Rockford Fosgate TM400X4ad 400W 4-Channel Marine Amplifier

The Rockford Fosgate TM400X4ad is a compact four-channel marine and powersports amplifier designed to add substantial, controlled power where installation space is limited. It delivers 100 watts RMS to each of four channels at either 4 or 2 ohms, making it suitable for powering full-range speakers in boats, motorcycles, side-by-sides, and other exposed applications. Its compact chassis helps simplify placement in locations where a conventional amplifier may not fit.

This amplifier is a practical choice for systems that need stronger speaker output without requiring a large multi-amplifier installation. Its Constant Power design maintains its rated 100-watt-per-channel output at 4- or 2-ohm stereo loads, which provides flexibility when selecting compatible speakers. It can also be bridged to run two channels at 200 watts RMS each into 4 ohms.

Rockford Fosgate uses proprietary Class-AD amplifier technology in the TM400X4ad for efficient full-range power delivery. The amplifier is dual-fan cooled and uses real-time thermal sensing to support operation under demanding conditions. A dual extruded-aluminum heat sink helps manage heat in its compact enclosure.

The TM400X4ad supports both low-level and high-level input signals, allowing it to integrate with aftermarket or factory-style source units. High-level input use enables the auto turn-on feature, while the 2/4-channel input switch can supply all four outputs from a two-channel source. C.L.E.A.N. input and output clip indicators assist with setting levels to help avoid distortion.

Built-in crossover and equalization controls help tailor the amplifier to a speaker system. Selectable high-pass, low-pass, and all-pass modes are paired with variable 50-250 Hz crossover points and 12 dB/octave Butterworth filtering. The Punch EQ provides adjustable bass and treble enhancement when appropriate for the installation and source material.

Key Features

• Four-Channel Constant Power: Delivers 100 watts RMS per channel at 4 or 2 ohms.
• Bridgeable Output: Supports two 200-watt RMS channels at 4 ohms bridged.
• Class-AD Topology: Provides efficient full-range amplification in a compact chassis.
• High-Level Auto Turn-On: Helps integrate with speaker-level factory audio signals.
• C.L.E.A.N. Clip Detection: Input and output indicators assist with accurate gain setup.
• Marine-Ready Circuit Protection: Epoxy-coated circuit boards resist demanding outdoor environments.

Design & Installation

The TM400X4ad uses a compact extruded-aluminum heat sink, dual cooling fans, and marine-grade two-part epoxy coating on its circuit boards. Top-mounted controls keep crossover, EQ, and level adjustments accessible after installation. Its chassis measures 1.6 inches high by 4.3 inches wide by 8.3 inches deep.

Use an 8 AWG power and ground connection, with a 60A fuse installed in the power wiring as specified. The amplifier accepts front and rear high- or low-level signals through its included input harnesses, and its two 4-pin speaker harnesses connect the front and rear speaker outputs. For a two-channel source, select 2-channel input mode; use 4-channel mode when separate front and rear signals are available.