Inter-m MX-1243 User manual

Operation Manual
Audio Mixer
MX-1243

AUDIO MIXER
Welcome
Welcome
A personal welcome o you from he managemen and employees of In er-M
All of the co-workers here at Inter-M are dedicated to providing excellent products with inherently good value,
and we are delighted you have purchased one of our products.
We sincerely trust this product will provide years of satisfactory service, but if anything is not to your complete sat-
isfaction, we will endeavor to make things right.
Welcome to Inter-M, and thank you for becoming part of our worldwide extended family!
RISK OF ELECTRIC SHOCK
DO NOT OPEN
CAUTION
CA TION: TO RED CE THE RISK OF ELECTRIC SHOCK.
DO NOT REMOVE COVER (OR BACK).
NO SER-SERVICEABLE PARTS INSIDE.
REFER SERVICING TO Q ALIFIED SERVICE PERSONNEL.
ATTENTION : RISQ E DE CHOC ELECTRIQ E
NE PAS Q VRIR
WARNING
To prevent fire or shock hazard, do not
expose the unit to rain or moisture.
*WARNING FOR YO R PROTECTION PLEASE READ THE FOLLOWING-WATER AND MOIST RE: nit should not be used near water(e.g.
near a bathtub, washbowl, kitchen sink, laundry tub, in a wet basement, or near a swimming pool, etc). Care should be taken so than objects do
not fall and liquids are not spilled into the enclosure through openings.
*Do not install this equipment in a confined space such as a book case or similar unit.
*Warning : To reduce the risk of fire or electric shock, do not expose this apparatus to rain or moisture and objects filled with liquids, such as vases,
should not be placed on this apparatus.
*This apparatus shall be connected to a mains socket outlet with a protective earthing connection.
*
To completely disconnect this apparatus from the AC mains, disconnect the power supply cord plug from the AC receptacle.
* The mains plug of the power supply cord shall remain readily accessible.
CAUTION
*These servicing instructions are for use by qualified service personnel only. To reduce the risk of electric shock, do not perform any servicing other
than that contained in the operating instructions unless you are qualified to do so.
NOTE
*This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are
designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment
generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful in-
terference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be
required to correct the interference at his own expense.
This symbol is intended to alert the user to the presence
of uninsulated “dangerous voltage” within the product’s
enclosure that may be of sufficient magnitude to
constitute a risk of electric shock to persons.
This symbol is intended to alert the user to the presence
of important operation and maintenance (servicing)
instructions in the literature accompanying the
appliance.
Caution: To prevent electric shock do not use this (polarized) plug with
an extension cord, receptacle or other outlet unless the blades
can be fully inserted to prevent blade exposure.
Attentions: Pour prévenir les chocs électriques ne pas utiliser cette fiche
polarisée avec un prolongateur, une prise de courant on une
autre sortie de courant, sauf si les lames peuvent étre
insérées à fond sans en laisser aucune partie à découvert.
Pour deconnecter completement l’appareil du reseau
d’alimentation. deconnecter le cordon d’alimentation de la
prise murale.
La prise du reseau d’alimentation doit demeurer aisement
accessible.

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MX-1243
Contents
Contents
Unpacking .......................................................................................................................................2
Installation
Environment....................................................................................................................................2
Important Safety Instructions.............................................................................................................2
Features....................................................................................................................3
Front Panel Controls ..................................................................................................4
Rear Panel Controls...................................................................................................7
Applications..............................................................................................................8
Block Diagram ..........................................................................................................9
Specifications ..........................................................................................................10
Service
Procedures....................................................................................................................................11
Schematic.....................................................................................................................................11
Parts List .......................................................................................................................................11
Variations and Options ...............................................................................................................11
Warranty .......................................................................................................................................11

