Inter-m MX-1242A Operating Manual

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MX-1242A

Professional Audio Mixer

Copyright 2004 Inter-M Corporation

MX-1242A Professional Audio Mixer

Contents

Welcome ..................................................................................................................................... 3

Unpacking ............................................................................................................................... 3

Warnings .................................................................................................................................. 3

Operation................................................................................................................................. 5

Professional Audio Mixer ........................................................................................................6

Features ....................................................................................................................................... 6

Top Panel Controls...................................................................................................................... 7

Rear Connector Panel.............................................................................................................. 11

Connectors and Cables...........................................................................................................13

Connections.............................................................................................................................. 14

Specifications............................................................................................................................ 15

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MX-1242A Professional Audio Mixer

Welcome

A personal welcome to you from the management and employees of Inter-M

Thank you for purchasing this fine Inter-M product. All of us here at Inter-M are dedicated
to providing you with the highest quality products and the best value.

We sincerely trust this product will provide you with years of satisfactory service, but if
anything is not to your complete satisfaction, we will endeavor to make things right.

Welcome to Inter-M, and thank you for becoming a part of our worldwide extended
family!

Unpacking

Please 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.

Warnings

Environment

Never place this product in an environment that could alter its performance or reduce its
service life. Such environments are usually characterized by high levels of heat, dust,
moisture, or vibration.

Safety

1. Read these instructions carefully.

2. Follow all instructions.

3. Keep all warnings.

4. Do not operate this apparatus near water.

5. Clean only with a damp cloth.

6. Do not block any of the ventilation openings.

7. Install in accordance with the instructions in this manual.

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MX-1242A Professional Audio Mixer

8. Do not install near any heat sources such as radiators, heat registers, stoves, or other
devices (including amplifiers) 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 is provided for
your safety. If the provided plug does not fit into your outlet, consult an electrician 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 it is attached to the apparatus.

11. Use only the attachments/accessories specified.

12. Use only with a cart, stand, tripod, bracket, or table specified, or sold with the
apparatus. When a cart is used, use caution when moving the cart/apparatus
combination to avoid overturning.

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
apparatus 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.

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MX-1242A Professional Audio Mixer

Operation

Make certain that power amps, speakers and input sources are properly connected
before switching on.

Keep volume levels at minimum gain and equalization set to 0dB position before
switching on.

NOTE: The system’s operation is delayed by approximately three seconds after pressing
the AC Mains power switch. This is due to the built-in protection circuitry, designed to
protect the speakers and other system components.

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MX-1242A Professional Audio Mixer

MX-1242A
Professional Audio Mixer

Features

Powerful Multi-Channel Mixer

• 12 input channels and four output channels plus two Aux Sends. Connect
microphones, instruments, CD or cassette players and mix decks in several effective
configurations.

Versatile EQ Controls

• Four-band EQ on each input channel gives versatile, sound-shaping control.

PFL Function

• Built-in PFL function for monitoring channel inputs via headphones or monitor out.

Phantom Power

• Built-in +48V Phantom Power for condenser microphones.

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MX-1242A Professional Audio Mixer

Top Panel Controls

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MX-1242A Professional Audio Mixer

1. Input Gain (Trim)

This knob is used to adjust the input signal to its optimal level. Set the TRIM Control
so that the PEAK Indicator (8) lights only occasionally, thereby achieving the best
balance of S/N and dynamic range. For the MIC INPUT, the gain range is –16dB to
–60dB. For the LINE INPUT, the gain range is +10dB to –26dB.

2. Line/Mic Selector Switches

These switches are used to select the input source for the associated input
channel. When a microphone or other mic-level source is connected to the rear­panel XLR input, this switch should be on the MIC setting. When a line-level or
instrument-level source is connected to the rear-panel line input, the switch
should be set to the LINE position.

3. EQ Controls

These knobs control the equalization for the associated input channel. Four bands
of equalization are provided:

Low (80Hz), ±15dB, shelving type
Lo-Mid (300Hz) ±12dB, peak type
Mid (3kHz) ±12dB, peak type
High (12kHz) ±15dB, shelving type

4. EFX Send 1/2

These knobs control the signal levels sent to the EFX SEND 1 and 2 busses. The EFX
SEND controls are post-fader, and are directly affected by the channel’s fader
setting.

5. AUX Send 1/2

These knobs control the signal levels sent to the AUX SEND 1 and 2 busses. The
AUX SEND controls are pre-fader, and are unaffected by the channel’s fader
setting.

