1. Introduction
This manual provides comprehensive instructions for the installation, operation, and maintenance of your MAOZUA SK-790.4 4-Channel 12V Sound Power Amplifier. Please read this manual thoroughly before using the product to ensure proper function and safety. This amplifier is designed to enhance your audio experience in both home and car environments, delivering powerful and clear sound.
Figure 1: MAOZUA SK-790.4 Amplifier Overview
Video 1: Product Overview
2. Features
The MAOZUA SK-790.4 amplifier incorporates advanced technology to deliver high-quality audio performance. Key features include:
- Digital pulse-width-modulated regulated power supply
- MOSFET power supply devices
- Fully complementary discrete audio stages
- Direct coupled output stage
- Discrete output transistors
- Low overall negative feedback
- 2 ohm stable in stereo mode
- Bridgeable to mono operation
- Stereo/mono setup simultaneously
- 4-way protection circuit: thermal, current, D.C. MOSFET, and overvoltage
- Soft start delayed turn-on
- Increased surface area and mass for continuous heat dissipation
- LED power on indicator
Figure 2: Amplifier Features
3. Setup and Installation
Proper installation is crucial for optimal performance and safety. Please follow these steps carefully.
3.1. Unpacking
Carefully remove the amplifier from its packaging. Inspect the unit for any signs of damage. Ensure all accessories, including the screw set and spare fuse, are present.
3.2. Installation Steps
Follow these general steps for installing the amplifier in your vehicle:
- Take out your car radio.
- Connect the radio car tail line using our ISO wiring harness DSP cable.
- Insert the terminal to the DSP amplifier.
- Finish installation. You can then use a computer or phone app to adjust the DSP sound.
Figure 3: Installation Steps
3.3. Power Connections
For your convenience, high current barrier strip terminals are provided, allowing the use of heavy gauge terminals and wire without splicing. Disconnect the battery positive (+) before making any power connections to the amplifier.
- B+ +12V: Connect the +12V pole of the power supply directly to the battery (+) terminal.
- GND: Connect the GND pole of the power supply directly to the negative ground battery terminal of the car chassis.
- REMOTE: Connect the "Remote" pole to an external switch for positive 12V ON/OFF. This may be connected to the power antenna or turn-on lead of the head unit.
- FUSE: Refer to the panel text for fuse specifications. Always use the proper size fusing, with a fuse at the battery and the amplifier (not supplied).
Important: Improper wiring connections can seriously damage amplifiers, accessories, or speakers. Please follow instructions carefully. Make sure all connections are clean and secure, and use grommets when going through the firewall and other metal bodywork.
Figure 4: Amplifier Connections and Internal Layout
3.4. Input Connections
Connect the pre-amp/low-level outputs from your source unit to the RCA jacks labeled "Input" on the amplifier. Be sure to route all signal cables away from power lines and use high-quality RCA cables to ensure better signal transfer and to avoid noise from entering the system.
- Stereo Mode: Connect the left and right RCA plugs from the source unit to their appropriate input jacks.
- Mono/Bridged Mode: Connection may be made to the right, left, or both input jacks.
If you are using a pre-amp device, connect the outputs of the front-end unit to the inputs of the pre-amp, then the outputs of the pre-amp to the inputs of the amplifier.
3.5. Output Connections
High current barrier strip terminals are provided for connection to the loudspeaker system.
- Stereo Mode: Connect the left speaker leads to the left terminal and the right speaker leads to the right terminal. Be sure to observe polarity. Stereo mode is designed for use with 2, 4, or 8 ohm speaker loads.
- Mono/Bridged Mode: Connect the speaker(s) lead to the R terminal and the speaker lead to the L-terminal. Mono mode is designed for 4-8 ohm loads and will not support a 2 ohm load.
Caution: Operation of the amplifier below its minimum impedance load can damage both the amplifier and your speakers, and will void your warranty.
