CleanDigital MA2B User manual

MA2B
Mini Digital Amplifier
All Rights Reserved
Version: MA2B_2016V1.0
User Manual

Mini Digital Amplifier
Preface
Read this user manual carefully before using this product. Pictures shown in this manual is for reference only, different model and
specifications are subject to real product.
This manual is only for operation instruction only, not for any maintenance usage. The functions described in this version are
updated till March 2016. Any changes of functions and parameters since then will be informed separately. Please refer to the dealers
for the latest details.
All product function is valid till 2016-3-1.
Trademarks
Product model and its logo are trademarks. Any other trademarks mentioned in this manual are acknowledged as the properties of
the trademark owner. No part of this publication may be copied or reproduced without our prior written consent.
FCC Statement
This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio communications. It has been tested and found to comply with the limits for a
Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against
harmful interference in a commercial installation.
Operation of this equipment in a residential area is likely to cause interference, in which case the user at their expense will be
required to take whatever measures may be necessary to correct the interference
Any changes or modifications not expressly approved by the manufacture would void the user’s authority to operate the equipment.

Mini Digital Amplifier
SAFETY PRECAUTIONS
To insure the best from the product, please read all instructions carefully before using the device. Save this manual for further
reference.
lUnpack the equipment carefully and save the original box and packing material for possible future shipment
lFollow basic safety precautions to reduce the risk of fire, electrical shock and injury to persons.
lDo not dismantle the housing or modify the module. It may result in electrical shock or burn.
lUsing supplies or parts not meeting the products’ specifications may cause damage, deterioration or malfunction.
lRefer all servicing to qualified service personnel.
lTo prevent fire or shock hazard, do not expose the unit to rain, moisture or install this product near water.
lDo not put any heavy items on the extension cable in case of extrusion.
lDo not remove the housing of the device as opening or removing housing may expose you to dangerous voltage or other
hazards.
lInstall the device in a place with fine ventilation to avoid damage caused by overheat.
lKeep the module away from liquids.
lSpillage into the housing may result in fire, electrical shock, or equipment damage. If an object or liquid falls or spills on to the
housing, unplug the module immediately.
lDo not twist or pull by force ends of the optical cable. It can cause malfunction.
lDo not use liquid or aerosol cleaners to clean this unit. Always unplug the power to the device before cleaning.
lUnplug the power cord when left unused for a long period of time.
lInformation on disposal for scrapped devices: do not burn or mix with general household waste, please treat them as normal
electrical wastes.

Mini Digital Amplifier
Table of Contents
1.!Introduction ............................................................................................ 1!
1.1.!Introduction to MA2B ..................................................................... 1!
1.2.!Features......................................................................................... 1!
1.3.!Package List .................................................................................. 1!
2.!System Connection Introduction ............................................................ 1!
2.1.!Audio Output.................................................................................. 1!
2.1.1.!Default output: 2x20Watt@4Ohm ...................................... 1!
2.1.2.!Bridge connection: 1x40Watt@8Ohm ................................ 1!
2.1.3.!Dual-mono Output .............................................................. 2!
2.2.!Microphone input ........................................................................... 2!
2.2.1.!48V phantom power input .................................................. 2!
2.2.2.!MIC input ............................................................................ 2!
2.2.3.!LINE input........................................................................... 2!
3.!Operation of the Control Panel and the IR Remote ............................... 2!
3.1.!Operation of the Control Panel ...................................................... 2!
3.1.1.!Audio switching .................................................................. 3!
3.1.2.!Volume/EQ controlling........................................................ 3!
3.2.!Usage of the IR Remote ................................................................ 3!
4.!System Diagram..................................................................................... 4!
5.!Communication Protocol and Command Codes .................................... 5!
6.!Specification........................................................................................... 5!
7.!Panel Drawing........................................................................................ 6!
8.!Troubleshooting & Maintenance ............................................................ 7!
9.!After-sales Service ................................................................................. 8!