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Installation
Unpacking
Unpacking
Although your MX-1243 is neither complicated nor difficult to operate, we recommend you take a few minutes to
read this brief manual and familiarize yourself with the important information regarding product features, setup
and operation.
As with most electronic devices, we strongly recommend you retain the original packaging. In the unlikely event
the product must be returned for servicing, the original packaging (or reasonable equivalent) is required.
Installation
Environment
Never place this product in an environment which could alter its performance or reduce its service life. Such envi-
ronments usually include high levels of heat, dust, moisture, and vibration.
IMPORTANT SAFETY INSTRUCTIONS
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with dry cloth.
7. Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including am-
plifiers) that produce heat.
9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with
one wider than the other. A grounding type plug has two blades and a third grounding prong. The wide blade
or the third prong are provided for your safety. If the provided plug does not fit into your outlet, consult an elec-
trician for replacement of the obsolete outlet.
10. Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and
the point where they exit from the apparatus.
11. Only use attachments/accessories specified by the manufacturer.
12. Use only with the cart, stand, tripod, bracket, or table specified by the manufacturer, or sold with the apparatus.
When a cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.
13. Unplug this apparatus during lightning storms or when unused for long periods of time.
14. Refer all servicing to qualified service personnel. Servicing is required when the appa-
ratus has been damaged in any way, such as power-supply cord or plug is damaged,
liquid has been spilled or objects have fallen into the apparatus, the apparatus has been
exposed to rain or moisture, does not operate normally, or has been dropped.
S3125A

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MX-1243
Fea ures
Fea ures
- 12CH INPUT AND 4 OUTPUT
Any sound source of microphones, cassette decks, electric guitars, organs can be applied to the 12 channel input,
and 4 AUX SEND, MONO OUT and MAIN L, R OUT are provided for convenient use.
- 3 BAND TONE CONTROLS
3 band tone controls are provided to adjust the acoustic characteristics according to microphones, speakers and
room structured.
- AUX SEND AND AUX RETURN
For the convenient use of effect equipment, reverb, delay or phasor AUX SEND and AUX RETURN function are
provided.
- OUTPUT MONITORING
You can monitor by LED meter and headphone.
- PFL/AFL FUNCTION
The PFL/AFL function allows you to monitor through headphone any input channel before the channel fader and
AUX output channel after the AUX SEND volume.
- PHANTOM POWER
Phantom power is provided for easy connection of condenser microphones requiring an external power supply.

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Fron Panel Con rols
Fron Panel Con rols
1
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3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

AUDIO MIXER
MX-1243
1. OUTPUT LEVEL METER
These meters show the level of output signal appearing at the STEREO OUT L, R and MONO OUT.
2. POWER SWITCH AND INDICATOR
The POWER switch is used to turn on and off the AC main power, and the LED is illuminated when the AC
main power is ON.
3. PHANTOM POWER SWITCH
This switch turns on and off the phantom power supply. The phantom power supply provides power for con-
denser type microphone through the microphone cable.
When switches on, it produces 48volts DC (with 6.8kohms source impedance) at pins 2 and 3 on all of the mi-
crophone input connectors. Pin 1 (the shield conductor) provides the ground return path.
This will power standard condenser microphones and will not affect most dynamic microphones. When switches
on or off, the voltage will ramp slowly up or down; it takes a few seconds to reach full level.
This prevents unwanted transients from reaching the microphone inputs.
4. PFL/AFL INDICATOR
This indicator will light when a PFL or AFL switch is turned on.
. AUX RETURN CONTROLS
These controls adjust the level of the L and R signals that are received at the rear panel AUX RETURN 1, 2. You
can use the AUX RETURN as auxiliary inputs, as well as affects returns.
6. AUX SEND CONTROL (OUTPUT CHANNEL)
This control adjusts the level of the signal output from the AUX SEND OUT.
7. AFL SWITCHES
Press this switch to monitor the AUX SEND signal through the HEADPHONE.
8. BALANCE CONTROL
This knob assigns the signal of AUX RETURN, determining the stereo of the sound.
9. HEADPHONE LEVEL CONTROL
This control is used for adjusting the level of headphone monitoring.
10. HEADPHONE JACK
Connect the headphones here. You can monitor the following signals.
1) Pre-fader signal When the corresponding PFL switch is ON.
2) AUX SEND signal When the corresponding AFL switch is ON.
3) Normally when PFL and AFL switch is OFF, the headphone will monitor the same signal as the STEREO L/R
jacks.
11. MAIN OUTPUT FADERS
The stereo and mono master faders independently adjust level of the L/R and MONO channel main buss
signals appearing at the STEREO L/R and MONO OUT connectors.

