User Guide

9. Why the power light still on even I switch the amp off? And does it unsafe when I leave it on?
The power light on means the power adapter plugged in, the amp will off when you switch off,
Please don’t worry, it’s safe and you can leave it on.
Fosi Audio class d amplifier troubleshooting tips
The following troubleshooting tips can help diagnose and correct most common issues with the
amplifier. We have attempted to make this list as comprehensive as possible, so some of these
may not apply to your issue, but please go through each tip and if the problem still persists then
open a support ticket here.
Be sure to include your results and we will then respond as quickly as possible and do our best to
resolve the issue. Support email: [e-mail]
1. Power supply indicator is not illuminated:
• Check to see that the AC power cord is securely connected to the power supply and to an AC
power outlet;
• Check that the AC power outlet is supplying power;
• If you can sure the power supply is defective, please contact us for exchange;
2. If the power supply light is on but you are experiencing an audio-related issue, try these tips:
• Verify that the volume/power control on the front panel is not turned all the way down or
powered off (we recommend setting the volume to at least the 10 o’clock position).
• Check that the volume level of your audio source component or device is not set to minimum
volume or powered off.
• Check speaker wire connections from the amp to the speakers by removing the speaker wire
from each speaker and then reconnecting. Also check the speaker wire polarity by verifying that
the wires are going to same terminals on both speakers.
• Check that the cables from your audio sources to the amplifier are properly connected.
Confirm this by unplugging the audio cables and then reconnecting.
• Try decreasing the volume of the input audio source and increase the volume of the amp.
Try using different audio input sources and/or devices to see if the problem follows.
• Try swapping your left and right speaker to see if the issue remains in the same channel or if it
follows the speaker.
• If you are using a computer connected to the amplifier, make sure the volume is up on your
media player, internet radio, master control, device volume, etc. and that the balance control is
centered.
• If you are using a wireless adapter, preamp, or an external DAC with your amplifier, remove
these (temporarily) and connect the audio source directly to the amplifier then to speakers.
• If your input source has its own EQ, please make sure the low end is at a moderate level, as
having too much bass in your signal can obviously cause some unwanted distortion.
• Move your amplifier and speakers to a different location to see if something is causing