Inter-m A-60 User manual

A-60/A-120
Public Address Amplifier
Copyright 2004 Inter-M Corporation

A-60/A-120 Public Address Amplifier
Contents
Welcome ..................................................................................................................................... 3
Unpacking ............................................................................................................................... 3
Warnings .................................................................................................................................. 3
Operation................................................................................................................................. 5
Public Address Amplifier......................................................................................................... 6
Features ....................................................................................................................................... 6
Front Panel Controls.................................................................................................................... 7
Rear Panel Controls .................................................................................................................... 8
Connecting Speakers................................................................................................................. 9
Applications .............................................................................................................................. 10
Block Diagram .......................................................................................................................... 11
Specifications............................................................................................................................ 12
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A-60/A-120 Public Address Amplifier
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
Although your A-60/A-120 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.
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 only in accordance with the instructions in this manual.
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A-60/A-120 Public Address Amplifier
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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A-60/A-120 Public Address Amplifier
Operation
Make certain that speakers and input sources are properly connected before switching
on.
Keep volume levels at minimum gain 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 speakers and other system components.
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A-60/A-120 Public Address Amplifier
A-60/A-120
Public Address Amplifier
Features
High Power, Low Distortion
• 60W (A-60) or 120W (A-120) of RMS power, with less than 1% THD.
Versatile and Easy to Use
• Three Mic inputs, two Aux Inputs.
Priority Muting
• Mic1 input mutes other inputs when in use.
Flexible Design
• Mono 4or 70V/100V High-Impedance Outputs
Tone Control
• Separate Bass and Treble controls to tailor your sound.
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A-60/A-120 Public Address Amplifier
Front Panel Controls
1. Power Switch
Pressing this switch switches the unit on, as indicated by the Power LED above the
switch. Pressing it again switches the unit off.
2. Master Volume
This knob controls the overall volume of the A-60/120 output.
3. Bass and Treble Controls
These knobs control the high and low frequency response, by adding up to 12dB
of cut (decrease) or boost (increase).
4. Aux Volume 1-2
These knobs control the volume of Aux Inputs 1 and 2.
5. Mic Volumes 1-3
These knobs control the volume of Mic Inputs 1-3.
6. Protection Indicator
This LED indicates the state of the amplifier’s protection circuitry. When the
Protection LED is on (illuminated), the protection circuitry is active, indicating that
the unit is not operating normally. This is typically due to overheating or power
limiting. Please check the Input and Output condition of the amplifier.
7. Output Level Display
This six-segment LED meter indicates the amplifier’s output level in RMS.
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A-60/A-120 Public Address Amplifier
Rear Panel Controls
1. Priority Mute Level
When Mic Input 1 is active, it mutes all other input signals (priority muting). When
priority muting is in effect, this control is used to set the amount of attenuation
(how much muting) is applied to the other inputs when a signal is present on Mic
Input 1. The amount of attenuation can range from very little to complete muting.
2. Mic 1,2,3 Inputs
These 1/4" phone jacks accept a standard mic-level input. Input impedance is
600Ω, and input sensitivity is 0.6mV.
3. Aux Inputs 1-2
These inputs are used for connecting line-level sources, such as CD, tuner or
cassette deck.
4. Speaker Output Terminals
These terminals are used to connect speakers to the unit. You may select either
4conventional operation, or High Impedance operation at either 70V or 100V.
5. AC Power Cable
Connect this cable to your AC outlet.
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A-60/A-120 Public Address Amplifier
Connecting Speakers
Before connecting speakers to your A-60/120 unit, be sure to disconnect the AC power
cable. Make certain that the total impedance is not less than the rated impedance
indicated.
For 4speakers, connect in parallel, with the positive (+) connectors to the 4terminal
and the negative (-) connectors to the COM terminal. See Figure below.
For high-voltage distibuted systems, connect with matching transformer to either 70V or
100V terminals, as per Figures below. Be certain that the total impedance does not equal
less than the rated impedance.
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A-60/A-120 Public Address Amplifier
Applications
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