Hifonics A800.4D 4-Channel Car Amplifier

The Hifonics A800.4D is a compact four-channel car audio amplifier designed to add dedicated power to front and rear speakers or a mixed speaker-and-subwoofer system. Its full-range Super D-Class design supports conventional multi-speaker upgrades while keeping the amplifier package relatively compact. With four amplified channels and bridgeable operation, it offers flexible options for systems that need more output and tuning control than a factory or aftermarket receiver alone can provide.

Rated output is 4 x 100 watts at 4 ohms or 4 x 200 watts at 2 ohms, with two bridged channels rated at 400 watts each into 4 ohms. This makes it suited to powering compatible component speakers, coaxial speakers, or a combination of speakers and properly matched bridged loads. Its 10 Hz to 45 kHz frequency response supports full-range audio applications rather than subwoofer-only use.

The A800.4D uses Hifonics Ultra-Fi MOSFET output devices and a pulse-width-modulated Twin Turbo Coil power supply. Its Full Range Super D-Class topology is engineered for efficient operation, while the aluminum alloy heat sink helps move heat away from the amplifier circuitry. Surface-mount construction is also used to help the internal electronics tolerate vehicle vibration.

For system tuning, the amplifier includes Accu-Cross electronic crossover controls, selectable operating modes, and adjustable high-pass and low-pass filtering. A variable bass EQ provides 0 to 12 dB of boost centered at 45 Hz. These controls allow an installer to direct suitable frequency ranges to connected speakers or bridged channels without relying entirely on source-unit processing.

Installation flexibility includes RCA inputs as well as speaker-level audio inputs for integration with a wider range of source units. The amplifier can be activated by a conventional remote turn-on lead or by signal sensing through its high-level inputs. It is a practical choice for a vehicle audio upgrade when paired with correctly matched speakers, appropriate wiring, and an externally fused power connection.

Key Features

• Four-Channel Output: Powers up to four speakers or supports bridged channel pairs.
• Super D-Class Topology: Full-range amplifier design focused on efficient power delivery.
• Bridgeable Channels: Delivers up to 2 x 400 watts at 4 ohms.
• Accu-Cross Filtering: Adjustable crossover settings help match output to connected speakers.
• High-Level Inputs: Supports connection to compatible factory-style speaker outputs.
• Auto Turn-On: Signal sensing can eliminate a remote-wire connection in compatible systems.

Design & Installation

The A800.4D has a black compact chassis with a heavy-duty aluminum alloy heat sink, Ultra-Fi MOSFET output devices, and surface-mount internal construction. Nickel-plated RCA connectors and nickel-plated, high-temperature-resistant hex screw terminals are used for signal, power, ground, and speaker connections. LED diagnostic indicators monitor overload and speaker-short protection conditions.

Use 4 AWG cable at the 12-volt and ground terminals, connect speakers with wire compatible with the 18 AWG speaker terminals, and install an external fuse in the amplifier power wiring. Configure the input mode and crossover settings for the speaker layout being used, and use bridged operation only with a 4-ohm bridged load. The high-level input auto-turn-on function senses a 6-volt DC offset from compatible source units; otherwise, use the remote turn-on connection.