nection (common mix); remote
master volume control
...
0, f4, +8 dBm, switch-select-
able (0.775, 1.23, 1.95 Vrms) at
1 kHz to 600-ohm load. [VU
RANGE Switch in
provides
(0.775 Vrms) to 600-ohm load1
0 VU reading of 0 dBm
....
phase with pin 9 of ACCESSORY OUTPUT, tips of
OUTPUT and PROGRAM LlNE
LEVEL OUTPUTS, and pin 3 of
PROGRAM
MIC LEVEL OUTPUTS (PHASE
Switch in
of ACCESSORY OUTPUT out
of phase with the above.
LlNE LEVEL and
0" position). Pins 1-8
0 position
LINK
Phase Switch Output polarity-reversing switch
30 Vdc Bus .Pin 10 on ACCESSORY OUTPUT
Operating Voltage
Power Consumption
Temperature Range:
Operating
Storage
Dimensions..
Installation
Weight 7.7 kg (17 Ib)
Finish
Certifications Listed by Underwriters' Labora-
...............
................
.........
.........
.90-132 Vac, 50/60 Hz (SR109)
....
90-132, 180-250 Vac, 50/60 Hz
...
20 watts max. (Mixer only). 500
-7O to 54OC (20' to 130°F)
......
.......
.........
...........
.........
.-29O to 71°C (-20' to 160°F)
133 mm H
Equipped for standard 19 in. (483
Matte black, with beige write-on
(0°, 180') (reverses phase of all
program outputs)
connector is regulated +30
k3.5 Vdc supply; pin 11 is
ground (earth). May be used
to power accessories up to
50
mA.
(SR109-2E)
watts max. (SWITCHED AC re-
ceptacle)
mm D (See Page 4.)
(51/4 in. x 19 in. x 9% in.)
mm) rack mounting;
(133 mm) height; may be oper-
ated in accessory
rying Case or in custom control
center.
trim strip
tories, Inc.; listed by Canadian
Standards Association as cer-
tified
(SR109 only)
x
483 mm W X 232
(SR109 only)
5% in.
A105A Car-
Page 4
SR109
Professional Mixer
TABLE OF CONTENTS
Section
SPECIFICATIONS
DESCRIPTION
OPERATING INSTRUCTIONS
Functional Identification
General Operating Instructions 3
Mounting and Ventilation 4
Power Supply 5
Functional Circuit Description
Inputchannels
Monitor Mixer System
Program Mix Amplifier 7
Link Jacks
Program Output
19 Board 2: Channel Equalizer
20 Board 3: Main Board
21 Board 9: Power Supply
22 Board
23 Lead Codes
24 SR109-2E Power Supply Circuit Diagram 30
25 SR109 Professional Mixer Circuit Diagram .3 2-33
1: Preamplifier
0: Program Mute
..........................
......................
.....................
.......
..........................
......................
................
......................
....................
....................
...............................
13
17
24
25
26
27
27
29
......
..
Page 5
SR109
Professional
DESCRIPTION
Mixer
The Shure Model SR109 Professional Mixer is a solidstate, eight-channel microphone mixer-preamplifier that
enables the operator to mix as many as eight microphones
with individual control over input attenuation, volume and
high- and low-frequency equalization. The Mixer has three
outputs: a program output, an accessory output and a
headphone output. In addition, channels
switch-selectable inputs for use with either low-impedance
microphones or line level sources. A master volume control regulates program output.
The program output has both a 600-ohm, balanced line
level output and a low-impedance, balanced, microphone
output. The
with separate volume control. A pair of link jacks facilitate
connection to an additional mixer, or external equipment
such as compressors, limiters or equalizers.
The
to one or more Shure
The
mixer designed to provide a separate stage monitor mix
that follows the program mix levels. In addition, it may be
used in multi-track recording as a submaster mix panel or
mixdown panel.
The
put limiter with an in-out switch and an indicator lamp
that flashes when the limiter is operating. The front panel
also contains an overload indicator lamp that signals when
headphqne output is an &ohm balanced output
SR109 rear panel contains provisions for connection
SR110 Professional Monitor Mixers.
SR110 is a self-contained, eight-channel, line level
SR109 contains a peak-responding, adjustable out-
7
and 8 contain
the output is clipping in the non-limiting mode.
The Mixer contains a
switch to adjust sensitivity to indicate program output level.
A built-in 1 kHz tone oscillator facilitates synchronization
of all meters in a system.
space for pencilled notations.
The regulated power supply is designed to operate
over a wide range of ac line voltages, permitting the use
of extremely long ac extension cables without performance
degradation. Accessory equipment drawing up to 500 watts
may be connected to the rear-panel switched ac
receptacle
The solid-state components in the
Mixer are protected against damage as a possible result
of open-circuit or short-circuit conditions on the inputs or
outputs. All components are conservatively rated and are
operated well within their respective ratings to assure
long life and trouble-free performance.
The Mixer is supplied with rack-mounting screws and
spare fuses.
The Mixer is Underwriters' Laboratories, Inc., listed,
and is listed by the Canadian Standards Association as
certified
The following are designed for use with the
fessional Mixer:
(SR109 only).
(SR109 only).
SR110 Professional Monitor Mixer
A1 05A Carrying Case
VU
meter and a meter sensitivity
A
front-panel trim strip provides
SR109 Professional
SR109 Pro-
Page 6
14
13
FIGURE 1. SR109 PROFESSIONAL MIXER FRONT PANEL
15 16 17 18
19
27
28
FIGURE
(SR109-2E
2.
SR109 PROFESSIONAL MIXER REAR PANEL
Only)
2
Page 7
SR109
Professional Mixer
FUNCTIONAL IDENTIFICATION (Refer to Figures 1 and 2,
Page 2.)
NOTE: All front panel controls are numbered for ref-
erence only.
-
Individual Channel Volume Controls (Eight)
trol volume and input clipping level of each channel
separately. Channel 1 contains TONE
push-pull Switch - Pulling switch outward turns oscillator on, and rotating control adjusts level of 1
kHz tone generated internally for set-up purposes.
Individual Channel
tary Controls (Eight) -Adjust low-frequency signal
equalization for each channel.
nal equalization for each channel.
LIMITER Indicator Lamp
when LIMITER Switch (11) is turned on (IN).
OVERLOAD Indicator Lamp
load condition (output clipping) when LIMITER
Switch (11) is turned off (OUT).
True VU Meter
output. (Meets all current standards for VU Meters.)
PHONES Rotary Control
PHONES Jack (8).
PHONES Output Jack- Provides for connection of
stereo or monophonic headphones for monitoring.
9. MASTER Volume Rotary control and POWER
-Adjusts level of totai program output, and applies
ac power to power supply and SWITCHED AC
Receptacle.
THRESHOLD
Control -Sets threshold level of limiter function.
LIMITER IN-OUT Slide Switch -Turns program output limiter on and off.
Ac Grounded Line Cord
to Mixer power supply
3AG-3/16A SLO-BLO Ac Fuse - Protects Mixer ac
input line against overload
SWITCHED AC Grounded Receptacle
to 500 watts of unfused switched ac power to accessory equipment
PROGRAM
verses phase (polarity) of
PHONE LEVEL program outputs with respect to
inputs.
VU METER RANGE Slide Switch
(6) sensitivity for three ranges of program level indication in
ACCESSORY OUTPUT/AUX LEVEL 1 1-Pin Connector
Monitor Mixer.
15
dB ATTENUATORS/IN-OUT Slide Switches (Eight)
-
Provide choice of input signal attenuation for each
channel.
INPUTS/MICROPHONE LEVEL LOW IMPEDANCE
Three-Pin Jacks (Eight)
nection of low-impedance sources to channels 1
OUTPUTS/PHASE Slide Switch - Re-
dBm.
-
Provides output connection to Shure SR110
FREQuency EQualizer-LOW Ro-
FREQuency EQualization-Hlgh
-
lndicates limiting action
-
lndicates Mixer over-
-
lndicates volume level of program
-
Controls volume level to
ADJustment Screwdriver-Adjustable
-
Connects ac power source
(SR109 only).
(SR109 only).
-
Provides up
(SR109 only).
LINE LEVEL and MICRO-
-
Selects VU meter
-
Provide for balanced con-
Con-
OSCillator
switch
through 8 inputs, or line level sources to channels
and 8.
MIC/LINE Slide Switches (Two) -Select low-impedance (MIC) or line level (LINE) input connections for
channels
LlNK OUTPUT Phone Jack - Provides output connection to external equipment or common mix bus to
combine two or more Mixers.
LlNK INPUT Phone Jack - Provides input connection
from external equipment (compressor, limiter, equal-
izer, etc.).
PROGRAM
nector
power amplifier.
PROGRAM
(Two)
nection to power amplifier.
PROGRAM
Pin Connector
phone-level program output.
VOLTAGE SELECTOR Slide Switch -Selects operating voltage range of 90 to 132 or 180 to 250
50/60 Hz (SR109-2E only).
AC (MAINS) POWER 3-Pin Connector
line cord to Mixer power supply
180-250V 0.1
Protects Mixer ac input line against overload
(SR109-2E only).
GENERAL OPERATING INSTRUCTIONS
7
and 8.
OUTPUTS/LINE LEVEL Three-Pin Con-
-
Provides balanced output connection to
OUTPUTS/LINE LEVEL Phone Jacks
-
Provide balanced or unbalanced output con-
OUTPUTS/MICROPHONE LEVEL Three-
-
provides low-impedance micro-
-
Connects ac
(SR109-2E only).
AT/90-132V 0.2AT SLO-BLO Ac Fuse
Vac,
WARNING
Voltages in this equipment are
Make all input and output connections before ac
power is connected. Refer servicing to qualified
service personnel.
1.
Using hardware provided, install Mixer securely in
standard 19 in. (483 mm) rack or optional
rying Case prior to making electrical connections.
2.
Set front-panel switches to off or OUT and all controls
to
0.
Set rear-panel PHASE Switch (15) to
3. Connect desired PROGRAM OUTPUT/LINE LEVEL
Connector (23, 24) to
ing cable. (NOTE: Shure
supplied with audio connecting cables.) If Mixer out-
put is to be fed to another mixer or tape recorder
microphone input, use PROGRAM
PHONE LEVEL Connector (25). If desired, connect
monophonic or stereo headphones to front-panel
PHONES Jack (8). Connect speakers to power ampli-
fier.
4.
Connect one or more low-impedance microphones to
rear-panel
PEDANCE Connectors (19). Any high-quality dynamic,
INPUTS/MICROPHONE LEVEL LOW IM-
power amplifier input connect-
hazardous to life.
A105A Car-
OO.
