Fosi Audio DA-2120C User Manual

Product Specifications

The Fosi Audio DA-2120C is a Bluetooth hi-res 2.1 channel amplifier featuring 120W x 2 stereo wireless stream with aptX, 24Bit/192kHz resolution. It's a compact mini power amplifier equipped with integrated USB, coaxial, and optical DAC inputs, supporting a subwoofer and including a remote control for mode and EQ adjustments to enjoy hi-res music.

Product Overview & Control Functions

The DA-2120C features a user-friendly interface with a mode select knob, power knob, volume control, and an LED display.

Main Unit Controls

• Power Knob: Short press to turn on; Long press to turn off.
• Mode Select Knob: Allows switching between input modes: Bluetooth, AUX, Coaxial, Optical, USB.
• Volume Control: Turn the knob to adjust the volume. Click the knob to mute/unmute.
• LED Display: Shows current mode and status.
• Bluetooth Antenna Interface: Connect the included Bluetooth antenna for improved signal reception.

Input/Output Ports

• DC Input: Supports 24V-36V power supply.
• Speakers Output: Connect passive speakers to the L and R speaker terminals.
• Sub Output: Connect to an active subwoofer.
• AUDIO IN (RCA): Analog audio input.
• COAXIAL: Digital coaxial audio input.
• OPTICAL: Digital optical audio input.
• PC-USB: USB audio input for computers.

Note: The amplifier supports 24Bit/192kHz input via USB, Optical, and Coaxial.

Remote Control

The included remote control provides convenient access to various functions:

Package Contents

• Fosi Audio DA-2120C unit *1
• Remote Control *1
• Optical Cable *1
• PC-USB Cable *1
• Bluetooth Antenna *1

Quick Setup

Preparation

1. Ensure you have the DA-2120C, a 32V power supply, passive speakers, and speaker wires or banana plugs.
2. Connect the DA-2120C to the passive speakers using speaker wires or banana plugs.
3. Connect the 32V power supply to the DC input port on the amplifier.
4. Short press the Power Knob to turn on the DA-2120C amplifier.

Connecting Speaker Wire

Method 1: Bare Wire Connection

1. Release the terminals on the speaker wire block.
2. Insert the stripped ends of the speaker wire into the corresponding holes on the amplifier and speaker terminals.
3. Tighten the terminals to secure the wires.

Note: Ensure speaker wires do not touch the amplifier casing to prevent short circuits.

Method 2: Banana Plugs Connection

1. Release the banana plug jacket.
2. Loosen the screw on the banana plug.
3. Insert the speaker wire into the banana plug and tighten the screw.
4. Tighten the banana plug jacket.
5. Insert the banana plug into the speaker and amplifier terminals.

Note: Be careful to avoid contact between metal-cased banana plugs to prevent short circuits.

Connection Examples

Bluetooth Connection

1. Press the Mode Select Knob to select Bluetooth mode; the "BT" display will flash.
2. On your Bluetooth device (e.g., phone), turn on Bluetooth and search for "BT HIFI AUDIO" or "Fosi Audio DA2120C". Connect to the DA-2120C. The "BT" display will remain solid when connected.
3. Open your audio application and play music.

PC-USB Connection

1. Connect your PC to the DA-2120C's USB interface using the provided PC-USB cable.
2. Press the Mode Select Knob to select USB mode.
3. On your PC, click the sound icon in the notification area, select "Select playback device," and choose "SPDIF 'Digital HiFi Audio'" or "Fosi Audio DA2120C" as the playback device.
4. Open your audio application and play music.

Optical Connection

1. Connect your optical device (e.g., TV) to the DA-2120C's optical interface using the optical cable.
2. Press the Mode Select Knob to select Optical mode.
3. On your TV, set the optical audio output to RAW/PCM. Note: The DA-2120C does not support Dolby or DTS audio formats. Selecting these may result in no sound or noise.
4. Open your audio application and play music.

Coaxial Connection

1. Connect your coaxial device (e.g., TV) to the DA-2120C's coaxial interface using a coaxial cable (not included).
2. Press the Mode Select Knob to select Coaxial mode.
3. On your TV, set the coaxial audio output to RAW/PCM. Note: The DA-2120C does not support Dolby or DTS audio formats. Selecting these may result in no sound or noise.
4. Open your audio application and play music.

RCA (AUX) Connection

1. Connect your audio device (e.g., phone) to the DA-2120C's RCA interface using a 3.5mm to RCA cable or RCA to RCA cable (not included).
2. Press the Mode Select Knob to select AUX mode.
3. Open your audio application and play music.

