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SR109 Professional Mixer
OPERATION AND SERVICE MANUAL
Manufactured by SHURE BROTHERS INC.
222 Hartrey Avenue
Evanston, Illinois 60204 U.S.A.
WARNING
To reduce the risk o f fire or electric shock, d o not expose this appliance t o rain o r extreme moisture.
Copyright 1979, Shure Brothers Inc. 27A1413 (SG)
Printed in U.S.A.
SR109 Professional Mixer
SPECIFICATIONS
Equipment Type
. . . . . . . All
silicon transistor mixer/preamplifier
Signal to Noise (20 Hz-20 kHz)
. . . . . .Typically
Number of lnput Channels Power Output Voltage Gain * Program -
..... . 8 . . . . . . . . . +19
dBm (program line level)
83 dB at maximum output with one channel Volume Control and MASTER Volume Control set at 8 (approximately 58 dB gain)
. . . . . . .87
-13 dB MIC input to LlNE LEVEL out
37 -+3 dB LlNE input to LlNE LEVEL out 37 -13 dB MIC input to MIC LEVEL out Headphones Link
. . . .69 -13
out
dB MIC input to PHONES
. . . . .. . . . . .54.5
k 3 dB MIC input to LlNK OUTPUT (with 600-ohm termination) 27 k 2 dB LlNK INPUT to LlNE LEVEL output
lnput Attenuation . . . . . . 0, 15 dB (switch-selected) lnput Clipping Level at 1 kHz: MIC lnput . . . . . . . . 100 mV (ATTENUATOR out; Ch. Volume at 2) 4.5 mV (ATTENUATOR out; Ch. Volume at 12) 0.56V (ATTENUATOR in; Ch. Volume at 2) 25 mV (ATTENUATOR in; Ch. Volume at 12) LlNE lnput
. . . . . . . .33V (ATTENUATOR out;
Accessory
. . . . . .59
t 3 dB MIC input to ACCESSORY output (via pins 1-8/INPUTS) 54.5 k 3 dB MIC input to ACCESSORY output (via pin 9/PROGRAM) (terminated with 600 ohms)
Ch. ume at 2) 1.35V (ATTENUATOR out; Volume at 12) 90V (ATTENUATOR in; Ch. ume at 2) 8.OV (ATTENUATOR in; Ch. ume at 12)
VolCh. VolVol-
Frequency Response . . . k 3 dB, 20 Hz-20 kHz (150-ohm source; 600-ohm load) lnput Sensitivity Distortion
lnput Common Mode Rejection
. . . . . I 0 0 dB at 100 Hz
. . . . . . .0.1
mV max. for +4 dBm program output
Low-Frequency Equalization . . . . . . . . 2 1 3 dB at 100 Hz with respect to 0 (flat) setting High-Frequency Equalization . . . . . . . . 2 1 2 dB at 10 kHz with respect to 0 (flat) setting Tone Oscillator
. . . . . . . . . . . .THD
less than 1% at +12 dBm, 30 Hz-20 kHz; IM distortion less than 1% at +12 dBm
Noise (300 Hz-20 kHz) . . . . .
. . . . .. . . 1
- 128 dBV (equivalent input noise
at full gain) -72.8 dBm output noise (MASTER Volume Control down) -38.8 dBm output noise (MASTER and one channel Volume Control up) lnput Impedance at 1 kHz: Microphone
kHz; less than 1% distortion; variable level
Hum and Noise (20 Hz-20 kHz) . . . . . .
- 125 dBV (equivalent input hum
and noise at full gain) -61.8 dBm output noise (MASTER Volume Control down) -34.8 dBm output noise (MASTER and one channel Volume Control up)
25- to 600-ohm microphones) Line (channels 7 and 8) . . . . . . . . . 66 kilohms balanced bridging Link lnput . . . . .35 kilohms unbalanced
. . . .2.1 kilohms balanced (for use with
.
Output Impedance: Program . .
.. . . .Balanced line level: 120 ohms ac-
tual (for use with 25- to 600ohm inputs) Microphone level: 0.5 ohms actual (for use with 25- to 600ohm inputs)
'Measurement conditions: MIC input through 150 ohms, LINE input through 33 kilohms LINK INPUT through 600 ohms PROGRAM LlNE LEVEL terminated in 600 oh&, PROGRAM MIC LEVEL terrhinated in 150 ohms, PHONES terminated in 8 ohms: MASTER Volume, Channel Volume and PHONES Controls full up; all other controls and switches 0 or out.
