1. Introduction
The Facmogu ST-838 is a compact yet powerful 2.1 channel HiFi stereo subwoofer amplifier designed to enhance your home audio experience. It delivers 20W x 2 (L/R) for passive speakers and 40W for a passive subwoofer, providing clear and full sound with low distortion. Its mini size and versatile input options make it suitable for various applications, including home, car, marine, RV, and golf cart setups.
2. Package Contents
Please check the package contents upon unboxing:
- 1x Facmogu ST-838 Power Amplifier
- 1x User Manual (this document)
- 1x DC 12V 3A Power Adapter
3. Product Overview
3.1 Front Panel Controls
- Power Button (ON/OFF): Toggles the amplifier power.
- Bass Volume Knob: Adjusts the output level of the passive subwoofer.
- Treble Knob: Adjusts the high-frequency response of the main speakers.
- Bass Knob: Adjusts the low-frequency response of the main speakers.
- Volume Knob: Controls the overall master volume of the main speakers.
- AUX Input (3.5mm): Connects external audio devices via a 3.5mm audio cable.
- Power Indicator: Red LED indicates power status.
- Bass Indicator: Blue LED illuminates when bass is active.
3.2 Rear Panel Connections
- Audio Input (RCA): Connects audio sources using RCA cables (e.g., CD player, TV, computer).
- Subwoofer Output (Super Bass): Connects to a passive subwoofer.
- Left Channel Output: Connects to the left passive speaker.
- Right Channel Output: Connects to the right passive speaker.
- DC 12V Input: Connects the included DC 12V 3A power adapter.
4. Setup Instructions
Follow these steps to connect your Facmogu ST-838 amplifier:
4.1 Connecting Speakers and Subwoofer
- Ensure the amplifier is turned OFF and unplugged from power.
- Connect your passive left speaker to the "L +" and "L -" terminals on the rear panel. Ensure correct polarity (+ to + and - to -).
- Connect your passive right speaker to the "R +" and "R -" terminals on the rear panel. Ensure correct polarity.
- Connect your passive subwoofer to the "Super Bass" terminals on the rear panel. Ensure correct polarity.
4.2 Connecting Audio Source
Choose one of the following methods to connect your audio source:
- RCA Input: Use an RCA audio cable to connect your audio source (e.g., CD player, TV, computer) to the "AUDIO INPUT" (R/L) jacks on the rear panel.
- AUX Input: Use a 3.5mm audio cable to connect your audio source (e.g., mobile phone, MP3 player) to the "AUX" input jack on the front panel.
4.3 Connecting Power
- Connect the included DC 12V 3A power adapter to the "DC 12V Input" port on the rear panel of the amplifier.
- Plug the power adapter into a standard wall outlet.
- The Power Indicator LED on the front panel will illuminate red.
5. Operating Instructions
Once all connections are made and the amplifier is powered on:
- Power ON/OFF: Use the toggle switch on the front panel to turn the amplifier on or off.
- Adjusting Main Volume: Rotate the large "Volume" knob on the front panel to increase or decrease the overall sound level of your main speakers.
- Adjusting Bass and Treble: Use the "Bass" and "Treble" knobs to fine-tune the low and high frequencies of your main speakers to your preference.
- Adjusting Subwoofer Volume: Use the "Bass Vol" knob to control the output level of your passive subwoofer independently. The blue Bass Indicator LED will light up when the subwoofer is active.
- Source Selection: The amplifier automatically detects the active input. If both AUX and RCA are connected, ensure only one source is playing at a time to avoid interference.
6. Specifications
| Feature | Specification |
|---|---|
| Brand | Facmogu |
| Model | ST-838 |
| Number of Channels | 2.1 |
| Output Power (RMS) | 20W x 2 (L/R) + 40W (Subwoofer) |
| Total Output Power | 80 Watts |
| Input Voltage | DC 12V |
| Minimum Supply Voltage | 11 Volts (DC) |
| Maximum Supply Voltage | 12 Volts |
| Audio Inputs | RCA, 3.5mm AUX |
| Mounting Type | Freestanding |
| Item Weight | 1.15 pounds (approx. 0.52 kg) |
| Package Dimensions | 10.08 x 9.02 x 2.36 inches (approx. 25.6 x 22.9 x 6 cm) |
7. Troubleshooting
- No Sound:
- Ensure the amplifier is powered on and the power indicator is red.
- Check all audio cable connections (RCA/AUX) to ensure they are secure and correctly plugged into both the amplifier and the audio source.
- Verify that speaker wires are correctly connected to the amplifier terminals with proper polarity.
- Confirm that the audio source is playing and its volume is turned up.
- Adjust the amplifier's main volume, bass, and treble knobs.
- Distorted Sound:
- Reduce the volume on both the audio source and the amplifier.
- Check speaker impedance (4-8Ω recommended).
- Ensure speaker wires are not frayed or short-circuiting.
- Adjust bass and treble controls to a neutral position.
- Subwoofer Not Working:
- Ensure the passive subwoofer is correctly wired to the "Super Bass" terminals.
- Increase the "Bass Vol" knob on the front panel.
- Check the subwoofer's own connections if it has an external power source or controls.
8. Maintenance
To ensure the longevity and optimal performance of your amplifier:
- Keep the unit in a dry, well-ventilated area, away from direct sunlight, heat sources, and moisture.
- Clean the exterior with a soft, dry cloth. Do not use liquid cleaners or solvents.
- Avoid blocking the ventilation fins on the sides of the amplifier to prevent overheating.
- Disconnect power before cleaning or when the unit will not be used for an extended period.
9. Warranty and Support
Facmogu products are designed for reliability and performance. For warranty information, technical support, or any inquiries regarding your ST-838 amplifier, please refer to the contact details provided with your purchase or visit the official Facmogu website. Please retain your proof of purchase for warranty claims.