Troubleshooting / FAQ

1. Q: Why is there loud hiss noise from the TV via optical input?

   A: Please turn off Dolby/DTS audio settings on your TV or TV App, as the DA-2120C does not support Dolby/DTS audio input.

2. Q: Why am I not getting enough power compared to a 50W x 2 amplifier?

   A: For low power output, long-press the "DISPLAY" button on the remote control to boost gain by +6dB.

3. Q: Can this product be used at 220 volts?

   A: Yes, the power supply works with any AC 110V-240V input.

4. Q: Does the DA-2120C support Bluetooth 5.0 & aptX?

   A: Yes, it supports Bluetooth 5.0 and backward compatibility (4.2, 4.0, etc.), and also supports Bluetooth aptX.

5. Q: Why can't I use aptX to connect to the DA-2120C?

   A: The DA2120C supports aptX, but your Bluetooth device (e.g., mobile phone) must also support aptX. Ensure aptX is enabled on your device or contact its customer service.

6. Q: Can I use headphones with this product?

   A: No, the DA-2120C does not support headphone output. It only supports passive speakers or active subwoofer output.

7. Q: Why does the sound crackle or produce electric noise?

   A: Ensure all cables are fully inserted. Incomplete connections can cause cracking. Remove all inputs to check if the noise persists; the issue might be with the audio source or input cables. If using a non-original power supply, try a standard one, as some aftermarket supplies can cause interference.

8. Q: My Bluetooth device can't pair with DA2120C?

   A: Ensure the DA-2120C is in Bluetooth mode ("BT" display flashing). Check if it's already paired with another device. Keep your device close to the DA-2120C and ensure no obstacles. Try a different Bluetooth audio source or restart the DA-2120C by unplugging and replugging the power supply. Testing with another brand of mobile phone is also recommended.

9. Q: No Dolby/DTS audio, and I still get noise through the USB input?

   A: Try connecting to a different USB port (e.g., USB 3.0 or a rear port) as some ports may have unstable data transmission. Test with another computer or replace the PC-USB cable. Also, try a different power supply, as an aging power supply can cause white noise; using a 9V-32V power supply is recommended for testing.

10. Q: USB Device not recognized on Windows?

    A: In Windows Device Manager, uninstall the DA-2120C (Digital HiFi Audio) device under Universal Serial Bus controllers, then restart your computer. USB controllers will reinstall automatically. Try connecting to another computer or a different USB 3.0 interface, and consider using an alternative USB cable.

11. Q: Why do I get an intermittent sound?

    A: Try switching the USB cable to a USB 3.0 port or a rear port for potentially more stable data transmission. Replace the PC-USB cable and restart the amplifier by replugging the power supply. Contact Fosi Audio customer support if the original cable is suspected to be faulty.

12. Q: Can I input through USB and output to optical with 5.1 surround?

    A: No, the optical port on the DA-2120C is an input only, not an output.

13. Q: Why is the actual power sometimes very powerful, but sometimes less than 120W per channel?

    A: While rigorously tested to meet 120W x 2 under normal circumstances, the actual perceived power can be influenced by the type of speakers used.

14. Q: One channel does not work?

    A: First, test if both Bluetooth and RCA inputs have the same issue. If so, swap speaker cables between left and right channels or try different speakers to see if the problem follows the channel or the speaker. If the issue is specific to RCA or Bluetooth, try a different audio source, RCA cable, and ensure all connections are secure.

15. Q: DA2120C supports subwoofer; can I connect the subwoofer directly?

    A: Yes, the sub output can be connected directly to an active/powered subwoofer, or to a subwoofer amplifier which then connects to a passive subwoofer.

16. Q: Can I leave the DA-2120C power on all the time? Is it safe?

    A: Yes, the DA-2120C is a Class D amplifier that consumes very low power when idle. It is safe to leave powered on continuously.

17. Q: Can I exchange the power supply for more power?

    A: The DA-2120C comes with a 32V 5A power supply, which is sufficient for most bookshelf speakers. For more power, you can use a power supply within the DC 12V-36V range, such as a 36V 8A or 36V 10A power supply.

Warranty Information

All Fosi Audio products come with an 18-month limited warranty covering parts and labor from the date of purchase. Please contact Fosi Audio customer support for any issues.

About Fosi Audio

Fosi Audio designs and builds innovative audio products with a focus on great sound, simple yet elegant designs, high-quality materials, and truly useful features. The company aims to provide enjoyable audio experiences for its customers.

Contact Information & Support

For any problems or technical support, please contact Fosi Audio:

• Email: support@fosiaudio.com
• Email: fosiaudio@hotmail.com
• Website: www.fosiaudio.com
• Amazon Store: www.amazon.com/fosiaudio
• YouTube Channel: Fosi Audio
• Facebook Page: Fosi Audio