Gravity GR1300.1 1300W Monoblock Car Amplifier

The Gravity GR1300.1 is a single-channel car audio amplifier designed to power a subwoofer system. It provides a maximum rated output of 1300 watts at 2 ohms and is intended for drivers adding dedicated low-frequency reinforcement to a vehicle audio system. Its monoblock layout keeps the focus on bass-channel amplification rather than full-range speaker power.

This amplifier is suited to systems that need adjustable subwoofer output and flexible source integration. It accepts both line-level and speaker-level inputs, which supports installation with many aftermarket head units as well as systems using speaker-level signal connections. A wired remote bass control is included for convenient level adjustment from the listening position.

The GR1300.1 uses a Class AB amplifier design with a MOSFET PWM power supply and high-current dual discrete drive stages. Its variable low-pass crossover operates from 50 Hz to 250 Hz, allowing the subwoofer channel to be limited to an appropriate bass range. The frequency response is specified from 10 Hz to 250 Hz.

For bass tailoring, the amplifier includes an enhanced variable bass boost specified at up to +12 dB at 50 Hz. Input sensitivity is rated from 200 mV to 6 V, helping it accommodate a range of source-output levels. The amplifier is rated for 2-ohm operation and does not list a 1-ohm power rating.

The GR1300.1 can serve as the bass amplifier in a factory-system upgrade or a separate aftermarket subwoofer installation. Its 10.5 x 2.25 x 10.75-inch chassis is sized for installations where amplifier placement must be planned around available mounting space. Built-in overload, thermal, and short-circuit protection are included to help protect the amplifier during operation.

Key Features

• Monoblock Output: A dedicated single channel for powering a subwoofer system.
• 2-Ohm Stable Design: Supports compatible 2-ohm subwoofer wiring configurations.
• Variable Low-Pass Filter: Adjusts the bass passband from 50 Hz to 250 Hz.
• Remote Bass Control: Lets the user adjust subwoofer level conveniently.
• Flexible Signal Inputs: Accepts line-level and speaker-level input signals.
• Protection Circuitry: Includes overload, thermal, and short-circuit safeguards.

Design & Installation

The GR1300.1 combines a Class AB circuit platform, MOSFET PWM power supply, and high-current dual discrete drive stages. Chrome-plated RCA, power, and speaker terminals support the connection points, while soft-start, muting, and LED power/protection indication functions are built into the design. The compact chassis measures 10.5 inches wide, 2.25 inches high, and 10.75 inches deep.

Install the amplifier in a dry, securely mounted location with sufficient room for wiring and ventilation. Use it with a compatible 2-ohm or 4-ohm subwoofer load, connect either line-level or speaker-level signal input as appropriate, and set the low-pass crossover and bass boost to suit the subwoofer and enclosure. The amplifier operates from a negative-ground 12V DC vehicle electrical system and uses a 25A fuse rating.