1: The power supply indicator is not illuminated.

• Make sure that the AC power cord is securely connected to the power supply and to an AC power outlet.
• Check whether the power LED on the power supply stays on. If not, the power supply is broken.
• If you make sure the power supply is defective, please contact us for exchange.
 

2: Which type of speakers works best with the TP-02 Amplifier?

• Fosi Audio TP-02 works well with most 2-8Ω subwoofers.
 

3: Why does the TP-02 make serious noise when used together with a radio?

• The common feature of Class D power amplifiers is that they can cause serious noise when used with a radio, so we do not recommend using the TP-02 with a radio or too close to it.
 

4: Why there is no voice from my amplifier?

• Please make sure that the AC outlet is on and working.
• Verify that the amplifier and your devices are turned on.
• Recheck speaker wire connections from the amplifier to the speaker.
• Please make sure that the cable from the power supply is connected to the amplifier and check whether the power LED on the power supply stays on. If not, the power supply is broken.
• Please make sure that the volume/power knob on the front panel is turned on and not set to the minimum volume.
• Please make sure that your devices (iPad, computer, etc.) are turned on and not set to the minimum volume. Please change the device with other one and try it again if you can. If it still not work then it is the problem of the amplifier.
• Please make sure that the cables from your devices are working and properly connected. You can change the cables with new one and see if it will work again. If not then it is the problem from the amplifier.
 

5: Why does the sound crack or make a lot of electric noise?

• When you put your hand on the volume knob or the amplifier case it will make some buzzing sound, it's normal because the amplifier case and the volume knob are made of aluminum. Once you move your hand away from the amplifier, the buzzing sound will disappear.
• Please make sure all the cables are completely pushed into the devices, an incomplete connection will cause the cracking sound. 
• Please unplug all of the signal input cables and then check whether cracking noise disappears, if not the crack is from the amplifier. 
• If you didn’t use the original factory standard power supply, please replace the power supply with the original standard power supply before testing. Many power supplies in the market have large interference coefficients, which will cause a lot of sound.
 

6: Why is there an interference sound after connecting the signal line?

• If you use unshielded signal lines, there will be interference signals entering the power amplifier. If you don’t like the sound, you are advised to use the shielded signal lines or unplug the signal lines.
 

7: Why does the amplifier stop working after a period? And after a while it work again?

• The amplifier is in this case normally overheat protected, and the output power may have exceeded the designed range, so you can lower the volume a little and try again.
 

8: How much power does this product use in standby mode? Can this amplifier be left on all the time?

• Power stable rated output of about 180watt. This is a Class D amplifier, which consumes some power in standby mode and has a stable rated output of about 150watt.
 

9: When the volume adjustment on the amplifier stays the same, why is the speaker's output volume different while different devices are used ( such as CDS and mobile phones )?

• The output voltage of different types of audio sources is different. For the mobile phone, it is 0.35mV, but the CD 1V. The signal output amplitude of the devices will directly influence the volume.
 

10: Why the sound of the power amplifier is not so good at the beginning and for the high frequency it is also not clear, but after working for 10 hours the sound is normal again?

• Speakers and amplifiers are very sensitive equipments. They need also to match themselves with each other. So usually the sound will be good again after the new power amplifier and the speaker work more than 10 hours.
 

11: Why the sound quality is not so good?

• Turn down the volume of the input device and turn up the volume of the amplifier.
• Please make sure that your subwoofer is passive, not active.
• Please unplug the RCA input and connect this amplifier to a subwoofer. Then connect the amplifier to the power supply, switch it on and turn up the volume. Hear whether noise or hum remains. If yes, the issue may come from the amplifier or your subwoofer; if not, the issue may come from your RCA cable or your device, then please exchange the device and audio cablewith other one and try again.
• Please make sure all the cables are completely pushed into thedevice, incomplete connection will create distortion.
• Please make sure your TP-02 amplifier has enough power to driveyour subwoofer and check the parameters of your subwoofer ifthey match themselves with ones of TP-02. And if you need moreelectricity power, you can use a more powerful power supply such as 24V 8A or 24V 10A.
 

12: How can the power which goes into the unit be 24v, 4.5a , 108 watts while the power of the unit are 220 watts?

• 220 watts are 'Peak' output. Since the power supply can only provide a maximal power of 108 watts, it can not supply any more than 108 watts continuously (Even the number 108 watts are impossible. That would be likely at 10% THD). However, the capacitor could provide a temporary peek boost to 220 watts for a very, very brief period. Maybe a few milliseconds. If you want to reach 220w power, you can use a 24V 8A or 24V 10A power adapter.
 

13: What are the true RMS wattage specifications for this device, when the power is 2Ω, 4Ω?

• 220 watts are the MAX power output. Its RMS power output is RMS 150watts @ 4Ω, RMS 120watts @ 8Ω with 24V 4.5A power supply. If you want to get more power, you can upgrade the power supply with 24V 8A.
 

14: Why cuts the sound in or out?

• Try to reduce the sound of your device. 
• Ensure that the positive and negative poles of the speaker output do not touch each other. Some relatively large banana plugs are easy to touch each other and will cause a short circuit. 
• Try to exchange your audio source to test, if still so then there are problems with the amplifier.
 

15: Low Volume.

• Recheck the volume on your device and turn up the sound of the amplifier. Make sure that it isn’t set to minimum volume.
• Please make sure if your device needs a pre-amp or not.
• If you are using the turntable, please make sure if your turntable needs a phono preamp or not. Some turntables have built-in phono preamp, some not.
 

16: Can I use the TP-02 in other countries?

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