SR105 Power Amplifiers are
OUTPUT/MICRO-
7
-
Page 8
ribbon or condenser low-impedance microphone may
be used. Connect line level sources to channel 7 or
8 connectors only. If line level inputs are used, set
corresponding
If external signal-processing equipment such as an
5.
MICILINE Switch (20) to LINE.
equalizer, compressor or limiter is to be used, con-
nect Mixer
equipment input and
external equipment output. (See
7, for detailed information.) If a Shure
LlNK OUTPUT Connector (21) to external
LlNK INPUT Connector (22) to
Link
Jacks,
Page
SR110
Monitor Mixer is to be used with the SR109, connect
multi-pin plug of
Connector (17) of
SR110 to ACCESSORY OUTPUT
SR109.
6. SR109: Connect ac line cord (12) to grounded 90- to
132-volt, 50160 Hz ac source. Line cord is a
2.4m
(8 ft), 3-conductor cord with 3-pin grounding plug.
If extension cords are required, use high-quality,
rubber-jacketed cable with 18 gauge (0.8 mm2) or
heavier wire.
SR109-2E: Obtain suitable &pin male ac connector
and attach to line cord: brown lead to "hot" or "live"
terminal, blue lead to neutral terminal, and
green1
yellow lead to ground or earth terminal. (Connector
should be installed by qualified service personnel.)
Select proper operating voltage (90-132V or
180250V) using VOLTAGE SELECTOR Switch (26). Note
that switch positions are marked 115 and 220 volts.
Make certain proper fuse is installed in fuseholder
(28):
O.1AT with switch set to 220, or 0.2AT with
switch set to 115. Insert female end of line cord into
chassis power connector (27) and connect male plug
to 3-wire grounded ac power receptacle providing
proper operating voltage.
7. Turn on front-panel MASTER Volume
ControllPOW-
ER Switch (9) and allow one to two minutes warmup
time. This warmup time allows the supply voltages
to stabilize and capacitors to charge to provide opti-
mum performance. Set 15 dB ATTENUATOR Switch
(18) initially to OUT for normal PA use, to IN for
"hard" rock music. For
nels 7 and 8), set
LINE INPUT sources (chan-
MICILINE switch (20) to LINE.
8. Set Master Volume Control (9) to 6. Set VU METER
RANGE Switch (16) to
(when using a Western Electric
0 for PA or telephone line use
308 Voice Coupler),
+4 for recording, or +8 for broadcast use. Have
someone sing or talk into microphone and raise channel Volume Control (1) to achieve desired sound level.
If meter reads low at proper sound level, reduce
power amplifier volume level and increase channel
volume level. For single microphone set-up, if meter
indicates excessively high level ("pinning" or "pegging" needle), decrease MASTER Volume Control to
obtain good meter reading and increase power amplifier volume level or input sensitivity to obtain proper
sound level. In multiple microphone set-up, it may be
necessary to decrease MASTER Volume Control in
order to maintain channel Volume Control setting.
Ideally, set the channel Volume Controls as high as
possible (consistent with an adequate mixing range),
and increase the MASTER Volume Control to obtain
a
0 VU Meter reading. Then increase the power amplifier level control to the desired level. Using the 15 dB
ATTENUATORS (18) may aid in maintaining this setting if the channel Volume Control is consistently
set low.
9. Set
HI and LO FREQ EQ Controls
use. Vertical position
response. Clockwise
(0) indicates "flat" frequency
(+)
(3,
2) for channel in
settings increase highfrequency (treble) or low-frequency (bass) level and
counterclockwise
(-)
settings decrease the high- or
low-frequency level.
10. With LIMITER Switch (11) in OUT position, OVERLOAD Indicator Lamp (5) will flash when Mixer output clipping level is exceeded. If limiting is desired,
adjust limiter as follows: Operate Mixer with program
material and adjust the channel and MASTER Volume
Controls (1, 9) for desired sound level. With small
screwdriver, turn THRESHOLD ADJ Control (10) full
counterclockwise. Set LIMITER
INIOUT Switch to
IN. Slowly increase (clockwise) THRESHOLD ADJ
Control until LIMITER Lamp
(4)
flashes intermittently,
indicating limiting action on program peaks. A con-
tinuous glow indicates an undesirable excess of lim-
iting: MASTER
andlor channel Volume Controls
should be reduced. Increasing channel or MASTER
Volume Controls will not increase mixer output above
the level just set. Should higher or lower maximum
output level be desired, increase or decrease
THRESHOLD ADJustment. (An alternate set-up pro-
cedure uses the TONE
OSCillator to produce a maximum desired VU level. The THRESHOLD ADJustment
is slowly increased (clockwise) until the VU Meter
reading just set is reduced by 1 dB. Note that with
this set-up, the program material level displayed on
the VU Meter will be lower because of the difference
between peak and average levels. However, limiting
action will take place at the same peak level. This
effect will be more evident on speech than on music.)
11. Monitor output is available at front-panel PHONES
Jack (8). Adjust PHONES Control (7) for comfortable
listening level.
12. NOTE: During temporary shutdown (break, intermission), do not turn off Mixer power. It is designed to
operate continuously, and optimum performance is
maintained after internal voltages are allowed to stabilize. Also, do not turn down all microphones. Leave
the master or announcer's microphone on so that if
the Mixer is left unattended, announcements may be
made, and the operator will be alerted that the next
performance is about
to begin.
MOUNTING AND VENTILATION
The Shure
SR109 Professional Mixer may be operated
in a standard 19 in. (483 mm) audio equipment rack (see
Figure 3, Page
5),
or in a Shure A105A Carrying Case.
Four rack-mounting screws are provided with the Mixer.
The Shure
rack-mounting space. When the
case, an additional rack-mounted unit such as the
A105A Carrying Case has a 7 in. (178 mm)
SR109 is mounted in this
SR110
Monitor Mixer may be mounted in the remaining 1% in.
(44.4 mm) space.
In rack-mounted installations, consider rear-panel ac-
cess before installation is made. Although most installa-
tions will not require frequent access, it should be re-
membered that input and output changes, and some switch
movements, will necessitate rear-panel access.
Page 9
FIGURE
3.
OVERALL DIMENSIONS
POWER
SUPPLY
SR109: The Mixer regulated power supply is designed
to operate from 90 to 132 volts ac,
50/60
Hz
without adjustments, allowing the Mixer to meet all specifications
over this wide range of ac input voltages.
A
three-conductor, grounded line cord (12) supplies ac power to the
Mixer through the front-panel POWER Switch (9). The
Mixer consumes 20 watts maximum (0.2 amperes) and the
ac line input is protected by a
(13) and a wired-in
3/10-ampere slow-blow fuse in series.
3/16-ampere slow-blow fuse
'(TYPICAL
-50 DB -1100 XFMR
ATTENUATOR ATTENUATOR
NOTE I
[-
m]
600A
RESISTOR
Y
OF
CHXNELS
23DB CHANNEL
200x~:HGH VOLUME CHANNEL
1-8)
m
0
v
0
PHONES
LEVEL
/
FIGURE
u
METER
1'
4.
SR109 BLOCK DIAGRAM
NOTES I MIC-LINE SWITCHES ON CHANNELS
2 TONE GENERATOR ON CHANNEL I ONLY
-
-
7
AND 8 ONLY
Page 10
These fuses should not be replaced with
CAUTION
any other size or type of fuse.
Accessory equipment may be connected to the
panel SWITCHED AC Receptacle (14). The accessory
equipment may consume up to 500 watts maximum, which
provides for use with high-power amplifiers such as the
SR105. Note that the receptacle is switched but not
Shure
fused; all accessory equipment used with the Mixer should
contain its own fuse.
SR109-2E: The SR109-2E regulated power supply is
designed to operate from either 90 to 132 volts ac or 180
to 250 volts ac,
VOLTAGE SELECTOR Switch (26). A three-conductor,
grounded line cord supplies ac power to the Mixer
through the front-panel POWER ON-OFF Switch (9). The
SR109-2E line cord does not have a connector on the
power source end of the cord. Obtain a suitable
male ac connector and install it on the line cord: brown
to "hot" or "live" terminal, blue lear to neutral terminal,
green/yellow lead to ground or earth terminal. (Con-
and
nector should be installed by qualified service personnel.)
The ac line is protected by a 0.1-ampere Slo-Blo fuse (for
180- to 250-volt operation) or a 0.2-ampere Slo-Blo fuse
(for 90- to 132-volt operation. A wired-in
fuse also protects the ac line.
FUNCTIONAL CIRCUIT DESCRIPTION
(See Figure 4, Page 5)
Each three-pin professional audio input MICROPHONE
LEVEL Connector (19) feeds its own low-impedance bal-
anced lnput Transformer, which provides gain of 23 dB.
Channels 7 and 8 also contain
which switch in a 50 dB bridging line-to-microphone
level Attenuator to accept line-level inputs. The lnput
Transformers (and, on channels 7 and 8, the
Switch) are fed to 15 dB ATTENUATOR Switches (18) and
then to the Preamplifier, which provides
gain. The amount of voltage gain provided by the Preamplifier (7 to 42 dB) is controlled by the Channel Volume
Control
as gain is reduced. The Preamplifier circuits contain the
individual Channel Volume Controls and feed the individual Channel Equalizer (HI and LO FREQ EQ) Controls
(3,2) which decrease the signal approximately 3 dB when
set to the 0, or "flat," setting.
fier and the ACCESSORY OUTPUT Connector (17) for
interconnection with
Mix Amplifier feeds through a 560-ohm resistor to the
LlNK jacks (21, 22). When accessory equipment is not
connected to the
the program signal is fed to the MASTER Volume Control
(9) and back to the ACCESSORY OUTPUT Connector.
a
The attenuated signal feeds a limiter, which is connected
to a Lamp Driver (for driving the LIMITER and OVERLOAD
lamps) and a Limiter THRESHOLD ADJ Control (10) for
setting the threshold of Limiter operation. Note that when
the LIMITER Switch (11) is turned off (OUT), the LIMITER
Lamp (4) will not light, but the OVERLOAD Lamp
flash whenever the output clipping level is exceeded.
The Limiter Attenuator also feeds a
Amplifier, also controlled by the MASTER Volume Control.
(I), providing an increase in input clipping level
The Equalizer outputs are fed to the Program Mix Ampli-
The output of the MASTER Volume Control, after feeding
0 dB gain Amplifier, is sent to a Limiter Attenuator circuit.
50/60 Hz, as selected by the rear-panel
3/10-ampere
MIC/LINE Switches (20)
+7 to +42 dB
SR110 Monitor Mixers. The Program
LlNK jacks, the jacks are bypassed and
+7 to +35 dB output
rear-
three-'pin
MIC/LINE
(5)
will
The signal then goes through a
and into the Program Output Transformer. The Trans-
former feeds three
24) and a MIC LEVEL Output Connector
50 dB below line level. The
fier also feeds the VU METER RANGE Switch
goes to a +22 dB Meter Amplifier and then to the VU
(6), and a PHONES Level Control (7), Headphones
Meter
Transformer and PHONES Output Jack (8).
