1. Introduction
The SUNBUCK AV-338ST is a versatile 5-channel HIFI digital stereo audio power amplifier designed for various audio applications, including home theater, karaoke, and small parties. It features a peak power output of 2000W, multiple input options including DVD, AUX, USB, SD card, and Bluetooth 5.0, along with FM radio functionality. The amplifier also includes two microphone inputs with reverb and delay adjustment for an enhanced karaoke experience, and a 5-band EQ mixer for fine-tuning audio output.
This manual provides detailed instructions for setting up, operating, and maintaining your AV-338ST amplifier to ensure optimal performance and longevity.
2. Setup Guide
2.1 Unpacking the Amplifier
Carefully unpack the contents of the box. Ensure all items are present and in good condition.
- 1 x SUNBUCK AV-338ST Audio Power Amplifier
- 1 x User Manual (this document)
- 1 x Remote Control
- 1 x Power Cable
2.2 Front and Rear Panel Overview
Familiarize yourself with the controls and connections on the front and rear panels of your amplifier.
| No. | Function | Description |
|---|---|---|
| 1 | Power ON / OFF | Main power switch for the unit. |
| 2 | ECHO | Adjusts the echo effect for microphones. |
| 3 | MIC VOL | Adjusts the volume of the microphones. |
| 4 | USB/SD Disk | Port for USB flash drives and SD cards for media playback. |
| 5 | MASTER VOL | Controls the overall master volume output. |
| 6 | BASS | Adjusts the low-frequency (bass) level. |
| 7 | TREBLE | Adjusts the high-frequency (treble) level. |
| 8 | LED Display | Digital display for status and track information. |
| 9 | CD Input | RCA input for CD players. |
| 10 | Speaker System | Terminals for connecting speakers (4-16 ohm). |
| 11 | Speaker Channel Output | Outputs for connecting speaker channels. |
| 12 | MIC Input | Two 6.35mm (1/4 inch) jack inputs for microphones. |
| 13 | Audio Input | General audio input. |
| 14 | DVD Input | RCA input for DVD players. |
| 15 | AUX Input | RCA auxiliary input for external audio devices. |
| 16 | FM ANT | Connector for FM antenna. |
2.3 Connecting Speakers
The AV-338ST supports a 5-channel output, including a center channel and two surround channels, in addition to the main stereo channels. Ensure your speakers have an impedance between 4 and 16 ohms.
- Connect your main stereo speakers to the 'Speaker System' terminals (R and L).
- Connect your center speaker to the 'C' terminal.
- Connect your surround speakers to the 'SR' (Surround Right) and 'SL' (Surround Left) terminals.
- Ensure correct polarity (+ to + and - to -) for all speaker connections.
2.4 Connecting Audio Sources
The amplifier offers various input options for your audio devices.
- DVD/CD/AUX Inputs: Use RCA cables to connect your DVD player, CD player, or other auxiliary audio devices to the corresponding RCA input jacks on the rear panel.
- USB/SD Card: Insert a USB flash drive or SD card (up to 64GB, not included) into the front panel USB or SD/MMC slot for direct media playback.
- Bluetooth: Pair your Bluetooth-enabled device (smartphone, tablet, laptop) with the amplifier. (See section 3.5 for detailed Bluetooth instructions).
- FM Antenna: Connect the included FM antenna to the FM ANT terminal on the rear panel for radio reception.
2.5 Microphone Connection
The amplifier features two microphone inputs for karaoke or public address.
- Connect your microphones to the MIC1 and MIC2 6.35mm (1/4 inch) jack inputs on the front panel.
3. Operating Instructions
3.1 Power On/Off
Press the 'Power ON/OFF' button on the front panel to turn the amplifier on or off. The LED display will illuminate when the unit is powered on.
3.2 Input Selection
Use the 'AUDIO INPUT SELECTOR' knob on the front panel to choose your desired audio source (e.g., DVD, AUX, USB, SD, FM, Bluetooth).
3.3 Volume and Tone Control
- MASTER VOL: Rotate the 'MASTER VOL' knob to adjust the overall output volume.
- BASS/TREBLE: Use the 'BASS' and 'TREBLE' knobs to adjust the low and high frequencies of the audio output, respectively. The amplifier features a 5-band EQ mixer for detailed tone control.
3.4 Microphone Usage
- MIC VOL: Adjust the 'MIC VOL' knob to control the volume of the connected microphones.
- ECHO: Use the 'ECHO' knob to add or remove echo effects to the microphone sound. The amplifier also supports microphone reverb and delay adjustment for a professional karaoke sound.
3.5 USB/SD Card Playback
Insert a USB disk or SD card into the respective slot. The amplifier will automatically detect and begin playing audio files. Use the front panel controls or remote control to navigate tracks and adjust playback.
3.6 Bluetooth Connectivity
The AV-338ST features Bluetooth 5.0 for wireless audio streaming.
