JL Audio RD400/4 4-Channel Class D Full-Range Amplifier 400W

The JL Audio RD400/4 is engineered to deliver impressive full-range performance from a remarkably compact chassis. Using JL Audio’s advanced NexD™ high-speed switching technology, this amplifier produces clean, powerful output with outstanding efficiency and minimal heat, making it ideal for space-restricted installations. It generates 100 watts per channel at 2 ohms (14.4 V, 1% THD) and is fully bridgeable, allowing flexible configurations including 200 W x2 at 4 ohms or a powerful 3-channel setup.

All controls are positioned on the top panel beneath a protective cover, while power and signal connections are neatly arranged along one side of the chassis for installer convenience. Studio-grade signal processing includes defeatable 12 dB/octave high-pass or low-pass filters for each channel pair, with continuously variable cutoff frequencies from 50–500 Hz. Dual-range, differential-balanced inputs ensure compatibility with both factory and aftermarket head units, and automatic turn-on simplifies OEM integration.

The RD400/4 also features onboard LED clipping indicators, allowing fast and accurate gain setting without special equipment. Integrated preamp outputs make it easy to expand your system, while the durable black powder-coated finish and top-mounted dual-colour LED status light complete a robust, professional-grade design.