The Mixer also contains a
in set-up and check-out. The Generator is activated and
controlled by the channel 1 Volume
Switch
and their uses is provided in the following paragraphs of
this section.
INPUT CHANNELS
LEVEL lnput Connectors (19) are provided on the rear
panel of the Mixer. The Mixer is designed to operate with
high-quality, low-impedance dynamic, ribbon or condenser
microphones. Each low impedance microphone input
connected to a low-impedance, balanced-input transformer
through a 15 dB input ATTENUATOR (18). Two
Slide Switches (20) are provided for channels 7 and 8.
These switches allow the user to select between either
low-impedance MICROPHONE or
additional line level inputs are required, Shure
lnput Adapters may be used in each microphone level
input.
vides input attenuations of
the user to compensate for the differences in levels due to
different sources, such as close talking or distant microphone placement, and to compensate for high output levels
from condenser microphones.
section, in a feedback circuit, sets the gain of the preamplifier; the second section is a preamplifier output
tenuator. This circuit configuration increases the preamplifier input clipping level as the Volume Control is
reduced to lower settings. Ideally, the control should operate in the middle range, between 4 and
be accomplished by proper 15 dB ATTENUATOR Switch
(18) setting.
equalizer circuit. Individual HI and LO FREQ EQ controls
(3,2) allow the user to shape the sound of each input channel without affecting the other channels of the Mixer. The
HI FREQ controls provide up to 13 dB of boost or cut at 10
kHz with a 1 kHz hinge point. The LO FREQ controls provide up to 13 dB of boost or cut at 100 Hz with a 1 kHz
bin-ge
cate boost, and minus (-) markings denote cut. A
ting provides a normal or "flat" frequency response.
PUT/AUX LEVEL Connector (17) and the Program Mix
Amplifier.
MONITOR MIXER SYSTEM
nector (17) of the
one or more Shure
The output of each individual channel after all channel
controls (volume, equalization and attenuation) appears
(I), and the Control output is fed to the Preamplifier.
A detailed description of the Mixer circuits and controls
Eight professional, three-pin, audio MICROPHONE
The 15 dB ATTENUATOR (18) two-position switch pro-
The Channel Volume Control
The output of the Channel Volume Control (1) feeds the
point. Control settings with plus
The output of the equalizer feeds the ACCESSORY
The rear-panel ACCESSORY
LlNE LEVEL Output Connectors (23,
SR109 provides for interconnection to
SRl10 Professional Monitor Mixers.
0'-180' PHASE Switch (15),
(25), which is at
+7 to +35 dB output Ampli-
(16), which
1 kHz Tone Generator for use
Control/TONE OSC
is
MIC/LIINE
LlNE LEVEL inputs. If
0 or 15 dB. This switch allows
(1) is a dual control: one
(+)
OUTPUT/AUX LEVEL Con-
A15LA Line
9.
This can often
markings indi-
at-
0 set-
OUT-
Page 11
on this connector as do the LlNK INPUT total mix signal
and the power supply connections. The
SR110 is a selfcontained, eight-channel, line level mixer designed for
use with the
SR109 or similar equipment. The SR110 can
provide a separate stage monitor "mix" that follows the
program "mix" levels coming from the eight channels of
SR109. In addition, it may be used in multi-track re-
the
cording as a submaster mix panel or as a "mixdown"
panel.
SR110 provides eight high-impedance, unbalanced,
The
line level inputs to its mixing circuity, one high-impedance,
unbalanced, line level input to its Output Selector Switch
for monitoring the program mix, and one line level,
600ohm, balanced output. Individual channel and master volume controls are provided, as is a switch to choose between monitoring the channels in use (Mixed Inputs) and
the total program mix (Program Input). The Mixed Inputs
position takes the signal from each channel frequency
equalization circuit, and the Program
Input position obtains
the mixed signal at the LlNK INPUT Jack (22).
SR110 has parallel accessory input/output male and
The
female connectors. These connectors permit the connec-
tion of addition tandem or "stacked"
SRllOs. A typical
application is shown in Figure 5, Page 7.
PROGRAM MIX AMPLIFIER
The program mix amplifier is an active mixing amplifier in which gain remains constant independent of the individual channel volume control settings. The output of
the program mix amplifier is connected through a 560-ohm
mixing resistor to the LlNK Jacks (21, 22).
SR1w LINE
MIXER LEVEL
ACC
OUT
SRl I0
MONITOR
MIXER
SRllO
MONITOR
MlXER
SRllO
MONITOR
MIXER
FIGURE
POWER
AMPLIFIER
POWER
AMPLIFIER
STEREO
TAPE
RECORDER
5.
SRllO MONITOR MlXER APPLICATIONS
PA
SPEAKERS
STAGE
MONITOR
SPEAKER
LlNK JACKS
The LlNK Jacks
(21,22) on the rear panel of the Mixer
enable the user to interconnect more Mixers for additional
inputs or add external equipment, such as equalizers,
compressors, or limiters. When connecting two or more
SR109 Professional Mixers together to provide many channel inputs, connect the LlNK OUTPUT Jacks (21) of all
the units together. It should be noted that the LlNK OUTPUT Jack is actually a two-way jack; the impedance at
this point is actually 600 ohms, and any number of units
may be tied together at this point. The LlNK INPUT Jack
(22) is an input-only jack and has switching contacts that
disconnect the LlNK OUTPUT signal from the MASTER Vol-
ume Control (9). Note that the
SR109 and the Shure SR101
Audio Console may be interconnected in the same manner.
If an equalizer, limiter or compressor is connected to
the Mixer, the LlNK OUTPUT Jack (21) is connected to
the input of the external unit and the output of the external
unit is connected to the LlNK INPUT Jack (22).
The signals at the LlNK Jacks are typically at a level
10 dB below line level. These jacks will accommodate signal levels in the range between
LlNK INPUT impedance is greater than 20
30 to +10 dBm. The
kilohms and
may be considered a bridging impedance. The output of
the LlNK Jacks feeds the MASTER Volume Control (9)
which is a two-section control similar to those used in the
individual channels. The LlNK INPUT Jack is connected
to the ACCESSORY
OUTPUT/AUX LEVEL Connector (17).
PROGRAM OUTPUT
The signal from the LlNK Jacks (22, 21) drives the program output amplifier. The gain of this amplifier is controlled by one-half of the MASTER Volume Control (9) (the
other half is an input attenuator for the output amplifier).
In addition to the limiter circuitry, the program output
amplifier also contains the front-panel OVERLOAD Indicator Lamp (5). This indicator will flash when the output
clipping level is exceeded, and only when the LIMITER
Switch (11) is in the OUT position. The output of the program amplifier is sent to the PHASE Switch (15) mounted
on the rear panel of the Mixer. This switch allows the user
to change the phase of the program output, which may be
helpful in eliminating or reducing low-frequency acoustic
feedback. Generally, this switch is adjusted to the position
which either gives the most gain before feedback or, if both
positions give the same gain before feedback, use the position that produces the highest pitch feedback. The program signal, after leaving the PHASE Switch, is routed
to the output transformer which provides both LlNE LEVEL
and MICROPHONE LEVEL outputs. The LlNE LEVEL output is connected to one professional three-pin, male, audio
output connector (23) and two three-circuit phone jacks
(24). The MICROPHONE LEVEL output is a low-impedance,
balanced output, 50 dB below the LlNE LEVEL output, and
is connected to a professional three-pin, male, audio output connector (25).
Note that all of the program outputs are balanced with
respect to ground. If a two-circuit type phone plug is used
to connect the mixer line level output to an amplifier or
tape recorder, the line outputs will automatically become
unbalanced. If the three-pin unbalanced output is used and
a phone jack output is also to be used, obtain a stereo
phone plug and
corrnect the tip and ring of the plug only.
(The sleeve is a shield and would cause a ground loop.)
If it becomes necessary to use the MICROPHONE LEVEL
Output Connector (25) to feed a high-impedance microphone input, use a line matching transformer such as one
of the Shure A95 Series at the high-impedance microphone
input.
The output of the program output amplifier is also fed
to the VU Meter (6) circuit.
VU METER CIRCUIT
To allow a wide range of signals to be handled by the
VU Meter
(6), a VU Meter amplifier is provided. The output
of the program amplifier is fed to the VU METER RANGE
Switch (16) which in turn feeds the VU Meter amplifier and
the Meter. The VU METER RANGE Switch provides a
Page 12
choice of 0, +4 or
The
0 setting is usually used for PA applications, +4 is the
standard for recording use, and
+8
dBm output levels for the VU Meter.
+8 is preferred for use
by broadcasters. The calibration of the VU METER RANGE
0
Switch is internally adjusted at the factory for
a 600-ohm load on the program output in the
VU across
+4 dBm
switch position. The VU Meter amplifier provides the
proper impedance and signal level for correct VU Meter
ballistics and calibration. This amplifier also isolates the
Meter from the program output and eliminates the distortion normally caused by the nonlinearities of VU meters.
LIMITER
The program output amplifier also contains a
peakresponding, rapid-acting, limiter circuit. When the LIMITER Switch (11) is turned on (IN), and the THRESHOLD
ADJ Control (10) is properly adjusted, the LIMITER Indicator Lamp (4) will flash whenever the limit threshold is
exceeded and the limiter is functioning. The dynamic range
of the limiter is approximately 30 dB.
Set the limiter THRESHOLD ADJ Control (10) as fol-
lows. Operate the Mixer with program material, and adjust
the individual channel and MASTER Volume Controls
(1, 9) for the desired level. With a small screwdriver, turn
the THRESHOLD ADJ Control full counterclockwise. Set
the LIMITER IN-OUT Switch (11) to IN. Slowly increase
(turn clockwise) the THRESHOLD ADJ Control until the
tion on program peaks. Note that increasing the channel
or MASTER Volume Controls will not increase the mixed
output above the level just set. Should a higher or lower
maximum output level be desired, increase or decrease
the THRESHOLD ADJ Control.
An alternate method of limiter threshold adjustment is
to turn on the TONE
Oscillator (1) to produce a maximum
reference level on the VU Meter (6). Adjust the THRESHOLD ADJ Control (10) clockwise until the VU Meter reading
just set is reduced by 1 dB. The program material dis-
played on the VU Meter will be lower because of the
difference between peak and average levels, but limiting
action will take place at the same peak level. This effect
will be more evident on speech than music.