Mini Digital Amplifier
1
1. Introduction
1.1. Introduction to MA2B
MA2B is a compact-size digital amplifier (Class-D) with 3 inputs (2 line in and 1 balanced MIC). It is integrated with powerful
functions, including bridge connection, dual-mono, EQ control, microphone mixer etc.
It has a good application in different places, including classroom, small meeting room, lecture hall, bar, pub etc.
1.2. Features
l2x20Watt@4Ohm as the default amplifier output.
lBridge connection function. User can switch MA2B to be 1x40Watt@8Ohm by bridge connection.
lTwo stereo audio inputs, switchable by button, IR remote & RS232.
lVolume/Bass/Treble controllable by buttons IR remote & RS232.
lMIC port can support balance/unbalance signal to help suppress the external noise.
lLine audio output at 3.5mm jack, with volume controllable.
lDual-mono function. User can sum up the stereo audio to two times mono audio.
lMIC mixer function. The microphone will be mixed to the line audio output, and be controlled separately.
lMIC input supports 48V phantom power, dynamic MIC and wireless MIC.
lAuto noise gate. It keeps detecting the audio and MIC input, will mute the output when there is no input.
lUltra low inrush current, no need for power sequencing. This allows multiple MA2B to be powered on simultaneously without
overloading power circuits.
lConvection cooler, fan is not needed.
lAntistatic case design: providing good protection for long-term and stable performance.
1.3. Package List
Ø1 x MA2B (The mounting ears and MA2B are as a whole.)
Ø2 x Pluggable Terminal Blocks
Ø1 x RS232 Cable
Ø1 x Power Adapter
Ø1 x Power Cord
Ø4 x Plastic Cushions
Ø1 x User Manual
Notes：
ØThe IR remote and its battery are offered for charge separately.
ØThe IR receiver is also offered for charge.
ØPlease confirm if the product and the accessories are all included, if not, please contact with the dealers.
2. System Connection Introduction
2.1. Audio Output
2.1.1. Default output: 2x20Watt@4Ohm
The default output of amplifier is 2x20Watt@4Ohm, so user can connect the amplifier output in the regular way. As the picture below:
2.1.2. Bridge connection: 1x40Watt@8Ohm
The MA2B has the bridge connection, to double the output power at 1x40Watt@8Ohm. It will sum up the input left channel and input
right channel to be mono output, and the power is up to 40Watt.
The bridge connection is:
Connecting the four pins, like this

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2.1.3. Dual-mono Output
The MA2B also has the function of double-mono output. It can sum up the left and right channel, to be the mono audio output. In this
way, the both of the outputs are showing the same mono audio.
The connection is:
2.2. Microphone input
The microphone input of MA2B has three modes, and different modes use different connections, as the picture below:
2.2.1. 48V phantom power input
When the switch turns to “48V”, the MIC input will provide a 48V phantom power. This is usually used for power supply for condenser
microphone, Connection is:
“+” connects to positive, “-” connects to negative and “╧” to ground.
Note: In this mode, only condenser microphone can be connected with.
2.2.2. MIC input
When the switch turns to “MIC”, the microphone input is used for connecting with dynamic microphone. There are two different
connections:
1) Unbalanced connection:
“╧” connects to ground, and “-” connects to signal.
“╧” connects to ground, and “+” connects to signal.
2) Balanced connection: “+” connects to positive, “-” connects to negative and “╧” connects to ground.
2.2.3. LINE input
When the switch turns to “LINE”, the microphone input is used for connecting with normal audio or wireless microphone output.
There are two different connections:
1) Unbalanced connection:
“╧” connects to ground, and “-” connects to signal.
“╧” connects to ground, and “+” connects to signal.
2) Balanced connection: “+” connects to positive, “-” connects to negative and “╧” connects to ground.
3. Operation of the Control Panel and the IR Remote
3.1. Operation of the Control Panel
The buttons provides the control of volume/EQ control and switching. The following content introduces audio switching and EQ
control in detail.
Connecting the two pins, like this
Connecting the four pins, like this

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3.1.1. Audio switching
There are two switchable stereo audio inputs, one 2xRCA input, and one 3.5mm jack input, switchable through the buttons as below:
3.1.2. Volume/EQ controlling
The line volume and MIC volume can be controlled by the buttons.
The MIC Volume/LINE volume/LINE bass/LINE treble will be selected by the buttons, and controlled up/down/mute by the function
buttons. Please check the picture below:
For example, to turn up the line volume, you should select the “LINE” first, and then press the button “ ”.
3.2. Usage of the IR Remote
Mute Mode:
MIC: Mute the
microphone volume.
LINE: Mute the line
volume.
SPEAKER: Unmute
Use to transmit the
infrared signal send by
the IR remote.
Audio Controlling Modes
MIC: turn up/down the
microphone volume.
LINE: turn up/down the line
volume.
BASS: bass tuning
TREBLE: treble of line volume.
Audio Inputs
1: RCA dual-mono audio inputs
2: 3.5mm jack
Source
Selection
Select the
function
from this
menu.
Then to turn
down/up the
level, or
mute the
output.

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Notice: The IR remote, the IR receiver, and the battery of the IR remote are all offered for charge.
4. System Diagram
IR receiver head, works in
conjunction with the IR
remote. Please point the IR
remote at the IR receiver
when use, to avoid getting out
of control as there is no signal
detected.
3.5mm jack, insert
it into the
specialized socket
(3.5mm) to connect
the IR receiver with
the amplifier