Figure 5: Car Audio System Upgrade Solution
4. Operating Instructions
4.1. Controls
- Low Level Input (RCA Type Terminal): This amplifier is provided with gold-plated RCA terminals for LOW LEVEL INPUT to match radios and equalizers with line level output. Couple the RCA input with the car stereo/equalizer output using RCA type connector cables.
- Input Level Control (LEVEL): The Level function can be selected to increase or decrease sound response output.
- Bass Boost Control (BASS BOOST or BASS EQ): The Bass Boost Control allows you to contour extra bass response into your system. The Bass can be boosted up to 12dB.
- Crossover or Filter:
- HPF (High Pass Filter): Set to the HPF position when the amplifier is used to drive a tweeter/midrange system. Frequencies below the crossover point will be attenuated at 12dB/octave. Permits adjustment from 50Hz to 150Hz as the crossover point.
- LPF (Low Pass Filter): Set to the LPF position when the amplifier is used to drive a subwoofer. Frequencies above the crossover frequency will be attenuated. Rotate the knob to select any frequency between 50Hz to 150Hz as the crossover point.
- FULL/FLAT: Set to the full/flat position when the amplifier will be used for driving full-range speakers. The full frequency bandwidth will be output to the speakers without high or low frequency attenuation.
4.2. Power On LED
When the unit is properly grounded, has proper power, and is receiving a remote power signal, the Green LED will light up, indicating correct power conditions.
4.3. Stereo Surround Sound
The high-fidelity chip makes the sound quality details more prominent, more delicate, and more layered, providing a 360-degree stereo surround sound experience.
Figure 6: 360-Degree Stereo Surround Sound
5. Maintenance
To ensure the longevity and optimal performance of your amplifier, follow these maintenance guidelines:
- Keep the amplifier clean and free from dust. Use a soft, dry cloth for cleaning.
- Ensure adequate ventilation around the amplifier to prevent overheating.
- Regularly check all connections for tightness and corrosion.
- Avoid exposing the amplifier to extreme temperatures or moisture.
6. Troubleshooting
If you encounter issues with your amplifier, refer to the following common problems and solutions:
- No Power / Power LED Off: Check all power connections (B+, GND, REMOTE) to ensure they are secure and properly wired. Verify the fuse at the battery and on the amplifier.
- Protection LED On: If the protection LED lights up, the unit is in protection mode. This can be caused by thermal overload, short circuits in speaker wiring, or incorrect impedance loads. Check speaker wiring for shorts, ensure proper ventilation, and verify speaker impedance matches the amplifier's specifications.
- No Sound Output: Check input connections from the source unit. Verify speaker connections and polarity. Ensure the input level control is not set too low.
- Distorted Sound: Check input signal level; it might be too high or too low. Adjust gain settings. Check speaker impedance and ensure speakers are not damaged.
7. Specifications
| Feature | Specification |
|---|---|
| Output Power | 4x100W or 4x80W or 4x50W |
| THD | <0.1% |
| Frequency Response | 10Hz-40,000Hz ±1dB |
| S/N Ratio | >85dB |
| Input Sensitivity | 200MV |
| Bass Boost | 12dB |
| Speaker Impedance | 2-16 Ω |
| Power Fuse | 20AX2 or 30AX2 (refer flank panel text) |
| Dimensions (LxHxW) | 310x260x55mm, 310x240x52mm, 330x245x53mm, 320x250x55mm, 310x253x55mm, 350x253x55mm, 400x240x57mm, 400x240x52mm |
| Includes | Screw Set & Spare Fuse |
Figure 7: Product Dimensions
8. Warranty and Support
For detailed warranty information and technical support, please refer to the official product documentation or contact the manufacturer directly. A user manual in PDF format is available for download for further reference: User Manual (PDF).
9. Important Safety Information
- Always disconnect the vehicle's battery before performing any electrical work.
- Ensure all wiring is properly insulated and secured to prevent short circuits.
- Do not operate the amplifier in wet or damp conditions.
- Avoid placing the amplifier in areas with poor ventilation to prevent overheating.
- Seek professional assistance if you are unsure about any installation or wiring procedures.