SR109 Professional Mixer
SPECIFICATIONS
Headphones Link
... .3.5 ohms actual (for use with 4- to
16-ohm headphones) aux level: 33 ohms actual (for use with 4K or higher loads)
Phase Switch
. . . . . . . . . Output
...........600 ohms (actual)
. . . . . . Unbalanced
polarity-reversing switch (0°, 180') (reverses phase of all program outputs)
Accessory
30 Vdc Bus
Limiter Threshold (adjustable) Range
..... .Typically
. . . . . . External
-20 to +20 dBm (at LlNE LEVEL output) 30 dB
............ .Approximately
Link Jack System
signal conditioning output/input; high-level auxiliary amplifier and tape recorder signal output; multiple Mixer connection (common mix); remote master volume control f4, +8 dBm, switch-selectable (0.775, 1.23, 1.95 Vrms) at 1 kHz to 600-ohm load. [VU RANGE Switch in 0 position provides 0 VU reading of 0 dBm (0.775 Vrms) to 600-ohm load1 3 of INPUT connectors in phase with pin 9 of ACCESSORY OUTPUT, tips of LINK OUTPUT and PROGRAM LlNE LEVEL OUTPUTS, and pin 3 of PROGRAM LlNE LEVEL and MIC LEVEL OUTPUTS (PHASE Switch in 0" position). Pins 1-8 of ACCESSORY OUTPUT out of phase with the above.
10 on ACCESSORY OUTPUT connector is regulated +30 k 3 . 5 Vdc supply; pin 11 is ground (earth). May be used to power accessories up to 50 mA. Operating Voltage . . . . .90-132 Vac, 50/60 Hz (SR109) 90-132, 180-250 Vac, 50/60 Hz (SR109-2E) Power Consumption . . . 20 watts max. (Mixer only). 500 watts max. (SWITCHED AC receptacle) (SR109 only) Temperature Range: 7 Operating . . . . . .- O to 54OC (20' to 130°F) to 160°F) Storage ....... .-29O to 71°C (-20' Dimensions..
..........Pin
VU Meter Calibration
. . . 0,
. . . . . . . . . 133 mm H x 483 mm W X 232 mm D (See Page 4.) (51/4 in. x 19 in. x 9% in.)
mm) rack mounting; 5% in. (133 mm) height; may be operated in accessory A105A Carrying Case or in custom control center.
Installation
. . . . . . . . . . . Equipped for standard 19 in. (483
Phasing (polarity)
. . . . .Pin
Weight Finish
. . . . . . . . . . . . . . . 7.7 kg (17 Ib)
black, with beige write-on trim strip
. . . . . . . . . . . . . . . . Matte
Certifications
. . . . . . . . . Listed
by Underwriters' Laboratories, Inc.; listed by Canadian Standards Association as certified (SR109 only)
SR109 Professional Mixer
TABLE OF CONTENTS
Page Section ii. iii SPECIFICATIONS DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
.............................
OPERATING INSTRUCTIONS Functional Identification . . . . . . . . . . . . . . . . . . . . . . . . . 3 General Operating Instructions . . . . . . . . . . . . . . . . . . . 3 Mounting and Ventilation . . . . . . . . . . . . . . . . . . . . . . . . 4 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Functional Circuit Description . . . . . . . . . . . . . . . . . . . . 6 Inputchannels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 Monitor Mixer System . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Program Mix Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Link Jacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Program Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 VU Meter Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Limiter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Tone Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 Basic Operating Hints . . . . . . . . . . . . . . . . . . . . . . . . . . 8 . SPECIAL OPERATING INSTRUCTIONS High-Impedance Microphones . . . . . . . . . . . . . . . . . . . . 9 Musical Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Tape Recording . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Record Playback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 . . Tape Playback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 Additional Mixer Inputs . . . . . . . . . . . . . . . . . . . . . . . . 11 . Additional Mixer Inputs (Two SRlO9s) . . . . . . . . . . . . 12 Redundant Mixer Set-up (Two SRIO9s) . . . . . . . . . . . .12 Stereo Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 . Remote Volume Control . . . . . . . . . . . . . . . . . . . . . . . . 13 . Telephone Line Surge Protection . . . . . . . . . . . . . . . . . 14
Section Page SERVICE INSTRUCTIONS Mixer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Fuse Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Knob Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Service Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Lamp Replacement ............................. 14 Board Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Limiter Internal Adjustment . . . . . . . . . . . . . . . . . . . . . . 16 Overload Indicator Check ....................... 16 VU Meter Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 VU Meter Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Parts Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Transistor and Diode Removal .................... 