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JL Audio XD400/4

400W 4-Channel Class D XD Series Full-Range Car Amplifier

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List price $449.95

$365.95

with warranty

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Quality, Efficiency, and Convenience with JL Audio XD Amplifiers

JL Audio's XD400/4 4-channel XD series amplifier encompasses high quality at an affordable price. When JL Audio sets out to make an affordable amplifier the one thing that you can bet they will not do is compromise on quality and performance. XD amplifiers feature NexD Class D Technology, that reduces distortion and increases efficiency. The use of an Advanced Rollback Protection system will allow the XD amplifiers to maintain both thermal and low-impedance protection by either limiting available peak voltage when overheating or rolling back peak voltage when low impedance is presented at the outputs. In order to minimize engine whine or alternator noise, XD amplifiers feature differential-balanced inputs that eliminate voltage sensitivity between one input terminal and ground thus reducing the occurrence of interference. In addition to all these great technologies, XD amplifiers also feature a relatively small chassis, making them easily mountable in any vehicle without extraneous hassle. When looking for a space-saving amplifier loaded with the latest technologies and unsurpassed quality and performance, then look no further than JL Audio's XD series car amplifiers.

  • XD Series 4-Channel Class D Car Amplifier
  • RMS Power Rating (14.4V):
    • 4 ohms: 75 watts x 4 chan.
    • 2 ohms: 100 watts x 4 chan.
    • Bridged, 8 ohms: 150 watts x 2 chan.
    • Bridged, 4 ohms: 200 watts x 2 chan.
  • RMS Power Rating (12.5V):
    • 4 ohms: 60 watts x 4 chan.
    • 2 ohms: 90 watts x 4 chan.
    • Bridged, 8 ohms: 120 watts x 2 chan.
    • Bridged, 4 ohms: 180 watts x 2 chan.
  • Unregulated MOSFET switching type power supply
  • NexD Ultra-High Speed Class D topology
  • Wired JL Audio HD-RLC remote level control sold separately
  • LED power (green) and protect (red/yellow) indicators
  • Independent input sensitivity controls
  • State-of-the-art microelectronic components
  • 4/3/2 channel operation
  • Advanced Thermal Rollback System completely eliminates annoying thermal shut-down events
  • Studio-grade signal processing with fully variable crossover filters
  • Extruded aluminum alloy system setting security cover
  • Total amplifier efficiencies exceeding 80%
  • Noise-killing, highly flexible differential-balanced inputs
  • Preamp RCA outputs to daisy chain multiple amps
  • 3-Way System Protection circuitry (thermal, overload, and speaker short protection)
  • Heavy duty compact unitary cast alloy heat sink for extreme heat dissipation
  • Silver-plated RCA level inputs
  • Silver-plated screw terminals
  • Input sensitivity:
    • Level: 100mV-4V
  • Variable high-pass filter (50-500 Hz, 12 dB/octave Butterworth)
  • Variable low-pass filter (50-500 Hz, 12 dB/octave Butterworth)
  • Damping factor: >150 @ 4 ohms per chan./ 50Hz
  • Frequency response: 12-22,000 Hz
  • Dimensions: 8-1/2"L x 7-1/16"W x 2-1/16"H
  • 8-gauge power and ground wiring is required for installation. Contact us for information regarding a discount on select amplifier kits when purchased together with this amplifier.
  • 1-year Sonic Electronix warranty

Product History:

JL Audio XD400/4V2 thumbnail
(newest, current model)
JL Audio XD400/4 thumbnail
(previous model, replaced by JL Audio XD400/4V2)

Power Specifications - Full Range Channels

RMS Power @ 4 ohms

The RMS power rating is the measure of continuous power that an amplifier can output, or a speaker can handle. It is the most accurate depiction of real, continuous power that the industry has so far.

If the final impedance of your speakers or subwoofers equals 4 ohms, this is how much power this amplifier will supply at that ohm level. The higher the RMS wattage, the more clean and loud your music will sound.

75 watts x 4 channels
RMS Power @ 2 ohms

The RMS power rating is the measure of continuous power that an amplifier can output, or a speaker can handle. It is the most accurate depiction of real, continuous power that the industry has so far.

