1. Overview
The Scosche SLC4 is a 4-channel line output converter designed to seamlessly integrate aftermarket amplifiers with your vehicle's factory stereo system. It converts high-level speaker signals into low-level RCA outputs, allowing for the addition of external amplifiers for enhanced audio performance without replacing the factory head unit. This adapter is ideal for upgrading your car audio system with subwoofers or additional speakers while maintaining the original vehicle aesthetics and functionality.
Image: The Scosche SLC4 4-Channel Line Output Converter unit, showing its compact design and input/output connections.
2. Product Features
- Unmatched Versatility: Compatible with a wide range of car audio systems, offering flexible installation options for converting speaker wires to RCA line-level signals or adding an aftermarket radio.
- Seamless Integration: Integrates factory stereo with an aftermarket amplifier, boosting car audio performance without complex rewiring. Can also be used to add an aftermarket radio while retaining factory amplifiers (e.g., JBL or Bose).
- Enhanced Audio Experience: Delivers crisp and clear sound quality for subwoofers and other speakers, ideal for audiophiles seeking high-fidelity sound.
- Compact and Durable Design: Engineered by Scosche for durability, fitting easily into tight spaces.
- Optimal Signal Quality: Designed to minimize signal interference and deliver clean, powerful sound, ensuring maximum audio performance.
3. Package Contents
The Scosche SLC4 package typically includes:
- Scosche SLC4 4-Channel Line Output Converter Unit
- Wiring Harness (integrated with the unit)
- Installation Hardware (e.g., connectors, mounting screws)
4. Installation Guide
4.1 Safety Precautions
- Disconnect the vehicle's battery before starting any electrical work.
- Ensure all connections are secure and properly insulated to prevent short circuits.
- Consult your vehicle's wiring diagram for accurate speaker wire identification.
- Do not overtighten screws on the unit.
4.2 Wiring Diagrams
Refer to the following illustrations for specific wiring configurations:
Illustration A: High to Low Level Converter
Connect speaker wires from the head unit to the SLC4 as shown. Ensure each wire is secure and do not overtighten.
Diagram showing how to connect the SLC4 as a standard high-to-low level converter, converting speaker outputs from a car stereo to RCA outputs for an amplifier.
Illustration B: Signal Tap Method for Adding Subwoofers
If you wish to add an amplifier to an existing system to power subwoofers, tap onto speaker wires from the existing unit. Do not cut existing wires. Ensure each wire is secure and do not overtighten.
Diagram illustrating the signal tap method for integrating the SLC4 to add subwoofers to an existing car stereo system.
Illustration C: Common Ground Adapter
Connect only positive speaker wires from the head unit to the SLC4 as shown. Do not connect negative speaker wires from the head unit. Ensure each wire is secure. A "common ground system" uses a single ground point for all speakers. This type of system is found on older vehicles (e.g., 1968-1995 Fords). To determine if you have a common ground system, check if your factory stereo has four (4) speaker wires or less than eight (8) speaker wires.
Diagram for connecting the SLC4 as a common ground adapter, suitable for older vehicle audio systems.
Illustration D: Factory Amplifier Interface (Premium/JBL/Bose Systems)
Connect speaker wires from the head unit to the SLC4 as shown. Ensure each wire is secure. These instructions are for most systems. Some Ford Premium Sound or Delco Bose common ground systems may require using the 'Common Ground' or 'Line Out' switch position.
Diagram for interfacing the SLC4 with factory premium amplifier systems like JBL or Bose.
4.3 Step-by-Step Installation
- Identify Speaker Wires: Locate the speaker output wires from your factory head unit or factory amplifier. These are typically color-coded.
- Connect High-Level Inputs: Connect the vehicle's speaker wires to the corresponding high-level input terminals on the SLC4 unit. Ensure correct polarity (positive to positive, negative to negative).
- Connect RCA Outputs: Connect RCA cables from the SLC4's RCA output jacks to the RCA input jacks on your aftermarket amplifier.
- Connect Remote Turn-On Wire: The SLC4 includes a remote turn-on wire (typically blue). Connect this wire to the remote input of your aftermarket amplifier. This will turn on the amplifier when the head unit is powered on.
- Ground Connection: Connect the ground wire from the SLC4 (if applicable, usually a black wire) to a suitable chassis ground point in the vehicle.
- Power Connection: Connect the power wire from the SLC4 (if applicable, usually a red wire) to a switched 12V power source.
4.4 Installation Video
Video: An official Scosche product video demonstrating the installation and features of the SLC4 Line Output Converter.
Video: A Scosche seller video demonstrating the installation process for a 2-channel line output converter, which shares similar wiring principles with the SLC4.
Video: A product summary video from a Scosche seller, showcasing the features and basic connections of a 2-channel line output converter.
5. Operation
The Scosche SLC4 features independent gain adjustments for each channel to match the output level of your factory stereo to the input sensitivity of your aftermarket amplifier. This ensures optimal sound quality and prevents distortion.
Image: Close-up of the Scosche SLC4 showing the line out gain adjustment screws for each channel.
Adjusting Gain Levels:
- Turn the gain controls on the SLC4 to their minimum (fully counter-clockwise) position.
- Turn on your car stereo and play a music track with a strong, consistent signal at about 75% of maximum volume.
- Slowly increase the gain controls on the SLC4 until you hear any distortion, then back off slightly.
- Fine-tune the gain controls on your aftermarket amplifier according to its instructions to achieve the desired volume and sound quality without distortion.
6. Maintenance
The Scosche SLC4 is designed for durability and requires minimal maintenance. Keep the unit free from dust and moisture. Periodically check all wiring connections to ensure they remain secure. Avoid exposing the unit to extreme temperatures or direct sunlight for prolonged periods.
7. Troubleshooting
- No Sound:
- Check all wiring connections, especially power, ground, remote, and speaker inputs/RCA outputs.
- Ensure the car stereo is powered on and playing audio.
- Verify the aftermarket amplifier is powered on (check its power indicator light).
- Confirm gain levels on both the SLC4 and the amplifier are not set too low.
- Distorted Sound:
- Reduce the gain levels on the SLC4 and/or the aftermarket amplifier.
- Ensure the car stereo volume is not set too high, causing distortion before the signal reaches the SLC4.
- Check for loose or corroded wiring connections.
- Engine Noise/Whining:
- Ensure the SLC4 and amplifier have a solid, clean ground connection.
- Check for proper routing of power cables away from RCA and speaker cables to prevent interference.
- If using a common ground system, ensure it is correctly configured as per Illustration C.
- Vehicle Battery Drain:
- Verify the remote turn-on wire is correctly connected to a switched 12V source that turns off with the vehicle's ignition. An improperly wired remote can keep the amplifier on, draining the battery.
8. Specifications
| Feature | Detail |
|---|---|
| Product Dimensions | 1.25 x 4.38 x 11.38 inches; 5.71 ounces |
| Item Model Number | SC-SLC4-4CH |
| Voltage | 14.4 Volts |
| Maximum Supply Voltage | 14.4 Volts |
| Mounting Type | Surface Mount |
9. Warranty and Support
The Scosche SLC4 Line Output Converter is backed by Scosche's Lifetime Tech Support and a Limited Warranty. For technical assistance or warranty claims, please contact Scosche customer service.
For more information, visit the official Scosche Store on Amazon.
