DOUK AUDIO A1 Bluetooth 5.0 Digital Power Amplifier User Manual

DOUK AUDIO A1 Bluetooth 5.0 Digital Power Amplifier

M4 front and back panel

1. On/off; Input switch (between AUX and USB/BT)
2. Previous song
3. Play/Pause (short press); U-disk/Bluetooth(long press)
4. Next song
5. Power indicator
6. Bluetooth (Blue)/U-Disk(Red) indicator
7. U-disk
8. CH4 volume knob
9. CH3 volume knob
10. CH2 volume knob
11. CH1 volume knob
12. CH1 &CH2 audio input interface (red to CHl channel input, white to CH2 channel input)
13. CH3&CH4 IN/OUT shared interface
14. CH3&CH4 Mode switch button
15. (Note: The switch pops up –CH4/CH4 in the input state, and the 4 speaker outputs of CH1-CH4 correspond to the 4 inputs CH1-CH4;
16. The switch is pressed — -in the output state, and CH3-CH4 can be used as both audio output and audio input:
17. As audio output: use speaker cable to connect CH3 and CH4 to the input of another amplifier or active speaker to build a multi-channel system.
18. As audio input: use the audio signal cable to connect CH3 and CH4 to another audio source, then two audio signals (CH1-2 / CH3-4) will be mixed, and the speaker output of CH1/2/3/4 channels will output the same mixing audio. (the same when in USB/BT input mode.)
19. Speaker interface (speakers must be two sets of the same/or four sets of the same, note the “+/-” pole when wiring)
20. Power interface(DC 12-24V)
21. Bluetooth antenna socket

Operation steps

1. Before use, please make sure the volume is at the minimum, and M4 is off.
2. Connect the 1 pair or 2 pairs of passive speakers to the output of M4.
3. Wired input:

Connect the audio source (via RCA cable) to the RCA input of M4; or insert a U-disk to its USB socket.

1. When the black switch on the back panel pops up, CH3 and CH RCA interface as an audio input mode, and the output of the CH1-CH4 speakers output corresponds to the four inputs of CH1-CH4 respectively.
2. When the black switch on the back panel is pressed, the CH3/CH4 RCA interface can be as both audio input and output.
   • A. As audio input: use the audio signal cable to connect CH3 and CH4 to another audio source, then two audio signals (CH1-2 / CH3-4) will be mixed, and the speaker output of CH1/2/3/4 channels will output the same mixing audio. (the same when in USB/BT input mode.)
   • B. As audio output: use speaker cable to connect CH3 and CH4 to the input of another amplifier or active speaker to build a multichannel system.
3. Connect the power adapter to M4 first then plug the power cable into the socket, and toggle the switch from the OFF position to the RCA or USB/BT position.
4. Wireless input
5. Please toggle the switch to the USB/BT position, and long press the P/M mode to switch to Bluetooth input mode (There will be a blue indicator flashing.). Turn on Bluetooth on your phone, search, and click to connect, the blue indicator will be steady blue after a successful connection. (U-disk with priority, the input mode will automatically switch to U-disk when U-disk is inserted).
6. Play music on the audio source, adjust the volume of CH1-4 separately according to your preferences, and enjoy the music.
7. After use, please toggle the power switch to the OFF position first, and then disconnect the power adapter.

Parameters

FAQ

Q: Why is the volume of the four speakers different?

• A: Because 4 independent volume knobs control 4 speakers’ volume, you must keep all of them on the same scale to maintain the same volume.

Q: Can it be formed into a home theater system?

• A: Just need to add a center and subwoofer amplifier to make a 5.1-channel home theater system.

Q: Can the CH3 &CH4 knob control the volume of the audio source output?

• A: No, each knob only controls the volume of the corresponding channel speaker independently.

Q: Why are all cables connected but there is no sound?

1. A: Check the power indicator light of M4: D If it can light up normally, please check if the corresponding input mode is selected.
2. If it cannot light up, please use another 12-24V power supply to detect whether the fault is the power supply or M4.
3. If the indicator light is on but there is no sound, the power supply is normal. Please continue to check according to the order of audio signal transmission: audio source → audio cable → preamp/ decoder › amplifier → speaker.
4. If all is fine, please check whether the audio source is muted, paused or the volume is too small.

Q: Why is the sound distorted?

• A: Maybe the input amplitude is too large. If the volume of the audio source and M4 both are turned to maximum, f easily causes distortion. Please turn down the volume of the audio source or M4.

Q: Why is there a loud current sound or buzzing sound on the speaker?

