Fosi Audio BT20A User Manual

Product Specifications

The Fosi Audio BT20A is a Hi-Fi wireless stereo 2-channel amplifier featuring 100W x 2 output and Bluetooth 5.0 with a streaming range up to 50ft (15m). It is a mini power amplifier equipped with bass and treble control, offering a simple, compact, practical, and powerful design for customers pursuing Hi-Fi sound.

Product Overview & Control Functions

Front Panel:

• 1. Power Switch (On/Off)
• 2. Treble Control
• 3. Bass Control
• 4. Volume Control
• 5. Power Indicator Light

Back Panel:

• 6. RCA Input
• 7. Speakers Output
• 8. DC 24V Input
• 9. Bluetooth Antenna

[Image Description: Diagram of the front and back panels of the Fosi Audio BT20A amplifier, showing the location of controls and input/output ports.]

Package Contents

• Fosi Audio BT20A Amplifier*1
• AC Power Cord*1
• 24V Power Supply*1
• Bluetooth Antenna*1
• Instruction Manual*1

Quick Setup

Preparation

1. Ensure you have the BT20A, 24V power supply, passive speakers, and speaker wires or banana plugs.
2. Connect the BT20A to the passive speakers using speaker wire or banana plugs.
3. Connect the 24V power supply to the DC input port.
4. Toggle the power switch on the front panel upwards to turn on the BT20A amplifier.

Note: Ensure the volume/power switch is in the OFF position before connecting the power supply.

How to connect the speaker wire?

Method 1: Bare wire connection illustration

1. Release the horn terminals block terminals.
2. Insert the two ends of the speaker wire into the amplifier and speaker terminal holes.
3. Tighten the horn terminals.

Note: Avoid exposed speaker wires touching the amplifier casing to prevent short circuits.

Method 2: Banana plugs connection illustration

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

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

[Image Description: Illustrations demonstrating bare wire and banana plug connections for speaker wires.]

Bluetooth for example

1. Install the Bluetooth antenna to the BT20A.
2. Turn on Bluetooth on your phone and search for "Fosi Audio" or "Fosi Audio BT20A". Once connected, the indicator light will show blue.
3. Open your audio application, play music, and enjoy!

RCA Input for example

Prepare: Audio source (e.g., phone), RCA cable or 3.5mm AUX to RCA cable.

1. Connect your phone to BT20A via a 3.5mm to RCA cable.
2. After connecting to BT20A, the indicator light will show red.
3. Open the audio application, play music, and enjoy!

Note: Keep the BT20A away from other electrical devices. The BT20A cannot be used with a radio simultaneously.

Troubleshooting/QA

1. What type of speakers work best with BT20A Amplifier?

   Fosi Audio BT20A works great with any 2-8Ω passive speakers. It is designed for passive speakers, not powered speakers or subwoofers.

2. Why Bluetooth is intermittent?
   • Try using another Bluetooth device.
   • Ensure no interference from other electronic equipment between the BT20A and the audio source.
   • Place your device closer to the BT20A.
   • Replug the power adapter.
3. Why does the BT20A make serious noise when used with a radio?

   Class D power amplifiers can cause noise when used with a radio. It is not recommended to use the BT20A with a radio or too close to it.

4. Can I connect a turntable to BT20A amp, why is the volume extremely low?
   • For turntables without a built-in preamp, an external phono preamp is required before connecting to BT20A.
   • For turntables with a built-in preamp, switch the preamp on before connecting BT20A.
5. Why does my power indicator not light up?
   • Check if the AC power cord is securely connected to the power supply and an AC power outlet.
   • Ensure the AC power outlet is supplying power; the power LED on the power supply should stay on.
   • Try replacing the power supply; 12-24V DC power supplies are suitable.
   • If the power supply is defective, contact Fosi Audio for exchange.
6. Why does the sound crackle or make a lot of electric noise?
   • Ensure all cables are completely pushed into the devices; incomplete connections can cause cracking.
   • Remove all inputs and check if the cracking noise disappears. The issue might be with the audio source or input cables.
   • If not using the original factory standard power supply, replace it. Many aftermarket power supplies have high interference coefficients that can cause noise.
7. Can I use headphones with this product?

