Shure SR101 Series II User Guide

SRlOl

Series 2 Audio Console

OPERATION AND SERVICE MANUAL

Evanston, Illinois

(SD)

(95E652)

Manufactured

SHURE BROTHERS INC.

222

Hartrey Avenue

60204

U.S.A.

Printed

U.S.A.

SR101 Series 2 Audio Console

SPECIFICATIONS

Equipment Type Number of

lnput Channels Power Output Voltage Gain*

Program

Monitor

Link

. . .

Accessory

Frequency Response

lnput Sensitivity Distortion

Noise

(300 Hz-20 kHz)

.....

. . .

. . . .

. .

. . . .

. . . . . . .

. .

. . . . . . . . .

. .

. . . .

All silicon transistor mixerlpre-

amplifier (20 Hz-20 kHz)

Hum and Noise

. . . .

+19

dBm (program line level)

.73

k3 dB MIC input to LlNE

LEVEL out

k3 dB AUX input to LlNE

LEVEL out

23 t3d~

out

. . .

.78 13 dB MIC input via PRO-

GRAM MONITOR to LlNE LEVEL out

GRAM MONITOR to PHONES out Input Clipping Level

nel MONITOR to LINE LEVEL out

.38 _t3 dB MIC input to LlNK OUT

(with 600-ohm termination)

out

. . .

.48 t2 dB MIC input to ACCES-

SORY output (via pins

PUTS)

43 i.3 dB MIC inputs to ACCES-

SORY output (via pin GRAM)

. .

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

source; 600-ohm load)

. . .

0.4 mV max. for f 4 dBm program output

THD less than

30 Hz -20 kHz; IM distortion less than 1% at t12 dBm

. .

128 dBV(equiva1ent input noise

at full gain)

78 dBm output noise (MASTER

Volume Control down)

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

MIC

input

MIC

LEVEL

k3 dB MIC input via PRO-

23 dB MIC input via one chan-

dB LlNK IN to LlNE LEVEL

1-8lIN-

91PRO-

at +12 dBm,

Signal to Noise Ratio

(20 Hz-20 kHz)

lnput Attenuation

MIC Input

AUX Input

Input Common

Mode

LOW-~requency

Equalization

Hig h-Frequency

kHz:

Rejection

. . . . .

. . . .

. . .

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)

. .

.Typically 81 dB at maximum out-

put with one channel Volume Control and MASTER Volume Control at 10 (approximately 60 dB gain)

.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 (INPUT ATTEN 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)

. . .

100 dB min. at 100 Hz (balanced

inputs)

. . .

-;I3 dB at 100 Hz with respect to 0 (flat) setting

k12 dB at 10 kHz with respect to

. . .

0 (flat) setting

'Measurement conditions: MIC input through

kilohms LlNK IN through LlNE

LEVEL

ohms. MONITOR PHONES terminated in 8 ohms: MASTER Volume. Channel ~olur;le and MONITOR Controls full up; all other controls and switches 0 or off.

terminated In

600

ohms PROGRAM LlNE LEVEL and MONITOR

600

O~~~.'PROGRAM MIC LEVEL terminated in

150

ohms, AUX input through

150

SR101 Series 2 Audio Console

SPECIFICATIONS

Feedback Filter VU Meter Calibration

Frequencies

Tone Oscillator

lnput Impedance

at 1 kHz:

Microphone Auxiliary

(Channels

and 8). .I70 kilohms unbalanced

Link Input .35 kilohms unbalanced

Output Impedances:

Program

Monitor

Link Output

Monitor System

Reverberation

System

Link Jack System

.......

........

.I30 Hz; 800 Hz; 2 kHz; 5 kHz

1 kHz; less than 1% distortion;

.....

.1.2 kilohms balanced (for use

........

.......

.........

......

.......

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

......

Balanced line level: 120 ohms

Microphone level: 0.5 ohms actual

.Unbalanced line level: 600 ohms

Headphones: 3 ohms

ACCESSORY AUX LEVEL

.600 ohms (actual)

Headphone andlor 600-ohm line

Spring type with individual chan-

External signal conditioning out-

variable level

with 25- to 600-ohm' phones)

actual (for use with 600-ohm lines)

(for use with 25- to 600-ohm inputs)

actual (for use with 600-ohm or high-impedance phones, or 600-ohm lines)

use with 4- to 16-ohm headphones)

anced) pins 1-811NPUTS: 33

actual (for use with 3-

ohms

kilohm

PROGRAM: 600 ohms actual

output; individual and mixed channel select or program; pre-

and post-link monitoring

nel and low-frequency equalization

putlinput; amplifier and tape recorder signal output; connection (mix bus); remote master volume

or greater loads); pin 91

intensity controls and high-

high-level auxiliary

multiple Console

control

micro-

actual (for

(unbal-

Phasing (polarity).

