JL Audio RD400/4

400W RMS RD-Series NexD 4-Channel Class-D Amplifier

JL Audio
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• 75 Watts RMS x 4 @ 4 ohms
• 100 Watts RMS x 4 @ 2 ohms
• Total Peak Power: 800 Watts
• Variable Bass Boost: 0 to +12 dB bass boost at 45 Hz
• Heavy duty aluminum alloy heat-sink
• 7"W x 9-3/16"L x 2-1/8"H

Learn more about the rd4004
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Purchase a qualifying amplifier and save 50% on an NVX XKIT44 True Gauge OFC amplifier installation kit. Simply click the "Add Both to Cart" button. This offer cannot be combined with any other coupons or offers.

JL Audio RD400/4

50% off

Priced separately $489 98

Promo Savings of $55 00

Total price:

$434 98

Product Highlights

• 75 Watts RMS x 4 @ 4 ohms
• 100 Watts RMS x 4 @ 2 ohms
• Total Peak Power: 800 Watts
• Variable Bass Boost: 0 to +12 dB bass boost at 45 Hz
• Heavy duty aluminum alloy heat-sink
• 7"W x 9-3/16"L x 2-1/8"H


JL Audio

Authorized dealer

General Features:

  • JL Audio RD-Series RD400/4
  • Class-D 4-Channel Amplifier
  • RMS Power Rating:
    • 4 ohms: 75 watts x 4 chan.
    • 2 ohms: 100 watts x 4 chan.
    • 1 ohm: ------------N/A------------
    • Bridged, 4 ohms: 200 watts x 2 chan
  • Total power output: 800 watts
  • NexD™ Technology delivers outstanding sound quality, efficiency and reliability
  • LED clipping indicators
  • Pulse Width Modulated MOSFET power supply
  • LED power (green) and protect (red) indicators
  • Soft start turn-on
  • DC Offset-Sensing and Signal-Sensing (auto-on)
    • Designed for high-level (speaker level) signals, not for lowlevel (preamp level) signals.
    • The circuit senses the input signal from CH. 1 only.
  • Mono channel operation
  • Speaker-level (high-level) inputs
  • Bridging switch for each channel pair
  • Preamp RCA outputs to daisy chain multiple amps
  • 3-way protection circuitry (thermal, overload, and speaker short protection)
  • Dual speaker terminals simplify the hookup of multiple speakers
  • Heavy duty aluminum alloy heat-sink for extreme heat dissipation
  • Input sensitivity:
    • Low level: 200mV - 2V
    • High level: 800mV - 8V
  • Frequency Response: 12 - 22,000Hz
  • Total Harmonic Distortion (THD): <1%
  • Variable low-pass filter: 50 - 500 Hz, 12 dB/octave
  • Variable high-pass filter: 50 - 500 Hz, 12 dB/octave
  • Low-Pass Slope (dB/octave): 12 dB/octave
  • Variable Bass Boost: 0 to +12 dB bass boost at 45 Hz
  • Fuse Rating: 40 A x 1
  • 4-8 gauge power and ground wiring is recommended for installation. Contact us for information regarding a discount on select amplifier kits from our website when purchased together with this amplifier. Click Here for our contact information.
  • Dimensions: 7"W x 9-3/16"L x 2-1/8"H
  • Authorized Internet Dealer
  • 1-year Manufacturer's Warranty

Check out the JL Audio Class-D 4-Channel RD400/4 Owner's Manual

Product history:

JL Audio RD400/4 thumbnail
(newest, current model)
JL Audio JX400/4D thumbnail
(previous model, replaced by JL Audio RD400/4)
JL Audio JX360/4 thumbnail
(previous model, replaced by JL Audio JX400/4D)

