Gravity GBR250-4D Compact 4-Channel Digital Amplifier

The Gravity GBR250-4D is a micro ultra-compact, four-channel full-range digital amplifier for adding external power where installation space is limited. It is rated for 360 watts RMS and uses RCA stereo inputs for connection with compatible source units. Its small footprint makes it a practical option for compact mobile-audio installations.

This amplifier is designed for stereo front-and-rear speaker systems in cars, motorcycles, RVs, ATVs, boats, and similar applications. Four channels allow it to power separate front and rear speaker pairs from one amplifier. It can also be configured in bridged operation for a two-channel setup when the connected speakers meet the stated load requirement.

The GBR250-4D is stable at 2-ohm and 4-ohm loads, providing 90 watts RMS per channel at 2 ohms. In bridged operation, it is rated at 180 watts RMS by two channels at 4 ohms. These published ratings help match the amplifier to compatible speaker wiring and power-handling needs.

Selectable low-pass, full-range, and high-pass crossover modes provide basic system-tuning flexibility. High-pass filtering can be used for speaker channels, while low-pass filtering supports installations that require a lower-frequency signal path. Full-range mode leaves crossover selection open for systems using external processing or speaker-specific filtering.

Measuring 1.5 x 3.25 x 7.5 inches, the GBR250-4D is intended for installations where a conventional full-size amplifier may be difficult to place. It uses a surface-mount installation format and can fit into compact custom audio layouts. RCA stereo input compatibility makes it suitable for systems built around a source unit with RCA preamp outputs.

Key Features

• Four-Channel Design: Powers front and rear speaker channels from one compact amplifier.
• 360 Watts RMS: Provides the published total continuous power rating.
• 2-Ohm Stable: Supports compatible 2-ohm speaker loads.
• Bridgeable Channels: Enables two-channel operation at 4 ohms bridged.
• RCA Stereo Input: Connects with compatible RCA-equipped source units.
• Selectable Crossovers: Offers LPF, full-range, and HPF operating modes.

Design & Installation

The GBR250-4D uses a compact digital amplifier design with a published 1.5 x 3.25 x 7.5-inch size. The available technical information identifies it as a surface-mount amplifier, but does not specify the enclosure material. Its compact form is intended to help accommodate installations with limited available mounting space.

Install the amplifier on a secure mounting surface with access for power, ground, speaker wiring, and RCA signal cables. Use the RCA stereo input with a compatible source unit, and select LPF, full-range, or HPF mode to suit the connected channels. Confirm speaker impedance and wiring before use: the amplifier is rated for 90 watts RMS x 4 at 2 ohms or 180 watts RMS x 2 at 4 ohms bridged.