Phase Switch Output polarity-reversing switch

30 Vdc Bus

Operating Voltage

Power Consumption

Temperature Range:

Operating Storage

Dimensions

Installation

Weight

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

Finish Certifications

.........

..........

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

..........

...........

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

.........

...

$4 dBm (1.23 Vrms) at 1 kHz to

600-ohm load (METER TlVlTY ~ontrol'in [22 dB-range METER SENSITIVITY position provides 0 VU reading of -18 ohm load]

.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 OUTPUT out of phase with the above.

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

.Pin 10 on ACCESSORY

LEVEL connector is regulated +30 ground (earth). May be used to power accessories with up to

....

.90-132 Vac, 50160 Hz (SR101)

90-132, 180-250 Vac, 50160 Hz

(SR101-2E)

...

20 watts max. (Console only). 500

watts max. (SWITCHED A. receptacle)

-7' to 54OC (20' to 130°F)

-29' to 71°C (-20' to 160°F)

.311 mm x 483 mm x 162 mm

(121/'"

Equipped for standard 19" rack

mounting be operated in accessory AlOlA Carrying Case or in custom control center

.22 Ib (10 kg)

Matte black, with beige write-on

trim strip

Listed by Underwriters' Labora-

tories, Inc.; listed by Canadian Standards Association as certified

Control in full clockwise dBm (0.1 Vrms) on 600-

~3.5 Vdc supply; pin 11 is

mA.

H x 19" W x 6%''

(12%" height); may

(SRIOI only)

CAL position)

SENSI-

AUX

iii

SR101 Series 2 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

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3 3 4 5 5 7

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7 8 8 9 9 9

9 10 10 11

11 11 12 12 12 13 13

Section Page

Additional Console Inputs (Two Consoles) Redundant Console Set-up (Two Consoles) 15 Stereo Operation 16 Remote Volume Control 17 Telephone Line Surge Protection 17

SERVICE INSTRUCTIONS

Console Service 18 Replacement Parts 18 Fuse Replacement 18 Knob Replacement ServiceAccess 18 Lamp Replacement 18 Reverberation Assembly 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 CONDENSED OPERATING INSTRUCTIONS

ARCHITECTS' AND ENGINEERS'

SPECIFICATIONS 47

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

LIST

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18 20 20 20 21 22 22 22 22 22 22

23 47

SR101

Figure Page

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

SR101 Audio Console Rear Panel

SRlO1 Audio Console Dimensional

Outline Drawing SR101 Audio Console Block Diagram

4 5 Monitor Mixer Applications 6 Tone Oscillator Applications 7 Preamplifier-Console Connnections 8 Tape Recording 9 Record Playback 13

Talkbackcircuit

10 11 Carbon Microphone Power Supply 12 Additional Mixer Inputs 13 Additional Inputs: Two Consoles 14 Redundant Consoles 15 Stereo Tape Recording

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Series 2 Audio Console

LlST

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

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

ILLUSTRATIONS

........

.........

..........

2 5

9 10 11 12

13 13 14 15 16 17

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 22 Board 3: Program Mix Amplifier 23 Board 4: Reverb Mix Amplifier 24 Board 5: Program Output

26 Board 7: Reverb Spring Amplifier 27 Board 8: Monitor 28 Board 9: Power Supply 29 Board 30 Transistor Lead Codes 31 32 Circuit Diagram

28: Reverb Equalizer

Board 6: Feedback Filters

0: Program Mute

SR101-2E Power Supply

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.4 4-45

21 33 34 34 35 35 36 37 37 38 38 39 41 42

SRIOI Series 2 Audio Console

DESCRIPTION

(Shown

in Carrying Case AlOlB

AIOIA

with

Panel Lamp)

The Shure Model SR101 series 2 Audio Console is a solid-state, eight-channel microphone mixer-preamplifier that enables the operator to mix as many as eight microphones 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. In addition, channels

and 8 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 monitor switches permit the operator to select the input signals

to be routed to each of 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 unbalanced 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 equipment such 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 connected to the front panel lamp connector for illumination of controls. Accessory equipment drawing up to 500 watts

may be connected to the rear-panel switched ac receptacle.