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12. TRIM CONTROLS
This control adjusts the input sensitivity of each channel from –16dB to –60dB for microphone source through
the XLR input, and from +24dB to –20dB for line source through the phone jack input.
For the best performance, adjust this TRIM control so that PEAK indicator LED lights occasionally.
13. MIC/LINE SELECTOR SWITCHES
These switch are used for selecting input level MIC and LINE. When a microphone is connected to the MIC IN
jack, set this switch to MIC. When a line source is connected to the LINE IN jack, set this switch to LINE.
14. EQ CONTROLS
Each input channel equalizer is divided into three band. This level is adjustable over a wide range of boost
and cut.
HIGH ±12dB at 12kHz
MID ±12dB at 2.5kHz
LOW ±12dB at 80Hz
1 . AUX SEND 1, 2 CONTROL (INPUT CHANNEL)
You can adjust the level which is assigned to AUX 1, 2 output from each input channel.
Since AUX signal is placed before the channel fader, it will be unaffected by the position of channel fader.
16. AUX SEND 3, 4 CONTROL (INPUT CHANNEL)
You can adjust the level which is assigned to AUX 3, 4 output from each input channel.
Since AUX signal is placed after the channel fader, it will be affected by the channel fader level.
17. PAN CONTROLS
This control assigns the signal of each channel to the STEREO L and R busses, determinating the stereo of
sound.
18. PEAK INDICATORS
This warning light indicates an overload situation. This indicator light in red when the pre EQ, post EQ, or post
fader signal of the corresponding channel’s input reaches a level 3dB below the clipping level.
19. PFL SWITCHES
Press this switch to monitor the pre-fader input channel signal through the HEADPHONE. This is useful when
you wish to monitor only the signal from a particular channel, or take a counter measure for a problem.
20. CHANNEL FADERS
This is the main level control for each input channel. It determines level of the signal sent from the corresponding
input channel to the master stereo buss. Faders of channels not in use should be pulled down.

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MX-1243
Rear Panel Con rols
Rear Panel Con rols
1. AUX RETURN JACKS
These are stereo type phone jacks. Usually the output from effects units such as delay and reverb are returned
to the main stereo mix via these jacks. However, you can use these as auxiliary inputs.
2. AUX SEND JACKS
These are final output of AUX and connected unbalanced phone jacks.
3. MIC IN
These XLR type connectors be connected with microphone. (Pin assignment 1 GND, 2 HOT, 3 COLD)
Impedance range is 50Ω to 600Ω.
These the phantom power switch ON to apply +48V DC to pin 2 and 3 of these connectors.
4. AC POWER ENTRY MODULE
An inlet socket to connect the power cable and fuse holder. A correct capacity of fuse should be applied. Please
make sure the value of fuse before replacing.
. MONO OUTPUT
This is XLR type connector used to connect a power amplifier. (Pin assignment– 1 GND, 2 HOT, 3 COLD)
6. STEREO L/R OUTPUT
These are XLR type connectors used to connect a stereo power amplifier.
(Pin assignment– 1 GND, 2 HOT, 3 COLD)
7. LINE IN
These are balanced input connector which can be connected line level equipment.
Impedance is 10kΩ.
AC IN PU T
220V 6 0H z, 25W
~
FUSE
0. 4A / 250 V
L
R
L/MON O 1
R
L/MO NO 2R
4321
AUX SEND
AUX RETU RN
MAIN OUTMONO O UT
MIC IN
12 11 10 987654321
12 11 10 987654321
LINE IN
123
4567

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Applica ions
Applica ions
CD Player
Tuner
Cassette Deck
PROTCLIP
POWER
CHANNEL 2CHANNEL 1
40dB 20dB40dB20dBCLIPPROT
OFF ON
Power Amplifier
PROTCLIP
POWER
CHANNEL 2CHANNEL 1
40dB 20dB40dB20dBCLIPPROT
OFF ON
Power Amplifier
Effect Processor
ON
ON
Main Speaker
Monitor Speaker
Electric Organ
Microphone
CD Player
Tuner
AC INP UT
220V 6 0H z, 2 5W
~
FUSE
0. 4A / 250 V
LR
L/MO NO 1
RL/MO NO 2R
4321
AUX SEND
AUX RETURN
MAIN OUTMONO OUT
MIC IN
12 11 10 987654321
12 11 10 987654321
LINE IN

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MX-1243
Block Diagram
Block Diagram

