1. Introduction
Thank you for choosing the SoundXtreme ST-1550.1 Monoblock Amplifier. This amplifier is engineered to deliver powerful and clear audio performance for your car audio system. It features a 1 Ohm stable design, providing up to 1550 Watts of maximum power, and includes a remote level control for convenient bass adjustment. This manual provides essential information for proper installation, operation, and maintenance to ensure optimal performance and longevity of your amplifier.
2. Safety Information
Please read all instructions carefully before installing and operating your amplifier. Failure to follow these guidelines may result in damage to the amplifier, vehicle, or personal injury.
- Always disconnect the vehicle's negative battery terminal before starting any installation.
- Ensure proper grounding. The ground wire should be as short as possible and securely connected to the vehicle's chassis.
- Use appropriate gauge wiring for power, ground, and speaker connections to prevent overheating and ensure stable performance.
- Install the amplifier in a dry, well-ventilated location, away from direct sunlight, heat sources, and moisture.
- Protect all wiring from sharp edges and moving parts. Use grommets where wires pass through metal.
- Do not attempt to repair or modify the amplifier yourself. Refer all servicing to qualified personnel.
3. Package Contents
Verify that all items are present in the package:
- SoundXtreme ST-1550.1 Monoblock Amplifier
- Remote Level Control (Bass Knob)
- Remote Level Control Cable
- Mounting Hardware (screws)
- User Manual
4. Product Overview
4.1. Amplifier Terminals
Image 1: Rear view of the SoundXtreme ST-1550.1 Monoblock Amplifier, illustrating the power input terminals (+12V, REM, GND), dual fuses, and speaker output terminals.
4.2. Amplifier Controls
Image 2: Front view of the SoundXtreme ST-1550.1 Monoblock Amplifier, displaying the RCA line inputs and outputs, gain control, Subsonic Filter (SSF), phase switch, Bass Crossover (LPF), Bass Boost, and the remote level control port.
The ST-1550.1 features chrome-plated RCA connectors, variable gain control, and LED indicators for power and protection status. Its compact design allows for flexible installation in various vehicle types.
5. Setup and Installation
Proper installation is crucial for optimal performance and safety. If you are unsure about any part of the installation process, consult a professional car audio installer.
5.1. Mounting the Amplifier
- Choose a mounting location that is dry, well-ventilated, and secure. Avoid areas exposed to direct sunlight, excessive heat, or moisture.
- Ensure sufficient airflow around the amplifier for cooling.
- Use the provided mounting hardware to securely fasten the amplifier to a solid surface in your vehicle.
5.2. Wiring Connections
Before making any connections, disconnect the negative (-) terminal of your vehicle's battery.
5.2.1. Power (BATT +12V) Connection
- Run a heavy gauge power cable (e.g., 4 AWG or larger) directly from the positive (+) terminal of the vehicle's battery to the amplifier's +12V terminal.
- Install an in-line fuse holder with a fuse (rated appropriately for the amplifier's power output, typically 60-80A) within 18 inches (45 cm) of the battery.
5.2.2. Ground (GND) Connection
- Connect a heavy gauge ground cable (same gauge as power cable) from the amplifier's GND terminal to a clean, unpainted metal surface of the vehicle's chassis.
- Ensure the ground connection is as short as possible (ideally less than 3 feet or 1 meter) and free of paint, rust, or dirt for a solid electrical connection.
5.2.3. Remote (REM) Turn-On Connection
- Connect a smaller gauge wire (e.g., 18 AWG) from the amplifier's REM terminal to the remote turn-on output of your head unit or a switched +12V source.
- This connection turns the amplifier on and off with your head unit.
5.2.4. RCA Input Connection
- Connect RCA cables from the pre-amp output of your head unit to the LINE INPUT RCA jacks on the amplifier.
- For optimal sound quality, route RCA cables away from power cables to minimize noise.
5.2.5. Speaker Output Connection
- Connect your subwoofer(s) to the SPEAKER output terminals on the amplifier.
- Ensure correct polarity (+ to + and - to -) for all speaker connections.
- The ST-1550.1 is stable at 1 Ohm, 2 Ohm, and 4 Ohm loads. Verify your subwoofer's impedance and wiring configuration to match the amplifier's capabilities.
5.2.6. Remote Level Control Connection
- Plug the remote level control cable into the BASS CONTROL/REMOCON port on the amplifier and mount the remote control in an accessible location for the driver.
6. Operating Instructions
Once all connections are made and verified, reconnect the vehicle's negative battery terminal.
6.1. Initial Power-Up
- Turn on your head unit. The amplifier's POWER LED should illuminate, indicating it is receiving power and is operational.
- If the PROTECTION LED illuminates, refer to the Troubleshooting section.