17 Active Component Checking ..................... 17 Service Illustrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Optional Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 REPLACEMENT PARTS LIST . . . . . . . . . . . . . . . . . . . . . .19 NOTES TO CIRCUIT DIAGRAM General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 29 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ac Voltage Measurements . . . . . . . . . . . . . . . . . . . . . . .29 Dc Voltage Measurements . . . . . . . . . . . . . . . . . . . . . . . 30 Resistance Measurements . . . . . . . . . . . . . . . . . . . . . . .30 CONDENSED OPERATING INSTRUCTIONS . . . . . . . . . .35 ARCHITECTS' AND ENGINEERS' SPECIFICATIONS . .35 GUARANTEE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 . SHIPPING INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . .35
SR109 Professional Mixer
LlST OF ILLUSTRATIONS
Figure Page Figure Page
1 2 3 4 5 6 7 8 9 10 11 12
SR109 Professional Mixer Front Panel . . . . . . . . . 2 SR109 Professional Mixer Rear Panel . . . . . . . . . . 2 Overall Dimensions . . . . . . . . . . . . . . . . . . . . . . . . 5 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 SR110 Monitor Mixer Applications . . . . . . . . . . . . 7 Tone Oscillator Applications . . . . . . . . . . . . . . . . 8 Preamplifier-Mixer Connections . . . . . . . . . . . . . . 9 10 Tape Recording . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Record Playback . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Tape Playback . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 Additional Mixer Inputs . . . . . . . . . . . . . . . . . . . . .11 Additional Inputs: Two SRIO9s . . . . . . . . . . . . . . .12
13 14 15 16 17 18 19 20 21 22 23 24 25
Redundant Mixers . . . . . . . . . . . . . . . . . . . . . . . . . .13 Stereo Tape Recording . . . . . . . . . . . . . . . . . . . . . .13 Remote Volume Control . . . . . . . . . . . . . . . . . . . . .13 Printed Circuit Board and Parts Location . . . . . . .16 Opto-Isolator Test . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Board 1: Preamplifier . . . . . . . . . . . . . . . . . . . . . .24 Board 2: Channel Equalizer . . . . . . . . . . . . . . . .25 Board 3: Main Board . . . . . . . . . . . . . . . . . . . . . . 26 Board 9: Power Supply . . . . . . . . . . . . . . . . . . . . 27 Board 0: Program Mute .................... 27 Lead Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 SR109-2E Power Supply Circuit Diagram . . . . . .30 SR109 Professional Mixer Circuit Diagram . . .32-33
SR109 Professional Mixer
DESCRIPTION
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 7 and 8 contain 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 headphqne output is an &ohm balanced output 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 SR109 rear panel contains provisions for connection to one or more 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 submaster mix panel or mixdown panel. The SR109 contains a peak-responding, adjustable output 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
the output is clipping in the non-limiting mode. The Mixer contains a VU meter and a meter sensitivity switch to adjust sensitivity to indicate program output level. A built-in 1 kHz tone oscillator facilitates synchronization of all meters in a system. A front-panel trim strip provides 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 (SR109 only). The solid-state components in the SR109 Professional 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 (SR109 only). The following are designed for use with the SR109 Professional Mixer: SR110 Professional Monitor Mixer A105A Carrying Case
FIGURE 1. SR109 PROFESSIONAL MIXER FRONT PANEL
15
16
17
18
14 19
13
(SR109-2E Only)
27
28
FIGURE 2. SR109 PROFESSIONAL MIXER REAR PANEL
2
SR109 Professional Mixer
FUNCTIONAL IDENTIFICATION (Refer to Figures 1 and 2, Page 2.) NOTE: All front panel controls are numbered for reference only. Individual Channel Volume Controls (Eight) - Control volume and input clipping level of each channel separately. Channel 1 contains TONE OSCillator 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 FREQuency EQualizer-LOW Rotary Controls (Eight) -Adjust low-frequency signal equalization for each channel. Individual Channel FREQuency EQualization-Hlgh Rotary Controls (Eight) -Adjust high-frequency signal equalization for each channel. LIMITER Indicator Lamp - lndicates limiting action when LIMITER Switch (11) is turned on (IN). OVERLOAD Indicator Lamp - lndicates Mixer overload condition (output clipping) when LIMITER Switch (11) is turned off (OUT). True VU Meter - lndicates volume level of program output. (Meets all current standards for VU Meters.) PHONES Rotary Control - Controls volume level to PHONES Jack (8). PHONES Output Jack- Provides for connection of stereo or monophonic headphones for monitoring. 