Hifonics BXX800.4 4-Channel Class AB Car Audio Amplifier

The Hifonics BXX800.4 is a four-channel Class AB car audio amplifier designed to add dedicated power to aftermarket speakers. It can be used to drive a full set of front and rear speakers, or configured in bridged pairs for higher-output applications. Its 2-ohm stereo stability provides flexibility when matching compatible speakers.

This amplifier is suited to vehicle owners upgrading beyond head-unit power and seeking more control over speaker output. It provides 100 watts RMS per channel at 4 ohms or 200 watts RMS per channel at 2 ohms. For bridged use, it is rated at 400 watts RMS per pair into 4 ohms.

The BXX800.4 uses a Class AB output stage with a MOSFET power supply and Ultra-Fi MOSFET output devices. This architecture is paired with an aluminum heat sink to help manage heat during operation. Three-way protection circuitry and illuminated status indicators assist with monitoring overload and speaker-short conditions.

Separate crossover controls for channel pairs 1/2 and 3/4 allow the amplifier to be tailored to full-range speakers, component systems, or selected bridged applications. Each channel pair offers selectable high-pass, full-range, and low-pass operation. Adjustable high-pass and low-pass filters, plus bass boost, support practical system tuning.

RCA inputs accommodate a compatible aftermarket receiver or other source with preamp outputs, while RCA outputs allow signal pass-through to another amplifier. A 2-channel or 4-channel input mode supports systems with either two or four input channels. This makes the BXX800.4 a practical foundation for a multi-speaker vehicle-audio upgrade.

Key Features

• Four-Channel Output: Powers four speakers or two bridged channel pairs.
• Class AB Design: Uses a Class AB amplifier topology and MOSFET circuitry.
• 2-Ohm Stereo Stability: Delivers up to 200 watts RMS per channel.
• Selectable Crossovers: Separately tunes channels 1/2 and 3/4.
• RCA Signal Connections: Includes RCA inputs and pass-through RCA outputs.
• Protection Monitoring: Uses protection circuitry with power and protect indicators.

Design & Installation

The BXX800.4 has an aluminum heat sink intended to reduce heat buildup, plus molded and angled connection areas for cable access. Nickel-plated RCA jacks are used for the low-level signal connections. LED power and protect indicators are located on the amplifier for basic system-status monitoring.

Install the amplifier in a secure, dry, ventilated location and use power and ground cable up to 4 AWG at its terminals. Speaker terminals accept wire up to 12 AWG, and the amplifier uses two onboard 25A fuses. Match speakers to the rated impedance, use a 4-ohm load for bridged channel pairs, and set gain and crossover controls after all wiring is complete.