AMC MA 240 User manual

IMPORTANT SAFETY INSTRUCTIONS
When using this electronic device,
basic precautions should always be
taken, including the following:
1. Read all instructions before using the product.
2. Do not use this product near water (e.g., near a bathtub, washbowl, kitchen sink, in a
wet basement or near a swimming pool etc).
3. Use this device when you are sure thatamplifierhas a stable base and it is fixed securely.
4. This product, in combination with loudspeakers may be capable of producing sound
levels that could cause permanent hearing loss. Do not operate for a long period of
time at a high volume level or at a level that is uncomfortable. If you experience any
hearing loss or ringing in the ears, you should consult with otorhinolaryngologists. The
product should be positioned so that proper ventilation is maintained.
5. The product should be located away from heat sources such as radiators, heat vents, or
other devices (including amplifiers) that produce heat.
6. The product should be connected to a power supply that is described in the operating
instructions or are marked on the product. Replace the fuse only with one of the
specified type, size and correct rating.
7. The power supply cord should be undamaged and never share an outlet or extension
cord with other devices so that the outlet or extension cord's power rating is
exceeded. Never leave device plugged into the outlet when it is not being used for a
long period of time.
8. Care should be taken so that objects do not fall into, and liquids would not be spilled
through, the enclosure's openings.
9. The product should be serviced by qualified service personnel if:
The power supply cord or the plug has been damaged.
Objects have fallen into or liquid has been spilled on the product.
The product has been exposed to rain.
The product has been dropped or the enclosure damaged.
10. There are some areas with high voltage inside, to reduce the risk of electric shock do not
remove cover of the amplifier. The cover should be removed by the qualified personnel only.
No user serviceable parts inside.

CONTENTS:
Before you start
Introductions 4
Features 4
Operation
Front panel 5
Rear panel 5
Function description 6
Output terminal 8
Controls and connectors
Connectors 9
Cable wiring examples 10
Specifications
General specifications 12

Introduction
MA mixing amplifiers for rack mount or stand alone. It is a widely used mixing amplifier designed for
different applications for public address and paging systems, useful for background music systems.
Universal structure of the units, audio signal mixing possibilities, various inputs and outputs have wide
application in simple installations. No need of professional installation assistance. Shop, bar or restaurant
personnel can manage the installation of these mixing amplifiers by itself. Can be used as a component
of voice evacuation or public address system. Line, microphone inputs, phantom power supply, different
connectors, preamp out and direct power amplifier stage input connectors expands the fields of
application of these high quality mixing amplifiers.
Features
Four balanced XLR mic/line inputs.
First XLR input – priority input.
Switchable phantom power on each XLR input.
AUX in and REC out connectors.
Preamplifier out and amplifier in connectors
DC 24V input connector for external power supply.
Tone control.
Output level indicator.

Front Panel
1. XLR inputs level control
2. AUX input level control
3. Tone control
4. Master volume
5. Output level indicator
6. Power switch
7. Power indicator
Rear Panel
1. Ventilation holes
2. Power connector and T6.3AL AC fuse
3. +24V DC terminal
4. Output terminal
5. Preamplifier output
6. Input to power amplifier stage
7. Stereo RCA REC output
8. Stereo RCA AUX input
9. Balanced XLR inputs
10. Music on hold level control
11. Connector for MOH equipment
12. TEL input
13. Gain and phantom power selector
14. TEL input gain control
15. Priority control

Functions description
Front panel:
1. XLR INPUTS LEVEL CONTROL
These rotary knobs are for adjusting volume level of the XLR inputs. First four inputs can be used as
balanced line level as well as microphone level inputs. The phantom power can be activated for these
inputs separately in rear panel. The input gain selector is located in the rear panel too.
2. AUX INPUTS LEVEL CONTROL
These rotary knobs are for adjusting volume level of the AUX input.
3. TONE CONTROL
The separate tone controls provide attenuation of bass and treble response. The flat position is obtained
when the knobs are set to middle position. Turn bass control knob (BASS) and treble tone control knob
(TREBLE), respectively, clockwise to raise tone level by approximately +10 dB; turn counterclockwise to
lower tone level by approximately -10 dB.
4. MASTER VOLUME
This potentiometer is designed to adjust audio level in the main output.
5. OUTPUT LEVEL INDICATION
This is level indicator of the master output. If the red LED indicator starts lighting continuously the output
is distorted. In this case, decrease the sound volume by master volume control.
6. POWER INDICATOR
This LED indicates status of the power. The LED lights up if the amplifier is powered.
7. POWER SWITCH
Use this switch to power on or off the amplifier. The LED in the front panel lights up if the amplifier is
powered.
Rear panel:
1. VENTILATION HOLES
To ensure proper amplifiers cooling leave these ventilation’s holes unblocked. Blocked ventilation’s holes
can be reason of amplifiers damage.
2. POWER CONNECTOR AND AC FUSE
Power connector is designed for main powers connecting to amplifier. This connector is combined with
fuse holder and 6.3A 250V fuse inside.
3. +24V DC TERMINAL
24V DC terminal is designed to power up the amplifier when the main power is unavailable. Use only
DC 24V power supply or batteries and take attention to polarity during the wiring. 24V DC Current - 20A.
4. OUTPUT TERMINAL
Output terminal is designed to connect audio line to amplifier. There are available 4 types of output: low
impedance 4 Ω output, 25 V, 70 V and 100 V outputs for audio line. Please find some connection examples
below in this user manual.
5. PREAMPLIFIER OUTPUT
This is line level output directly from device preamplifier. Preamplifier output and amplifier input are
designed to insert signal processor such as equalizer or limiter.