6.2. Adjusting Controls
- GAIN Control: This matches the amplifier's input sensitivity to the output level of your head unit. Start with the gain set to minimum. Play a familiar track at about 75% of your head unit's maximum volume. Slowly increase the amplifier's gain until you hear distortion, then back off slightly.
- LPF (Low Pass Filter): This control sets the upper frequency limit for the amplifier's output, typically used for subwoofers. Adjust it between 50 Hz and 250 Hz to blend with your main speakers.
- SSF (Subsonic Filter): This filter removes ultra-low frequencies that are inaudible and can waste amplifier power or damage subwoofers. Set it to a frequency below your LPF setting, typically around 20-30 Hz.
- PHASE Switch: This switch (0° or 180°) helps to align the phase of the subwoofer with the rest of your audio system. Experiment with both settings to find the one that provides the most impactful bass.
- BASS BOOST: This control provides an adjustable bass equalization boost at a specific frequency. Use sparingly to avoid distortion and potential speaker damage.
- Remote Level Control: This allows for convenient adjustment of the subwoofer output level from the driver's seat without accessing the amplifier directly.
7. Maintenance
Regular maintenance ensures the longevity and performance of your amplifier.
- Cleaning: Periodically wipe the amplifier's exterior with a soft, dry cloth. Do not use harsh chemicals or abrasive cleaners. Ensure ventilation openings are free from dust and debris.
- Connection Checks: Annually, or if you notice performance issues, check all power, ground, remote, and speaker connections for tightness and corrosion. Loose connections can cause power loss or intermittent operation.
- Fuse Replacement: The amplifier is protected by internal fuses. If a fuse blows, the amplifier will not power on. Replace blown fuses only with fuses of the exact same type and rating (e.g., 25A ATC fuses). Using an incorrect fuse can cause serious damage or fire.
8. Troubleshooting
If you experience problems with your amplifier, consult this section before contacting support.
| Symptom | Possible Cause | Solution |
|---|---|---|
| No Power (POWER LED off) | Blown fuse; Loose power/ground/remote connection; Faulty head unit remote output. | Check and replace fuses; Verify all power, ground, and remote wire connections are secure; Test head unit remote output. |
| Protection Mode (PROTECTION LED on) | Speaker short circuit; Overheating; Low impedance load; DC offset. | Check speaker wiring for shorts; Ensure proper ventilation; Verify speaker impedance is within amplifier's stable range (1-4 Ohm); Disconnect speakers and test for DC offset. |
| No Sound Output | RCA cables disconnected/faulty; Gain set too low; Speaker wires disconnected; Head unit volume too low. | Check RCA connections; Adjust gain control; Verify speaker wire connections; Increase head unit volume. |
| Distorted Sound | Gain set too high; Improper LPF/Bass Boost settings; Poor ground connection; Damaged speakers. | Reduce gain; Adjust LPF/Bass Boost; Verify ground connection; Inspect speakers for damage. |
| Engine Noise/Whine | Poor grounding; RCA cables routed near power wires; Faulty RCA cables. | Improve ground connection; Reroute RCA cables away from power wires; Try different RCA cables. |
9. Specifications
The following table outlines the technical specifications for the SoundXtreme ST-1550.1 Monoblock Amplifier:
| Feature | Specification |
|---|---|
| Model | ST-1550.1 |
| Output Power | 1550 Watts (Max) |
| Class | AB |
| Stable Impedance | 1 Ohm, 2 Ohm, 4 Ohm |
| Number of Channels | 1 (Monoblock) |
| Signal-to-Noise Ratio (S/N) | > 70 dB |
| Input Sensitivity | 200mV - 6V |
| Input Impedance | 22k Ohms |
| Low Pass Filter (LPF) | 50 Hz ~ 250 Hz |
| Frequency Response | 10 Hz ~ 30 kHz |
| Voltage | 6 Volts (Operating Range) |
| Dimensions (L×W×H) | 9.5 x 2.5 x 10.5 inches (Product) / 10 x 2.5 x 9 inches (Item) |
| Item Weight | 6 Pounds |
| Mounting Type | Freestanding |
| UPC | 701160333600 |
10. Warranty Information
SoundXtreme products are designed and manufactured to the highest quality standards. This amplifier is covered by a manufacturer's warranty against defects in materials and workmanship. The specific terms and duration of the warranty may vary by region and retailer. Please retain your proof of purchase for warranty claims. For detailed warranty information, refer to the warranty card included with your product or contact your authorized SoundXtreme dealer.
11. Support
If you have any questions or require technical assistance beyond the scope of this manual, please contact your authorized SoundXtreme dealer or visit the official SoundXtreme website for support resources.