Switches (15), and rear-panel PHASE

Switch (26). In addition, any mixer used in this set-up re-

quires a 2.2-kilohm resistor in series with the mixer output

to provide an attenuator bridging connection; the resulting

signal level will be down -10 dB (see Figure 12D, Page

14). The M67 Mixer headphone jack has suitable built-in

resistors and may be connected directly to the Console

LlNK OUTJack. Only mixerswith 600-ohm line outputs may

be used in this configuration. Note that the Shure M68FC

mixer cannot be usedthis way.

The mixer-to-link jack connection can also be used with

several mixers. Each mixer output must contain its own

2.2-kilohm resistor prior to being joined in a

"Y"

adapter.

Any number of M67 mixers may be interconnected by

connecting their headphone jacks in parallel. The paral-

leled headphone output is then connected to a Console

AUX. LEVEL lnput Connector (32). The INPUT ATTEN

Control (14) should be set at -20 as an initial position and

adjusted in balance with the M67 meter reading and the

channel 7 (or 8) Console Volume Control setting (1). In this

set-up the M67 VU meter switch should be set at +4, the

master volume to 3, and the individual volume controls to

7or

ADDITIONAL CONSOLE INPUTS (TWO CONSOLES)

A total of 16 microphone inputs can be obtained using

two Consoles in a common mix mode. Connect a cable to

the "slave" Console LlNK OUT Jack (31) and to the "mas-

ter" Console LlNK OUT Jack (Figure 13A, Page 15). Note

that the LlNK OUT Jack is both an input and output jack.

This interconnection provides a two-way path between the

two Consoles. When operating the two Consoles side by

side, the slave input can be monitored on the master Con-

sole as part of the total program output with the POST

LINK/PRE LlNK Switch (29) set to POST LlNK and the

PROGRAM MONITOR Switch (11) depressed. With the

POST LINKIPRELlNK Switch inthe PRE LlNK positionthe

Program Monitor only monitors the eight inputs on that

Console. The monitor point is switched ahead (PRE) of the

LlNK Jacks. In this set-up both Consoles contain the total

program mix. Each Console MASTER Volume Control (20)

is independent, and may be used to control two separate

programoutputs.

An expansion of this methodof interconnecting two Con-

soles which will enable full monitoring involvesthesacrifice

FIGURE

13.

ADDITIONAL INPUTS: TWO CONSOLES

INPUTS

OPTIONAL SLAVE

1111111

LINK LINK

111111

TO POWER AMPLIFIER

LINE

OUT OUT OUT

of one master Console input channel (Figure 13B,Page 15).

Connect a cable between the master Console channel 7

(or 8) AUX. INPUT Jack (32) (phone jack) and the slave

Console rear-panel MONITOR LlNE LEVEL Output Jack

(30) (phonejack). Set the master Console channel

(or 8)

INPUTATTEN Control (14)to -30, channel Volume Control

(1) to mid-range, and channel PROGRAM Switch (13) to

off. To monitor, for instance, channel 2 on the slave Con-

sole, depress the slave channel 2 MONITOR Switch (12),

release the PROGRAM MONITOR Switch (ll),and preset

the channel

Volume Control to mid-range. On the master

Console,depress the MONITOR Switch for channel

(or8),

and release the PROGRAM MONITOR Switch. With the

master Console MONITOR Level Control (1) previously ad-

justed for normal listening, adjust the slave Console MONI-

TOR Level Controlfor the same level.

The interconnections used in the above paragraph may

also be used ina set-up where the slave Console is to feed

a built-in, or "house" PA (Figure 138, Page 15). In this set-

up, the master Console feeds the portable power amplifier

and speakers, or

broadcast line feed, or a tape recorder.

Connect the slave Console program output, either LlNE

LEVEL (25,27) or MIC LEVEL (24) to the input of the

"house" PA. The master Console MASTER Volume Control

(20) will control the portable system speakers; the slave

Console MASTER or channel Volume Controls (1) will con-

"SLAVE"

SRlOl

AUDIO CONSOLE

trol the "house" speakers. Note that this set-up provides

total

selective channel monitoring from the slave Con-

sole at the master Console.

A different set-up that uses the slave Console as a sub-

master is made by connecting the slave Console LlNK OUT

Jack (31) to the master Console channel

(or 8) AUX. IN-

PUTJack (32) and theslave LlNK INJack (28) to the master

LlNK OUT Jack (31) (refer to Figure 13C, Page 15). In this

set-up the total mix from the slave Console enters channel

7 (or8) on master Console channelsand may be monitored

from the master Console; individual slave Console channels

must be monitoredfrom the slave Console monitor system.

This set-up is helpful.whenan orchestra (or band) is mixed

on the slave Console. The channel 7 (or 8) Volume Control

on the master Console provides a single control (sub-

master) to mix the total orchestra sound with the vocals.

The result is that the two MASTER Volume Controls (20)

provide two independent outputs, each with the total pro-

gram mix and eachwith separate equalization adjustments.

Note that two Shure SRllOs may be added to provide a

monitor output for the

inputs.

"MASTER"

SRlOl

AUDIO CONSOLE

REDUNDANT CONSOLE SET-UP

(TWO

CONSOLES)

Two Consoles can be connected in parallel such that

certain types of failure in one will not cause the loss of

channels connected to that Console; in a failure in the

INPUTS

TO POWER AMPLIFIER

AUDIO CONSOLE AUDIO CONSOLE

TO POWER AMPLIFIER,

TO HOUSE PA BROADCAST LINE. OR

TAPE RECORDEE

output of one Console, the channel inputs of both units

will be routed through the operative Console. This type of

system is termed "redundant," that is, the reliability of the

system is enhanced through parallel functioning devices.

