DSPPA Alfatron ALF-250W-UB User manual

User Manual
ALF-250W-UB Mini Mixer Amplifier

1
Safety Precautions
1. Safety Precautions
Warning! To reduce the risk of electric shock or equipment damage, please follow
the following requirements:
● Please do NOT connect this device to the power source, before the system is correctly connected.
● It is important to ensure that input voltage to the device is the same as required voltage of the device;
otherwise the device may be damaged.
● There is dangerous voltage in the device, which may cause personal electric shock. Please do NOT open
the case without permission, to avoid potential risks of electric shock.
● The device is not completely disconnected from power source when it is switched "OFF". For sake of safety,
please disconnect the device from the socket if it is not in use.
● Please do NOT place the device where it is extremely cold or hot.
● Good ventilation must be provided in the working environment of the device, to avoid excessive temperature
during its operation, which may cause damages to the device.
● Please unplug the device from power socket in raining and wet days or if it is not in use for a long time.
● Please disconnect the power plug from sockets, to ensure the device has been completely disconnected
from power source, before any component is removed from or re-installed in the device or before any electric
connector of the device is disconnected or reconnected.
● In case of any failure of the device, please do NOT open the case and repair without permission from a
professional personnel, to avoid accident or additional damages to the device.
● Please do NOT place any corrosive chemicals near or on the device.
Please note the following symbols:
The lightning triangular symbol is used to alert the user to the risk of electric shock.
The exclamation point triangle symbol is used to alert the user to important operational
or maintenance instructions.

CONTENT
Introduction............................................................................................................................................... 1
Product Overview..................................................................................................................................... 1
Product Features................................................................................................................................. 1
Front Panel.......................................................................................................................................... 1
Rear Panel .......................................................................................................................................... 3
Operating Instructions......................................................................................................................... 4
Remote Controller............................................................................................................................... 4
Specification............................................................................................................................................. 5
Packing List .............................................................................................................................................. 5

1
Introduction
Thanks for using our products. All our products are tested strictly before leaving the factory, with
guaranteed quality. Our products are widely used in such places as schools, gymnasiums, square halls,
parks, parking lots, railway stations, airports, villa communities and mall supermarkets, etc., and they will
be your ideal choice for public address system.
For better installation, commissioning and use of the product, please read this manual in detail before
installation.
Product Overview
Product Features
⚫Built-in Bluetooth, radio and USB function.
⚫2 MIC IN, 2 EMC IN, 2 LINE IN, 1 LINE OUT.
⚫100V or 70V constant voltage output, 4Ω~16 Ω constant resistance output.
⚫Support IR remote control.
⚫With priority function, priority is EMC/MIC1>AUX1/AUX2/MIC2.
⚫With master volume control, and individual volume control of MIC & LINE, as well as treble and bass
volume control.
Front Panel

Guangzhou DSPPAAudio Co., Ltd 2
1. Display Screen
2. USB Interface
Insert a USB to provide programs to built-in MP3.
3. Play/Pause
In USB and Bluetooth mode, press this button to
pause / play.
In FM mode, press this button to search the radio
automatically.
4. Last Song/ (Last Radio in FM)
In USB/Bluetooth mode, press this button to
switch to the “Last Song”.
In FM mode, press this button to switch to the
“Last Radio”.
In FM/Bluetooth/USB mode, long press this
button to turn down the volume.
5. Next Song/ (Next Radio in FM)
In USB/Bluetooth mode, press this button to
switch to the “Next Song”.
In FM mode, press this button to switch to the
“Next Radio”.
In FM/Bluetooth/USB mode, long press this
button to turn up the volume.
6. Mode Button
It can switch to Bluetooth mode (BLUE), USB
mode (USB), line input mode (AUX) and FM
mode (FM).
7. MIC1 IN
This button has priority function. (Level with EMC
IN on the rear panel)
8. MIC1 VOL.
Adjust the volume of MIC1, turn clockwise to turn
up the volume, and turn counterclockwise to turn
down the volume.
9. MIC2/AUX2 VOL.
Adjust the volume of MIC2/AUX2, turn clockwise
to turn up the volume, and turn counterclockwise
to turn down the volume.
10.AUX1 VOL.
Adjust the volume of AUX1, turn clockwise to turn
up the volume, and turn counterclockwise to turn
down the volume.
11. BASS VOL.
Take the central position as the benchmark, turn
counterclockwise to turn down the bass, and turn
clockwise to turn up the bass.
12. TREBLE VOL.
Take the central position as the benchmark, turn
counterclockwise to turn down the treble, and turn
clockwise to turn up the treble.
13. MASTER VOL.
Adjust the level of all signals (except for EMC IN
on the rear panel), turn clockwise to turn up the
volume, and turn counterclockwise to turn down
the volume.
14. POWER
Press “ON” to turn on the power, while press
“OFF” to turn off the power.
15. LEVEL LED
Display the audio output level.