TONE OSCILLATOR
The Mixer contains a built-in 1 kHz tone oscillator for
set-up and check-out purposes. The TONE OSC Control
and On-Off Switch
(1)
injects the 1 kHz tone into the channel 1 preamplifier. The tone is processed through the program channel in the same manner as microphone or line
input signals.
The tone oscillator may be used as follows: With the
VU METER RANGE Switch (16) set to
MASTER Volume Control
until a
0
VU reading is obtained on the VU Meter. A tone
(9)
and TONE OSC Control (1)
+4,
increase the
reference level has now been established. The Mixer LlNE
LEVEL Output (23,
24)
is now
4-4
dBm (1.23 volts across a
600-ohm load) and the MICROPHONE LEVEL Output (25)
is approximately 4 millivolts. These reference signals may
be used to set up power amplifiers, tape recorders, or other
equipment connected to these outputs (Figure
6A, Page
8). By adjusting the input level (or volume) controls on
the associated equipment, all meters in the audio system
can be made to "track." This allows the Mixer operator to
observe only the Mixer VU Meter.
The tone oscillator may also be used to provide a check
of cables and equipment connected to the link output.
With the
LlNK OUTPUT Jack (21) connected to the input
@
MIC
LINE LINE
TAPE
RECORDER
GATED
COMPRESSOR
MIXER
6B,
Page 8). Set
(23)
(15)
-
SLO-BLO
has not
is not be-
@
SR 109
MIXER
POWER AMPL
SR
109
MIXER
FIGURE
6.
TONE OSCILLATOR APPLICATIONS
POWER
AMPLIFIER
-
MIC
AUX LEVEL
INPUT JACK
of external equipment, such as a Shure SE30 Gated Compressor/Mixer which in turn feeds a broadcast line, disconnect the Mixer output, either at the back of the Mixer,
power amplifier or speakers (Figure
the MASTER Volume Control
(9)
to 6 or the normal operating position, and increase the TONE OSC Control (1)
for a
0 VU reading on the VU Meter (6). Set the MASTER
Volume Control to
0.
Under this set-up condition, the external equipment may now be calibrated or checked out
without affecting the Mixer output. After calibrating the external equipment, turn off the tone oscillator, and return
the MASTER to the previous setting. Reconnect the power
amplifier or speakers.
BASIC OPERATING HINTS
Should any difficulty be encountered in Mixer operation,
the problem may often be traced to some simple source
such as an error in interconnection. The following is offered as a basic guide to problems of this sort.
Symptom: Mixer is "dead" (no output, VU METER lamps
out)
Check: 1. Check that ac power source is "live" and
that Mixer is plugged in.
2. Check that POWER OFF Switch (9) is on.
3. Check to see that rear-panel
Fuse (13, 28) is good.
Symptom:
Mixer is "dead" (no output, VU Meter lamps
lit)
Check: 1. Check that cable from PROGRAM OUT
PUT/LINE LEVEL Connector
accidentally been connected to PROGRAM
OUTPUT/MICROPHONE LEVEL
Connector (25).
2. Check that PHASE Switch
tween positions.
3. If external equipment is connected to
LlNK Jacks (21, 22), disconnect external
equipment to determine whether fault is
in external equipment.
Symptom: One channel is "dead" (other channels oper-
ating properly)
Check:
1.
Check for defective input cable or source.
Check that
2.
nels
7
MIC/LINE Switch (20) (chan-
and 8 only) is not between positions
or in the wrong position.
Page 13
SR109
Professional Mixer
SPECIAL OPERATING INSTRUCTIONS
The previous section described normal interconnection nel 7 or 8 jack with MIC/LINE Switch in LlNE position). If
and operation of the
provides information on special set-ups to more fully uti- 1 and the hot conductor to pin 3 of the input jack. As an
lize the capabilities of the Mixer.
HIGH-IMPEDANCE MICROPHONES
High-impedance
phones (crystal
mended)
MICROPHONE LEVEL Input Jacks (191, providing a line
matching transformer (Shure A95 Series) is used. NOTE:
The
sate
microphones.
The high-impedance cable should be limited to 6m (20
ft).
of high-impedance, single-conductor, shielded cable (Bel-
den #8401, #8410, or #8411) between the microphone Output the speaker jack; damage
and line matching transformer, and add as much low-im- may may be
pedance, two-conductor,
or
Mixer
frequency
and noise.
MUSICAL INSTRUMENTS
Musical
tical-electrical, or electrified, may be amplified through
the Mixer. For acoustical instruments, place a microphone
close to the instrument strings, sounding board, or mouth.
Adjust equalization and volume controls as necessary.
For acoustical-electrified instruments such as classic or
folk guitars with pickups and preamplifier outputs, or
pianos with pickups and preamplifier outputs, either place
the microphone as described above, or connect the pickup
to a line matching transformer as described under
High-Impedance Microphones (Page 9). Adjust the 15 dB
ATTENUATOR Switch (8) for the channel
the desired sound level with the channel Volume
(1) set at about mid-scale.
To use a preamplifier auxiliary output (instrument or impedance auxiliary tape recorder input, connect a cable
tape recorder preamplifier, or hi-fi amplifier tape monitor from one LlNE LEVEL Jack to the tape recorder input (see
output jack, or headphone jack; not the speaker jacks- Figure 8, Page 10). If the LlNE LEVEL Output is being
amplifier damage may result) with the Mixer, connect the used and a two-circuit phone jack is used to connect the
preamplifier auxiliary output to a LlNE LEVEL input (chan- Mixer to the tape recorder, this will unbalance the LlNE
l5
dB
the
If a long
#8422)
input
can
ATTENUAToR Switch
very high Output produced
cable
as
jack.
signal loss and reduce the possibility of hum
instr~ments, aco~stical (n0n-electrified), acous-
SR109 Professional Mixer; this section the source is unbalanced, connect the cable shield to pin
alternate connection, connect the preamplifier auxiliary
output through up to 3m (10 ft) of cable to the high-impe-
dynamic, ribbon or condenser micro-
Or
ceramic
be
used
with
One
length
necessary between
These
is
required,
shielded
precautions
may
are recorn-
the
1°w-im~edance
be
used
use
up
to
cable
(Belden
the
transformer
will
help
avoid
in use to provide nection, the operator should decide whether he wants the
'Ompen-
3m
#8412
high-
Control tape level to follow the MASTER Control and LIMITER.
dance side of a line matching transformer (Shure A95
series)
impedance side of the transformer through a low-imped-
ante
MICROPHONE LEVEL Input Jack (19). Adjust Mixer
equalization controls
15 dB ATTENUATOR Switch (18) for the channel in use to
provide the desired sound level with the channel Volume
Control (1) set at about mid-scale.
ft)
a
scribed above. It is important to note that the tonal quality
of fully electrified instruments is primarily formed by the
and
instrument amplifier and speaker; an external microphone
picking up
provide a more desirable sound than that obtained by di-
rect connections.
microphones also apply to most musical instruments (see
High-Impedance Microphones, Page 9).
TAPE RECORDING
from either the LINE LEVEL Output (23,241, MICROPHONE
LEVEL Output (25) or LINK OUTPUT (21) Jacks. The Mixer
Program Outputs are after the MASTER Volume Control
(9) and LIMITER Switch (11); the LINK OUTPUT Jack is
before these features. In planning a tape recorder con-
as
shown
microphone cable (up to 300m-1000 ft) to a Mixer
Fully electrified instruments may also be amplified using
the
The cable length restrictions applying to high-impedance
The Mixer output may be recorded on a tape recorder
To use a
LINE LEVEL Output Jack (23,24) feeding a high-
in
in
front of
fed
instrument
~i~~~~
for
7,
Page
9.
connect the
optimum sound. ~dj~~t the Mixer
the
instrument speaker,
to an jack as de-
Output may very
Or
the
low-
in-
r
AUX OR HEADPHONE
OUT
PREAMPLIFIER
3
m
(10')
MAX.-
HIGH IMPEDANCE
FIGURE
p=-UP
>
A95
LINE
MATCHING
TRANSFORMER
LOW IMPEDANCE
MICROPHONE
7.
PREAMPLIFIER-MIXER CONNECTIONS
LOW IMPEDANCE
CABLE
TO
300
m
(1000')
1
MIC LEVEL
INPUT
SR
109
MIXER
1
9
Page 14
LEVEL Output (refer to Program Output, Page
7).
If the MICROPHONE LEVEL Output Jack (25) is to be
used, connect a cable from it to the tape recorder
low-
impedance microphone input. If the microphone input on
the tape recorder is designed to be used with
high-imped-
ance microphones (greater than 1000 ohms), insert a
line matching transformer (Shure A95 Series with proper
connectors) between the MICROPHONE LEVEL Output
Jack and the tape recorder input (refer to Program Output,
Page
7).
To use the LlNK OUTPUT Jack (21), use a two-circuit
phone plug on the cable to the tape recorder auxiliary or
line input. The input impedance of the tape recorder should
be 600 ohms minimum.
The output impedance of the
LlNK OUTPUT Jack (21) is
low; this provides for unlimited cable length between the
Mixer output and tape recorder input. Low-capacitance,
single-conductor, shielded cable (Belden
#8401, #8410,
or #8411) is recommended to reduce the possibility of
hum and noise pickup.
For operation with a stereo tape recorder, refer to Stereo
Operation, Page
12.
RECORD PLAYBACK
To play records through the Mixer using a turntable or
record changer with a stereo magnetic cartridge and no
preamplifier, the most expedient method is to join the left
and right channel leads from the turntable in a
"Y"
adapter
and connect the joined output through an A95 Series Line
Matching Transformer to a MICROPHONE LEVEL lnput
Connector (19) on the Mixer (see Figure
9A, Page 10).
Note that the total lead length between the turntable and
the A95 should not exceed
1.5m (5 ft). To approximate the
RlAA equalization curve, set the Mixer FREQ EQ-LO Con-
trol (2) to +4, the FREQ EQ-HI Control
15
dB
ATTENUATOR Switch (18) to 0 for the channel being
(3)
to -6, and the
used. Adjust the channel Volume Control (1) as necessary.
LOW
IMPEDANCE
I
1
I
I
MIC
BALANCED
LEVEL
OUTPUT
FIGURE
LINE
8.
1
I
TAPE
RECORDING
A better method of performing this interconnection in-
volves the use of a phono preamplifier such as the Shure
M64 Stereo Preamplifier (see Figure
96, Page 10). In
this set-up, RlAA equalization will be achieved at the preamplifier, before the signal enters the Mixer. In this manner,
the Mixer equalization controls may be used to optimize
the room sound, rather than compensating for the input
signal. The joined turntable leads enter the channel 1 input
of the preamplifier, and the output is taken from the channel 1 low level output and fed to a MICROPHONE LEVEL
lnput Jack (19) of the Mixer. Set the Mixer 15 dB
ATTENU-
ATOR Switch (18) to 0 with this set-up.
