Inter-M MA-106A User Manual

MADE IN KOREA

March 2012 130177

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.

13875 Artesia Blvd. Cerritos, CA 90703 USA
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]

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Operation Manual

Public Address Amplifier

MA-106A

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Welcome

Welcome

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

C

AUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK.

DO NOT REMOVE COVER (OR BACK).

NO USER-SERVICEABLE PARTS INSIDE.

REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.

WARNING

To prevent fire or shock hazard, do not
expose the unit to rain or moisture.

*WARNING FOR YOUR PROTECTION PLEASE READ THE FOLLOWING-WATER AND MOISTURE: Unit 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.

*CLASS 2 WIRING (Adjacent to speaker terminal): The speaker output of this apparatus can exceed 10 Watts and could be a shock injury.

Connection to speakers should be performed by a skilled person.
*Do not install this equipment in a confined space such as a book case or similar unit.
*This apparatus shall not be exposed to dripping or splashing and no objects filled with liquids, such vases, shall be placed on the apparatus.
*This apparatus shall be connected to a mains socket outlet with a protective earthing connection.
*

It has heed to be easy to disconnect the device. To disconnect the device from power, separate AC input cable from inlet or unplug the AC Cord.
*

The socket-outlet shall be installed near the equipment and shall be easily 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

interference 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.

T

his symbol is i ntend ed t o al ert the u se r to t he
presence of uninsulated “dangerous voltage” within
the prod uct’s e nclosure that may be of suff icient
magnitude to constitute a risk of electric shock to
persons.

This s ym bol is intende d to a lert the user to t he
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 ins ér ées à fo nd sans e n laisser auc un e pa rtie à
découvert.

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MA-106A

Contents

Contents

Unpacking .......................................................................................................................................2

Installation

Environment....................................................................................................................................2

Important Safety Instructions.............................................................................................................2

Features............................................................................................................................................3

Operation ........................................................................................................................................3

Front Panel ......................................................................................................................................4

Rear Panel .......................................................................................................................................5

Connecting Speakers.....................................................................................................................8

Typical Applications .......................................................................................................................9

Block Diagram ..............................................................................................................................10

Specifications ................................................................................................................................11

Service

Procedures....................................................................................................................................13

Schematic.....................................................................................................................................13

Parts List .......................................................................................................................................13

Variations and Options ...............................................................................................................13

Warranty .......................................................................................................................................13

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MA-106A

Installation

Unpacking

Unpacking

Although your MA-106A 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
environments 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
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 are 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 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
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.

S3125A

S3125A

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MA-106A

Features

Features

Features

-

1U Size Compact Design

- 60W High Efficiency Digital Amp Circuit

- SMPS Power Circuit

- Volume control on INPUT 1~3 – enable to adjust each input channel level

- Display the input signal of INPUT 1~3

- Base and Treble Controls

- Diverse Features -Phantom Mic Power, External MUTE, etc.

- PRIORITY Function

- MIX Configuration DIP switches

- Without input signal for 25 Min, automatically converted to Master System standby Mode

Operation

Operation

1. Before you plug the power cord to AC outlet, please set the power switch OFF, Tone Control center, and

volume level minimum.

2. Please make sure the speakers and input jacks are properly connected before turn the power switch on.

3. Be sure the AC power is correct voltage before you plug into the power cord.

4. Please push the power switch, then the power input LED is on and the unit will be operated.

5. Please use your own with adjustment the volume using each input volume and master volume, the tone using

the tone control.

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Front Panel

Front Panel

1. INPUT 2 JACK

This is a 3.5mm Tip Ring Sleeve (TRS) jack on the front panel that drives input 2. This jack is very useful for
connecting MP3 players, and overrides all input 2 connections on the back panel.

2. INPUT SIGNAL LEDS

These LEDs flash when input signal is present.

3. INPUT LEVEL CONTROLS

These control the level of the three input channels.

4. BASS AND TREBLE CONTROLS

These control the bass and treble of the main amplifier output.

5. MASTER VOLUME CONTROL

This controls the main amplifier output level. There is a separate rear panel level control for zone 2 output.

6. POWER LED

This LED lights blue when the unit is powered on and active, and red when in standby mode.

7. POWER SWITCH

This switch turns the power on or off.

12

357

461 2 64

3 5 7

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Rear Panel

Rear Panel

1. AC MAINS

Connect this cable to an AC outlet.

2. MAIN SPEAKER OUTPUTS

This 5.08mm Euroblock connector is used for the main speaker output wiring. For low impedance speaker
loads, minimum 4Ω, connect between the COM and 16V/4Ω pins. For 70V/82Ω or 100V/167Ω speaker
loads (USA/CANADA & Associated : 25V/11Ω or 70V/82Ω), the LINK wire must first be installed between
the 16V/4Ω pin and OPT IN pin, then connect the speaker load between COM and 70V or 100V pins.