A front-panel trim strip provides space for pencilled notations.

The regulated power supply is designed to operate over a wide range of input voltages, permitting the use of extremely long ac extension cables without performance degradation.

The solid-state components in the

SR101 Audio Console 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

(SRI 01 only).

The following accessories are specifically designed for

use with the

SRlOl Series 2 Audio Console:

AlOlA Carrying Case A101 B Panel Lamp Accessory SR110 Professional Monitor Mixer

FIGURE 1. SRlOl SERIES 2 AUDIO CONSOLE FRONT PANEL

(SR101

Only)

FIGURE

(SR101 - 2E

SRlOl SERIES 2 AUDIO CONSOLE REAR PANEL

Only)

SR101

Series 2 Audio Console

OPERATING INSTRUCTIONS

FUNCTIONAL IDENTIFICATION (Refer to Figures 1 and 2, Page 2.) NOTE: All push-button switches are "on" when in (depressed) 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 channel separately.

Con-

OUT-

2. REVERB INTENSITY Rotary Controls (Eight) 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 Adjusts low-frequency reverb signal equalization. lndividual Channel FREQuency EQualizer-LOW Rotary

Controls (Eight) ization for each channel.

6. REVERB FREQuency

Adjusts high-frequency reverb signal equalization.

7. lndividual Channel FREQuency

tary Control (Eight) equalization for each channel.

8. PHONES Output Jack

stereo or monophonic headphones for monitoring.

9. Panel LAMP Accessory Connector nection for optional panel lamp accessory to illuminate front panel.

10. MONITOR Level Rotary Control level to PHONES Jack (8) and MONITOR OUTPUT/ LlNE LEVEL Jack (30).

11. PROGRAM MONITOR Push-Button Switch nects total program output (all channels and reverb) to PHONES Jack (8) and MONITOR

LEVEL Jack (30).

12. lndividual Channel MONITOR Push-Button Switches

(Eight) out reverb) to PHONES Jack (8) and MONITOR PUT/LINE

ITOR Switch (11) is off.

13. lndividual Channel PROGRAM Push-Button Switches (Eight) gram output.

14. lndividual Channel INPUT Switches (Eight) tenuation for each channel. Dual switches on channels 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 Turns on and adjusts level of 1 internally for set-up purposes.

17. True VU Meter output. (Meets all current standards for VU Meters).

18. METER SENSITIVITY Rotary Control 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 program output.

Connect individual channel outputs (with-

LEVEL Jack (30) when PROGRAM MON-

Connect individual channel inputs to pro-

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

Oscillator LEVEL SwitchIRotary Control

EQualizer-LOW Rotary Control

Adjust low-frequency signal equal-

EQualizer-Hlgh Rotary Control

EQualization-Hlgh Ro-

Adjusts high-frequency signal

Provides for connection of

Provides con-

Controls volume

OUTPUT/LINE

ATTENuator Rotary

Provide choice of input signal at-

kHz

tone generated

Indicates volume level of program

Adjusts VU

Adjusts level of total

21. Ac Grounded Line Cord to Console power supply 3AG-3/16A SLO-BLO Ac Fuse - Protects Console ac

22. input line against overload

23. SWITCHED A. C. Grounded Receptacle

to 500 watts of switched ac power to accessory equip-

iSR101 only).

ment

24.

PROGRAM OUTPUTSIMICrophone LEVEL 3-Pin Con-

nector program output.

25. PROGRAM (Two) nections to power amplifier.

26. PROGRAM verses phase (polarity) of program outputs with respect to inputs.

27. PROGRAM

Provides balanced output connection to power

amplifier.

28. LlNK IN Phone Jack- Provides input connection for external equipment (compressor, limiter, equalizer, etc.).

29. MONITOR Switch after external equipment connection to LlNK Jacks (28,

31).

30. MONITOR vides monitor output connection to power amplifier.

31. LlNK OUT Phone Jack for external equipment, or mix bus to add Consoles. INPUTS/AUX. LEVEL Phone Jacks (Two) - Provide

32. 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 output connection to Shure

35. AC (MAINS) POWER 3-Pin Connector-Connects ac power cable to Console power supply

36. VOLTAGE SELECTOR Slide Switch-Selects operating voltage range of 90 to 132 or 180 to 250 50/60

37. 180-250V 0.1 Console ac input line against overload

only).