Specifications & Details

Power Specifications - Full Range Channels
RMS Power @ 4 ohms
75 watts x 4 channel
RMS Power @ 2 ohms
100 watts x 4 channel
Bridged RMS Power
200 watts x 2 channel
Amplifier Specifications
RD Series
Marine Certified
Amplifier Class
Number of Channels
Total Peak Power Output
800 watts
Total RMS Power Output
400 watts
Maximum Input Gauge Size
Minimum Impedance Unbridged
2 ohms
Minimum Impedance Bridged
4 ohms
Frequency Response
12 - 22,000 Hz
THD at Rated RMS Power
Speaker Level Inputs
Preamp Outputs
1 pair
Built-in Crossover
Low-Pass (LP)
High-Pass (HP)
High-Pass Crossover Frequency
50 - 500 Hz
Low-Pass Crossover Frequency
50 - 500 Hz
Signal-to-Noise Ratio
84 dB
Channel Separation
12 dB
Bass Boost
0 - 12 dB
Remote bass/level controller
Optional (Accessory required and sold separately)
Fan Cooled
Fuse Rating
40A x 1 
Total Fuse Rating
CEA-2031 Compliant
Sonic Certified Amplifier
Not Tested
Amp Bluetooth Connectivity
Hi-Res Certified
What is in the box?
User manual
WITB: Amplifiers
Other Accessory #6
Warranty and Return Policy
Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider

Item Details


Model Number:




Internal SKU:


Internal Product ID:


Product and How-to Videos

  • JL Audio RD Series Car Amplifiers | Clipping LED Demonstration | CES 2017
  • JL Audio RD Amplifier Product Spotlight
  • How To Install an Amplifier: Car Amplifier Basics Part 2

Customer Ratings & Reviews

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Great Deal on a great product

I could not be happier with this amp. True quality from top to bottom. The sound is fantastic. I used this as a full range four channel amp to drive four kicker speakers. It gets its signal from the factory Nissan HU which is a very low quality HU in my opinion. I decided to try to keep the factory HU due to the factory steering wheel controls, bluetooth and stock look for theft deterrent appearance. I found the front channels on the HU clipped out way early compared to the rear when setting up the amp. So i switched the amp to 2 channel input / four channel output the set it up with the clip lights ....and perfection! What a great feature. I am very happy.

By Gerry on March 16, 2017 checkmarkIcon Verified purchase


found this helpful.

JL Audio Class-D 4-Channel RD400/4

Great prices on great equipment and Fast delivery thanx sonic

By Anonymous on March 6, 2019 checkmarkIcon Verified purchase


found this helpful.

Great Product

Pros: Easy to install, all the needed features, underrated.


By Dustin on February 8, 2018 checkmarkIcon Verified purchase


found this helpful.

Open box saved me $70

JL lives up to their reputation again. Replaced my kicker 4 channel with this amp. A smaller footprint operates at a cooler temperature, and all of the wirings is on one side for cleaner wire installation.

By Christopher on January 24, 2021 checkmarkIcon Verified purchase


found this helpful.

Excellent app at a great price. Fast delivery also!

I needed the amp I bought quickly and Sonic Electronix was the only company that had it in stock and at the right price.

Great amp, shipped fast. 100% satisfied.

By David on August 7, 2020 checkmarkIcon Verified purchase


found this helpful.


Very good sound quality amp and small enough to put under the seats

By Anonymous on March 30, 2019 checkmarkIcon Verified purchase


found this helpful.

JL Audio Class-D 4-Channel RD400/4

I would recommend this amp it sounds so clean!!!! I have it running 4 6.5 Phoenix gold coaxal speakers I have had this amp for 6 months and works perfectly.

By Anonymous on December 14, 2018


found this helpful.


Very pleased so far.. sounds just as my amp that I replaced.. easily installed, with a very small space required for installation... don't know about durability yet.. but we will see.. for the $$ and power/size ratio I would recommend this amp to anybody.. JL makes some of the best

By Marc on September 24, 2017


found this helpful.

Sounds good for the money

Using this in conjunction with an RD1500 in a regular cab Silverado. Not yet installed but it is running on my test bench on a set of Kicker's bookshelf demo speakers. Good, clean sound and plenty of power while running in 2 channel mode.

Shipping and customer service experience was not what I expected; both were slower than promised. Product is great.

By Ryan on November 24, 2021 checkmarkIcon Verified purchase


found this helpful.

Excellent price Great power

This amp was a great price and I love the convenience in size. I replaced my factory amp and the Boston acoustic speakers now sound like high-end audio. Very easy to install and with the new clipping feature I have no issues. Will be buying another soon.

By Christopher on March 19, 2020 checkmarkIcon Verified purchase


found this helpful.


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