3. ZONE 2 AND PREAMP OUTPUTS

In addition to the main 60 Watt amplifier output, there is a separate ZONE 2 output which is a switch
selectable mix of channels 1, 2, or 3. This output is not effected by the priority ducking/mute action or by
the bass/treble EQ controls.
The ZONE-2 output provides two signals; 1) a low impedance output that is capable of continuously driving
1 Watt into an 8 Ohm loudspeaker, and 2) a 600 Ohms transformer balanced output. Zone 2 output is
controlled by the rear panel Zone 2 level control, as well as the three channel assign DIP switches.
The PRE OUT connection is used for driving additional external devices with the same signal that drives the
main MA-106A power amplifier. The PRE OUT 600 Ohms output signal is taken before the master volume
control.

4. INPUT 3 CONNECTORS

3.5mm Euroblock connectors and summed stereo RCA jacks are used for input 3. If wiring an unbalanced
input signal into a balanced Euroblock input, be sure to ground the (-) input pin.

5. INPUT 2 CONNECTORS

3.5mm Euroblock connectors and summed stereo RCA jacks are used for input 2. If wiring an unbalanced
input signal into a balanced Euroblock input, be sure to ground the (-) input pin.

1 2 3 4 5 6

12111097

8

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6a) MANUAL MUTE CONTACT CLOSURE

Contact Closure between pins 1 and G will mute input channel 2, or mute channels 2 and 3 together if they
a

re linked using mix configuration switch #6. This is typically used when a microphone plugged into channel
1 has a push-to-talk switch, whereby the pressing of the switch not only turns on the mic but also mutes the
signal on channel 2, or channels 2 and 3 if they are linked. When the switch is released, the signal on
channels 2 and 3 returns.

6b) MASTER SYSTEM STANDBY

The MA-106A has a power saving standby mode which can be triggered by 25 minutes of audio
inactivity(below a certain audio input level), or by contact closure of the Master System Standby connector
pins G & 2. When in standby mode, the front panel power LED will turn red, changing back to blue for
normal operating mode. Standby mode is ended when there is audio signal present again, or when the
Master System Standby circuit is opened. Master system standby has priority over standby due to inactivity.

7. ZONE 2 LEVEL CONTROL

This controls the level of the Zone 2 output signal.

8. MIX CONFIGURATION DIP SWITCHES

- Switches 1, 2, and 3: Zone 2 Assign
These assign each input to Zone 2 output, post-level control. There is no effect to the main output mix.

- Switches 4-5: VOX Trigger ­The MA-106A has the ability to trigger a mute on channel 2 or 3 from the presence of an audio signal on
channel 1 or 2. This is called Voice Operated Switching, or VOX. Input 2 has priority over input 3, and
input 1 has priority over input 2. Input 1 also has the ability to use a contact closure trigger such as a mic
push-to-talk switch for priority muting of channel 2. Additionally, input 1 can be set to have priority over
both inputs 2 and 3 together (see switch 6).
The MA-106A has audio detecting LEDs on each input. When the VOX TRIG switches are set to ON for
inputs 1 or 2, the same signal level which activates the LED is used as the VOX trigger. VOX mutes the
dependent channel until the trigger signal falls back below the LED threshold. Each input features a rear
panel gain trim that first optimizes the overall input sensitivity for each input, but can also serve to fine-tune
the sensitivity of the signal detector which creates the VOX trigger point for each input.

- Switch 6: Mute Link 2&3
When this switch is turned on, it sets the channel 1 VOX trigger or Manual Mute contact closure to mute
both channels 2 and 3. If only channel 2 is to be affected, leave it off.

- Switch 7: Low-Cut Filter
This switch turns on a 400Hz 6dB/oct low-cut filter affecting the main and PRE outputs but not the zone 2
outputs. This is useful for providing the proper EQ for paging horns.

- Switch 8: CH 1 MIC Phantom Power
This provides +18V phantom power to input 1 for use with condenser and electret microphones.

9. INPUT 3 GAIN CONTROL

Input 3 gain trim range is adjustable from -10dB to +10dB.

10. INPUT 2 GAIN CONTROL

Input 2 gain trim range is adjustable from -10dB to +10dB. This control is also used to fine tune the signal
threshold that will trigger the muting of input 3.

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MA-106A

11. INPUT 1 GAIN CONTROL

Input 1 gain trim range is adjustable from 0dB to +50dB. A typical line level input setting would be close to
0

dB. A typical Microphone input setting would be closer to +50dB. This control is also used to fine tune the

signal threshold that will trigger the muting of input 2 or inputs 2 and 3 if linked.