GENERAL OPERATING INSTRUCTIONS

Provides low-impedance microphone-level

OUTPUTS/LINE LEVEL Phone Jacks

Provide balanced or unbalanced output con-

OUTPUTS/PHASE Slide Switch - Re-

OUTPUTSILINE LEVEL 3-Pin Connector

OUTPUTIPOST LINK-PRE LlNK Slide

Selects program monitoring either before or

OUTPUTILINE LEVEL Phone Jack - Pro-

Hz (SRIOI-2E only).

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

Connects ac power source

(SRlO1 only).

(SRlOl only).

Provides up

LlNE LEVEL and MIC LEVEL

Provides output connection

1 I-Pin Connector-Provides

SR110 Monitor Mixer.

(SRlOl-2E only).

WARNING

Voltages in this equipment are hazardous to life. Make all input and output connections with ac power disconnected. Refer servicing to qualified service personnel.

1. Using hardware provided, install Console securely in standard ing Case prior to making electrical connections. For custom installations, see mounting template supplied with Console. If desired, connect Accessory to LAMP Connector (9).

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

AlOlB Panel Lamp

Vac,

(SR101-2E

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

3. Connect desired PROGRAM OUTPUT/LINE LEVEL Connector ing cable. (NOTE: Shure are supplied with audio connecting cables.) If Console output is to be fed to another mixer or tape recorder microphone input, use PROGRAM LEVEL Connector (24). If desired, connect monophonic 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 (33). Any high-quality dynamic, ribbon or condenser low-impedance microphone may be used. Connect high-impedance microphones or auxiliary high-level sources to channels 7 or 8 only. If AUX. LEVEL Connectors are used, set corresponding front-panel ATTEN) Switch (14) to AUX.

5. If external signal-processing equipment such as an equalizer, compressor or limiter is to be used, connect Console equipment input and Console to external equipment output. (See Link Jacks, Page

SR101: Connect ac line cord (21) to grounded 90- to 132-volt,

Line cord

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, yellow lead to ground or earth terminal. (Connector should be installed by qualified service personnel.)

Select proper operating voltage (90-132V or 250V) that switch positions are marked 115 and 220 volts.

Make certain proper fuse is installed in fuseholder

(37):

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 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 that channel initially to for instrumental music, or to -20 or -30 for "hard"

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

0. Set rear-panel PHASE Switch (26) to 0'. (25,27) to power amplifier input connect-

SR105 Power Amplifiers

OUTPUT/MIC

INPUTS/MICROPHONE LEVEL Connector

INPUTS/AUX. LEVEL Connectors (32) in

MIC/AUX (INPUT

LlNK OUT Connector (31) to external

LlNK IN Connector (28)

for detailed information.)

50/60 Hz ac source.

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

blue lead to neutral terminal, and green/

using VOLTAGE SELECTOR Switch (36). Note

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

warmup time. This warmup time

ATTEN Control (14) for

0 for normal or PA use, to -10

180-

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. Have someone 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, increase METER SENSITIVITY Control until normal me-

ter movement

occasional peak excursions into red area

operation in black area of scale with

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 excessively 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 decrease MASTER Volume Control in order to maintain channel Volume Control setting. Ideally, channel Volume Control should remain approximately at mid-

range (7-9) to facilitate increases or decreases in control setting due to program change; INPUT Control (14) adjustment will aid in maintaining this setting. If feedback occurs below desired sound level,

consult section on Feedback

9. Set HI and LO FREQ EQ Controls (7,5) for channel in use. Vertical position sponse. Clockwise quency (treble) or low-frequency (bass) equalization

and counterclockwise

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 settings are: speech 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-

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

TOR 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 desired, 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, intermission), it is not necessary to turn off Console power. It

is designed to operate continuously, and optimum performance is maintained after internal voltages are allowed to stabilize. Also, do not turn off all microphones.

Leave the master or announcer's microphone on (PROGRAM Switch depressed) so that unattended, announcements may be made, and the Console operator will be alerted that the next performance is about to begin.

MOUNTING AND VENTILATION

The Shure 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 provided with the Console. These screws may also be used if the Console is to be custom-mounted in a metal-top control center.