If the final impedance of your speakers or subwoofers equals 2 ohms, this is how much power this amplifier will supply at that ohm level. The higher the RMS wattage, the more clean and loud your music will sound.

100 watts x 4 channels
Bridged RMS Power

Bridging refers to combining two channels on an amplifier to create one channel with double the voltage and an increased power output. A 2-channel amplifier will bridge down to 1-channel and a 4-channel amplifier can bridge to create 2-channels. An amplifier is most commonly bridged to drive a subwoofer.

Remember, once you bridge two channels down to one its final impedance will be 4 ohms unless otherwise specified. This rating lists the RMS power created once an amplifier is bridged.

200 watts x 2 channels

Amplifier Specifications

Amplifier Series
This designates the series of the amplifier. Many amps are available in a litany of different wattage and channel configurations, but maintain consistent features throughout the product line.
XD (JL Audio)
Amplifier Class

An amplifier increases the power of the signal being fed to it by taking energy from its power supply and matching the signal but increasing its amplitude. Amplifiers use many different methods for converting these electrical signals and have been categorized into classes.

Class A/B: Greater than 50% of the input signal is amplified while the other percentage is “off”. These amplifiers have a small amount of current flowing through the output transistors all the time which almost eliminates crossover distortion. Class A/B has great sound quality but is not as efficient as class D. These amps are most commonly used to drive speakers.

Class D: Also known as switching amplifiers, class D amps have output transistors that are completely turned “on” or “off”. This means that when the transistors are on, there is almost no voltage across them but when they are off there is significant voltage but no current flowing through it which makes these amplifiers very efficient at the cost of sound quality. These amps are most commonly used to drive subwoofers.

Other Classes: You may see classes such as GH, bD, X, FD, etc. by some manufactures. These amplifiers tend to be either class A/B, D or a hybrid of the two but with improvements to their designs that can make them more efficient or offer better sound quality.

D
Number of Channels
Each channel on an amplifier will power one speaker using a positive and negative cable. There are various types of amplifiers, each designed to power a certain number of speakers. Monoblock amplifiers, also known as single channel, are designed to power one or more subwoofers. These amplifiers often have very high power ratings. On the other hand, multi-channel amplifiers power multiple speakers, usually at lower power ratings. 2-Channel and 4-Channel amplifiers can power car speakers or low powered subwoofers. Occasionally you might see a 5 or 6-channel amplifier that can power speakers and subwoofers at the same time. The most common setup is a monoblock amp to run subwoofers and a 4-channel amp to run door speakers. Check out our Knowledge Base for more information.
4
Total RMS Power Output
Total RMS power is measured by multiplying RMS power per channel by the number of channels, and is calculated at the lowest level of operating impedance.

RMS power is the amount of continuous power, measured in watts, that an amplifier produces is called RMS power. The higher the RMS figure, the louder and cleaner your music sounds.

The RMS output figure is much more accurate than the peak rating when comparing products.

400 watts
Maximum Input Gauge Size
This is the largest gauge wire that will fit into the power and ground terminals of this device. The lower the gauge number, the thicker the wire is. For example, a 4 gauge wire is thicker than an 8 gauge wire and thus has higher current carrying capacity. Always do your best to get this size wire to reduce the risk of damage to your components.
8 AWG
Minimum Impedance Unbridged
The lowest impedance the amplifier will handle when it is not bridged.
2 ohms
Minimum Impedance Bridged
The lowest impedance the amplifier will handle when it is bridged.
4 ohms
THD at Rated RMS Power
The amount of change in harmonic content of the signal as it is amplified. A lower figure indicates less change and a more accurate amp. THD below 0.10% is inaudible.
1.0%
Speaker Level Inputs
Speaker level inputs are commonly referred to as high-level inputs and vice versa. This input type allows you to get your audio signal directly from the speaker wire in your vehicle, instead of using RCA cables. The advantage of this is factory integration, as most stock radios do not have RCA outputs to run amplifiers.
No
Preamp Outputs
Many amplifiers are equipped with RCA preamp outputs which pass the original music signal from the source to additional amplifiers. This is known as daisy chaining because the source connects to the first amp, and the first amp connects to the second amp, etc. The advantage to daisy chaining is you only need one 2-channel RCA cable to transfer the signal from the head-unit to the amplifier, and then one additional cable for each amp being daisy chained.
1 pair
Built-in Crossover