9. MASTER Volume Rotary control and POWER switch -Adjusts level of totai program output, and applies ac power to power supply and SWITCHED AC Receptacle. THRESHOLD ADJustment Screwdriver-Adjustable Control -Sets threshold level of limiter function. LIMITER IN-OUT Slide Switch -Turns program output limiter on and off. Ac Grounded Line Cord - Connects ac power source to Mixer power supply (SR109 only). 3AG-3/16A SLO-BLO Ac Fuse - Protects Mixer ac input line against overload (SR109 only). SWITCHED AC Grounded Receptacle - Provides up to 500 watts of unfused switched ac power to accessory equipment (SR109 only). PROGRAM OUTPUTS/PHASE Slide Switch - Reverses phase (polarity) of LINE LEVEL and MICROPHONE LEVEL program outputs with respect to inputs. VU METER RANGE Slide Switch - Selects VU meter (6) sensitivity for three ranges of program level indication in dBm. ACCESSORY OUTPUT/AUX LEVEL 11-Pin Connector - Provides output connection to Shure SR110 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) - Provide for balanced connection of low-impedance sources to channels 1
through 8 inputs, or line level sources to channels 7 and 8. MIC/LINE Slide Switches (Two) -Select low-impedance (MIC) or line level (LINE) input connections for channels 7 and 8. 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, equalizer, etc.). PROGRAM OUTPUTS/LINE LEVEL Three-Pin Connector - Provides balanced output connection to power amplifier. PROGRAM OUTPUTS/LINE LEVEL Phone Jacks (Two) - Provide balanced or unbalanced output connection to power amplifier. PROGRAM OUTPUTS/MICROPHONE LEVEL ThreePin Connector - provides low-impedance microphone-level program output. VOLTAGE SELECTOR Slide Switch -Selects operating voltage range of 90 to 132 or 180 to 250 Vac, 50/60 Hz (SR109-2E only). AC (MAINS) POWER 3-Pin Connector - Connects ac line cord to Mixer power supply (SR109-2E only). 180-250V 0.1 AT/90-132V 0.2AT SLO-BLO Ac Fuse Protects Mixer ac input line against overload (SR109-2E only). GENERAL OPERATING INSTRUCTIONS
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.
1. Using hardware provided, install Mixer securely in standard 19 in. (483 mm) rack or optional A105A Carrying 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 OO. 3. Connect desired PROGRAM OUTPUT/LINE LEVEL Connector (23, 24) to power amplifier input connecting cable. (NOTE: Shure SR105 Power Amplifiers are supplied with audio connecting cables.) If Mixer output is to be fed to another mixer or tape recorder microphone input, use PROGRAM OUTPUT/MICROPHONE LEVEL Connector (25). 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 INPUTS/MICROPHONE LEVEL LOW IMPEDANCE Connectors (19). Any high-quality dynamic,
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 MICILINE Switch (20) to LINE. 5. If external signal-processing equipment such as an equalizer, compressor or limiter is to be used, connect Mixer LlNK OUTPUT Connector (21) to external equipment input and LlNK INPUT Connector (22) to external equipment output. (See Link Jacks, Page 7, for detailed information.) If a Shure SR110 Monitor Mixer is to be used with the SR109, connect multi-pin plug of SR110 to ACCESSORY OUTPUT Connector (17) of 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 ControllPOWER 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 optimum performance. Set 15 dB ATTENUATOR Switch (18) initially to OUT for normal PA use, to IN for "hard" rock music. For LINE INPUT sources (channels 7 and 8), set MICILINE switch (20) to LINE. 8. Set Master Volume Control (9) to 6. Set VU METER RANGE Switch (16) to 0 for PA or telephone line use (when using a Western Electric 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 (3, 2) for channel in use. Vertical position (0) indicates "flat" frequency response. Clockwise (+) settings increase highfrequency (treble) or low-frequency (bass) level and counterclockwise (-) settings decrease the high- or low-frequency level. 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 continuous glow indicates an undesirable excess of limiting: 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 procedure 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.) Monitor output is available at front-panel PHONES Jack (8). Adjust PHONES Control (7) for comfortable listening level. 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.
10.
11.
12.
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 A105A Carrying Case has a 7 in. (178 mm) rack-mounting space. When the SR109 is mounted in this case, an additional rack-mounted unit such as the SR110 Monitor Mixer may be mounted in the remaining 1% in. (44.4 mm) space. In rack-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.
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 3/16-ampere slow-blow fuse (13) and a wired-in 3/10-ampere slow-blow fuse in series.