A custom-mounting template is supplied with the Console. Cutting dimensions and drill hole locations are given, as are clearances for insertion and ventilation. The

SR101 Audio Console may be operated in a

(0) indicates "flat" frequency re-

(+)

0, vocals - 3-6, instruments

Filters

settings increase high-fre-

(-)

settings decrease fre-

(Page 8).

the Console is left

ATTEN

dimen-

sions given should be followed to provide adequate cable clearance (see Figure 3, Page 5).

In either rack- or custom-mounted installations, consider rear-panel access before installation is made. Although most installations will not require frequent access, it should 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

FIGURE

DIMENSIONAL OUTLINE DRAWING

SRlOl AUDIO CONSOLE

DEPTH.

POWER SUPPLY

SR101: The SR101 regulated power supply is designed 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

(22) and a wired-in

3/10-ampere slo-blo fuse in series. A

3/16-ampere slo-blo fuse

wired-in 1-ampere slo-blo fuse protects the 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

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

SR105. Note that the receptacle is switched but not

Shure

fused; all accessory equipment used with the Console

should contain its own fuse.

SR101-2E: The SR101-2E regulated power supply is designed to operate from either 90 to 132 volts ac or 180 to 250 volts ac,

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

line cord does not have a connector on the power source end of the cord. Obtain a suitable three-pin male ac connector 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

rear-

SR101-2E

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

(See Figure 4, Page 6)

Each 3-pin professional audio input Microphone Connector (33) feeds its own low-impedance lnput Transformer, which provides a gain increase of 23 dB. Channels

also contain switchable AUX 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

A6 to $30 dB gain increase. The amount of gain provided by the Preamplifier (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 individual Channel Volume Controls and feed the individual Channel Equalizer (HI and LO FREQ EQ) Controls which decrease the signal approximately 2 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 Channel Equalizer outputs going to the Program circuits

go first to the individual channel PROGRAM Switch

SR110 Monitor Mixers. The

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

depressed

the REVERB INTENSITY Control feeds the

REVERB Switch (3)

Reverb Intensity Mix Amplifier, Reverb Equalizer, Reverb Driver and Differential Amplifiers, Reverb Output Mix Amplifier, and then 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

MONITOR Switch (1 through the MONITOR Level Control Amplifier, and to the rear-panel MONITOR

I), where it may be selected to continue

(lo), +40 dB 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 connected 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

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

a 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

and 8

(73)

(13),

NOTE

(

TYPICAL OF CHANNELS 1-8

lMlCROPHONE LEVEL

200

HIGH

X~~~

1+23 dB1

RESISTOR

0-30 dB CHANNEL

INPUT

ITTEN

TONE

OSC

LEVEL

VOLUME - CHANNEL

(SECTION

CHANNEL REVERB

VOLUME

(SECTION

-2

dB REVERB

EWALIZER

0) (SECTION A)

pimq

OUT

IN (SECTION 0)

FEEDBACK

FILTERS]

INTENSITY

(SECTION

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

ON CHANNELS

AND 8 ONLY.

FlGUR,E

[PHASE]

MASTER

VOLUME

MON

LEVEL

1-10 dB1

SRlOl SERIES 2 CONSOLE BLOCK DIAGRAM

PROGRAM OUTPUTS

LEVEL

Output Transformer. The Transformer feeds three LlNE

LEVEL Output Connectors (25,27) and a MIC LEVEL Output Connector

to $-31 dB Amplifier also feeds the METER SENSITIVITY Control (18), which goes to a +22 dB Meter Amplifier, and then to the VU Meter (17).

The Console also contains a 1 use in set-up and checkout. The Generator is activated and controlled by the TONE OSC LEVEL and the control output is fed to the Program Mix Amplifier.

A detailed description of the Console circuits and controls and their uses is provided in the following paragraphs of this section.