- Switch the input selector to 'Bluetooth' mode. The LED display will indicate Bluetooth pairing mode.
- On your mobile device, search for available Bluetooth devices and select 'AV-338ST' (or similar name).
- Once paired, you can stream audio wirelessly from your device to the amplifier.
3.7 FM Radio
Switch the input selector to 'FM' mode. The amplifier will automatically scan for available radio stations. Use the CH+/- buttons on the remote control to change stations.
3.8 Remote Control Functions
The included remote control provides convenient access to various amplifier functions.
| Button | Function |
|---|---|
| ON/OFF | Power on/off the amplifier. |
| MODE | Cycles through input modes (DVD, AUX, USB, SD, FM, Bluetooth). |
| CH+/- | Changes FM radio stations or navigates tracks. |
| EQ | Selects equalizer presets. |
| Previous/Next | Skips to the previous or next track during media playback. |
| Play/Pause | Plays or pauses media playback. |
| Volume+/- | Adjusts the master volume. |
| 0-9 | Direct song selection (for USB/SD playback). |
| Cycle | Toggles playback repeat modes. |
4. Maintenance
4.1 Cleaning
To maintain the appearance and performance of your amplifier, regularly wipe the exterior with a soft, dry cloth. Do not use liquid cleaners or abrasive materials, as they may damage the finish or internal components.
4.2 Internal Components
The amplifier contains sensitive electronic components. Do not attempt to open the casing or perform any internal repairs yourself. This could lead to electric shock, damage to the unit, and void your warranty. Key internal components include:
- Power tube
- 4 Tube
- Speaker protect circuit
- Filter Capacitor
- Small capacitor
- Toroidal Transformer
- Zener tube
- Mic socket
- Toggle switch
- Fuse
For any service or repair needs, please contact authorized service personnel.
5. Troubleshooting
If you encounter any issues with your amplifier, please refer to the following common troubleshooting steps before seeking professional assistance.
- No Power: Ensure the power cable is securely connected to both the amplifier and a working power outlet. Check the power switch on the front panel.
- No Sound: Verify that the correct input source is selected. Check all audio cable connections to and from the amplifier. Ensure speakers are properly connected and their volume is not muted or set too low. Adjust the MASTER VOL knob.
- Distorted Sound: Check if the input signal is too strong (reduce volume on the source device). Ensure speaker impedance matches the amplifier's specifications (4-16 ohm).
- Microphone Not Working: Ensure microphones are properly plugged into MIC1/MIC2. Adjust MIC VOL and ECHO knobs.
- Bluetooth Connection Issues: Ensure the amplifier is in Bluetooth mode and your device's Bluetooth is enabled. Try unpairing and re-pairing the device.
- USB/SD Playback Issues: Ensure the USB disk or SD card is formatted correctly (FAT32) and contains compatible audio files. Try a different USB/SD card.
6. Specifications
Detailed technical specifications for the SUNBUCK AV-338ST amplifier.
| Feature | Specification |
|---|---|
| Model | AV-338ST |
| Channel | 5 Channel |
| Rated Voltage | 110V/220V 50 / 60Hz |
| Frequency Response | 20Hz - 20KHz (+/-10dB) |
| Rated Power | 1200W |
| Peak Power | 2000W |
| Standard Impedance | 4 to 16 ohm |
| Signal to Noise Ratio | 90dB |
| Total Harmonic Distortion | ≤ 0.5% |
| Signal Input Sensitivity | 200mv (± 30mv) |
| Microphone Input Sensitivity | 9 mv (± 2mv) |
| Recording Level Output | 1V |
| Auxiliary Level Output | 1V |
| DC12V Support | No |
| Media Support | USB Disk/Max 64GB SD Card (Not included) |
| Color | Black, Gold |
| Dimensions (L x W x H) | 25 x 21.5 x 6 cm (9.8 x 8.5 x 2.4 inches) |
| Category | Item | Quantity |
|---|---|---|
| Input | Speaker System | x4 |
| Audio Input | x2 | |
| AUX Input | x2 | |
| LINE Output | x2 | |
| SD Card | x1 | |
| FM ANT | x1 | |
| USB Disk | x1 | |
| MIC Input | x2 | |
| Keys | Power On/Off | x1 |
| Microphone Volume | x1 | |
| Master Volume | x1 |
7. Warranty and Support
Your SUNBUCK AV-338ST amplifier comes with the following service commitments:
| Service Type | Description |
|---|---|
| On-Time Delivery | Full refund if the product is not received within the guaranteed delivery time. |
| Longer Protection | 15 days more protection after order completion. |
| Returns Extra | Return any product, provided it is in perfect condition. |
| Guaranteed Quality | Guaranteed quality or a full refund. |
For further assistance, technical support, or warranty claims, please contact your retailer or the manufacturer's customer service. Please have your model number (AV-338ST) and purchase information ready when contacting support.