'(TYPICAL OF
CHXNELS 1-8)
- 5 0 DB ATTENUATOR NOTE I
-1100 ATTENUATOR
23DB 200x~:HGH XFMR
CHANNEL VOLUME
CHANNEL
-[
6 0 0 A RESISTOR
m ]
Y
m
0
vu
0
METER NOTES I MIC-LINE SWITCHES ON CHANNELS 7 AND 8 ONLY 2 TONE GENERATOR ON CHANNEL I ONLY
1'
PHONES LEVEL
-
/
FIGURE 4. SR109 BLOCK DIAGRAM
CAUTION
These fuses should not be replaced with any other size or type of fuse. Accessory equipment may be connected to the rearpanel 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 Shure SR105. Note that the receptacle is switched but not 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, 50/60 Hz, as selected by the rear-panel 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 three-'pin male ac connector and install it on the line cord: brown to "hot" or "live" terminal, blue lear to neutral terminal, and green/yellow lead to ground or earth terminal. (Connector should be installed by qualified service personnel.) The ac line is protected by a 0.1-ampere Slo-Blo fuse (for 180- to 250-volt operation) or a 0.2-ampere Slo-Blo fuse (for 90- to 132-volt operation. A wired-in 3/10-ampere 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 balanced lnput Transformer, which provides gain of 23 dB. Channels 7 and 8 also contain MIC/LINE Switches (20) 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 MIC/LINE Switch) are fed to 15 dB ATTENUATOR Switches (18) and then to the Preamplifier, which provides +7 to +42 dB gain. The amount of voltage gain provided by the Preamplifier (7 to 42 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 (3,2) which decrease the signal approximately 3 dB when set to the 0, or "flat," setting. The Equalizer outputs are fed to the Program Mix Amplifier and the ACCESSORY OUTPUT Connector (17) for interconnection with SR110 Monitor Mixers. The Program Mix Amplifier feeds through a 560-ohm resistor to the LlNK jacks (21, 22). When accessory equipment is not connected to the LlNK jacks, the jacks are bypassed and the program signal is fed to the MASTER Volume Control (9) and back to the ACCESSORY OUTPUT Connector. The output of the MASTER Volume Control, after feeding a 0 dB gain Amplifier, is sent to a Limiter Attenuator circuit. 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 (5) will flash whenever the output clipping level is exceeded. The Limiter Attenuator also feeds a +7 to +35 dB output Amplifier, also controlled by the MASTER Volume Control.
The signal then goes through a 0'-180' PHASE Switch (15), and into the Program Output Transformer. The Transformer feeds three LlNE LEVEL Output Connectors (23, 24) and a MIC LEVEL Output Connector (25), which is at 50 dB below line level. The +7 to +35 dB output Amplifier also feeds the VU METER RANGE Switch (16), which goes to a +22 dB Meter Amplifier and then to the VU Meter (6), and a PHONES Level Control (7), Headphones Transformer and PHONES Output Jack (8). The Mixer also contains a 1 kHz Tone Generator for use in set-up and check-out. The Generator is activated and controlled by the channel 1 Volume Control/TONE OSC Switch (I), and the Control output is fed to the Preamplifier. A detailed description of the Mixer circuits and controls and their uses is provided in the following paragraphs of this section. INPUT CHANNELS Eight professional, three-pin, audio MICROPHONE 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 is connected to a low-impedance, balanced-input transformer through a 15 dB input ATTENUATOR (18). Two MIC/LIINE Slide Switches (20) are provided for channels 7 and 8. These switches allow the user to select between either low-impedance MICROPHONE or LlNE LEVEL inputs. If additional line level inputs are required, Shure A15LA Line lnput Adapters may be used in each microphone level input. The 15 dB ATTENUATOR (18) two-position switch provides input attenuations of 0 or 15 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; the second section is a preamplifier output attenuator. 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 9. This can often be accomplished by proper 15 dB ATTENUATOR Switch (18) setting. The output of the Channel Volume Control (1) feeds the 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 point. Control settings with plus (+) markings indicate boost, and minus (-) markings denote cut. A 0 setting provides a normal or "flat" frequency response. The output of the equalizer feeds the ACCESSORY OUTPUT/AUX LEVEL Connector (17) and the Program Mix Amplifier. MONITOR MIXER SYSTEM The rear-panel ACCESSORY OUTPUT/AUX LEVEL Connector (17) of the SR109 provides for interconnection to one or more Shure SRl10 Professional Monitor Mixers. The output of each individual channel after all channel controls (volume, equalization and attenuation) appears
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 the SR109. In addition, it may be used in multi-track recording as a submaster mix panel or as a "mixdown" panel. The SR110 provides eight high-impedance, unbalanced, 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). The SR110 has parallel accessory input/output male and female connectors. These connectors permit the connection 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).