(24), which is at

dB below line level. The

kHz Tone Generator for

SwitchIControl (16),

INPUT CHANNELS

Eight professional, three-pin, audio MICROPHONE LEVEL lnput Connectors (33) are provided on the upper rear panel of the Console. The Console is designed to operate with high-quality, low-impedance dynamic, ribbon or condenser microphones. Two additional AUX. LEVEL In-

and

put Connectors (32) are provided for channels These standard quarter-inch phone jacks allow connection to auxiliary high-level sources or high-impedance micro-

phones. Switches on the channels 7 and Control (14) allow the user to select between either the low-impedance microphone input (MIC), or the pedance auxiliary input (AUX). Each low-impedance microphone input is connected to a low-impedance, balancedinput transformer, the output of which is connected to a 0-30 dB input attenuator. On channels 7 and of the low-impedance microphone transformer and the AUX. LEVEL lnput Jack (32) terminate in the AUX-MIC Switch. The output of this switch goes 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 AUX input circuit. When the AUX input is not selected, this

resistor is grounded, placing the input. If the source connected to this input is also bridged to feed other inputs, an additional isolation resistor may be required.

The INPUT

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 microphone placement, and to compensate for high output levels from condenser microphones.

The Channel Volume Control (1) is a dual control: one section, in a feedback circuit, sets the gain of the preamplifier, and the second section is a preamplifier output

ator.

input clipping level as the Volume Control is reduced to lower settings. Ideally, the control should operate in the

middle range, between 7 and complished by proper INPUT

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

equalizer circuit. Individual HI and LO FREQ EQ controls

(7,5)

channel without affecting the other channels on the Console. 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

I-kilohm isolation resistor is provided in the

I-kilohm load on the AUX

ATTEN (14) four-position switch provides

This circuit configuration increases the preamplifier

This can generally be ac-

ATTEN Control (14) setting.

allow the user to shape the sound of each input

INPUT ATTEN

the outputs

high-im-

attenu-

(+)

a 1 kHz hinge point. Control settings with plus

(-)

indicate boost, and minus setting provides a normal or "flat" frequency response.

The output of the equalizer feeds the channel PROGRAM and MONITOR Switches selects the channels to be connected to the program out-

put. The MONITOR switches select the channels to be connected to the monitor output. The two switches are independent and have no effect on each other.

markings denote cut. A 0

(13,12). The PROGRAM Switch

markings

SOURCE CUING

Microphones, tape recorders, or other sources may be preset, or cued, during a performance in the following manner. With PHONES Jack (8) or rear-panel Jack (30) (high-impedance headphones only), depress the PROGRAM MONITOR Switch (11) and a PROGRAM Switch (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 microphone placement and the performer's microphone technique 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 (14) setting is required, wait until the vocalist takes a breath or the instrumentalist takes a rest to 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 is set too high when the channel is turned on, the sound may "blast" the audience, or cause acoustic feedback, or both. Either condition will prove embarrassing to the Console operator.

headphones connected to the front-panel

MONITOR

(1)

level. If a change in the INPUT ATTEN

LlNE LEVEL

REVERBERATION

The SR101 Audio Console contains a built-in electromechanical spring-type reverberation device utilizing four coil springs in two transmission paths. Reverberation is accomplished 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

is sensitive to mechanical shock.

The Console is designed to provide a foundation of "dry,"

or non-reverb, signal on the total output, no matter how the channel REVERB INTENSITY Controls (2) are set. Of great

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

increased without increasing overall gain.

which employ artificial reverberation, the total gain

In most units

in-

creases as the intensity of the reverberant signal is increased. This generally leads to acoustic feedback. However, the 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

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

The reverb mix amplifier combines the output of all channel REVERB INTENSITY Controls sending it to the REVERB FREQ EQ Controls output of the reverb equalizer circuit drives the reverbation system. The separate REVERB FREQ EQ-HI and -LO Controls 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 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 differential amplifier whose output is connected to the REVERB Switch (3). This switch turns the reverb system on (in) and off (out) without affecting the overall level or the RE-

VERB INTENSITY Controls (2). In this manner, the REVERB INTENSITY Controls may be preset, and when the REVERB Switch is depressed, the reverb level is predetermined. The reverb signal, after passing through the REVERB Switch, is routed to the program mix amplifier and combined with the "dry" signals from the program channels.

SR101 Audio Console reverb mixing system

0 for

(2), mixing the signal and

(6,4). The

"boomy" (low-frequency resonant) room, de-

MONITOR SYSTEM

The output of the individual channel MONITOR Switches

(12) are combined in the monitor mix amplifier. The channels 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 output to be fed to the monitor output. This may be useful for providing a

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 contribution 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

talkback or for a "click track" signal feed.

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

monitor output amplifier. The signal from this amplifier

appears on the MONITOR

on the rear panel, and also through a headphone matching

transformer to the PHONES Jack

These two outputs may be used simultaneously.