A crossover is a type of filtering system that permits only certain frequencies to play. A Low-Pass (LP) crossover allows only frequencies below its setting to get through which is good in the case of some subwoofers. A High-Pass(HP) filter allows frequencies above its setting to pass through, this is normally used on speakers.

When a crossover is set to FULL it means no filtering is added and the full frequency spectrum is allowed through the amplifier. Filtering is important because feeding a speaker frequencies it cannot reproduce effectively creates distortion.

Low-pass (LP)
High-pass (HP)
High-Pass Crossover Frequency
The high-pass crossover frequency can be a fixed crossover point or a variable crossover range. A variable high-pass crossover allows you to select a specific crossover point which allows frequencies above the set crossover point to pass, while making frequencies below the set point gently or harshly roll-off, depending on the steepness of the slope.

The steepness of the roll-off slope is measured in dB/octave and refers to the rate of attenuation (lowering of volume) outside their pass bands.

50 - 500 Hz
Low-Pass Crossover Frequency
The low-pass crossover frequency is typically used for subwoofers. It can be a fixed crossover point or a variable crossover range. A variable low-pass crossover allows you to select a specific crossover point which allows frequencies below the set crossover point to pass, while making frequencies above the set point gently or harshly roll-off, depending on the steepness of the slope.

The steepness of the roll-off slope is measured in dB/octave and refers to the rate of attenuation (lowering of volume) outside their pass bands.

50 - 500 Hz
Signal-to-Noise Ratio
This spec compares the strength of the signal to the level of background noise. A higher value indicates less background noise.
>104 dB
Bass/Gain Remote
If the amp comes with a bass/gain remote you will be able to control the level of your bass from your dashboard. Typically bass remotes also include a 16-20 ft. wire for installation.
Optional (Accessory required and sold separately)
Fan Cooled
A great feature to have if an amp generates a large amount of heat. Cooling fans can help regulate the temperature to prevent the amp from overheating (burning).
No
Fuse Rating
The amperage and the number of fuse(s) an amp requires.
40A x 1 
CEA-2006 Compliant
Amplifiers that have been tested to meet specific standards. When a car amplifier meets these standards, you can be sure that it will be able to produce the amount of power specified by the official CEA-2006 rating. Usually, these rating consist of the following items:
  • RMS Power
  • Signal-to-Noise Ratio

This rating applies to both external car amplifiers, as well as the amplifiers inside of in-dash stereos.

No

Warranty and Return Policy

Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider
Sonic Electronix

Summary of Customer Ratings & Reviews

Rating Distribution

5 Star
92%
4 Star
8%
3 Star
0%
2 Star
0%
1 Star
0%

Average Attribution Rating

Durability
5.0
Value
4.4
Features
4.8
Design
5.0
Usability
5.0
jose

mayra leon

Overall
Durability
Value
Features
Design
Usability
very nice amp sound clean

May 5, 2014

Very good amp small and sounds clean

0 of 0 found this helpful

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Max

mcallen, TX

Overall
Durability
Value
Features
Design
Usability
Amazing Amp

April 23, 2014

I am impressed with the power of this amp, I had two amplifiers rockford fosgate for focal's access and Poliglass, also for a couple of subwoofers jl Audio 12W1, and really did not know what kind of brands buy it. I decided to buy this amp but I was afraid if that brand was I'm looking for. I have a surprise, it's pretty good and quite practical, and has a power that leave me very satisfied

0 of 0 found this helpful

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thomas

EL PASO, TX

Overall
Durability
Value
Features
Design
Usability
love it

October 18, 2013

i have been experimenting with different amps over the past few years and i think this is the one. the small size and efficiency are great and the output is exactly what i have been looking for i have tried lower and higher power this is a good match for me i have no complaints

0 of 0 found this helpful

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Cody

Dalton, Ga

Overall
Durability
Value
Features
Design
Usability
AMAZING Amp!