• A: Please use the original power supply. Many power supplies in the market have interference, which will cause current sound.
• When using an unshielded signal cable with no load, there will be interface signals. Please use the shielded signal cable or unplug it.
• If there is still noise after eliminating the above situations, please confirm whether it is external noise or internal noise. Disconnect all inputs and only retain the power supply and power cable.
• If the noise disappears, it is from audio input; if the noise is still there, it is possibly caused by a power supply or the internal of M4.

Q: Why does the amplifier stop working after working for a period of time and then be normal after disconnecting for a while?

• A: Maybe the actual output power of the amplifier exceeds its rated power, just lower the volume of an amplifier or place it in a well-ventilated area.

Q: Why does the volume of different audio sources(such as changing CD player to phone) differ when the volume of M4 is unchanged?

• A: Different audio devices can output different signal amplitudes, for example, the phone usually is 0.35V, while the CD player is 1V.

Q: Why is the sound of the power amplifier not good at first, with unclear high frequency, but the sound is normal after working for a period of time?

• A: For new speakers and amplifiers, we recommend burn-in for at least 10 hours to get better sound.

Q: Why there is no sound or very little sound after the amplifier is connected to the speaker?

• A: 1. Please check the audio source has been turned on and the volume is not at the minimum.
• Please confirm whether the speaker and amplifier match ( For example, the speaker is fixed resistance or fixed voltage, the power of the speaker is too much over the power of the amplifier, etc).

Q: What are the reasons for the unbalanced left and right volume of the speakers and how to eliminate them?

• A: Please check the audio source, input cable, and volume potentiometer (some amplifiers have balanced control or separate volume control of left and right channels),
• speaker cable, speakers (whether the position and the distance are symmetrical), and other factors.

Q: Why Bluetooth cannot be searched? How to switch to Bluetooth mode?

• A: Toggle the input switch on the panel or press the “SELECT” button on the remote control to switch to BT mode, there will be a blue light flashing, then use your phone or tablet to search for “BT HiFi AUDIO”, click and connect it, then play music. (The Bluetooth name may be different in different models of products, please refer to the user manual of each product).

Q: Why does the Bluetooth playback lag or even disconnect?

• Why is the Bluetooth background noise/current noise obvious
• A: Please check whether the Bluetooth antenna is installed correctly, whether there is interference or blocking (such as WiFi router/wireless telephone / FM radio, etc., since they may be in the same frequency band as Bluetooth, and inductive loads such as fans/refrigerators/air conditioners will also cause some interference), whether the Bluetooth is blocked or too far away from the device (more than 15 meters).

Q: Can M4 be connected to my computer via Bluetooth?

• Why is the no sound when connected to a PC
• A: Compared with phones, computers with poor compatibility and troublesome operations when using Bluetooth. Need the computer with Bluetooth function and to update the driver and set the output device to Bluetooth after connection.

Q: Why is there no music output after inserting a U-disk?

• A : Please confirm the format and capacity of the U-disk, as well as the file format of the U-disk (only supports U-disk in FAT32 format within 64G).

Q: Why is U-disk playback sometimes laggy?

• A: In general, MP3/FLAC/APE/WMA/WAV and other common formats are supported, please confirm the file format of the U-disk. (Please put the music files under the root directory, don’t create a new folder, or don’t play other unsupported files, or else there may be an error).

Q: Why is there a thumping sound when switching on/off?

• A: Please confirm the on-off sequence is correct, normally it follows the order of signal transmission when turned on: audio source → preamp / DAC → amplifier → speaker. (The sequence is reversed when switching off.
• The internal capacitors will be discharged for a while after shutdown. If turn off the preamp first and then turn off the amplifier, impact sound will be easily caused which may damage the amplifier or speaker in severe cases).

Warning

1. Please do not open the shell by yourself, improper operation may cause a risk of electric shock.
2. Please use the regular manufacturer’s switching power supply, otherwise, there will be a risk of damage to M4.
3. Please do not use the M4 in a high-temperature or humidity environment.
4. A default 24V/4.5A power supply can satisfy the needs of most home speakers. If you want higher output, please prepare a high-quality and larger power adapter.

Contact information

• Website:www.doukaudio.com
• Email:nobsound@doukaudio.com
• WeChat/Whatsapp: +86-17704028602
• Address: Room 1329, Wang Cheng Building, Long Guan East Road,
• Long Hua District, Shen Zhen, Guang Dong, China, 518000

Documents / Resources

| DOUK AUDIO A1 Bluetooth 5.0 Digital Power Amplifier [pdf] User Manual
A1 Bluetooth 5.0 Digital Power Amplifier, A1, Bluetooth 5.0 Digital Power Amplifier, 5.0 Digital Power Amplifier, Power Amplifier, Amplifier
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