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5. Communication Protocol and Command Codes
Communication Protocol: RS232 Communication Protocol
Baud rate: 9600 Data bit: 8 Stop bit: 1 Parity bit: none
Command
Function Description
Feedback Code
1A1.
Switching the audio to input 1
A: 1 -> 1
2A1.
Switching the audio to input 2
A: 2 -> 1
0A0.
Mute Audio of MIC and Line out
Mute
1A0.
Mute audio of MIC
Mute MIC
2A0.
Mute audio of line out
Mute LIN
0A1.
Unmute Audio
Unmute
3A0.
Switch on Noise Gate
Gate On
4A0.
Switch off Noise Gate
Gate Off
600%
Checking the working status
A: 1 -> 1
Volume: 30
Bass: 00
Treble: 00
601%
MIC volume up
Volume of MIC: 51
602%
MIC volume down
Volume of MIC: 51
603%
Line volume up
Volume of LINE: 51
604%
Line volume down
Volume of LINE: 51
605%
Bass level up
Bass of LINE: 04
606%
Bass level down
Bass of LINE: 04
607%
Treble level up
Treble of LINE: 04
608%
Treble level down
Treble of LINE: 04
609%
Initialization, back to the default
setting
Init OK
5[x][x]%
Preset MIC volume, [xx] arranges
from [00] to [60].
61 degrees in total.
Volume of MIC: 50
7[x][x]%
Preset line volume, [xx] arranges
from [00] to [60].
61 degrees in total.
Volume of LINE: 50
8[x][x]%
Preset the bass level, [xx] arranges
from [00] to [08].
9 degrees in total.
Bass of LINE: 04
9[x][x]%
Preset the treble level, [xx] arranges
from [00] to [08].
9 degrees in total.
Treble of LINE: 04
Notice:
1: The letter inside bracket [ ] is the variable code, which is changeable.
2: The bracket [ ] is not included to the RS232 commands.
3: Any dot “.” after the letters is part of the commands.
Example 1:
Switching the input 2 to the line out, RS232 command is: [2A1.]
Example 2:
Turning up the volume of line audio, RS232 command is: [603%]
Example 3:
Preset the MIC volume to “21” degree, RS232 command is: [521%]
Example 4:
Checking the working status of MA2B, RS232 command is: [600%]
6. Specification
Audio Input
Audio Output
Input
2 stereo audio,
1 MIC
Output
1 amplifier,
1 stereo audio
Input
Connector
2 RCA
1 3.5mm jack
1 pluggable terminal
block (3P, 3.81mm),
Output
Connector
1 3.5mm jack
1 pluggable terminal
block (4P, 5.08mm)

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Input
Impedance
>10KΩ
Output
Impedance
50Ω/stereo,
4~8Ω/Amplifier
Audio General
Frequency
Response
20Hz ~ 20KHz
CMRR
>70dB@20Hz~20KH
z
SNR
80dB at maximum
output
Bandwidth
20Hz ~ 25KHz
Stereo
Channel
Separation
>75dB@20Hz to
20KHz
THD + Noise
1%@1KHz,
0.3%@20KHz
at nominal level
Voltage Gain
32dB
Power Output
2x20 Watts (4 Ohms)
Control Function
RS232 Control
3-hole phoenix
connector
Panel Control
Optional button
control
IR Remote
Optional IR remote
7. Panel Drawing
123 mm
57 mm
87 mm
99 mm
13 mm

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8. Troubleshooting & Maintenance
1) When there is no output audio:
lCheck if there is any signal at the input.
lCheck if there is any signal at the output.
We can check these by using an oscilloscope or a multimeter. If there is no signal input/output, maybe the input/output
cables broken or the connectors loosen, please change for another cable.
lCheck if the output port number is the same with the controlled one.
lIf not the problem mentioned above, probably there is something broken inside the unit; please send it to the dealer for
repairing.
2) If the POWER indicator doesn’t work or no respond to any operation, please make sure the power cord connection is good.
3) If the output sound is interfered, please make sure the system is grounded well.
4) If the static becomes stronger when connecting the audio connectors, it probably due to bad grounding, please check the
grounding and make sure it connected well, otherwise it would damage the converter.
5) If the MA2B amplifier cannot be controlled by the keys on the front panel, RS232 port or IR remote, the unit may has already
been broken. Please send it to the dealer for repairing.

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9. After-sales Service
If there appear some problems when running the device, please check and deal with the problems referring to this user
manual.
1) Product Limited Warranty: We warrant that our products will be free from defects in materials and workmanship for
three years, which starts from the first day you buy this product (The purchase invoice shall prevail).
Proof of purchase in the form of a bill of sale or receipted invoice which is evidence that the unit is within the Warranty
period must be presented to obtain warranty service.
2) What the warranty does not cover (servicing available for a fee):
lWarranty expiration.
lFactory applied serial number has been altered or removed from the product.
lDamage, deterioration or malfunction caused by:
lNormal wear and tear
lUse of supplies or parts not meeting our specifications
lNo certificate or invoice as the proof of warranty.
lThe product model showed on the warranty card does not match with the model of the product for repairing or
had been altered.
lDamage caused by force majeure.
lServicing not authorized
lAny other causes which does not relate to a product defect
lDelivery, installation or labor charges for installation or setup of the product
3) Technical Support: Email to our after-sales department or make a call, please inform us the following information
about your cases.
lProduct version and name.
lDetailed failure situations.
lThe formation of the cases.
Remarks: For any questions or problems, please try to get help from your local distributor.