Gravity GR300.4 4-Channel Class AB Car Amplifier

The Gravity GR300.4 is a four-channel Class AB car audio amplifier designed to add dedicated amplification to an upgraded speaker system. It can be used for front and rear door speakers, component speakers, or other full-range drivers in a 12-volt vehicle audio system. With four amplified channels, it offers a practical route beyond factory head-unit power.

This amplifier is rated for up to 300 watts per channel at 2 ohms and up to 150 watts per channel at 4 ohms, both specified at 1% THD. Its 2-ohm stereo stability gives installers flexibility when matching compatible speakers to the amplifier. The Class AB design is intended for full-range system applications where controlled, clean output is important.

Variable high-pass and low-pass crossover controls help tailor the frequency range sent to connected speakers. The high-pass filter adjusts from 80 Hz to 1.2 kHz, while the low-pass filter adjusts from 50 Hz to 250 Hz. A variable bass boost of up to +12 dB at 50 Hz provides an additional tuning option when system design calls for more low-frequency emphasis.

The GR300.4 supports line-level and speaker-level inputs, allowing it to work with many aftermarket and factory-source systems. It also supports bridgeable and tri-mode operation for compatible system layouts. An included remote level-control knob provides a convenient way to adjust the assigned bass level from the listening position.

Protection circuitry helps safeguard the amplifier against overload, thermal, and short-circuit conditions. Soft-start and muting functions are designed to reduce turn-on noise, while status indicators assist with system monitoring. The compact chassis can be integrated into a variety of vehicle installations when mounted with adequate ventilation and secure wiring.

Key Features

• Four-Channel Class AB Design: Powers a full front-and-rear speaker arrangement from one amplifier.
• 2-Ohm Stereo Stability: Supports compatible 2-ohm or 4-ohm stereo speaker loads.
• Variable Crossovers: Lets installers direct appropriate frequencies to connected speakers.
• Bass Boost Control: Adds up to +12 dB at 50 Hz.
• Flexible Input Options: Accepts line-level and speaker-level audio signals.
• Integrated Protection: Helps protect against overload, heat, and short circuits.

Design & Installation

The GR300.4 uses a compact amplifier chassis with chrome-plated RCA, power, and speaker terminals. Its Class AB circuit design includes high-current dual discrete drive stages, a MOSFET PWM power supply, soft-start operation, muting, and power/protection indicators. These features support dependable daily use when the amplifier is installed and configured correctly.

Use this amplifier in a negative-ground 12-volt vehicle electrical system and mount it securely in a dry, ventilated location. Match speaker wiring to the supported 2-ohm or 4-ohm stereo loads, set crossover points for the speakers being used, and connect either line-level or speaker-level inputs as appropriate for the source unit. The package includes the amplifier, remote bass control, and user manual.