6. Pan Controls

These knobs control the associated channel’s stereo positioning being sent to the
Stereo L/R buss.

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MX-1242A Professional Audio Mixer

7. PFL Switches

These buttons are used to monitor each channel’s output status via the
HEADPHONE jack and MONITOR OUT.

When monitoring the channel’s input signal, PFL position allows you to hear the
input at a level unaffected by the position of the channel’s fader, Aux Send and
Pan settings.

8. Peak Indicators

These PEAK LEDs will light at 3dB before clipping to indicate that the input signal is
near clipping. The Peak Indicator is placed after the EQ in the signal chain.

9. Channel Faders

These faders control the output level (the level sent to the output buss) for the
associated input channel. Levels of unused channels should be set to the
minimum setting.

10. Output Level Meter

The multi-segment LED meters indicate the output levels of the Aux 1/2 and
Stereo L/R busses.

11. Power Switch and Indicator

This switch is used to switch the unit on, as indicated by the associated LED
indicator.

12. EFX 1 and 2 Master Send

These knobs control the output level of EFX 1 and 2 busses sent to external
processing equipment connected to the respective output.

13. Monitor Control

This knob controls the signal level being sent to the MONITOR OUT L/R jacks.

14. Headphone Out Jack

This 1/4” stereo phone jack accepts standard headphones. Headphones can be
used to monitor the following signals:

• Stereo L/R buss – when no PFL switch is engaged, the headphone output
receives the same signal as the master Stereo buss.

• Post-EQ signal – when one or more PFL switches are engaged, the
headphone output monitors those input channels’ signal.

• Pre-fader signal – when the corresponding Stereo L/R PFL switch is engaged,
the headphone output monitors the pre-fader signal.

• Pre-Aux Send fader signal – when the corresponding Aux Send PFL switch is
engaged, the headphone output monitors the pre-Aux Send signal.

15. Headphone Level Control

This knob controls the output level of the HEADPHONE OUT jack.

16. Aux Return Master 1 and 2

These knobs control the L/mono or stereo level received at AUX RETURNS 1 and 2,
controlling the level mixed to the Stereo L/R buss.

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MX-1242A Professional Audio Mixer

17. EFX Return Master 1 and 2
These knobs control the L/mono or stereo level received at EFX RETURNS 1 and 2,
controlling the level mixed to the Stereo L/R buss.

18. Aux Output Faders

These faders control the Aux Send 1 and 2 output levels.

19. Stereo L/R Master Fader

These faders control the level of the combined input channel faders being sent to
the STEREO Out. 10dB of gain is possible per channel, with 0dB representing Unity
Gain (recommended). Use the Stereo L/R METERS to monitor the output levels.

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MX-1242A Professional Audio Mixer

Rear Connector Panel

1. Mic Inputs 1-12

Each channel provides a low impedance (“low-Z”) input on a balanced 3-pin XLR
jack for mic-level sources such as condenser and dynamic microphones.

NOTE: When phantom power is switched on, +48V power is sent to the 3-pin XLR
jacks of ALL channels. To avoid damaging high-Z devices, be sure sources not
requiring phantom power are connected only to the high-Z 1/4” jacks.

2. Line Inputs 1-12

Each channel provides a high impedance (“high-Z”) input on an unbalanced
1/4” connector for line-level devices (synths, drum machines, etc).

3. EFX Return Jacks 1 and 2

These are line-level inputs on unbalanced 1/4" connectors, provided for
connection to the output of external effects processing devices. Their level is
controlled by the front-panel EFX Return controls.

4. EFX Send Jacks 1 and 2

These are line-level outputs on unbalanced 1/4" connectors, provided for
connection to the input of external effects processing devices. Their level is
controlled by the front-panel EFX Send controls.

5. AUX Send Jacks 1 and 2

These are line-level outputs on unbalanced 1/4" connectors, provided for
connection to the input of external effects processing devices. Their level is
controlled by the front-panel AUX Send controls.

6. AUX Return Jacks 1 and 2

These are line-level inputs on unbalanced 1/4" connectors, provided for
connection to the output of external effects processing devices. They may also
be used as auxiliary inputs. Their level is controlled by the front-panel AUX Return
controls.