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

impedance) without rewiring. High-impedance mono-

phonic headphones may be connected to the rear-panel

MONITOR

to use headphones to 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. Note that it is also possible to use the monitor output to

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

nel

signal on the program output.

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 instruments have microphones but the 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 to the input of an auxiliary power amplifier that is connected in turn to monitor speakers located on stage.

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

OUTPUT/LINE LEVEL Jack (30)

(8)

on the front panel.

(8)

Note that the front-panel PHONES Jack

OUTPUTILINE LEVEL Jack (30).

The purpose of the monitor system is to allow an operator

or 8 AUX. LEVEL lnput Jack (32) without having the

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

OUTPUT/LINE LEVEL Jack (30) is connected

permits the

MONITOR MIXER SYSTEM

The rear-panel ACCESSORY OUTPUT/AUX LEVEL Connector (34) of the to eight Shure

put of each individual channel after the volume, equal-

ization and attenuation channel controls appears on this connector as do the and the power supply connections. The

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

can provide a separate stage monitor "mix" that follows the program "mix" levels coming from the eight channels of the track recordings: use two quadriphonic.

line level inputs to its mixing circuitry, one high-impedance,

unbalanced, line level input to its Output Selector Switch for monitoring the program mix, and one line level,

ohm, balanced output. Individual channel and master vol-

ume 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 lnput position ob-

tains the mixed signal at the PRE

(29).

female connectors. These connectors permit the connect-

ion of additional tandem or "stacked"

application is shown in Figure

SRlOl Series 2 or similar equipment. The SR110

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

The

SR110 provides eight high-impedance, unbalanced,

The SR110 has parallel accessory inputloutput male and

SR101 provides for interconnection to up

SR110 Professional Monitor Mixers. The out-

LlNK INPUTIOUTPUT total mix signal

SRllOs for stereo and four for

LINK/POST LlNK Switch

SRI10 is a self-

600-

SRllOs. A typical

Page 9.

POWER PA

AMPLIFIER SPEAKERS

LEVEL

SRllO STAGE

MONITOR

MIXER

SRllO

MONITOR

MIXER

MONITOR

FIGURE

PROGRAM

SR110 MONITOR MIXER APPLICATIONS

MIX

AMPLIFIER

POWER MONITOR

AMPLIFIER

STEREO

RECORDER

SPEAKER

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 connected through a 560-ohm mixing resistor to the LlNK

(28,31).

Jacks

LlNK JACKS

The LlNK Jacks (28,31) on the rear panel of the Console enable the user to interconnect more Consoles for additional 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 IN Jack (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

levels in the 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

Hz,

800

Hz,

filters whose center frequencies are 130

and

kHz.

These jil'lers are designed

minimize

kHz,

the

acoustic feedback (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 affecting 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.

If feedback is present, locate the one FEEDBACK FILTER

Switch (15) which eliminates it. Then increase the VOLUME

(1) or FREQ EQ Controls (5,7) as desired until another feedback 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 reduce overall gain 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-

back filters.

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 of the MASTER Volume Control (20) (the

other half is a preamplifier output 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-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 MIC LEVEL outputs. The LlNE LEVEL output is connected to one professional

threepin, male, audio output connector (27) and two three-circuit phone jacks (25). The MIC LEVEL output is a

low-im-

pedance output, 50 dB below the LlNE LEVEL output, 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

also

output is used and a phone jack output is

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 the VU Meter (17) circuit.

VU METER CIRCUIT

To allow a wide range of signals to be handled by the VU Meter output of the program amplifier is fed to the METER SENSITIVITY Control (18) which in turn feeds the VU Meter amplifier 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 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. The TONE OSC LEVEL Con-

trol 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 by passed.

When using the tone oscillator, calibrate the Console VU Meter (17) and proceed as follows: With the METER SENSITIVITY Control (18) set to CAL, increase the MASTER

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

until a reference level has now been established. The Console LlNE LEVEL Output the MIC LEVEL Output (24) 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

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 between the Console MIC INPUT Jack (33) (any channel) and the MIC LEVEL Output Jack (24) (refer to Figure

10). Connect headphones to the PHONES Jack (8). Release the PROGRAM MONITOR Switch being used, depress the MONITOR Switch PROGRAM Switch to 0, the channel Volume Control (1) to mid-range, and INPUT 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

