PAC SNI-35 Variable Line Output Converter User Manual

1. Introduction

The PAC SNI-35 is an adjustable 2-channel line output converter designed to integrate an aftermarket amplifier into a vehicle's factory audio system. It converts speaker-level audio signals from a factory radio into a low-level RCA output signal, suitable for an aftermarket amplifier. This unit supports factory radios with 2 to 50 watts per channel and features transformer isolation for optimal sound quality and performance, maintaining correct audio phasing.

2. Product Features

• Adjustable Line Output Converter: Converts high-level speaker outputs to low-level RCA outputs.
• Wide Input Range: Accepts speaker level input from 2 to 50 watts per channel.
• Transformer Isolated: Provides noise isolation for clear audio output.
• Phase Adjusted: Ensures correct audio phasing for optimal sound.
• Linear Frequency Response: Delivers a linear 20Hz to 20,000Hz output based on the input signal.
• Variable Level Control: Allows adjustment of the output signal level to match amplifier input sensitivity.

3. Package Contents

The PAC SNI-35 package includes:

• PAC SNI-35 Line Output Converter unit
• Instruction Manual

4. Specifications

5. Setup and Installation

The PAC SNI-35 is designed for straightforward installation. Always ensure the vehicle's battery is disconnected before beginning any electrical work.

5.1 Wiring Connections

1. Identify Speaker Wires: Locate the speaker wires from your factory radio or amplifier that you intend to use as the input for the SNI-35. Typically, these are the wires leading to the rear speakers for subwoofer applications, or front speakers for full-range amplifier integration.
2. Connect Input Wires: The SNI-35 has a multi-colored wiring harness. Connect the speaker-level output wires from your factory system to the corresponding input wires on the SNI-35.
   • Red/White (Left Channel Positive)
   • Black/White (Left Channel Negative)
   • Red (Right Channel Positive)
   • Black (Right Channel Negative)
   Ensure correct polarity to maintain proper audio phasing.
3. Connect Ground Wire: Connect the brown wire from the SNI-35 to a reliable chassis ground point in the vehicle. A good ground connection is essential for noise-free operation.
4. Connect RCA Outputs: Plug standard RCA cables into the RCA output jacks on the SNI-35. These cables will then connect to the RCA input jacks on your aftermarket amplifier. The SNI-35 provides stereo RCA output.

5.2 Level Adjustment

The SNI-35 features two small adjustment potentiometers (pots) on the unit. These allow you to fine-tune the output level to match the input sensitivity of your aftermarket amplifier. This is crucial for preventing distortion and achieving optimal sound quality.

1. Start with the adjustment pots turned fully counter-clockwise (minimum output).
2. Turn on your factory radio and play a music source at a moderate volume (around 75% of maximum).
3. Slowly turn the adjustment pots clockwise until you hear clear, undistorted sound from your aftermarket amplifier. If you hear distortion, reduce the level slightly.
4. Adjust both pots equally for balanced left and right channel output.

It is recommended to set the amplifier's gain control to its minimum setting initially and then adjust it after setting the SNI-35's output levels.

6. Operating Instructions

Once properly installed and adjusted, the PAC SNI-35 operates automatically. It converts the speaker-level signal from your factory radio into a low-level signal for your amplifier whenever the radio is active. No further user interaction is typically required during normal operation.

If you notice any changes in sound quality or volume, re-check the level adjustments on the SNI-35 and your amplifier.

7. Troubleshooting

• No Sound:
  • Verify all wiring connections are secure and correct, especially the input speaker wires and RCA outputs.
  • Ensure the factory radio is powered on and producing sound.
  • Check the amplifier's power and settings.
  • Confirm the SNI-35's level adjustments are not set to minimum.
• Distorted Sound:
  • Reduce the level adjustments on the SNI-35.
  • Reduce the gain setting on your aftermarket amplifier.
  • Ensure the factory radio's volume is not excessively high, causing clipping before the SNI-35.
• Noise (Hiss, Whine, Buzz):
  • Ensure the SNI-35's brown ground wire is connected to a clean, solid chassis ground point.
  • Verify that RCA cables are routed away from power wires to prevent interference.
  • The SNI-35 features transformer isolation to help prevent ground loop noise. If noise persists, check all ground connections in the audio system.
• Unbalanced Sound (Left/Right):
  • Adjust the individual level pots on the SNI-35 to balance the left and right channels.
  • Check speaker wire polarity for correct connection.

8. Maintenance

The PAC SNI-35 requires minimal maintenance. Keep the unit free from dust and moisture. Do not expose it to extreme temperatures. Ensure all connections remain secure over time.

9. Warranty and Support

PAC products are designed for reliability. Please refer to the warranty information provided with your purchase for specific terms and conditions. Generally, the warranty does not cover product misuse.

For technical support or further assistance, please contact PAC customer service through their official website or the contact information provided in your product packaging.

10. Safety Information

• Always disconnect the vehicle's battery before installing or servicing any electrical components.
• Ensure all wiring is properly insulated and secured to prevent short circuits and damage.
• Do not install the unit in locations exposed to excessive heat, moisture, or direct sunlight.
• If you are unsure about any installation steps, consult a professional car audio installer.