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MX-1242A Professional Audio Mixer

7. Monitor Outputs

These are unbalanced 1/4” tip-sleeve phone jack outputs. The MONITOR OUT can
be used for an alternate monitoring system. The MONITOR OUT signal source is:

• Stereo L/R buss – when no PFL switch is engaged, the Monitor Out receives the

same signal as the master Stereo buss.

• Post-EQ signal – when one or more PFL switches are engaged, the Monitor

Out receives those input channels’ signal.

• Pre-fader signal – when the corresponding Stereo L/R PFL switch is engaged,

the Monitor Out receives the pre-fader signal.

• Pre-Aux Send fader signal – when the corresponding Aux Send PFL switch is

engaged, the Monitor Out receives the pre-Aux Send signal.

8. Stereo (Main) Out Jacks

Connect the Main L/R balanced XLR outputs to your power amp or powered
speakers. This is the main stereo output of the Stereo L/R buss, outputting the
combined signals of all active input channels with the L/R buss selected. The
output level is controlled by the Stereo Master Faders.

9. Phantom Power Switch

This switch activates the phantom power supply for the mic input channels. When
the switch is switched on, +48VDC power is supplied to pins 2 and 3 of each
channel’s XLR input connector. Use phantom power when connecting
condenser microphones that require an external power supply.

NOTE: It is safe to connect most modern dynamic microphones or line level
devices to the channel inputs when phantom power is activated. However, some
older ribbon microphones may be damaged by phantom power, and certain
unbalanced line level devices may malfunction or produce an audible hum
when phantom power is active.

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MX-1242A Professional Audio Mixer

Connectors and Cables

Use of low quality or improper cables to connect the equipment can result in
exaggerated or deficient high frequency response, degradation of signal to noise ratio,
and other problems. Use of proper cables is essential if the full potential of your sound
equipment is to be achieved. These power mixers are fitted with only three types of
audio connectors; 3-pin female XLR, 1-conductor (tip-sleeve) 1/4” phone jacks, and 2­conductor (tip-ring-sleeve) 1/4” phone jacks (sometimes referred to as stereo phone
jacks).

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MX-1242A Professional Audio Mixer

Connections

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MX-1242A Professional Audio Mixer

Specifications

Maximum Output Level
Main Out L/R +24dB@600Ω, 0.5% THD at 1kHz
Aux/EFX Send 1-2 +20dB@600Ω, 0.5% THD at 1kHz

T.H.D. (-14dB @ 600Ω, 20Hz – 20kHz) <0.1%

Frequency Response
Main Out @ 600Ω 20Hz – 20kHz, +1dB, -2dB @ +4dB
Aux/EFX Send 1-2 @ 600Ω 20Hz – 20kHz, +1dB, -2dB @ +4dB

Hum and Noise (EIN) -127dB

Maximum Voltage Gain
Mic In - to Main Out 84dB
Line In - to Main Out 50dB
Mic In - to EFX Send 1-2 86dB
Mic In - to Aux Send 1-2 80dB
Mic In - to Monitor Out 84dB
Line In 1-6 - to PFL Mon Out 90dB

Aux Return - to Main Out 30dB
EFX Return - to Main Out 30dB

Crosstalk
Adjacent Input Channels -70dB

Input to Output (exc. betw. Main L/R) -60dB
Input to Output (between Main L/R) -55dB

Channel EQ Controls

High 12kHz, ±15dB, shelving type
Hi-Mid 3kHz, ±12dB, peak type
Lo-Mid 300Hz, ±12dB, peak type
Low 80Hz, ±15dB, shelving type

Phantom Power +48V DC

Power Source

US and Canadian Models 120VAC, 60Hz
General Model 230VAC, 50Hz

Power Consumption 36W

Weight 8.5kg (18.74 lbs)

Dimensions 483(W) x 130.2(H) x 32.6(D) mm

19(W) x 5.1(H) x 12.6(D) in

Specifications and design subject to change without notice for product improvements.

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MX-1242A Professional Audio Mixer

audiovias.com

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.

INTER-M AMERICAS, INC.

1 EAST BEACON LIGHT LANE, CHESTER, PA, USA 19013-4409
TEL: [phone], FAX: [phone]
Home Page:http://www.inter-m.net, E-mail: [e-mail]

INTER-M Corporation

SEOUL OFFICE: 653-5 BANGHAK-DONG, DOBONG-KU, SEOUL, KOREA
TEL: [phone]~8, FAX: [phone]
Home Page:http://www.inter-m.com, E-mail: [e-mail]

0804MX1242A PRINTED IN KOREA

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