Audio General PA2X20 User manual

PA2X20
Mini Digital Amplifier
All Rights Reserved
Version: PA2X20_2017V1.0
User Manual

Mini Digital Amplifier
Preface
Read this user manual carefully before using the product. Pictures shown in this
manual are for reference only, different models 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 is updated till December 15, 2017. In the constant
effort to improve our product, we reserve the right to make functions or parameters
changes without notice or obligation. Please refer to the dealers for the latest details.
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 own 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.
Unpack the equipment carefully and save the original box and packing material for
possible future shipment
Follow basic safety precautions to reduce the risk of fire, electrical shock and injury
to persons.
Do not dismantle the housing or modify the module. It may result in electrical shock
or burn.
Using supplies or parts not meeting the products’ specifications may cause damage,
deterioration or malfunction.
Refer all servicing to qualified service personnel.
To prevent fire or shock hazard, do not expose the unit to rain, moisture or install this
product near water.
Do not put any heavy items on the extension cable in case of extrusion.
Do not remove the housing of the device as opening or removing housing may
expose you to dangerous voltage or other hazards.
Install the device in a place with fine ventilation to avoid damage caused by
overheat.
Keep the module away from liquids.
Spillage 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.
Do not twist or pull by force ends of the optical cable. It can cause malfunction.
Do not use liquid or aerosol cleaners to clean this unit. Always unplug the power to
the device before cleaning.
Unplug the power cord when left unused for a long period of time.
Information 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 Mini Digital Amplifier .....................................................................1
1.2. Features...............................................................................................................1
1.3. Package List.........................................................................................................2
2. System Connection Introduction.................................................................................3
2.1. Audio Output ........................................................................................................3
2.1.1. Default output: 2x20Watt@4Ohm..................................................................3
2.1.2. Bridge connection: 1x40Watt@8Ohm............................................................3
2.1.3. Dual-mono Output .........................................................................................3
2.2. Microphone input............................................................................................4
2.2.1. 48V phantom power input..............................................................................4
2.2.2. MIC input.......................................................................................................4
2.2.3. LINE input......................................................................................................5
3. Operation of the Control Panel and the IR Remote ....................................................6
3.1. Operation of the Control Panel.............................................................................6
3.1.1. Audio switching..............................................................................................6
3.1.2. Volume/EQ controlling...................................................................................6
3.2. Usage of the IR Remote.......................................................................................7
4. System Diagram.........................................................................................................9
5. Communication Protocol and Command Codes.......................................................10
6. Specification..............................................................................................................12
7. Panel Drawing ..........................................................................................................13
8. Troubleshooting & Maintenance ...............................................................................14
9. Warranty Service ......................................................................................................15

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1
1. Introduction
1.1.Introduction to Mini Digital Amplifier
The Mini Digital Amplifier 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
2x20Watt@4Ohm as the default amplifier output.
Bridge connection function. User can switch the Mini Digital Amplifier to be
1x40Watt@8Ohm by bridge connection.
Two stereo audio inputs, switchable by button, IR remote & RS232.
Volume/Bass/Treble controllable by buttons IR remote & RS232.
MIC port can support balance/unbalance signal, suppress the external noise
effectively.
Line audio output at 3.5mm jack, with volume controllable.
Dual-mono function. User can sum up the stereo audio to two times mono audio.
MIC mixer function. The microphone will be mixed to the line audio output, and be
controlled separately.
MIC input supports 48V phantom power, dynamic MIC and wireless MIC.
Auto noise gate. It keeps detecting the audio and MIC input, will mute the output
when there is no input.
Ultra low inrush current, no need for power sequencing. This allows multiple Mini
Digital Amplifier to be powered on simultaneously without overloading power
circuits.
Convection cooler, fan is not needed.
Antistatic case design: providing good protection for long-term and stable
performance.

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1.3.Package List
1 x Mini Digital Amplifier
2 x Pluggable Terminal Blocks
1 x RS232 Cable
1 x Power Adapter
1 x Power Cord
4 x Plastic Cushions
1 x User Manual
Notes ：
The IR remote and its battery are offered for charge separately.
The IR receiver is also offered for charge.
Please confirm if the product and the accessories are all included, if not, please
contact with the dealers.

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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 Mini Digital Amplifier 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:
2.1.3. Dual-mono Output
The Mini Digital Amplifier 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:
Connecting the two pins, like this
Connecting the four pins, like this

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2.2.Microphone input
The microphone input of Mini Digital Amplifier 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.
Connecting the four pins, like this

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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.

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3. Operation of the Control Panel and the IR Remote
3.1.Operation of the Control Panel
The buttons provide the control of volume/EQ control and switching. The following
content introduces audio switching and EQ control in detail.
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:
Source
Selection

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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
Firstly to
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.
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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4. System Diagram

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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

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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 Mini DigitalAmplifier, RS232 command is: [600%]

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6. Specification
Audio Input
Input
(2) Stereo audios; (1) MIC
Input Connector
(2) RCA; (1) 3.5mm jack;
(1) Pluggable terminal block (3P,3.81mm),
Input Impedance
>10KΩ
Audio Output
Output
(1) Amplifier; (1) Stereo audio
Output Connector
(1) 3.5mm jack; (1) Pluggable terminal block (4P,
5.08mm)
Output Impedance
50Ω/stereo; 4~8Ω/Amplifier
Audio General
Frequency Response
20Hz ~ 20KHz
CMRR
>70dB@20Hz~20KHz
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

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7. Panel Drawing

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8. Troubleshooting & Maintenance
1) When there is no output audio:
Check if there is any signal at the input.
Check 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.
Check if the output port number is the same with the controlled one.
If 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 Mini Digital Amplifier cannot be controlled by the keys on the front panel,
RS232 port or IR remote, the unit may have already been broken. Please send it
to the dealer for repairing.

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9. Warranty Service
If there is any question about the need for service, please call technical support at
1-267-288-0300. Before sending a product back for repair, please obtain a return
authorization by calling customer service or by emailing [email protected].
Please have a copy of your invoice with the serial number ready before calling.
1) Warranty
The limited warranty period of the product is three years from date of purchase to
the original purchaser.
2) Warranty Exclusions
No invoice.
Factory applied serial number has been altered or removed from the product.
Damage, deterioration or malfunction caused by:
✓Use of supplies or parts not meeting our specifications.
✓Damage caused by excessive force.
✓Operating in a way contrary to written instructions.
✓Damage caused by unauthorized servicing.
✓Any other causes which does not relate to a product defect.
Shipping fees from the customer to the warranty service center
Installation or labor charges for setup of the product.
Consequential damages