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Specifica ions
Specifica ions........................................................................
0dB=0.775Vrms
* Design and specification are subject to be changed for the improvement of product quality without pre notice.
MX-1243
Maximum Output Level
+24dB @ 600Ω, 0.5% THD at 1kHz (BAL) Main Out L/R
+24dB @ 600Ω, 0.5% THD at 1kHz (BAL) Mono Out
+20dB @ 600Ω, 0.5% THD at 1kHz (UNBAL) AUX Send 1-4
100mW @ 40Ω, 0.5% THD at 1kHz Headphone
Input Sensitivity & Impedance
-60dB @ 600Ω (BAL) Mic (CH1-CH12)
-20dB @ 10kΩ (BAL) Line (CH1-CH12)
+4dB @ 10kΩ (UNBAL) AUX Return
THD 0.1% @ +14dB, 20-20kHz
(MAIN OUT L/R @ 600Ω, MONO OUT @ 600Ω, AUX SEND @ 600Ω)
Frequency Response +1dB/-2dB, 20-20kHz @ +4dB
(MAIN OUT L/R @ 600Ω, MONO OUT @ 600Ω, AUX SEND @600Ω)
EQ Characteristics
±12dB 12kHz Shelving (Max ±15dB) High
±12dB 2.5kHz Peaking Mid
±12dB 80Hz Shelving (Max ±15dB) Low
Hum & Noise
(Average, Rs=150Ω)
(Measured with DIN Audio)
-127dB Equivalent Input Noise
-95dB Residual Noise
(MAIN OUT L/R @ 600Ω, MONO OUT @ 600Ω, AUX SEND @ 600Ω)
-76dB Main Out L/R, Mono Out
(INPUT VR & FADER MIN/OUTPUT FADER MAX)
-68dB AUX Send 1-4 (INPUT VR & FADER MIN/OUTPUT VR & FADER MAX)
Crosstalk -70dB Adjacent Input Channels
-70dB Input to Output
Maximum Voltage Gain
84dB Mic to Main Out L/R, Mono Out
76dB Mic to AUX Send
44dB Line to Main Out L/R, Mono Out
36dB Line to AUX Send
20dB AUX Return to Main Out L/R, Mono Out
Gain Adjustment 44dB Mic In/Line In
LED Meter “0” +4dB Output Level
CH. Peak Indicators Red LED on each channel lights when pre-EQ or post-fader signal reaches 3dB below clip level.
Operating temperature -10˚C ~ +40˚C
Phantom voltage DC +48V
Power Source AC 100-120V or AC 220-240V, 50/60Hz
(Supplied AC mains transformer depends on country requirements)
Power Consumption 25W
Dimensions 7.5kg
Weight 482(W)×104(H)×310(D)mm

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MX-1243
Service
Service
Procedures
Take steps to insure the problem is not related to operator error or other products within the system. Information
provided in the troubleshooting portion of this manual may help with this process. Once it is certain that the
problem is related to the product contact your warranty provider as described in the warranty section of this man-
ual.
Schematic
A Schematic is available by contacting your warranty provider.
Parts List
A Parts List is available by contacting your warranty provider.
Variations and Options
Variations and Options
Variations
Products supplied through legitimate sources are compatible with local AC power requirements.
Options
No optional items are available for this product.
Warranty
Warranty
Warranty terms and conditions vary by country and may not be the same for all products. Terms and conditions
of warranty for a given product may be determined first by locating the appropriate country which the product
was purchased in, then by locating the product type.
To obtain specific warranty information and available service locations contact Inter-M directly or the authorized
Inter-M Distributor for your specific country or region.

MADE IN KOREA
September 2015 115551
Inter-M, Ltd. (Korea) began operations in 1983.
Since then, Inter-M has grown to become one of the largest manufacturers
of professional audio and commercial sound electronics equipment in the world.
Inter-M has gained worldwide recognition for its own branded products,
as well as private label manufacturing of electronics sold under other names (OEM).
The company is no longer just a Korean company, but rather a global company
that is truly international in scope, with factories and offices in Korea and China,
and sales and marketing operations located in Japan, Europe, and the U.S.A.
With more than 850 employees around the globe,
Inter-M is well-poised for further growth and expansion.
In er-M Americas, INC.
13875 ARTESIA BLVD. CERRITOS, CA 90703 USA
TEL [phone], FAX [phone]
Home Page http //www.inter-m.net, E-mail [email protected]
In er-M Corpora ion
SEOUL OFFICE 719, DOBONG-RO, DOBONG-GU, SEOUL, KOREA
TEL [phone]~8, FAX [phone]
Home Page http //www.inter-m.com, E-mail [email protected]