Connect a cable between the LlNK OUT Jacks (31) of

each Console. Construct a resistor network as shown in

Figure 14, Page 16, and insert it between the LlNE LEVEL

Output Jacks (27) on both Consoles and the balanced

bridging input of the power amplifier. The resistor network

matches the output of the two Consolesto the balanced line

to the power amplifier.

A method of total redundancy using two Consoles is to

parallel-connect

("Y")

all inputs using Switchcraft 391Q13,

391Q53 or equivalent adapters. The second (redundant)

Console may be kept on with all Volume Controls (1,20)

down, and the required controls brought up to the desired

level only upon. failure of one channel. The same output

attenuator network as described above is required.

STEREO OPERATION

Stereo operation, for PA or tape recording purposes,

may be accomplished in several ways. The most common

are described in the following paragraphs.

Stereo operation is most easily achieved using the set-

up previously described in Monitor Mixer System, Page 8.

The use of Shure SRllOs as shown in Figure 5, Page 9,

provides for a stereo tape recorder mix which is separate

from the PA and stage monitor mixes.

Stereo operation may obviously be obtained by using

two Consoles in separate PA systems without any system

interconnections. If it is desired to have one microphone

connected to both systems, use

"Y"

adapter (Switch-

craft 391Q13, 391(2.53 or equivalent) on the microphone

and feed its output to a MIC LEVEL lnput Jack (33) on

FIGURE

14.

REDUNDANT CONSOLES

each Console. To record stereo tapes with this set-up,

connect the LlNE LEVEL Output Jack (25) on one Con-

sole to the left input channel of a stereo tape recorder and

the LlNE LEVEL Output Jack on the other Console to the

rightinput channel.

An alternate method of stereo operation using only a

single Console involves the use of the program output sys-

tem as one stereo channel (right) and the monitor output

system as theother channel (left).With microphonesplaced

for stereo effect, connect a PROGRAM LlNE LEVEL Out-

put Jack (25) to the right power amplifier and speaker set

(or the right channel input of a stereo tape recorder), and

the MONITOR LlNE LEVEL Output Jack (30) to the left

power amplifier and speaker set (or the left channel input

of the stereo tape recorder). Depress the channel PRO-

GRAM Switches (13) for the microphones assigned to the

right, and depress the MONITOR Switches (12) for micro-

phones assigned to the left. Release the PROGRAM MON-

ITOR Switch (11). Center microphones may be assigned

to both left and right channels by depressing both PRO-

GRAM and MONITOR Switches for those inputs. Note that

the channel MONITOR Switches should be preset and not

changedduring a performance becausethetotal MONITOR

level changes as a function of the number of inputs as-

signed to the MONITOR system. Also note that reverb is

obtainable only on those inputswhose PROGRAMSwitches

are depressed. This set-up works well for stage plays

where the left and right speakers are closely spaced,

such as to the sides of a narrow stage, and are projecting

into a deep room. Shure speaker columns are an ideal

speaker choice because of their wide horizontal coverage

pattern.

A convenient method of stereo recording is to record

the vocals on one tape channel and the instruments on

the other. For this set-up, connect either the Console MIC

LEVEL (24) or LlNE LEVEL (25) Output Jack to one chan-

nel input of a stereo tape recorder (refer to Tape Record-

ing, Page 12). Connect a microphone to the remaining

tape channel input; an omnidirectional unit suspended

from the ceiling will pick up the full acoustic output of the

instruments.

An expansion of the stereo recording set-up described

above-separate vocal and instrument channels-depends

on whether the stereo tape recorder to be used has a

single set of inputs (MIC) or whether it also has auxiliary

(AUX) inputs with separate volume controls. With micro-

phone and auxiliary inputs, connect the system as shown

in Figure 15A, Page 17. Place the vocal microphones as

required and connect them to the MIC LEVEL lnput Jacks

(33) of the Console. Connect the LlNE LEVEL Output Jack

(25) through a

"Y"

adapter to the auxiliary inputs of the

tape recorder. Place the instrumental microphones as re-

quired and connect them to the microphone inputs of the

tape recorder.

If the stereo tape recorder has a single set of inputs,

that is, when the auxiliary inputs are connected, the micro-

phone inputs are disconnected, or if separate volume con-

trol ofthe microphone and auxiliary inputs cannot be main.-

tained, then a stereo mixer such as the Shure M688 may

be used to combine the Console output prior to entering

the recorder (refer to Figure 15B, Page 17).Place the vocal

microphones and connect them to the Console MIC LEVEL

lnput Jacks (33). Connect the Console MIC LEVEL Output

Jack (25) to the MIC 4 input of the M688. Place the instru-

mental microphones as desired and connect them to the

MIC 1 (left) and MIC 2 (right) inputs of the M688. Connect

LlNK

OUT

SR lOl

AUDIO CONSOLE

POWER

AMPLIFIER

LINE

LEVEL I

RESISTIVE

NETWORK

LINK

OUT

SRlOl LlNE

AUDIO CONSOLE LEVEL

POWER

AMPL

BALANCED

BRIDGING

LINE LEVEL

INPUT

RESISTORS ARE CARBON COMP.. 112 W,5%

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