   No, the BT20A cannot be connected to headphones; it only supports passive speakers.

8. How can I switch between Bluetooth input and RCA input?

   You can connect via Bluetooth or wired input. If Bluetooth is connected, playback from RCA input is interrupted. Turn off Bluetooth on your device if using RCA input during Bluetooth pairing. Input priority: Bluetooth input > RCA input.

9. Why is there no voice from my amplifier?
   • Check if the power supply cable is connected to BT20A and the power indicator is on.
   • Ensure the BT20A's indicator light is on when the power is turned on.
   • Verify that the BT20A and your source components are turned on and not set to minimum volume. Try replacing your source and testing again.
   • Check that the wire connections from the audio source to each speaker are correct.
   • Ensure cables are not loose or damaged; incomplete connections are a common cause of no sound.
   • Confirm Bluetooth is paired. If Bluetooth is connected, RCA input playback will be interrupted. To use RCA input, interrupt the Bluetooth connection first.
10. My Bluetooth device cannot pair with BT20A?
    • Ensure BT20A is powered on.
    • Ensure BT20A is not paired with other devices.
    • Ensure the distance between your device and BT20A is not too great; move your device closer to BT20A.
    • Ensure there are no obstacles between your device and BT20A, as obstacles affect Bluetooth operation distance.
    • Try connecting with another Bluetooth audio source.
    • Reconnect the power supply to the BT20A, move it to another room, and try again.
    • Restart the BT20A and try connecting again, or try using another Bluetooth device.
11. How much power does this use in standby mode? Can this amp be left on all the time?

    This is a Class D amplifier that uses very low power in standby mode. It can be left connected all the time and is safe without significant power consumption.

12. Sound quality is not good?
    • Ensure all cables are fully connected.
    • Adjust the treble and bass controls on the amplifier to achieve the desired tone.
    • Try changing the sound source and cables for testing.
13. Should I unplug the power cord?

    If the item will not be used for a long time, unplug the power cord to prevent damage from lightning strikes.

14. Can I bridge channel 1 and channel 2 to get 200watts?

    No, this amplifier cannot be bridged.

15. How can I connect BT20A to TV?

    Because the BT20A has an RCA input, it can be connected to a TV.

16. Can BT20A accept signal from a Bluetooth microphone?

    If your Bluetooth microphone is a Bluetooth transmitter, then yes. This amplifier functions as a Bluetooth receiver amplifier.

17. Why the sound cut in and cut out?
    • Try reducing the volume of the sound source.
    • Try changing the audio source for testing.
    • Reduce the volume of the treble and bass knobs on the BT20A.
    • Ensure the positive and negative poles of the speaker output do not touch. Relatively large banana plugs can easily touch and cause a short circuit.
18. What is the difference between BT20A and BT10A?

    Fosi Audio BT20A has a 100 Watts*2 MAX power output, while the Fosi Audio BT10A has a 50 Watts*2 MAX power output.

19. Can I take the BT20A to other countries?

    Yes, the wide voltage AC 110-240V for power input can be used in any country. You only need to match the power cord adapter for the corresponding country.

Warranty Information

All Fosi Audio products have an 18-month limited warranty on parts and labor from the date of purchase. Please contact Fosi Audio 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. Fosi Audio hopes users enjoy their products as much as they enjoyed creating them.

• Our website: www.fosiaudio.com
• Amazon store: www.amazon.com/fosiaudio
• Our Youtube channel: Fosi Audio
• Our Facebook page: Fosi Audio

After-sale Service and Technical Support Email:

• support@fosiaudio.com
• fosiaudio@hotmail.com

[Image Description: QR code linking to Fosi Audio product information.]

FCC WARNING

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, including 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 Part 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, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

• 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.

To maintain compliance with FCC's RF Exposure guidelines, this equipment should be installed and operated with a minimum distance of 20cm between the radiator and your body. Use only the supplied antenna.