May 19, 2013

Upgraded from an MB Quart 4.80 to this amp, the difference is night and day. Twice the price DOES mean twice the amp in this case! Aside from the power, and the sound quality achievable with this amp, the build quality is second to none. It has a good bit of weight for an amp as small as it is, and the gain & filter knobs are very well made and easy to adjust. Powering Focal access series 6.5" components in the front with Rockford Power series 3-way 6x9's in the back and i couldnt be happier!

0 of 0 found this helpful

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Jared

Atlanta, GA

Overall
Durability
Value
Features
Design
Usability
This Thing Rules!

April 21, 2013

This amp is compact, powerful, stays cool, and is very, very efficient. Hook any set of speakers up to this and it will drive them hard with beautiful, clean sound. This unit may be expensive, but you get what you pay for!

0 of 0 found this helpful

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Robert

Casper, WY

Overall
Durability
Value
Features
Design
Usability
Quality Product

February 20, 2013

I purchased this amp to replace the factory amp in my 2012 Camaro. The instructions were very easy to follow and clearly stated. The amp has performed flawlessly in the 6 months I have used it. The sound quality is very good, especially for an amp in this price range. I would highly recommend the JL Audio XD400/4 to anyone looking for a quality amp at a great price.

0 of 0 found this helpful

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HD GLIDE

Chicago, il

Overall
Durability
Value
Features
Design
Usability
awesome purchase

September 2, 2012

This amp rocks! Its makes my 2 tweeters, 2 6-1/2 and 2 6x9s sound very clear.

0 of 0 found this helpful

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ROAD GLIDE

IL

Overall
Durability
Value
Features
Design
Usability
JL AUDIO AMP!

August 30, 2012

This amp performs great. I have it connected to 2 6x9; 2 6 1/4; and two tweeters which pumps out awesome result with clarity on the vocals and the music tracks. I'm thinking of upgrading to the 600 series because I want to add a woofer for more drop in the bass.

0 of 0 found this helpful

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Zach

Australia

Overall
Durability
Value
Features
Design
Usability
JL XD400/4

July 1, 2012

Once again JL has lived up to its reputation for providing quality audio products that I can see lasting for many years. When you spend this amount of money on audio gear you don't want it to last a short period of time then fail and you definitely don't want a flop in terms of reproduction quality. If you have come in search for a good quality, compact, and feature rich little amplifier then you have selected the right product.

0 of 0 found this helpful

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Guy w/stereo

Chanute, KS

Overall
Durability
Value
Features
Design
Usability
Right Amp, Right Size

May 14, 2012

Connected this unit to a couple pair of 6.5 components in my crew cab pick up. Sounds great. Replaced an RF Prime xd400.4 that smoked out in about 5 minutes under the same load. This amp was more, but well worth it. Thanks JL Audio and Sonic.

0 of 0 found this helpful

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Ben

Chanute, KS

Overall
Durability
Value
Features
Design
Usability
Blessing in disquise

May 11, 2012

I hooked this unit up to my 6.5" components in a 4 channel / 4ohm configuration and was not disappointed in any way. Spend the extra $120 and buy this amp over the competitors. Money well spent in my opinion. I first bought a RF Prime 400w D-class unit that fried in a matter of minutes at 3/4 volume. Thank god it failed because I bought this one instead. Blessing in disquise! Pros: Sleek look, easy to install, crossover dial detents (awesome!), small size w/big sound. Cons: Absolutly none that I can think of.

0 of 0 found this helpful

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Reggie

Birmingham, AL

Overall
Durability
Value
Features
Design
Usability
Awesome

April 5, 2011

This is an awesome affordable amp. The ouput of this amp is unbelievable. I compared this to the Alpine PDX4.1 and let me tell you this thing is worth the money and out performs the others. Great amp JL Audio. You out did yourself this time.

0 of 0 found this helpful

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michael

Canada

Overall
Durability
Value
Features
Design
Usability
Awesome. Perfectly replaces OEM JEEP JK AMP IN DASH

February 9, 2011

Perfect !