Note also that this set-up removes the cable restriction
between turntable and Mixer described above; although
I
@
@
TURNTABLE
r
TURNTABLE
A95
MIC
INPUT
SR
109
MIXER
1.5
m
(5')
MAX.-=
4f
CHAN.1
INPUT
ONLY
FIGURE
ONE
M64
PREAMPLIFIER
CHANNEL
9.
RECORD
STEREO
IS
p-UP
'
CHAN.
LOW LEVEL
i
OUTPUT
USED
FOR
PLAYBACK
FREQ. EQ-L0:+4
(
FREQ.
I
THIS
APPLICATION.
EP-HI:
TO
300
-6
rn
(1000')
)
1
MIC
SRlOS
MIXER
INPUT
Page 15
a maximum of 1.5m (5 ft) between turntable and preamplifier is mandatory, the cable length between the preamplifier and Mixer is virtually unlimited.
TAPE PLAYBACK
To play tape-recorded material through the Mixer, con-
a
nect
output to the channel 7 or 8
For unbalanced tape recorder outputs, connect a
conductor, shielded cable as shown in Figure 10, Page 11.
Connect the tape recorder output cable shield to pin
and the "hot" conductor to pin
lnput Jack.
or 8 (whichever is being used) to LINE. Set the 15 dB
TENUATOR Switch (18) to 0, and the channel Volume
Control (1) as required.
cable from the tape recorder auxiliary or line level
LlNE LEVEL lnput Jack (19).
3
of the SR109 LlNE LEVEL
Set the rear-panel
TAPE RECORDER
AUX OUTPUT
MIC/LINE Switch (20) on channel 7
c-------
-------
\
--
I
SR109 MlXER
(CHANNEL 7 OR
single-
AT-
8)
-
ure 11B, Page 11). Set the SR109 15 dB ATTENUATOR
Switch (18) to
this set-up with other mixers, essentially the same procedure is followed. The Shure M67 mixer, for instance, may
be connected to the
mixer line out connector (binding posts) or headphone output (phone jack) (Figure 11 C, Page 11).
If a mixer is to be used with the
to maintain as many
can be connected to the
IlD, Page 11). However, this requires sacrificing the
1
channel equalization functions for the sources entering
through the mixer. The only
erating on the mixer sources in this set-up are the MASTER
Volume Control
PHASE Switch (15). In addition, any mixer used in this setup requires a
output to provide an attenuator bridging connection; the
resulting signal level will be down -10 dB (see Figure
Page 11). The M67 Mixer headphone jack has suitable
built-in resistors and may be connected directly to the
SR109 LlNK OUTPUT Jack. Only mixers with 600-ohm line
outputs may be used in the configuration. Note that the
M68FC mixer cannot be used this way.
Shure
mixer-to-link out jack connection can also be used
The
with several
0 and the MIC/LINE switch to LINE. To use
SR109 LlNE INPUT Jack through the
SR109 but it is desirable
SR109 channels as possible, the mixer
LlNK OUTPUT Jack (21) (Figure
SR109 control functions op-
(9), LIMITER Switch (11) and rear-panel
2.2-kilohm resistor in series with the mixer
mjxers. Each mixer output must contain its
11E,
FIGURE
ADDITIONAL MlXER INPUTS
Additional microphone or other source inputs may be
obtained using a high gain, low noise, microphone mixer
such as the Shure
PHONE LEVEL
provide a total of 11 inputs (see Figure
(Note that adding a mixer at an
channel to a submaster control; the total number of inputs
will thus be the mixer total plus the
minus 1 for the submaster.)
A common practice when adding a mixer in this manner
is to connect similar-use microphones (for instance, all
drum, string or horn microphones) to a single mixer which
is fed into the
ume Control (1) then controls an entire section, facilitating
adjustment of that section during a performance. With this
set-up, set the channel 15 dB ATTENUATOR Switch (18)
0 and adjust the mixer channel volume controls in the
to
mid-to-high range. Adjust the mixer master volume control
as required to keep the
the desirable middle range.
M68FC mixer has a switch-selectable low- or high-
The
impedance microphone output. When using an M68FCtype mixer into an SR109 MICROPHONE LEVEL lnput Jack
(19), set the mixer MIC OUT switch to low impedance, and
make necessary adjustments as described above. It is
sometimes desirable to use the auxiliary output from the
mixer into the
(Refer to
this set-up.)
To use this set-up with an
between the mixer auxiliary output (phono pin jack) and
SR109 LINE INPUT Jack (19) on channel 7 (or 8) (Fig-
the
lnput Jack (19), the M68FC and SR109 will
SR109. The SR109 individual channel Vol-
SRl09 channel 7 (or 8) LlNE INPUT (19).
Tape
Playback,
10.
TAPE PLAYBACK
M68FC. When connected to a MICRO-
11A, Page 11).
lnput Jack converts that
SR109 total
SR109 channel volume control in
Page 11, for a description of
M68FC mixer, connect a cable
---8
-
@
0
0
LOW IMPEDANCE
MIC LEVEL
M68FC SR109
MIXER MIXER
AUX LEVEL
MIXER MIXER TOTALaII CWNNELS
LlNE OUT OR
PHONES OUT
MIXER MIXER
PHONES
MIXER MIXER ON
,
M6"Tv
,
600Ll
LlNE OUT
MIXER
FIGURE
11.
MIC
LEVEL
TOTAL.11 CHAP:NELS
LlNE LEVEL
SR109
LlNE LEVEL
SRlOS
SRlOS (NO EWALlZATlON
SRIO,
MlXE R
;$
ADDITIONAL MIXER INPUTS
TOTAL: I
TOTAL I2 CHANNELS
,
,
M67
TOTAC. I2 CHANNELS
(NO EOUAUZATI ON
ON MlXER
I
CHANNELS
INPUTS)
INPUTS1
Page 16
Page 17
LlNK
OUT
SR1Os
MIXER
LINK
OUT
SR1Os
MIXER
LlNE LEVEL
FIGURE
LINE
LEVEL
LlNE
LEVEL
RESISTORS ARE CARBON COMP., 1/2 W.5%
13.
RESISTIVE
NETWORK
1
I
I
I
I
I
I
I
I
I
I
BALANCED
I BRIDGING
I
L
-- - - - -
-
-J
REDUNDANT MIXERS
AMPLIFIER
POWER
AMPL
INPUT
POWER
D
D
SR109
MlXER
FIGURE
SRllO
MONITOR
MlXER
ACC OUT
AUX LEVEL
14.
STEREO TAPE RECORDING
SRllO
MONITOR
MlXER
L
-
STEREO
RECORDER
R
-
-
I
TAPE
REMOTE VOLUME CONTROL
A remote volume control may be constructed for adjusting the output level at a considerable distance from the
Mixer. For remote control up to
15m (50 ft), obtain a lineartaper potentiometer with knob (any value from 1000 to
2500 ohms), a standard phone plug, and a length of
single-
conductor, shielded microphone cable (such as Belden
#8401, #8410, or #8411). Connect the potentiometer and
plug as shown in Figure
15A, Page
13,
and connect the
phone plug to the Mixer LlNK OUTPUT Jack (21).
If hum or noise is encountered with the above set-up, it
may be necessary to provide a two-wire control. Using the
same potentiometer, obtain two standard phone plugs and
twice the desired length of single-conductor, shielded
microphone cable. Connect the potentiometer and plugs
ing tape channel input; an omnidirectional unit suspended
from the ceiling will pick up the full acoustic output of
the instruments.
An ideal method of recording the
is to use two
method allows the
SR110 Professional Monitor Mixers. This
SR109 output to be used for the PA
SR109 output in stereo
system. Connect the SRllOs as shown in Figure 14, Page
13, with the output of one
of the tape recorder and the other
SR110 feeding the left input
SR110 feeding the right.
Note that the controls of the SRllOs permit spatial po-
sitioning ("panning" from left to right) and also allow different level settings to be used on the recording as opposed to the PA level. Spatial channel assignment or
positioning is accomplished as follows: If the
SR109 channel 1 input is to be recorded on the left tape channel, set
the left
level and leave the right
at
(both left and right), adjust both
SR110 channel 1 volume control for the proper
SR110 channel 1 volume control
0. If the second tape input is to be recorded "centered"
SR110 channel 2 volume
controls to the same setting. Note that these two controls
combine the functions of record level and panning or
positioning.
SR109 instrumental channels that are set at a low level
for PA use with respect to vocal channels should be set
higher on the SRllOs to provide a proper recording balance. Once the
SR110 levels are set, the SR109 provides
the "mix" for both PA and tape recording.
An expansion of the above method may be used to re-
cord 4-channel (quadriphonic) sound. In this-method, four
SRllOs are connected to the four tape recorder inputs, and
adjustments are made as described above.
@
SRlOS
@
SRlOS
MIXER
-
-
0
SRIOS
MIXER IN
LlNK
OUT
FIGURE
--
I
-
-
--
--
LlNK
15.
,\
WHITE
BLACK
REMOTE VOLUME CONTROL
r-------7
I
"
L
---------
I
I
I
I
I
I
J
Page 18
as shown in Figure 158, Page 13, and plug the control
assembly into the
(22) Jacks.
For distances over 15m (50 ft) or for permanent installations where hum or noise may be encountered, use
low-capacitance, two-conductor, shielded cable
den #8412 or #8422). Connect as shown in Figure 15C,
Page 13, and use a metal box to contain the potenti-
ometer. The cable shield must be connected to the metal
box containing the potentiometer, to the common conductor (black), and not to the sleeve connections of the
LlNK OUTPUT (21) and LlNK INPUT
(Bel-
phone plugs. IMPORTANT: To avoid hum caused by a
ground loop, do not ground the metal box to any metal
such as electrical conduit, water pipes, heating ducts, or
structural steel.
TELEPHONE LINE SURGE PROTECTION
When using the Mixer to feed a telephone line that may
be subject to lightning-induced voltage surges, the follow-
ing part should be installed across the telephone line to
provide additional protection for output circuit components: Thyrector, General Electric Part No.
6RS20SPlBl.
SR109
Professional Mixer
SERVICE INSTRUCTIONS
MIXER SERVICE (SEE GUARANTEE, Page
The SR109 Professional Mixer uses components of the
highest quality, operating well within their respective ratings to assure long life.
WARNING
Voltages in this equipment are hazardous to life.
Make all input and output connections before ac
power is connected. Refer servicing to qualified
service personnel.
REPLACEMENT PARTS
Parts that are readily available through local electronics
parts distributors are not shown on the accompanying
Parts List. Their values are shown on the Circuit Diagram
(Figure 25, Pages 32-33). Commercial parts not readily
available and unique parts are shown on the Parts List
and may be ordered directly from the factory.