12. INPUT 1 CONNECTOR

A 3.5mm Euroblock connector is used for input 1, and can be used as a mic level or line level input. As a
balanced line input, it can connect to a telephone paging system instead of a microphone. If the input signal
is unbalanced, be sure to ground the unused (-) input pin.

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Connecting Speakers

Connecting Speakers

Before connecting speakers to MA-106A unit, be sure to disconnect the AC power cable.

NOTE : 1. Make certain that the total impedance is not less than the rated impedance indicated.

2. Don’t have to use several speaker terminals at the same time.

3. If you’re just dealing with the high impedance terminal, then make sure that 4Ω output terminal is
connected with OPT-IN terminal.

4Ω

SPEAKER

8

Ω 8

Ω

- FOR 70V TERMINAL - FOR 100V TERMINAL

(ONE 4Ω SPEAKER) (TWO 8Ω SPEAKERS)

- FOR 4Ω TERMINAL

*3*3

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Typical Applications

Typical Applications

- RESTAURANT SYSTEM

This two tiered priority ducking example allows for background music to be present on channel 3, which can be
overridden by the presence of audio on channel 2 from a TV signal, both of which can be overridden by a
keyed microphone announcement on channel 1. Stereo audio signals using RCA jacks are summed to mono at
the input.

In this example, all three inputs are assigned to Zone 2 via the DIP switches. Because the mic is set up for push­to-talk, the IN 1 VOX trigger switch is left off. IN 2 VOX trigger is switched on however, so that signal from the
TV will automatically override the background music. Mute Link is switched on so that the keyed mic will mute
both Inputs 1 and 2.

A 70V distributed speaker system runs off of the main power amplifier, and an external amplifier is run off of
the Zone 2 600Ω output. A small 1W 8Ω speaker is run off of the Zone 2 Low Z output.

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Block Diagram

Block Diagram

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Specifications

Specifications

M

A-106A

Rated Output Power (T.H.D 1%) 60W(RMS)

Output Voltage

EC & Associated, JAPAN 4Ω/16V 82Ω/70V 167Ω/100V
USA/CANADA & Associated

4Ω/16V 11Ω/25V 82Ω/70V

Frequency Response

Input 1, 2, 3

+1/-3dB, 80Hz-15kHz

(1W@1kHz)
T.H.D (60W@1kHz) Less than 1%
S/N Ratio

(60W@1kHz A-weighted)

INPUT 1, 2, 3 Better than 70dB

Input Sensitivity

INPUT 1 -10dBV to -50dBV
INPUT 2, 3 0dBV to -20dBV

Tone Control

BASS (100Hz) ±10dB
TREBLE (10kHz) ±10dB

Residual Noise Master volume min -65dB
(Input 1-3 vol min, tone at center)

Master volume max -55dB

Zone 2 Output

Rated power 8Ω (RMS, THD 3%)

1W

BAL 600Ω 2.4V

PRE Out (input -10dBV) 0dBV

SW1 Zone 2 Assign Input 1
SW2 Zone 2 Assign Input 2
SW3 Zone 2 Assign input 3
SW4 VOX Trigger Input 1
SW5 VOX Trigger Input 2
SW6 Mute Link Input 2 & 3
SW7 Low-Cut, 400Hz 6dB/Oct.
SW8

INPUT1 Phantom Power, +18V
Manual Mute Contact Closure Pin 1 & G=Input 1 Mute Trigger
Master System Standby Contact Closure Pins G & 2=Power Standby
Operating Temperature -10°C ~ +40°C

Power Source

100–120VAC or 220–240VAC, 50/60Hz

(Supplied AC mains transformer depends on country requirements)
Power Consumption 24W
Weight (SET) 3.1kg/6.8lb
Dimensions (SET) 300(W) x 44(H) x 230(D)mm/11.8(H) x 1.7(H) x 9.1(D)in

* Specifications and design subject to change without notice.

* Remark : 1. All specifications are measured with AES-17 filter.

2. This system is used digital Amplifier (PWM Modulation) so the PWM leakage signal will appear to
output terminal, but it doesn’t matter. You can’t hear the PWM leakage sound because of PWM
frequencies is very higher than Audio frequencies.

* 0dBV = 1.0Vrms

Mix Configuration Switches

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MA-106A

※

D

IMENSIONS

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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
manual.

Schematic

A Schematic is available by contacting your warranty provider.

Parts List

A Parts List is available by contacting your warranty provider.

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.

Variations and Options

Variations and Options

Variations

Variations of this product exist to reflect the variations in AC power requirements throughout the world. Product
supplied through local sources are compatible with local AC power requirements.

Options

No optional items are available for this product.

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