(22) is an input-only jack and has switching contacts that disconnect the LlNK OUTPUT signal from the MASTER Volume 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 3 0 to +10 dBm. The LlNK 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 (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
SR1w MIXER OUT ACC
LINE LEVEL
POWER AMPLIFIER
PA SPEAKERS
SRl I 0 MONITOR MIXER
POWER AMPLIFIER
STAGE MONITOR SPEAKER
SRllO MONITOR MlXER STEREO TAPE RECORDER SRllO MONITOR MIXER
FIGURE 5. SRllO MONITOR MlXER APPLICATIONS
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
choice of 0, +4 or +8 dBm output levels for the VU Meter. The 0 setting is usually used for PA applications, +4 is the standard for recording use, and +8 is preferred for use by broadcasters. The calibration of the VU METER RANGE Switch is internally adjusted at the factory for 0 VU across a 600-ohm load on the program output in the +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 follows. Operate the Mixer with program material, and adjust the individual channel and MASTER Volume Controls (1, 9) for the desired level. With a small screwdriver, turn the THRESHOLD ADJ Control full counterclockwise. Set the LIMITER IN-OUT Switch (11) to IN. Slowly increase (turn clockwise) the THRESHOLD ADJ Control until the LIMITER Indicator Lamp (4) flashes, indicating limiting action 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 displayed 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 +4, increase the MASTER Volume Control (9) and TONE OSC Control (1) until a 0 VU reading is obtained on the VU Meter. A tone 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 SR 109 MIXER LINE LINE POWER AMPLIFIER
MIC
TAPE RECORDER
-
@
POWER AMPL AUX LEVEL INPUT JACK GATED COMPRESSOR MIXER
SR 109 MIXER
FIGURE 6. TONE OSCILLATOR APPLICATIONS
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 6B, Page 8). Set 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: Check: Mixer is "dead" (no output, VU METER lamps out) 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 SLO-BLO Fuse (13, 28) is good. Mixer is "dead" (no output, VU Meter lamps lit) 1. Check that cable from PROGRAM OUT PUT/LINE LEVEL Connector (23) has not accidentally been connected to PROGRAM OUTPUT/MICROPHONE LEVEL Connector (25). 2. Check that PHASE Switch (15) is not between positions. 3. If external equipment is connected to LlNK Jacks (21, 22), disconnect external equipment to determine whether fault is in external equipment. One channel is "dead" (other channels operating properly) 1. Check for defective input cable or source. 2. Check that MIC/LINE Switch (20) (channels 7 and 8 only) is not between positions or in the wrong position.
Symptom: Check:
Symptom: Check:
SR109 Professional Mixer
SPECIAL OPERATING INSTRUCTIONS
The previous section described normal interconnection and operation of the SR109 Professional Mixer; this section provides information on special set-ups to more fully utilize the capabilities of the Mixer. nel 7 or 8 jack with MIC/LINE Switch in LlNE position). If the source is unbalanced, connect the cable shield to pin 1 and the hot conductor to pin 3 of the input jack. As an alternate connection, connect the preamplifier auxiliary output through up to 3m (10 ft) of cable to the high-impedance side of a line matching transformer (Shure A95 series) as shown in ~i~~~~ Page 9. connect the low7, impedance side of the transformer through a low-impedante microphone cable (up to 300m-1000 ft) to a Mixer MICROPHONE LEVEL Input Jack (19). Adjust Mixer equalization controls for optimum sound. ~ d jthe Mixer ~ ~ t 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. Fully electrified instruments may also be amplified using a in front of the instrument speaker, Or the inOutput the speaker jack; damage may may be fed to an jack as described above. It is important to note that the tonal quality of fully electrified instruments is primarily formed by the instrument amplifier and speaker; an external microphone Output may very picking up the instrument provide a more desirable sound than that obtained by direct connections. The cable length restrictions applying to high-impedance microphones also apply to most musical instruments (see High-Impedance Microphones, Page 9).
HIGH-IMPEDANCE MICROPHONES High-impedance dynamic, ribbon or condenser microphones (crystal Or ceramic are recornmended) can be used with One the 1°w-im~edance MICROPHONE LEVEL Input Jacks (191, providing a line matching transformer (Shure A95 Series) is used. NOTE: The l5 ATTENUAToR Switch may be used dB 'Ompenthe very high Output produced sate microphones. The high-impedance cable should be limited to 6m (20 ft). If a long cable length is required, use up to 3m ft) of high-impedance, single-conductor, shielded cable (Belden #8401, #8410, or #8411) between the microphone and line matching transformer, and add as much low-impedance, two-conductor, shielded cable (Belden #8412 or #8422) as necessary between the transformer and Mixer input jack. These precautions will help avoid highfrequency signal loss and reduce the possibility of hum and noise. MUSICAL INSTRUMENTS aco~stical (n0n-electrified), acousMusical instr~ments, 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 in use to provide the desired sound level with the channel Volume Control (1) set at about mid-scale. To use a preamplifier auxiliary output (instrument or tape recorder preamplifier, or hi-fi amplifier tape monitor output jack, or headphone jack; not the speaker jacksamplifier damage may result) with the Mixer, connect the preamplifier auxiliary output to a LlNE LEVEL input (chan-
TAPE RECORDING The Mixer output may be recorded on a tape recorder 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 connection, the operator should decide whether he wants the tape level to follow the MASTER Control and LIMITER. To use a LINE LEVEL Output Jack (23,24) feeding a highimpedance auxiliary tape recorder input, connect a cable from one LlNE LEVEL Jack to the tape recorder input (see Figure 8, Page 10). If the LlNE LEVEL Output is being used and a two-circuit phone jack is used to connect the Mixer to the tape recorder, this will unbalance the LlNE
r
PREAMPLIFIER
3 m (10') MAX.A95 LINE MATCHING TRANSFORMER
p=-UP
>
TO 3 0 0 m (1000')
HIGH IMPEDANCE
LOW IMPEDANCE
AUX O HEADPHONE R OUT
LOW IMPEDANCE MICROPHONE CABLE
1
1
SR 109 MIXER 9
MIC LEVEL INPUT
FIGURE 7. PREAMPLIFIER-MIXER CONNECTIONS
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 lowimpedance microphone input. If the microphone input on the tape recorder is designed to be used with high-impedance microphones (greater than 1000 ohms), insert a line matching 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.