The commercial alternates shown on the Parts List
are not necessarily equivalents, but may be used in the
event that direct factory replacements are not immediately
available. To maintain the highest possible performance
and reliability, Shure factory replacement parts should be
used. When ordering replacement parts, specify the Shure
Replacement Kit Number (RKC), description, product
model number, and serial number.
FUSE REPLACEMENT
To replace line fuse F1 (with no apparent problems in
the Mixer), disconnect the line cord from the ac source
and remove the rear-panel fuseholder cap. Replace the
defective fuse only with a
(SR109 only; SR109-2E contains a 0.1A Slo-Blo fuse for
180- to 250-volt operation, or a
to 132-volt operation).
3AG-3/16A Slo-Blo fuse
0.2A Slo-Blo fuse for 90-
35.)
CAUTION
If trouble symptoms -overheating, erratic
eration, etc. -were apparent before the fuse
blew, or if the replacement fuse blows, a qualified serviceman should troubleshoot the Mixer
carefully to find the source of the trouble. Do
not continue to replace fuses until the trouble has
been corrected.
The Mixer also contains a wired-in fuse in series with
rear-panel line fuse
becomes necessary, replace only with an identical fuse.
KNOB REPLACEMENT
All front-panel control knobs are pull-off types and are
interchangeable with others of the same function. When
ordering replacement knobs, be sure to order the proper
color-coded type for the desired control.
SERVICE ACCESS
To open the Mixer for servicing, remove the eight Phillips head screws securing the top cover and remove the
top cover. Rear-panel-mounted parts and the preamplifier
assembly may be reached by removing the eight Phillips
head screws securing the rear panel, and carefully moving
the rear panel assembly out and downward. Front-panelmounted parts may be reached by removing the two screws
at the top of the cover channels and the four screws at the
bottom of the chassis, and carefully moving the front panel
assembly out and downward.
LAMP REPLACEMENT
To replace either of the two
luminating the VU Meter (MI), carefully raise the metal
cli~ assemblv holdina the
of; the power suppry printed circuit board biacket. Lift
the lamp socket upward, taking care not to crimp or break
any associated wiring. Replace the defective lamp and
carefully return the lamp assembly to its original position.
To replace either of the two light-emitting diodes
(DI,D2) mounted on the front panel, remove the outer
insulating tubing and mounting ring from the rear of the
LED. Press against the front-panel portion of the LED envelope to force it out the back through the mounting clip.
F1 (F2, 3/10A, Slo-Blo). If replacement
#47
lamps (PLl,PL2)
lam^
to be re~laced uoward and
op-
il-
(LED'S)
Page 19
Unsolder both LED gray leads from the Power Supply assembly. Remove the Power Supply assembly and
(see
VU
Meter Removal, Page 16). Unsolder the LED
orange lead from the LIMITER OUT-IN Switch
THRESHOLD ADJ Control
be replaced). Insert the replacement LED in the front
panel and place the mounting ring and insulating tubing
over the leads. Solder the orange lead in place, loosely
coiling the two LED orange leads together. Replace the
VU Meter and Power Supply assembly. Loosely coil the
two LED gray leads together and re-solder them to the
Power Supply ground terminal.
The above is the recommended procedure for LED re-
placement. In an emergency, the LED wires may be spliced
and insulated (with tape or tubing) without removing the
VU Meter or Power Supply.
BOARD REMOVAL
The various printed circuit boards are mounted in different manners. The following paragraphs describe the
best method of removing these boards after wires and
cable assemblies have been removed. IMPORTANT: When
disconnecting push-on terminals or soldered board connections, make sure each wire is identified for proper
reconnection. This may be done by affixing a piece of
masking tape marked with the connection or terminal
letter to each wire.
Wire colors are given in the following table.
Similar wire colors are used in different circuits;
make sure proper re-connections can be made.
Take care not to bend or break the push-on terminals. Remove or replace terminals by grasping
the terminal itself; do not pull on the associated
wire.
Letter Wire Color Letter
Brown G/Ch. 6
Orange
Yellow
Green
3
Red
Black
Brown
White/Red
Orange
White
Gray
Blue
Green
Yellow
Orange
White/Red
Brown
Black
A
B
C,D/Ch. 1
C,D/Ch. 2
C,D/Ch.
A
B
C
D
E
F
G
H
J
(R10) (depending on which is to
CAUTION
Preamplifier Board
G/Ch.
Equalizer Boards
C,D/Ch. 4
C,D/Ch.
C,D/Ch. 6
C,D/Ch.
C,D/Ch. 8
Main Board
K
L
M
N
Q
R
S
T
V
8
5
7
VU
Meter
(S12) or
Wire Color
White
Black
Yellow
Green
Blue
Gray
White
Blue
White/Purple
Gray
White/Green
Yellow/Red
Yellow
Purple
Orange
Green
Main Board (Cont'd.)
Black White/Red
"1
A A Black AG Red
AB White
F
G Black (7)
NOTE:
Refer to Figure 16, Page 16, for the location of each board.
The function of each board assembly is defined in the table
below.
Board No. Component Numbering
When removing front-panel control retaining nuts with a
Y2"
nutdriver or wrench, be careful not to damage the
black plastic surface.
Remove boards from nylon fasteners by squeezing the
upper protruding tab on the circuit board side inward and
sliding the board outward and off the fastener. The fasteners may be removed from the support bracket by squeezing both tabs securing the fastener to the bracket and
pushing the fastener through the bracket hole. NOTE:
When replacing nylon fasteners, be sure the protruding
tab on the circuit board side is oriented towards the top
of the chassis. Failure to do so will make future board
removal difficult.
Preamplifier (Board 1): Remove the board from the
seven nylon fasteners (see procedure above) securing the
board to the vertical bracket, disconnect the eight
coded channel output leads, and lift the board up for
service access.
Channel Equalizer (Board 2):
boards may be removed by removing the two front-panel
equalizer control knobs and retaining nuts associated with
that channel. The Channel Equalizer Boards are identical
and may be interchanged without modification.
Main Board (Board
nylon fasteners (see procedure above) securing the board
to the vertical bracket, remove the 41 push-on leads, and
lift the board upward.
Power Supply (Board 9): Remove the four screws securing the board and lift straight up.
White
Red
White/Green AF
Power Supply Board
Red (5)
Green Black
Yellow Gray
Program Mute Board
Green/White E
I
Red
Production variations may result in wire colors
differing from those in the table.
Preamplifier Board 100's
Equalizer Boards (8) 200's
Main Board 300's
Power Supply Board 900's
Program Mute Board 90's
3):
1:;
AH
ID
Each of these eight
Remove the board from the six
Green
1
Brown
Black
Black
Yellow
White
Green
color-
Page 20
FIGURE 16. PRINTED CIRCUIT BOARD AND PARTS LOCATION
Program Mute (Board 0): Remove the board from the
four nylon fasteners securing the board to the vertical
bracket and lift upward.
LIMITER INTERNAL ADJUSTMENT
To adjust the limiter function following replacement of
circuit components, set the MASTER Volume Control
(R9)
to full clockwise. With the LIMITER Switch (S12) in the
OUT position, turn on the TONE
OSCillator (Rl) (with all
other microphone inputs full counterclockwise) and adjust
channel 1 Volume Control to produce a VU Meter
(MI)
reading of 0 VU with the VU RANGE Switch (S13) set to
+4. This provides
Output Connector
adjust the THRESHOLD ADJ Control
output by 1 dB on the VU Meter (to
internal LED potentiometer
+4 dBm (f1.8 dBV) at the LlNE LEVEL
(Jl). Set the LIMITER Switch to IN and
(R10) to reduce the
+0.8 dBV). Adjust the
(R379) so that the LIMITER In-
dicator Lamp (Dl) just begins to light.
OVERLOAD INDICATOR CHECK
Set up as for Limiter Internal Adjustment and set the
LIMITER Switch
PHONES Jack, listen to the tone with a 600-ohm
(S12) to OUT. Connect headphones to the
LlNE OUTPUT load, and increase the channel 1 volume. The OVERLOAD Lamp
(D2) should light 2 dB before distortion can
be heard on the headphones.
VU METER REMOVAL
If the VU Meter (MI) requires replacement, remove it as
follows. Remove the top cover. Remove the two screws at
the top of the cover channels and the four screws at the
bottom of the chassis, and move the front panel out and
downward. Remove the hex nuts, wire leads and washers
from both meter terminals. Loosen the 1-inch screws in
the meter retaining brackets at either side of the meter
until the brackets slip off the screws in the sides of the
meter. Carefully pass the meter assembly out through the
front panel. To replace the meter, reverse the above steps,
taking care to engage the slots in the meter retaining
brackets with the screws in the sides of the meter. Tighten
the 1-inch screws as necessary to retain the meter against
the front panel. Reattach the meter leads, and close and
secure the front panel. Replace the top cover.
CAUTION
Do not overtighten screws so as to deform meter
retaining brackets.
VU
METER CALIBRATION
With the Mixer turned off, the front-panel VU Meter (MI)
should read 0 on the lower of the two meter scales. If it
does not, adjust the screw below the meter face to obtain
the correct reading.
To calibrate the meter, set the VU RANGE Switch
(S13)
Page 21
to +4 and connect a 600-ohm load and an ac voltmeter
across the
Mixer and adjust the TONE OSC Control
MASTER Volume Control
(1.228V across 600 ohms) is obtained on the voltmeter.
Adjust potentiometer R355 (VU Calibrate) on the Main
Board until the VU Meter reads
scales.
Note that the VU Calibrate potentiometer range allows
the VU Meter to be adjusted to
0 dBm and +8 dBm.
PARTS REMOVAL
Access to certain parts in the Mixer is not always apparent due to the large number of parts and assemblies,
and the requirements for their placement. The following
information is given to help locate and gain access to these
parts (see Figure 16, Page 16).
Parts mounted on the rear panel may be replaced by removing the eight screws securing the rear panel to the
chassis and moving the rear panel out and downward.
Parts mounted on the front panel may be replaced by
removing the two screws at the top of the cover channels
and the four screws at the bottom of the chassis, and
moving the front panel out and downward.
To remove transformers
the bottom of the chassis holding the three-board bracket
assembly to the chassis. Carefully lift the entire assembly
upward, and remove the nut and washer securing the desired transformer.
Front panel controls located below the VU Meter
(LIMITER Switch S12, THRESHOLD ADJ Control R10,
MASTER Volume Control R9, PHONES Level Control R14
and PHONES Jack J15) may be reached by lowering the
front panel as described above.
Headphones transformer
removing the Power Supply board and bracket as de-
scribed under Board Removal.