0 of 0 found this helpful

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Accessory Tools and Products

Accessories added

NVX XKIT84 4-Channel 8-Gauge Wiring Kit

In case you didn't know, NVX has top notch wire and this kit has everything you need!

Your Price $69.99

Kicker PK8 8-Gauge Wiring Kit

Great wire for your awesome new amp! Don't forget the RCA's!

Your Price $29.95

NVX XBG3PK 1/0 Gauge OFC Big 3 Upgrade Kit

Comes with everything you need to upgrade your power and ground wire.

Your Price $59.99

Kicker Big 3 Package 1/0 Gauge Big 3 Upgrade Kit

Get all you need including wire cutters to upgrade your power and ground wire.

Your Price $151.99

Belva BBG3KT CCA 1/0 Gauge Big Three Kit

Features everything needed to upgrade factory power and ground wire.

Your Price $39.99

JL Audio HD-RLC

Remote Level Control for Select JL Audio Amplifiers

Your Price $34.95

StreetWires FB4

4 AWG / 4 Gauge Firewall Bushing

Your Price $6.95

NVX XDBU4 - Top of the Line!

Distribution Block with Two 1/0 or 4 AWG Inputs and Four 4 or 8 AWG Outputs

Your Price $17.99

NVX XIV45 4-Channel RCA Audio Interconnect Cable

5 Meters (16.4 ft.) 4-Channel RCA Audio Interconnect Cable with Dual Twisted Pair Hyper-Flex Technology

Your Price $23.99

NVX XIX45 X-Series RCA Interconnect Cable

16.4 ft. of 4-Channel X-Series RCA Cable with Dual Twisted Pair Hyper-Flex Technology

Your Price $34.99

StreetWires ZN9 Series Interconnect Cable

16.4 ft. of 4-Channel RCA Cable with Rhodium-plated contacts and ZeroNoise construction for clear signal transfer!

Your Price $99.95

Kicker 4-Channel RCA Audio Interconnect Cable

4 Meters (13 ft.) 4-Channel K-Series RCA Audio Interconnect Cable

Your Price $19.95

NVX XWS1225 12 AWG Speaker Wire

25 ft. of True 12 Gauge 100% Copper EnvyFlex Speaker Cable/Wire

Your Price $39.99

NVX XWS1250 Speaker Wire

50 ft. of True 12 Gauge 100% Copper EnvyFlex Speaker Cable/Wire

Your Price $29.99

Belva BBSW167 16 AWG Speaker Wire

16 Gauge 7 Meter (23 Ft) Speaker Wire (CCA)

Your Price $12.99

The Install Bay IB-CAP1F

True 1.0 Farad Car Audio Capacitor for up to 1000W Max

Your Price $37.99

e2 ECAP1 by Scosche - Mid-Level 1 Farad

Digital 1.0 Farad Car Audio Capacitor for up to 1000W Max

Your Price $49.99

Rockford Fosgate RFC1D - Top of the Line 1 Farad

Digital 1.0 Farad Car Audio Capacitor for up to 1000W Max

Your Price $99.99

Scosche SPL Meter SPL1000F

Handheld boomSTICK measures your SPL range from 60 to 135 dB

Your Price $21.99

XIX2025 Strapping RCA

0.25 Meter (0.86 ft) Hyper-Flex RCA cable w/ Serpentine-Cut Nickel Plated Connectors

Your Price $12.99

Product Summary

Manufacturer

Model Number

XD400/4

UPC

699440982610

Weight

5.50lbs

Internal SKU

xd4004

Internal Product ID

26843

Sonic Electronix Wiring Guide

Wiring Diagram Legend

Warning: The image depicted shows the resistance change when wiring multiple subwoofer terminals. Please refer to your subwoofer's owner's manual for the proper wiring of its terminals. Sonic Electronix, Inc. is not responsible for damage caused to your audio system or vehicle due to improper installation. Please call tech support at 1-877-289-7664 if you require additional assistance.

Product Name: JL Audio XD400/4