I
LOW IMPEDANCE BALANCED LINE I
1
I
MIC LEVEL OUTPUT
I
1
I
FIGURE 8. TAPE RECORDING
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 Control (2) to +4, the FREQ EQ-HI Control (3) to -6, and the 15 dB ATTENUATOR Switch (18) to 0 for the channel being used. Adjust the channel Volume Control (1) as necessary.
A better method of performing this interconnection involves 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 ATTENUATOR Switch (18) to 0 with this set-up. Note also that this set-up removes the cable restriction between turntable and Mixer described above; although
@
TURNTABLE
A95
M I C INPUT
SR 109 MIXER
(
FREQ. EQ-L0:+4 FREQ. EP-HI: -6
)
@
15 m .
(5')
M-. A = X
CHAN.1
M 6 4 STEREO PREAMPLIFIER i
p-UP
'
TO 300 rn
(1000')
L W LEVEL O
OUTPUT
CHAN. I
r
T R T BE U NAL
4f
1
MIC INPUT
SRlOS MIXER
INPUT
OL NY
ONE CHANNEL IS USED FOR THIS APPLICATION.
FIGURE 9. RECORD PLAYBACK
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, connect a cable from the tape recorder auxiliary or line level output to the channel 7 or 8 LlNE LEVEL lnput Jack (19). For unbalanced tape recorder outputs, connect a singleconductor, shielded cable as shown in Figure 10, Page 11. Connect the tape recorder output cable shield to pin 1 and the "hot" conductor to pin 3 of the SR109 LlNE LEVEL lnput Jack. Set the rear-panel MIC/LINE Switch (20) on channel 7 or 8 (whichever is being used) to LINE. Set the 15 dB ATTENUATOR Switch (18) to 0, and the channel Volume Control (1) as required.
TAPE RECORDER AUX OUTPUT
SR109 MlXER
c-------
\ ------- --I
(CHANNEL 7 OR 8)
ure 11B, Page 11). Set the SR109 15 dB ATTENUATOR Switch (18) to 0 and the MIC/LINE switch to LINE. To use this set-up with other mixers, essentially the same procedure is followed. The Shure M67 mixer, for instance, may be connected to the SR109 LlNE INPUT Jack through the mixer line out connector (binding posts) or headphone output (phone jack) (Figure 11C, Page 11). If a mixer is to be used with the SR109 but it is desirable to maintain as many SR109 channels as possible, the mixer can be connected to the LlNK OUTPUT Jack (21) (Figure I l D , Page 11). However, this requires sacrificing the channel equalization functions for the sources entering through the mixer. The only SR109 control functions operating on the mixer sources in this set-up are the MASTER Volume Control (9), LIMITER Switch (11) and rear-panel PHASE Switch (15). In addition, any mixer used in this setup requires a 2.2-kilohm resistor in series with the mixer output to provide an attenuator bridging connection; the resulting signal level will be down -10 dB (see Figure 11E, 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 Shure M68FC mixer cannot be used this way. The mixer-to-link out jack connection can also be used with several mjxers. Each mixer output must contain its
FIGURE 10. TAPE PLAYBACK
MIC LEVEL LOW IMPEDANCE
MIC
LEVEL
ADDITIONAL MlXER INPUTS Additional microphone or other source inputs may be obtained using a high gain, low noise, microphone mixer such as the Shure M68FC. When connected to a MICROPHONE LEVEL lnput Jack (19), the M68FC and SR109 will provide a total of 11 inputs (see Figure 11A, Page 11). (Note that adding a mixer at an lnput Jack converts that channel to a submaster control; the total number of inputs will thus be the mixer total plus the SR109 total ---8 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 SR109. The SR109 individual channel Volume 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) to 0 and adjust the mixer channel volume controls in the mid-to-high range. Adjust the mixer master volume control as required to keep the SR109 channel volume control in the desirable middle range. The M68FC mixer has a switch-selectable low- or highimpedance 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 SRl09 channel 7 (or 8) LlNE INPUT (19). (Refer to Tape Playback, Page 11, for a description of this set-up.) To use this set-up with an M68FC mixer, connect a cable between the mixer auxiliary output (phono pin jack) and the SR109 LINE INPUT Jack (19) on channel 7 (or 8) (Fig-
M68FC MIXER
SR109 MIXER
TOTAL.11 CHAP:NELS
AUX LEVEL
L l N E LEVEL
@
