Thank you very much for purchasing the T3 Tube amplifier. Please read the instructions carefully before using this product.

Packing List
Product Overview
Quick Steup
Warranty Information
About Fosi Audio


Thank you very much for purchasing the T3 Tube amplifier. Please read the instructions carefully before using this product. If you have any problems or suggestions for the product, please contact us via support@fosiaudio.com.


Fosi AudioT3 is a Hi-Fi Bluetooth stereo 2.1-channel Tube amplifier that features 100W output, and Bluetooth signal range up to 10 meters. It provides multiple input options and its working voltage is AC110-240V. T3 Tube Amplifier stage imparts a warm and natural sound quality while the solid state power amp offers superb audio fidelity and efficiency.

Product name

 2.1-channel Tube amplifer  


Output power

RMS 50Watts*2  


Input type



Bluetooth Transmission

Up to 35 Ft  


Signal to noise ratio

≥80 DBA  


Speaker frequency

45Hz -20KHz  





Terminating Impedance

4 – 8 Ω




Packing List

Product Overview & Control Functions​

Quick Setup​

Bluetooth Mode


Step 1:Turn on the power switch

Step 2:The default input setting is Bluetooth mode after booting the T3 Tube Amplifier, and the machine will automatically enter the pairing mode.

AUX Mode

connection of source devices

Up to two sources with stereo line output can be connected to the stereo RCA input “AUX 1/AUX2”


Step 1:Up to two sources with stereo line output can be connected to the stereo RCA input “AUX 1/AUX2”

Step 2:Plug your device to the corresponding AUX1 or AUX2 input port prior to turning the mode knob to AUX 1 or AUX2


1. What type of speakers work best with T3 tube Amplifier?

Fosi Audio T3 works great with any 4-8Ω passive speakers.

Note: please note that the T3 amplifier is for passive speakers, and subwoofer output only supports active speakers.


2. Why Bluetooth connection is intermittent? 

Use another Bluetooth device to have a try.

Ensure that there is no interference from other electronic equipment between the T3 and the audio source.

Put your device close to the T3.

Replug the power adapter.


3. Why the sound is cracking or making a lot of electric noise? 

Use another Bluetooth device to have a try.

Please make sure all the cables are completely pushed into the devices. Incomplete connection will cause this cracking.

Please remove all the inputs then check whether cracking noise disappear or not. The cracking may be from the audio source or input cables.

If you are not using the original factory standard power supply, please replace the power supply before testing. Many power supply adapters in the market have large interference coefficient, which will cause a lot of current sound.


4. Can I use headphone with this product? 

Yes, the T3 as a headphone amplifier will easily drive most headphone to deliver a colossal sound stage and effortless dynamic range.

Note: when headphones are plugged to the headphone jack, the speaker output connections are disengaged.


5. Why there is no voice from my amplifier? 

Please check whether the cable of power supply is connected to T3 and the power switch is on.

Please check that the T3 and your source components are turned on and not set to minimum volume. If possible replace your source and test again.

Check that the wire connections from the audio source to each speaker in the amplifier are connected correctly.

Please check that the cable is not loose or damaged. Incomplete connection is one of the main reasons leading to no sound.

Please make sure the Bluetooth is paired. If Bluetooth is connected, the playback of RCA input will be interrupted. If you want to connect this amplifier with a RCA cable, you need to disconnect the Bluetooth first.


6. My Bluetooth device cannot pair with T3? 

Make sure that T3 is powered on.

Make your device closer to T3 to have a try.

Make sure there are no obstacles between your device and T3. Obstacles will affect the Bluetooth operation distance.

Please try to use another Bluetooth audio source to test.

Please reconnect the power supply to the T3, and move the T3 to another room to have a try.

Restart the T3 and then try to connect again, try to use another Bluetooth device.

Warranty and Maintenance

All Fosi Audio products have an 24-month limited warranty on parts and labor from the date of purchase. Please contact us if you have any problems.

About Fosi Audio​

• Fosi Audio designs and builds innovative audio products with all your music in mind. Great sound, simple but elegant designs, high-quality materials, and truly useful features are what Fosi Audio is about. We sincerely hope you get as much enjoyment from our products as we’ve had to create them!

Our website: www.fosiaudio.com

Amazon store: www.amazon.com/fosiaudio 

Our Youtube channel: Fosi Audio

Our Facebook page: Fosi Audio

WhatsApp: +8613716612254

Call us: +49 33389171782

After-sale Service and Technical Support Email:  support@fosiaudio.com