3
Rear Panel
RISKOFELECTRICSHOCK
DONOTOPEN
CAUTION
请勿打开,以免触电
警告
DC IN
24V/4A
COM
4Ω
-16 Ω
70V
100V
AMPLIFIER OUT
AUX OUT AUX1 IN AUX2 IN
+24V
MIC2 IN
AUX2 MIC2 PHANTOM
VOL
FM ANT
EMC IN
VOL
350mV
100V
AC110-120V 50-60Hz AC220-240V 50-60Hz
INPUT VOLTAGE SWITCH
PUSH
3 4 5678910 11 12 13 14
21
1. POWER IN (Can switch to 110-220V)
Connect working power. Insert the plug into the machine and then connect the power grid.
2. Radio Antenna Interface
Connect the radio antenna.
3. DC24V Power Input
DC24V backup power input interface.
4. Audio Power Output Terminal
Note: No terminal can be connected to the “Ground wire”, no matter directly or through other devices.
5. AUX OUT
6. AUX1 IN
7. AUX2 IN
8. Audio Source Selection Switch (AUX2-MIC2. Note: Please turn down the volume or turn off the
device before using the switch.)
AUX2 and MIC2/24V. Phantom voltage switch by turning left and right.
9. Phantom Voltage LED
10. MIC2 Balanced IN
11. AUX2/MIC2 VOL.
12. 100V EMC IN (Note: When using external 100V emergency signal input, the machine ground wires
of the two devices can not be connected.)
13. EMC IN VOL.
14. General EMC IN

Guangzhou DSPPAAudio Co., Ltd 4
Operating Instructions
1. MIC Mode
In any mode, when there is a broadcasting through the microphone, the system will detect the voice from
the microphone and mute other sources. And it will return to the original play status when the
microphone has no signal.
2. Bluetooth Mode
Press the MODE button to display “BLUE” on the digital screen. The “BLUE”will keep flashing until the
pairing is successful. Please turn on the Bluetooth of mobile phone or other audio source devices to
search the Bluetooth device “MP250UB”for pairing, with wireless transmission distance≈10m.
3. USB Mode
When a USB is inserted, it will be adjust to USB mode automatically (Plug and play).
4. LINE Mode
Press the MODE button to display “AUX” on the digital screen and enter the AUX mode.
5. FM Mode
Please refer to the part 3, 4 and 5 of “Front Panel” for operation details.
Remote Controller
The remote controller is as shown below..
Function Keys:
①Mode button for working mode switching.
②Power switch
③Play/Pause / (Auto radio searching in FM)
④EQ button
⑤0-9 numeric keys, can be combined as a
digital channel in FM for selection.
⑥Mute button
⑦Last song / (Last radio in FM)
⑧Next song / (Next radio in FM)
⑨Vol-
⑩Vol+
⑪Cycle
⑫Record button

5
Specification
*Note: When the power supply is switched to 110V, the machine can not be powered by 220V,
otherwise it will be burned.
Packing List
Component Quantity
Mini Mixer Amplifier.................................................................................................................................... 1
User Manual............................................................................................................................................... 1
Warranty Card............................................................................................................................................ 1
Certificate ................................................................................................................................................... 1
Remote Controller ...................................................................................................................................... 1
Bluetooth Receiving Antenna..................................................................................................................... 1
Model
ALF-250W-UB
Power Supply
AC110-120V / AC220~240V 50/60Hz(Select via the switch)
MIC1 IN Sensitivity
10mV±10%
MIC2 IN Sensitivity
15mV±10%
AUX1 IN Sensitivity
350mV±10%
AUX2 IN Sensitivity
350mV±10%
EMC IN Sensitivity
350mV±10%
MIC Frequency Response
200Hz～10kHz（±3dB）
AUX Frequency Response
100Hz～16kHz（±3dB）
Noise
<10mV
Distortion
<1% 1KHz
Treble Adjustment
10dB（±2）
Bass Adjustment
10dB（±2）
Rated Output Power
250W
Interface Output Voltage
70V,100V(Constant voltage output).
Machine Dimension (D×W×H)
363×292×106mm
Package Dimension
363×292×106mm (1PC)
Maximum Package Dimension
610×390×240mm (4PCS)
Net Weight
3KG
Gross Weight
3.7Kg (1PC)

© DSPPAAudio 丨The specification will be subject to changes without notices.
FCC Statement
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions:
(1) This device may not cause harmful interference, and (2) this device must accept any interference received, inclu
ding interference that may cause undesired operation.
Any Changes or modifications not expressly approved by the party responsible for compliance could void the user’s
authority to operate the equipment.
Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to p
art 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in
a residential installation. 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. However, t
here is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful
interference to radio or television reception, 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 communicati
ons. However, there is no guarantee that interference will not occur in a particular installation. If this equipment doe
s cause harmful interference to radio or television reception,
—Reorient or relocate the receiving antenna.
—Increase the separation between the equipment and receiver.
Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
—Consult the dealer or an experienced radio/TV technician for help.
FCC RF Radiation Exposure Statement
The device has been evaluated to meet general RF exposure requirement.