MIXER
SR109 MIXER
TOTALaII CWNNELS
LlNE OUT OR PHONES OUT
LlNE LEVEL
0
0
,,
MIXER
SRlOS MIXER
PHONES
MIXER vT" 6 M
SRlOS MIXER
600Ll LlNE OUT MIXER SRIO, MlXE R
; $
, ,
TOTAL: I I CHANNELS
TOTAL I 2 CHANNELS (NO EWALlZATlON ON M67 INPUTS)
TOTAC. I 2 CHANNELS (NO EOUAUZATI ON ON MlXER INPUTS1
FIGURE 11. ADDITIONAL MIXER INPUTS
D
LlNK OUT
SR1Os MIXER
SR109 MlXER
SRllO MONITOR MlXER ACC OUT AUX L E V E L SRllO MONITOR MlXER
L STEREO TAPE RECORDER R -
I
D
LINE LEVEL RESISTIVE NETWORK 1 I I I POWER AMPLIFIER
-
LINK OUT SR1Os MIXER LlNE LEVEL
I I
I
I
FIGURE 14. STEREO TAPE RECORDING
POWER AMPL BALANCED BRIDGING INPUT
I I I
I
I
LlNE LEVEL
L
- - - - - - - -J
RESISTORS ARE CARBON COMP., 1/2 W.5%
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 singleconductor, 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, i t 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
FIGURE 13. REDUNDANT MIXERS
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 SR109 output in stereo is to use two SR110 Professional Monitor Mixers. This method allows the SR109 output to be used for the PA system. Connect the SRllOs as shown in Figure 14, Page 13, with the output of one SR110 feeding the left input of the tape recorder and the other SR110 feeding the right. Note that the controls of the SRllOs permit spatial positioning ("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 SR110 channel 1 volume control for the proper level and leave the right SR110 channel 1 volume control at 0. If the second tape input is to be recorded "centered" (both left and right), adjust both 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 record 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
LlNK OUT
--
I
--
--
@
SRlOS MIXER
---
0
SRIOS MIXER LlNK IN
, \
r - - - - - - - 7
I
I
WHITE BLACK
I I I
L- - - - - - - - I
"
I
J
FIGURE 15. REMOTE VOLUME CONTROL
as shown in Figure 158, Page 13, and plug the control assembly into the LlNK OUTPUT (21) and LlNK INPUT (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 (Belden #8412 or #8422). Connect as shown in Figure 15C, Page 13, and use a metal box to contain the potentiometer. 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
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 following 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 35.) The SR109 Professional Mixer uses components of the highest quality, operating well within their respective ratings to assure long life.
CAUTION
If trouble symptoms -overheating, erratic operation, 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 F1 (F2, 3/10A, Slo-Blo). If replacement 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 #47 lamps (PLl,PL2) illuminating the VU Meter (MI), carefully raise the metal c l i assemblv holdina the lam^ to be r e ~ l a c e d ~ uoward and 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 (LED'S) (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.
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 3AG-3/16A Slo-Blo fuse (SR109 only; SR109-2E contains a 0.1A Slo-Blo fuse for 180- to 250-volt operation, or a 0.2A Slo-Blo fuse for 90to 132-volt operation).
Unsolder both LED gray leads from the Power Supply assembly. Remove the Power Supply assembly and VU Meter (see VU Meter Removal, Page 16). Unsolder the LED orange lead from the LIMITER OUT-IN Switch (S12) or THRESHOLD ADJ Control (R10) (depending on which is to 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 replacement. In an emergency, the LED wires may be spliced and insulated (with tape or tubing) without removing the VU Meter or Power Supply.
AA AB
"1 ;1: 1
Main Board (Cont'd.)
Black White Red White/Green Black White Red (5)
AF AG AH
White/Red Green Brown Black Red Black
Power Supply Board
F G
Green Yellow Black (7)
Program Mute Board
Yellow Black Gray
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.
NOTE:
Production variations may result in wire colors differing from those in the table.
I
Green/White Red
ID
E
White Green
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
CAUTION
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.
Preamplifier Board Letter Wire Color Letter Wire Color
Preamplifier B