6. INPUT TO POWER AMPLIFIER STAGE
This is line level input directly to device power amplifier. Preamplifier output and amplifier input are
designed to insert signal processor such as equalizer or limiter.
7. REC OUTPUT
This is line level stereo RCA output to connect audio recording equipment.
8. AUX INPUT
Line level stereo RCA input. AUX input allows to connect the line level audio, input level can be adjusted by
using AUX knob, located in the front panel.
9. BALANCED XLR INPUTS
These balanced XLR inputs are universal, the gain (MIC or LINE) of these inputs are selectable by switch
located near the input in the rear panel. If the 24V PHANTOM power is activated the input gain sets to
microphone level automatically. Please note: Phantom power is switchable on each XLR input separately.
First balanced XLR input have a priority against other inputs.
10. MUSIC ON HOLD LEVEL CONTROL
This rotary knob allows adjusting volume level in the MOH output.
11. CONNECTOR FOR MOH EQUIPMENT
1W 8Ω and 0dB 600Ω outputs are designed for music on hold.
12. TEL INPUT
Emergency input (from PBX station etc). The volume of this input can be controlled by level knob. This
knob is located near the TEL input connectors.
13. GAIN AND PHANTOM POWER SELECTOR.
This selector is designed to adjust the gain for the balanced XLR inputs and select 24V phantom power if
condenser microphones are connected.
14. TEL INPUT GAIN CONTROL
This rotary knob allows adjusting gain level in the TEL input.
15. PRIORITY
Input 1 can be set as priority input. To set priority, please turn priority potentiometer to the right until the
end. To deactivate priority turn to the left until the end.

Output terminal

Each of the amplifier channels (4 Ω, 25V, 70V, 100V) can run only one output configuration at the same time.
Operating amplifiers using 4 ohm and 70 or 100 volt concurrently may cause damage to the amplifier or
connected speakers.
There is possibility to connect external power supply, external battery etc. Please find the connection
example.
Connectors
TS connector
TRS connector
XLR male connector XLR female connector
RCA connector

Cable wiring examples
Cable to balanced input from balanced output. TRS connectors.
Cable to unbalanced input from balanced output. TRS and TS connectors.
Cable to balanced input from unbalanced output. TS and TRS connectors.
Cable to unbalanced input from unbalanced output. TS connectors.
Cable to balanced input from balanced output. XLR connectors.
Cable to unbalanced input from balanced output. XLR and TS connectors.
Cable to balanced input from unbalanced output. TS and XLR connectors

Cable to balanced input from balanced output. TRS and XLR connectors.
RCA cable.
Cable to unbalanced input from RCA output. RCA and TS connectors.
Cable to balanced input from RCA output. RCA and XLR connectors.
Cable to balanced input from RCA output. RCA and TRS connectors.
Cable to RCA input from balanced output. RCA and XLR connectors.
Cable to RCA input from balanced output. RCA and TRS connectors.

General specifications
MA 240
Power supply
AC 230 V, 50 Hz or 24 V DC
Fuses
Fuse for AC power: 6.3A, 250V, 5.2x20mm.
Output power
240 W
AC power consumption
600 W
Total harmonic distortions
< 1 %
Priority
Input 1
Input sensitivity
Line -8 dBu
MIC -50 dBu
AUX -4 dBu
S/N ratio
80 dBu
Frequency response
80 Hz – 16 kHz
Indicators
Power indicator, output level meter
Output
4Ω - (31 V)
25V - (2.6 Ω )
70V - (20.5 Ω),
100V - (41 Ω)
REC OUT - 4.7K ohms, 0 dBu
MOH OUT - 8 ohms 1W/ 600
ohms, 1V
Dimensions
88mm(H) x 420mm(W) x 330mm(D)
Weight
12.8 kg
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