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-

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

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

a-nd ON-OFF Switch (16) injects the 1 kHz tone into the

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

(25,27) is now +4 dBm (1.23 volts) and

6A, Page 10). By adjusting the input

(ll), and for the channel

(12), release the

(13), and set the FREQ EQ Controls (5,7)

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

good microphone cable, make the connec-

6B, Page

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 being checked (Figure

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

The tone oscillator may also be used to provide a check

of cables and equipment connected to the link output. With

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

the ternal equipment, such as a Shure SE30 Gated

pressor1Mixer connect the program output, either at the back of the Console, power amplifier or speakers (Figure 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

Slide the MASTER Volume Control down to set-up condition, the external equipment may now be calibrated or checked out without affecting the program output. After calibrating the external equipment, turn off the tone oscillator, and return the MASTER to 7. Reconnect the

power amplifier or speakers.

MIC~

AUDIO CONSOLE AMPLIFIER RECORDER

which in turn feeds a broadcast line, dis-

ILINE,

SR I01 POWER TAPE

MIC LEVEL

INPUT JACK OUTPUT JACK

INPUT JACK

AUx.

POWER AWL

SR lOl

AUDIO CONSOLE

FIGURE

6C, Page 10). Set the MIC/AUX

6D, Page 10).

Meter (17) reading.

0. Under this

LINE^

AUDIO CONSOLE

LEVEL

AUDIO CONSOLE

PHONES JACK

TON'E OSCILLATOR APPLICATIONS

MIC LEVEL

lOl

OUTPUT JACK

101

LlNE LEVEL

AUX LEVEL

INPUT JACK

C0E;:SOR

GATED

MIXER

or 8)

Com-

BASIC OPERATING HINTS

Should any difficulty be encountered in Console operation, the problem may often be traced to some simple source

is offered as a basic guide to problems of this sort.

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

Symptom:

Check: 1. Check that PROGRAM Switch or Switches

such as an error in interconnection. The following

out)

that Console is plugged in.

Check that POWER ON-OFF Switch (19) is on.

3. Check to see that rear-panel SLO-BLO Fuse (22) is good. 2. Check that channel PROGRAM Switch (13)

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

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

(13) are depressed.

"dead" (no output, VU Meter lamps

3AG-3116A Check: 1. Check for defective input cable or source.

Symptom:

2. Check that cable from PROGRAM PUT/LINE accidentally been connected to PROGRAM OUTPUT/MIC LEVEL Connector (24).

3. Check that PHASE Switch (26) is not between positions.

4. Check that external equipment is properly connected to

One channel is "dead" (other channels

ating properly)

is depressed.

and 8 only) is not between positions or in

the wrong position.

LEVEL Connector (27) has not

LINK Jacks (28,31).

OUT-

oper-

SR101 Series 2 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 information on special set-ups to more fully utilize (10 ft.) of high-impedance, single-conductor, shielded the capabilities of the Console.

HIGH-IMPEDANCE MICROPHONES

UP to two high-impedance dynamic, ribbon or condenser microphones (crystal or ceramic microphones are not recommended) can be used with the need for line matching transformers simply by using the AUX. INPUT Jacks (32) on channels corres~ondincl INPUT ATTEN Switch (14) to AUX. NOTE:

very highoutput produced by s0m.e dondenser micro-

The

phones may be compensated for by proper setting of the

INPUT

the low-impedance MIC LEVEL Input Jacks

matching transformer (Shure A95 Series) must be used.

ATTEN Control.

If a high-impedance microphone is to be used with one of

Console without the

or 8 and moving the

(33), a line

cable (Belden phone and line matching transformer, and add as much

low-impedance, two-conductor, shielded cable #8412,' and Console input jack. These precautions will help avoid high-frequency hum and noise.

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

#8401, #8410, or #8411) between the micro-

(Belden

or #8422) as necessary between the transformer

signal loss and reduce the possibility of

INSTRUMENTS

(non-electrified), acous-

neces-

AUX OR HEADPHONE OUT

PREAMPLIFIER

3.05

(10') MAX.

FIGURE

-I

A95 LINE

MATCHING

TRANSFORMER

LOW IMPEDANCE

MICROPHONE

PREAMPLIFIER-CONSOLE CONNECTIONS

PUP

LOW IMPEDANCE HIGH IMPEDANCE

CABLE

305 m (1000')

MIC LEVEL

INPUT

AUDIO CONSOLE

lOl

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