To gain access to channel Volume Control potentiom-
eters
TRANSISTOR AND DIODE REMOVAL
Most transistors and all diodes used in the Mixer are
mechanically supported by their leads. When replacing
these devices, proper lead configurations must be fol-
lowed. Minimum soldering heat (preferably with a low-
wattage soldering iron) should be used to avoid damage
to the device. Be sure to place heat-shrinkable tubing or
"spaghetti" on leads where the original device contained
such tubing. Transistor lead codes are included in the
Notes to Circuit Diagram (Figure 23, Page 29). IMPORTANT: Be sure to replace ferrite bead rings on those transistor leads where they were removed.
LINE LEVEL OUTPUT (J12-J14). Turn on the
(Rl) and the
(R9) until a reading of +4 dBm
0 on the upper of the two
0 for any output between
TI-T8, remove the five screws at
(MI)
TI0 may be reached by first
R1-R8, lower the front panel.
ohmmeter "plus" probe on the anode end of a diode, and
the "minus" probe on the cathode end, the ohmmeter
should read approximately 2000 ohms or less. With the
meter probes reversed, a reading of about 10,000 ohms or
more should be obtained. If either of these conditions is not
met, the diode should be replaced.
To check transistors, the ohmmeter should be set to
the 100- or 1,000-ohm scale. Transistors and diodes
must be removed from the circuit before testing.
conditions in the following table are met, the transistor
may be considered free of any major defect; if any of the
following conditions are not met, the transistor should be
replaced. See Notes to Circuit Diagram, Figure 23, Page
29, for transistor lead codes.
OHMMETER CONNECTIONS
"Plus" Lead "Minus" Lead
Collector Emitter
Emitter Collector
Collector Base
Emitter Base
Base Collector
Base Emitter
*Not a significant measurement.
To check LEDs (OVERLOAD or LIMITER), disconnect
the orange LED lead and connect a
resistor between the +30 Vdc supply and the orange LED
lead (gray lead is still grounded). The LED should light
with power applied. Replace any LED that does not light.
NOTE: Do not check LEDs with an ohmmeter; the ohmmeter may damage the LED or give erroneous readings.
To check the
impedance ohmmeter (VOM or VTVM), a 1 V2V battery and
a 100-ohm resistor. Disconnect the leads to
as follows.
1. Connect the ohmmeter across the light-dependent
resistor side of
greater than 10 megohms.
2.
With ohmmeter connected as above, connect battery
and resistor as shown in Figure 17, Page 17. (IMPORTANT: Connect only as shown to avoid damage
to the LED.) The resistance reading should drop to
less than
are not met.
opto-isolator (UI) on Board 3, obtain a high-
U1. Resistance reading should be
1000 ohms. Replace
I00
n.
OHMMETER READING
NPN PNP
Transistor Transistor
High High
High High
High Low
Low
Low High
Low
I-,
1.5-, or 2.2-kilohm
U1 and check
U1
if these conditions
If all
*
ACTIVE COMPONENT CHECKING
Defective transistors and diodes may be located by use
of a standard ohmmeter such as a
of the ohmmeter must be verified before these checks are
made.
With a known diode orientation, measure the diode re-
sistance in the forward and reverse directions. The lowest
meter reading will establish the probe at the cathode end
(schematic symbol arrow points to cathode) as the "minus"
probe while the other probe will be "plus." Some ohmmeters
"volts plus probe" and "volts minus probe." With the
Ere not polarized in this manner with relation to
Simpson 260. Polarity
1.5V
+,
-=
FIGURE
CATHODE END
(CODED DOT)
17.
OPTO-ISOLATOR TEST
Page 22
SERVICE ILLUSTRATIONS
Immediately following the parts list on the pages that fol-
low are parts location drawings (Figures
24-27),
25,
and an overall Circuit Diagram (Figures
Pages
30
and
32-33).
Once a board has been located
through the parts location photo (Figure
18
16,
to
22,
Page
Pages
24
16),
and
the
components on that board may be located from the corresponding parts location drawing. Foil circuit paths are
shown as shaded areas on the drawings. The overall
Circuit Diagram (Figures
24
and
25,
Pages
30
and
32-33)
shows all board circuits and chassis-mounted parts.
OPTIONAL ACCESSORIES
The following optional companion unit and accessory
are designed for use with the Shure
SR109
Professional
Mixer:
SRI 10
Professional Monitor Mixer
A1 05A
Carrying Case
SR109
The
and an
mount in a single
SR110
A105A
Monitor Mixer will conveniently
case.
Page 23
NOTE:
SR109
Professional
Mixer
REPLACEMENT PARTS LIST
The commercial alternates shown in the following lists are not necessarily equivalent parts, but are electrically
and mechanically similar, and may be used if direct factory replacements are not immediately available.
maintain highest possible performance and reliability, Shure Factory Replacement Parts should be used.
insure low noise figure, order transistors from Shure Brothers Inc.
Part of R1
Switch, Slide, TPDT, LIMITER
Switch, Slide, DPTT, VU RANGE
Switch, Slide, DPDT, PHASE
Part of
Switch, Slide, DPDT, VOLTAGE
SELECTOR
Transformer and Shield Assembly,
Mic Input
Transformer, Line Level
Output
Of:
Description
(SR109-2E only)
6.3V
50k, with TONE OSC
(SR109)
(SR109-2E)
MIC/LINE
R9
(SR109-2E only)
50k,
50k,
Commercial
Alternate
None
Stackpole 57-0181
Ferronics 21-031
API Instruments
361 -2, A-Scale
None
None
None
None
None
None
GE 47
2N3441
RCA
None
None
None
None
None
None
None
None
None
None
None
None
None
;
J
'
Parts listed as RKC
in RKC quantities.
Kits should be ordered
by that kit
number. Any orders
received for piece parts where RKC Kit number
is shown will be shipped
Page 25
Reference
Designation
PREAMPLIFIER (BOARD
C130, C140,
C150, C160,
C170, C180,
C190, C191
Replacement
Kit No.
"
1)
Qty.
-
-
Replacement Kit Consists
Part No.
51 D228
51A262
51A265
95A632
90A1888
95A429
95A604
1
95A657
50KB104 I Capacitor, Film, 0.1
868629 Capacitor, Electrolytic,
Transformer, Headphone
Output
Transformer, Ac Power (SR109)
Transformer, Ac Power (SR109-2E)
Line Cord, Ac, Grounded,
2.7m (9 ft) (SR109)
Line Cord, Ac, Grounded, %Foot,
Single Connector (SR109-2E)
Fuseholder, Miniature,
Panel-Mounting
Fuseholder, Miniature, Panel-
Mounting (SR109-2E)
Lampholder and Bracket
Assembly
1
22pF, 35V
Capacitor, Electrolytic,
4.7 or 5
pF, 35V
Description
(SR109)
Of:
NF,
Commercial
Alternate
None
None
None
Belden 17408
None
Littelfuse 342014
None
None
Sprague
CDE DMF-1 PI-10
Sprague 502D226G050CE10;
Mallory
MTV-25CB35
Sprague 30D-TE1303;
CDE NLW-5-50
225P10491;
Capacitor, Electrolytic,
50
p.F, 35V
Capacitor, Electrolytic,
250
pF,
40V
Silicon Rectifier,
Ferrite Bead Ring
Transistor, Silicon, Low
Power, NPN
Transistor, Silicon, Low
Power, PNP
Transistor, Silicon, NPN
Parts listed as RKC Kits should be ordered by that kit number. Any orders received for piece parts where RKC Kit number is shown will be shipped
in RKC quantities.
100V,
Y2A
Sprague
CDE NLW-50-50
None
Motorola
Stackpole 57-01 80;
Ferronics 21
Motorola 2N5210
Motorola or
Fairchild
Motorola 2N5088;
TI 2N3711
30D-TE1307;
1
N4002
-0305
2N5087
Page 26
REPLACEMENT PARTS LIST FOR SR109 PROFESSIONAL MIXER
Reference
Designation
Replacement
Kit No.
~ty. I part
Replacement Kit Consists
NO.
I
Of:
Description
I
EQUALIZER (BOARD
C200, C201,
C205. C208
Q200, (2201,
(2202 TI 2N3711
R204, R208
MAIN BOARD (BOARD
I
I
2)
-
RKC9
-
3)
86A630 Capacitor, Electrolytic,
1-1
1
4
(
86A349
-
46A034
4.7 or 5 ,F, 35V
I
1
Transistor, Silicon, NPN Motorola 2N5088;
Potentiometer, 50k, HI
and LO FREQ EQ
Capacitor, Electrolytic,
22,F, 35V
Capacitor, Electrolytic,
,
F, 35V
50
Capacitor, Electrolytic,
250
,F, 40V
Capacitor, Electrolytic,
1
,F, 25V
Capacitor, Electrolytic,
.1 ,F, 1oov
Capacitor, Electrolytic,
4
,F, 25V
Capacitor, Electrolytic,
100
,F, 25V
Capacitor, Electrolytic,
47
,F,
16V
Silicon Rectifier,
50V, 112A
Sprague 30D-TE1303;
CDE NLW-5-50
None
spGgue
CDE NLW-5-50
Sprague
226G050CE10;
Mallory MTV-25CD35
Sprague 30D-TE1307;
CDE N LW-50-50
None
Sprague
CDE NLW-1-25
Sprague
CDE DMF-lP1-10
I
None
Sprague
Mallory MTA-100F35;
CDE NLW-100-25
Sprague
476G016;
Mallory MTV-35CB25
Motorola 1 N4001
Commercial
Alternate
GD-TEI~O~;
502D-
30D-TE1200;
225P10491;
30D-TE1211;
503D-
Diode, Silicon, Computer,
75v
Silicon Zener Diode,
Ferrite Bead Ring
Transistor, Silicon, NPN
Transistor, Silicon, PNP
Parts listed as RKC Kits should be ordered by that kit number. Any orders received for piece parts where
in
RKC
quantities.
22
22V, 5%
Motorola 1 N4748A
Stackpole 57-0180;
Ferronics 21-031
Motorola 2N5210
RKC
Kit number is shown will be shipped
J
Page 27
REPLACEMENT PARTS LIST FOR SR109 PROFESSIONAL MIXER
Reference
Designation
POWER
SUPPLY
Replacemtent
Kit No.
Qty.
I
RKC65 86A334 Transistor, Silicon, NPN
I
111
-
86A348 Transistor, Silicon, Low
1-1
-
RKC9
RKC12
-
-
1-1
4
1
86A329 Transistor, Silicon,
86A349
86A336
46D033 Potentiometer, look,
1-1
-
(BOARD
9)
1 - 1
86A901
Replacement Kit Consists
Part No.
