User Manual

1
Fosi Audio Class D Amplifier Troubleshooting Tips
Q: How to contact us?
A: Please contact us via email at [e-mail].
Q: What type of speakers work best with the Fosi Audio amplifiers?
A: Fosi Audio Amplifiers work great with any 2, 4, 6, or 8ohm passive Speakers. But Please know that the
amplifier is for passive speakers, not for powered speakers and subwoofers.
About Useful Service Life:
Q: Can I leave the Fosi Audio amps power on all the time?
A: Sure, the Fosi Audio amps have the power-saving idle mode that activates after you stop playing music,
and they are Class D amplifiers, which will cost very low power when nothing playing through it.
Q: Why does the amplifier stop working after a period of time? After a period of time off, it
was working again?
A: Normally, in this case, the amplifier is overheat protected, and the output power may have exceeded the
designed power, so you can lower the volume a little and try again.
Q: Why the sound of the power amplifier is not very good at the beginning, the high
frequency is not clear, but after working for 8 hours the sound is normal?
A: Speaker and amplifier are very sensitive equipment, also need to know each other, and the matching
process, usually the sound will be good after the new power amplifier and the speaker work more than ten
hours.
Q: Why is my device stop working after a short time of use?
A: Make sure your audio source and the headphones, amplifier, or powered speakers you connected are
works well. And please check all the connections of the input and output cables, please change the audio
source, output devices, and cables to try again. Also please check the power supply works or not.
About the Sound:
Q: Sound quality is not good?
• Make sure all the cables are fully connected.
• Adjust the treble and bass control of the power amplifier to achieve the right tone.
• Please try to change the sound source and cables to test.
Q: Why does the volume of the machine stay the same, while the sound of different audio
sources (such as CDS and mobile phones) is different?
A: The output range of different types of audio source devices is different, the mobile phone is usually
0.35mV, and the CD is 1V.The signal output amplitude of the sound source will directly influence the
volume.
Q: One channel does not work?
• Please test whether the Bluetooth and RCA input have the same problem first.
• If the two modes have the same problem, swap the speaker cables of the left and right channels, or change
another speaker, and then test whether this channel still does not work;
• If only RCA or Bluetooth mode does not work, change the audio source, change the RCA cable and test
again, and make sure that all the cables are completely pushed into the device.