1. Why is the sound coming out of the MC101 so low until the volume is adjusted to a higher level?
The MC101's volume control adopts a Taper A potentiometer that increases volume logarithmically. The increase in sound is slight in the early stage but increases significantly in the latter stage. Human ears perceive sound logarithmically rather than linearly, so this design can better match the characteristics of human hearing to provide a more natural and intuitive volume control.

2. Why is there no sound output when the product is connected and music is played upon startup?
A. The amplifier is not powered on, please check whether the mode indicator is on;
B. The volume of the amplifier is too small, please turn the volume knob clockwise and adjust it to the right level;
C. The audio cable is connected incorrectly, please reconnect it according to the steps in the instruction manual;
D. The audio source is not playing or muted, please check the audio source equipment.

3. Why is the power indicator light very dim or flashing constantly after powering on?
It is normal for the blue light to blink in Bluetooth mode when it is waiting to be connected, and the blue light will stay steady when successfully connected;
The blinking power indicator in RCA mode may be due to insufficient power supply voltage, please make sure you are using the supplied 24V/4.5A power supply.

4. What is the purpose of the pre-out interface?
The MC101's pre-out interface can be used to expand your audio system. You can connect a powered subwoofer, active speakers, or another amplifier to the MC101 via the pre-out port. Please note that the volume of the pre-out interface is controlled by the volume knob and the toggle switch, but is not affected by the bass and treble controls.

5. How do I clear the existing Bluetooth connection?
The MC101 supports an auto-reconnect feature, which automatically re-establishes the Bluetooth connection if it's interrupted due to reasons like the device being moved too far, powered off, or experiencing a power outage. If you need to manually disconnect from a paired Bluetooth device, please long press the volume knob for about 5 seconds until the mode indicator light starts to flash.

6. What is the purpose of the VU meter?
The VU meter is an instrument used to measure the level of audio signals, assisting in monitoring the strength and dynamic range of audio signals. It helps prevent overload and avoids distortion.

If you have any further questions, please contact our support team via support@fosiaudio.com