I
I
I
Power, PNP
I
N-Channel, Field Effect
I
Transistor, Silicon, NPN
Transistor, Silicon, NPN
Potentiometer, 10k, VU Cal
LIMITER Lamp Cal
I
1
Optical Isolator, LED
Photoconductor
Capacitor, Electrolytic,
250
p.F,
60V
Of:
Description
Motorola or
Fairchild
Motorola 2N5458
Motorola
TI 2N3711
I
I
None
Commercial
Alternate
2N5087
2N5088;
PROGRAM
Parts listed as RKC Kits should be ordered by that kit number. Any orc
in RKC quantities.
MUTE
(BOARD
I I
0)
1
Capacitor, Electrolytic,
250
p.
F, 40V
Capacitor, Film,
1
IOOV
Silicon Rectifier, IOOV, 1 /2A
I
Silicon Zener Diode, 32V, 5%
Transistor, Silicon,
Power, NPN
Resistor, Fixed, 2.0 ohms,
1
W.
5%
Capacitor, Film,
1 OOV
Capacitor, Electrolytic,
1000
p.F,
25V
Silicon Rectifier,
Transistor, Silicon, NPN
Transistor, Silicon, NPN
Relay, Reed, SPST,
24 Vdc
!rs received for piece parts where RKC Kit number is shown will be shipped
.I
pF,
.I
pF,
100V, 1/2A
CDE BR250-50
Sprague
CDE DMF-I PI-10
Motorola 1 N4002
Motorola 1 N4752B
RCA 40347
None
Sprague 225P10491;
CDE DMF-1P1-I0
Sprague TVA-1211
I
Motorola 1 N4002
Motorola
TI 2N3711
I
TI TIS97
None
225P10491;
2N5088;
Page 28
Page 29
FIGURE
19.
BOARD
2:
CHANNEL
EQUALIZER 2247-2/2246-3/587-4
Page 30
Page 31
FIGURE
21.
BOARD
9:
POWER SUPPLY
2210-9/2251-3/591-4
FIGURE 22. BOARD
0:
PROGRAM MUTE
2254415923
Page 32
Page 33
SR109
Professional Mixer
NOTES
GENERAL
Shure part numbers are not shown in the Parts List accompanying the Circuit Diagram (Figures 24 and 25, Pages
30 and 32-33) if parts are readily available through local
electronics parts suppliers. In these instances, the Circuit
Diagram shows only the reference designation and value
of the standard parts.
All capacitor values are shown in microfarads unless
otherwise designated. All
100 working volts dc or more unless otherwise specified.
Electrolytic capacitors are shown in microfarads x volts.
All resistor values are shown in ohms (k = 1000). Re-
sistors are 10% tolerance unless otherwise specified.
Resistors are
Transistor lead codes are shown in Figure 23. Accept-
general troubleshooting process is as follows: If the
Mixer is completely "dead," check the ac power source,
%-watt unless otherwise specified.
non-electrolytic capacitors are
/$7
_L
-
-
6
TO
CIRCUIT DIAGRAM
B
fuses, and power supply output (30V between pins
G, Board 9). If the indicator lamps are on but the output is
distorted, low or not present, apply an input signal as
described under
termine that the input and output voltage to each board assembly is correct. If an incorrect ac voltage is found at any
board output, perform
board as described below to isolate the problem area.
A~
V~~~AGE
~h, numbers
circuit
the following test conditions:
diagram
1. Voltages measured with respect to chassis unless
otherwise indicated.
2. Line voltage:
3. Test signal of 1 mV, 1 kHz applied between pins
and 3 of connector J1.
4.
Ac voltage measurements may vary 220% from
values shown.
5.
Measurements made with ac VTVM of 1 megohm or
greater input impedance.
9. Tone oscillator circuit measurements on Main
Board (Bd.
3)
made with TONE OSC Switch on
(out).
LIMITER Switch in IN position.
10.
4..
Dc voltage measurements may vary &20% from
values shown.
5. Measurements made with VTVM of 11 megohms or
greater input impedance.
6. Tone oscillator circuit measurements on Main Board
3)
(Bd.
made with TONE OSC Switch on.
DC VOLTAGE MEASUREMENTS
The numbers within elliptical symbols
a
on the
circuit diagram denote the dc voltages at that point under
the following conditions:
1. Voltages measured with respect to chassis unless
otherwise indicated.
Line voltage:
2.
120V, 50/60
Hz
(SR109)
120V or 240V, 50/60 Hz (SR109-2E)
3.
No input signal applied.
RESISTANCE MEASUREMENTS
With the ac line cord disconnected from the ac source
and the POWER OFF Switch in the OFF position, the
following ohmmeter measurements may be made:
1. Transformers may be checked for continuity of each
winding.
2. To test transistors and diodes, see Page 17.
3.
To check LEDs, see Page 17.
4. To check opto-isolator, see Page 17.
FIGURE 24. SR109-2E POWER SUPPLY CIRCUIT DIAGRAM
81227-11-1
Page 35
FIGURE
25.
SR109 PROFESSIONAL MIXER CIRCUIT DIAGRAM
Page 36
MAIN
BOARD
FIGURE 25. SR109 PROFESSIONAL MIXER CIRCUIT DIAGRAM
33
Page 37
SR109
Professional Mixer
CONDENSED OPERATING INSTRUCTIONS
1. Set all switches and controls to OFF or 0.
2. Connect PROGRAM OUTPUT (LINE or MICROPHONE LEVEL) to power amplifier, broadcast line
feed, etc. Connect speakers to power amplifier.
Connect headphones to PHONES Jack.
3. Connect sources (microphones, tape recorders,
etc.) to INPUT Connectors. Set Channel 7 or 8
MIC/LINE Switches as necessary.
4. Connect external signal-processing equipment
(compressor, equalizer, etc.) to LlNK Jacks. (To
connect two Mixers, connect LlNK OUT Jacks
together.)
Connect ac line to ac source.
5.
Turn on POWER Switch and allow one to two min-
6.
warmup time.
utes
ARCHITECTS' AND ENGINEERS' SPECIFICATIONS
The Mixer shall be a self-contained 90- to 132-volt, 50
to 60 Hz, line-operated, all-silicon transistor mixing amplifier with preamplifiers and controls to mix eight independent low-impedance microphone input signals.
Each input channel in the Mixer shall have independent
HIGH-FREQUENCY and LOW-FREQUENCY controls,
position zero to 15 dB ATTENUATOR Switch and rotarymotion level control. The 7th and 8th input channels shall
each have an additional input switch to select the de-
sired input level (MIC or LINE).
The PROGRAM OUTPUT circuit shall have a 600-ohm
balanced line level output rated at
1% distortion with a minimum clipping level of
and a low-impedance, balanced, microphone-level output
at a level 50 dB below the LlNE LEVEL output. A PHASE
switch shall be provided to reverse the phase of both the
LlNE and MICROPHONE LEVEL outputs.
The program channel shall have a rotary motion MAS-
TER LEVEL control, and a 76.2 mm (3 in.) illuminated
+4,
VU meter with a 0,
Switch.
A pair of LlNK Jacks shall be provided in the program
circuit to allow connection to external equipment such as a
compressor, limiter, equalizer, additional mixer or console, etc.
The Mixer shall have a PHONES level control and a
transformer-coupled headphone (PHONES) output.
The Mixer shall have a voltage gain of 87
maximum microphone input sensitivity of 0.1 millivolts for
+4 dBm program output.
a
The microphone input clipping level, with a zero
ator setting, shall be 4.5 millivolts minimum with the level
control at maximum and shall increase to 100 millivolts
minimum with the level control near minimum.
*
All specifications apply to
180-250
volts; no switched
+8 dBm VU METER RANGE
SR109-2E
AC
receptacle is provided.
+I2 dBm at less than
%3 dB and a
except: operating voltage is
two-
+I9 dBm
attenu-
90-132
7. Set 15 dB ATTENUATOR Switches to preliminary
position for type of material to be used
speech or instrumental music, -15 for "hard"
rock music).
8. Set VU METER RANGE Switch for present applica-
9. Set MASTER Volume Control to 6. With source in-
10. Adjust HI and LO
11. Turn on LIMITER and adjust-THRESHOLD ADJ
0 for PA, +4 for recording, or
tion:
cast.
put, raise Channel Volume Control for desired
sound level. Readjust ATTENUATOR Switch if
necessary.
trols as necessary.
Control if desired.
FREQuency EQualization Con-
+8
for broad-
*
The Mixer shall contain a peak-responding adjustable
output limiter with an in-out switch and an indicator lamp
that flashes when the limiter threshold is exceeded. An
overload lamp, which operates only when the limiter
is not activated, shall indicate when the output clipping
level of the Mixer is exceeded.
An 11-pin accessory monitor output connector shall
provide for connection to one or more Shure
fessional Monitor Mixers to provide separate monitor
mixes for stage monitoring (foldback), multi-channel tape
recording, or stereo broadcasting.
The Mixer shall be enclosed in a metal housing designed
for rack-mounting in a standard 19-inch (483 mm) audio
equipment rack, or mounting in an accessory vinyl-covered
wood portable case.
The Mixer dimensions shall .be 133
height, 483
depth. The weight shall be not more than 7.7 kg (17 Ib).
The Mixer shall have a built-in tone oscillator and a level
control built into the channel 1 program circuit. A POWER
on/off switch shall also be located on the front panel. A
switched ac receptacle rated for 500 watts maximum load
shall be provided.
The MICROPHONE INPUT connectors shall be
female professional audio type. The LlNK Jacks, and tho
PROGRAM LlNE LEVEL OUTPUT Jacks shall be %-inch
phone jacks. One PROGRAM LlNE LEVEL OUTPUT connector and the MIC LEVEL OUTPUT connector shall be
three-pin male professional audio type. The headphone
(PHONES) connector shall be a three-circuit
jack to be used with either mono or stereo phones with an
impedance of 4 ohms or higher.
Any Mixer not meeting all of the above specifications
shall be deemed unacceptable under this specification.
The Mixer shall be a Shure Model
or
mm (19 in.) in width, and 232 mm (9% in.) in
SR109.
SR110 Pro-
mm (5Y4 in.) in
%-inch phone
(0 for
three- in
GUARANTEE
This Shure product is guaranteed in normal use to be
free from electrical and mechanical defects for a period
of one year from date of purchase. Please retain proof of
purchase date. This guarantee includes all parts and
labor. This guarantee is in lieu of any and all other guarantees or warranties, express or implied, and there shall
be no recovery for any consequential or incidental
damages.
SHIPPING INSTRUCTIONS
Carefully repack the unit and return it prepaid to:
Shure Brothers Incorporated
Attention: Service Department
1501 West Shure Drive
Arlington Heights, Illinois 60004
If outside the United States, return the unit to your dealer
or Authorized Shure Service Center for repair. The unit
will be returned to you prepaid.
35
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