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 83 dB at maximum output with one channel Volume Control and MASTER Volume Control set at 8 (approximately 58 dB gain) Number of lnput Channels Power Output ..... . 8 . . . . . . . . . +19 Voltage Gain * Program - dBm (program line level) . . . . . . .
SR109 Professional Mixer SPECIFICATIONS Headphones ... .3.5 ohms actual (for use with 4- to . . . . . . . . . Output Phase Switch polarity-reversing switch (0°, 180') (reverses phase of all program outputs) 16-ohm headphones) Link ...........600 ohms (actual) Accessory Limiter Threshold (adjustable) Range . . . . . . Unbalanced aux level: 33 ohms actual (for use with 4K or higher loads) ..... .Typically -20 to +20 dBm (at LlNE LEVEL output) ............ .Approximately Link Jack System . . . .
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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.
FIGURE 1. SR109 PROFESSIONAL MIXER FRONT PANEL 15 16 17 18 14 19 13 (SR109-2E Only) 27 28 FIGURE 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.
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.
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.
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.
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.
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.
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.
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).
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.
D LlNK OUT SRllO SR109 MONITOR MlXER D SR1Os MIXER RESISTIVE NETWORK LINE LEVEL I L STEREO MlXER TAPE ACC OUT AUX L E V E L POWER AMPLIFIER RECORDER SRllO 1 I I I MONITOR MlXER R - - I I LINK OUT I SR1Os MIXER FIGURE 14. STEREO TAPE RECORDING I LlNE LEVEL I I I I LlNE LEVEL I L POWER AMPL BALANCED BRIDGING INPUT - - - - - - - -J RESISTORS ARE CARBON COMP., 1/2 W.
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.
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.
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.
to +4 and connect a 600-ohm load and an ac voltmeter across the LINE LEVEL OUTPUT (J12-J14). Turn on the Mixer and adjust the TONE OSC Control (Rl) and the MASTER Volume Control (R9) until a reading of +4 dBm (1.228V across 600 ohms) is obtained on the voltmeter. Adjust potentiometer R355 (VU Calibrate) on the Main Board until the VU Meter reads 0 on the upper of the two scales. Note that the VU Calibrate potentiometer range allows the VU Meter to be adjusted to 0 for any output between 0 dBm and +8 dBm.
SERVICE ILLUSTRATIONS Immediately following the parts list on the pages that follow are parts location drawings (Figures 18 to 22, Pages 24-27), and an overall Circuit Diagram (Figures 24 and 25, Pages 30 and 32-33). Once a board has been located through the parts location photo (Figure 16, Page 16), 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.
SR109 Professional Mixer REPLACEMENT PARTS LIST NOTE: 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. To maintain highest possible performance and reliability, Shure Factory Replacement Parts should be used. To insure low noise figure, order transistors from Shure Brothers Inc.
REPLACEMENT PARTS LIST FOR SR109 PROFESSIONAL MIXER Reference Designation I "eg~mfnt I Replacement Kit Consists Of: Qty. Part No.
Reference Designation Replacement Kit No. " Qty. - 51D228 51A262 51A265 95A632 90A1888 95A429 95A604 - Commercial Alternate Replacement Kit Consists Of: Part No. Description 1 95A657 1 Transformer, Headphone Output Transformer, Ac Power (SR109) Transformer, Ac Power (SR109-2E) Line Cord, Ac, Grounded, 2.
REPLACEMENT PARTS LIST FOR SR109 PROFESSIONAL MIXER Replacement Kit No. Reference Designation ~ty. I Commercial Alternate Replacement Kit Consists Of: part NO. Description I I EQUALIZER (BOARD 2) C200, C201, C205. C208 Q200, (2201, (2202 R204, R208 I I - RKC9 - 11 - 1 ( 86A630 4 86A349 - 46A034 1I Capacitor, Electrolytic, 4.
REPLACEMENT PARTS LIST FOR SR109 PROFESSIONAL MIXER Replacemtent Kit No. Reference Designation Qty. RKC65 - 1 1 1 1-1 I I I I 86A334 86A348 1-1 86A329 I I I Transistor, Silicon, NPN Transistor, Silicon, Low Power, PNP Motorola or Fairchild 2N5087 Transistor, Silicon, N-Channel, Field Effect Motorola 2N5458 Motorola 2N5088; TI 2N3711 RKC9 4 86A349 Transistor, Silicon, NPN RKC12 1 86A336 Transistor, Silicon, NPN - - Commercial Alternate Replacement Kit Consists Of: Part No.
FIGURE 19.
FIGURE 21. BOARD 9: POWER SUPPLY FIGURE 22.
SR109 Professional Mixer NOTES TO CIRCUIT DIAGRAM 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 Equalization Controls in 0 (flat) setting. All Volume Controls set to maximum (12). Tone oscillator circuit measurements on Main Board (Bd. 3) made with TONE OSC Switch on (out). 10. LIMITER Switch in IN position. 4.. Dc voltage measurements may vary &20% from values shown. 5. Measurements made with VTVM of 11 megohms or greater input impedance. 6. Tone oscillator circuit measurements on Main Board (Bd. 3) made with TONE OSC Switch on.
FIGURE 25.
MAIN BOARD 33 FIGURE 25.
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.
