How To Bypass A Factory Amplifier

So, you're looking to upgrade your car's audio system. You've picked out a shiny new head unit and some killer speakers, ready to blast your favorite tunes with unparalleled clarity. But then you hit a snag: the dreaded factory amplifier. These amplifiers, often hidden away and integrated deep within the car's electrical system, can throw a major wrench into your upgrade plans. Bypassing them isn't always straightforward, but with a little knowledge and the right approach, it's definitely achievable. Let's dive into how to do it.

The Problem: Factory Amplifiers and the Aftermarket

Why do factory amplifiers cause so much trouble? Think of it like this: imagine trying to connect a modern, high-definition television to an old VCR. The VCR, in this analogy, is the factory amplifier. It's designed for a specific, often outdated, signal standard. Your new head unit, like the modern TV, outputs a different kind of signal – one the factory amp might not understand or be compatible with. This mismatch can lead to distorted sound, low volume, or even complete silence.

Factory amplifiers are often designed to work with specific impedance levels of the factory speakers. Aftermarket speakers, while offering superior sound quality, often have different impedance ratings. Connecting them directly to the factory amplifier can overload it, leading to damage or poor performance. Furthermore, many modern cars use complex infotainment systems where the amplifier is integrated with other functions like navigation, Bluetooth, and even safety features. Removing or disconnecting the amplifier without proper planning can disable these features, potentially causing significant issues. This is often made even more complex by the CAN-BUS (Controller Area Network) which modern cars use to transmit digital signals between different modules.

Understanding How Factory Amplifiers Work

Signal Flow and Impedance Matching

To effectively bypass a factory amplifier, you need to understand its role in the car's audio system. Typically, the signal flow goes something like this:

1. Head Unit: The source of the audio signal (radio, CD player, Bluetooth, etc.). It outputs a low-level signal, often referred to as a "pre-out" signal.
2. Factory Amplifier: Takes the low-level signal from the head unit and amplifies it to a higher power level suitable for driving the speakers.
3. Speakers: Convert the amplified electrical signal into audible sound.

The impedance of the speakers is a crucial factor. Impedance, measured in ohms, is the electrical resistance the speaker offers to the amplifier. Factory amplifiers are designed to work with a specific impedance range, typically 2 or 4 ohms. Using speakers with a different impedance can strain the amplifier and affect sound quality or damage the amp. Think of it like trying to force water through a pipe that's too narrow or too wide – it just doesn't work efficiently.

Types of Factory Amplifiers

Factory amplifiers come in various forms, and understanding the type you're dealing with is essential for choosing the right bypass method:

• External Amplifiers: These are separate units located in the trunk, under a seat, or behind the dashboard. They're often easier to identify and bypass.
• Integrated Amplifiers: These are built into the head unit itself. Bypassing them usually involves replacing the entire head unit.
• Fiber Optic Amplifiers: Some high-end vehicles use fiber optic cables to transmit audio signals between the head unit and the amplifier. Bypassing these systems requires special adapters or signal converters. MOST (Media Oriented Systems Transport) is a common fiber optic standard in the automotive industry.

Methods for Bypassing a Factory Amplifier

There are several ways to bypass a factory amplifier, each with its own set of advantages and disadvantages:

1. Running New Speaker Wires

This is the most straightforward method, especially if you're replacing both the head unit and the speakers. It involves disconnecting the factory amplifier and running new speaker wires directly from the new head unit to the speakers. This ensures a clean signal path and eliminates any potential compatibility issues with the factory amplifier.

Pros:

• Clean signal path
• Eliminates compatibility issues
• Allows for full control over the audio system

Cons:

• Requires more effort and wiring
• May involve removing interior panels

Use Case: Ideal when replacing both the head unit and the speakers, especially in older vehicles where the factory wiring may be degraded.

2. Using a Wiring Harness Adapter

Wiring harness adapters, also known as bypass harnesses, are designed to plug into the factory amplifier's wiring harness and provide a direct connection to the speakers. These adapters effectively "jump" over the amplifier, allowing the new head unit to directly power the speakers.

Pros:

• Relatively easy to install
• Minimizes the need for cutting and splicing wires
• Preserves the factory wiring harness

Cons:

• Requires finding the correct adapter for your specific vehicle
• May not be available for all vehicles
• Can be expensive for some models

Use Case: A good option for newer vehicles where preserving the factory wiring is desirable, and a compatible adapter is available.

3. Using a Line Output Converter (LOC)

A Line Output Converter (LOC) is a device that converts the amplified speaker-level output from the factory amplifier into a low-level RCA signal that can be used by an aftermarket amplifier. This allows you to retain the factory head unit and amplifier while adding an aftermarket amplifier for more power and better sound quality. You're not technically bypassing the factory amp, but you are using it in a way to integrate with an aftermarket system.

Pros:

• Allows you to retain the factory head unit
• Adds more power to your sound system

Cons:

• Technically not bypassing, factory amplifier is still in the circuit.
• Additional cost of LOC and aftermarket amplifier

Use Case: Used when retaining the factory head unit is a necessity, but more power and better sound are desired.

4. Replacing the Factory Amplifier

In some cases, you might choose to replace the factory amplifier with an aftermarket amplifier. This allows you to retain the factory head unit while upgrading the amplification system. This typically involves running new speaker wires and connecting the aftermarket amplifier to the factory head unit's output.

Pros:

• Preserves the factory head unit's functionality
• Provides a significant improvement in sound quality and power

Cons:

• Can be complex to install
• Requires careful wiring and configuration

Use Case: Ideal when you want to keep the factory head unit's features but need more power and better sound quality.

Manufacturer Examples and Specific Considerations

Different car manufacturers use different types of amplifiers and wiring configurations. For example:

• BMW: Often uses fiber optic amplifiers that require special adapters or signal converters to bypass.
• Mercedes-Benz: Similar to BMW, often incorporates fiber optic audio systems, making bypassing more complex.
• General Motors: Vehicles with the Bose audio system often have complex integration with the factory amplifier, requiring careful planning and specific bypass harnesses.
• Ford: Many Ford vehicles utilize the SYNC system, which integrates with the factory amplifier. Bypassing the amplifier may require specialized adapters or programming.

Before attempting to bypass a factory amplifier, it's crucial to research your specific vehicle and audio system. Online forums, vehicle-specific websites, and professional installers can provide valuable information and guidance.

Real-World Insights and Recommendations

Based on experience, here are some insights and recommendations for bypassing factory amplifiers:

• Plan carefully: Before you start, research your vehicle's audio system thoroughly. Understand the type of amplifier, wiring configuration, and any potential challenges.
• Use quality components: Invest in high-quality wiring, connectors, and adapters. This will ensure a reliable and long-lasting connection.
• Take your time: Bypassing a factory amplifier can be a complex task. Don't rush the process. Take your time to ensure that everything is wired correctly.
• Consider professional help: If you're not comfortable working with car electronics, consider hiring a professional installer. They have the experience and expertise to bypass the amplifier safely and effectively.
• Document your work: Take pictures of the wiring before you disconnect anything. This will help you reassemble everything correctly if you run into problems.

Bypassing a factory amplifier can be a challenging but rewarding project. By understanding the principles of audio systems, researching your specific vehicle, and following these recommendations, you can achieve a significant improvement in your car's audio system. Remember to prioritize safety and take your time to ensure a successful installation. With the right approach, you'll be blasting your tunes with crystal-clear sound in no time.