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JL Audio XD400/4

4-channel car amplifier — 75 watts RMS x 4 (New Stock)

21 Reviews | 1 question - 1 answer

Item # 136XD4004

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Overview

Our take on the JL Audio XD400/4

Each JL Audio XD amp packs a wallop far beyond what you'd expect from something so small. This super-compact amp plays your music with true fidelity and impressive impact, without straining your car's electrical system. A cast alloy heatsink and an advanced cooling system keep these amps at optimal temperature, eliminating thermal shut-downs so your music keeps going strong without interruption.

Each JL Audio XD amp packs a wallop far beyond what you'd expect from something so small. This super-compact amp plays your music with true fidelity and impressive impact, without straining your car's electrical system. A cast alloy heatsink and an advanced cooling system keep these amps at optimal temperature, eliminating thermal shut-downs so your music keeps going strong without interruption.

The JL Audio XD400/4 4-channel amp can deliver 75 watts RMS per channel to 2 pairs of speakers, or it can drive a full set of separate tweeters and woofers with its four channels. You can even bridge the XD400/4 into 2-channel mode to power a couple of subs with 200 watts each. High- and low-pass filters give you intimate control over the character of your sound.

"Differential-balanced" inputs keep the signals clear of outside noise, and allow you to connect this amp to just about any in-dash stereo, even a factory radio with no preamp outputs. An optional wired remote lets you tweak the level from your front seat.

Swampy out a pair of crappy amps for a pair of these and it like a whole new world. Fantastic sound and with bass volume knob it is perfect. Incredible sound.

Mike, Valley stream , ny

What's in the Box:

  • 4-Channel class-D amplifier
  • Hex-key
  • JL Audio emblem
  • Owner's Manual

Product Highlights:

  • 4-channel car amplifier
  • 75 watts RMS x 4 at 4 ohms (100 watts RMS x 4 at 2 ohms)
  • 200 watts RMS x 2 bridged at 4 ohms (4-ohm stable bridged)
  • variable low- and high-pass filters (50-500 Hz, 12 dB/octave)
  • optional wired remote for level control
  • Class D amplifier design with NextD™ switching amp technology
  • differential-balanced inputs eliminate noise coming from your vehicle's electrical system
  • Advanced Rollback Protection System prevents thermal shut-down
  • speaker- and preamp-level inputs (speaker-level input requires an optional adapter)
  • preamp outputs
  • 4-gauge power and ground leads and a 40-amp fuse recommended — wiring and hardware not included with amplifier
  • no onboard fuses — when installing multiple amps in a system, an additional 40-amp in-line fuse between the distribution block and the amplifier is recommended
  • 8-1/2"W x 2"H x 7-3/8"D
  • warranty: 2 years
  • Our 60-day money-back guarantee
Reviews

JL Audio XD400/4 Reviews

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(21 Reviews)
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Details

Hands-on research

Product Research

Features
Controls
Connections

Features

4-Channel Full-Range Amplifier: The JL Audio XD400/4 is a four-channel, full-range audio amplifier utilizing NexD ultra-high speed switching technology to deliver outstanding fidelity and efficiency. The XD400/4 can be operated with a wide variety of source units and system configuration.

Amplifier Rating: The JL Audio XD400/4 Class D 4-channel amplifier is rated at 75 Watts RMS x 4-channels in 4-ohm at 20 to 20,000Hz with a signal-to-noise-ratio of 104 dB and a total harmonic distortion of 1% while receiving 14.4 Volts.

NexD Class D Technology: NexD is a state-of-the-art switching amplifier design that combines exceptional audio quality with excellent efficiency and less complexity. This results in an affordable compact amplification with exceptional audio quality and unsurpassed total efficiency.

Advanced Rollback Protection: The XD-Series amplifiers employ advanced thermal and low-impedance protection to virtually eliminate annoying amplifier shut-down events. Should any XD-Series amplifier ever overheat, its intelligent, unregulated power supply reacts by limiting available peak voltage until the amplifier returns to a safe temperature range. Likewise, if an impedance lower than optimal for the amplifier is present at the outputs, the XD amplifier will roll back peak voltage to protect itself without shutting down.

Differential-Balanced Inputs: The JL Audio amplifier features differential-balanced input architecture to effectively control noise and ensure compatibility with a wide variety of source units, including many OEM systems. Without resorting to line output converters, you can directly connect most OEM source units to the JL Audio amplifier without creating any noise or compatibility issues. Unlike conventional single-ended inputs, the differential-balanced design does not connect one side of the audio signal to chassis ground. This eliminates any voltage sensitivity between one input terminal and ground and greatly reduces the incidence of alternator whine in a typical car audio installation.

Note: You will need two speaker wire to RCA adaptors (136XDCLR2S, sold separately) to connect this amplifier to your headunit via speaker-level.

Protection Circuitry With Status Indicator Lights: There is a single multi-color LED on the top panel of the amplifier to indicate the amplifier's operating status.

  • Flashing Green: When the LED is flashing green, the amplifier is powering up and audio output is muted.
  • Constant Green: This LED lights green to indicate that the amplifier is turned on and operating normally.
  • Constant Red: This Red LED lights to indicate that the amplifier has exceeded its safe operating temperature, putting the amplifier into a self-protection mode, which reduces the power output of the amplifier. The red light will shut off and the amplifier will return to normal, full-power operating mode if the heat sink temperature drops back to a safe level.
  • Constant Amber (Yellow): The Amber (Yellow) LED light indicates that an over-current condition has occurred and is accompanied by a muting of the amplifier's output. Over-current condition can be caused by a speaker inpedance lower than the optimum load impedance range for the amplifier or a short-circuit in the speaker wiring.
  • LED Off: The only condition that will shut down an undamaged XD400/4 completely is if battery voltage or remote turn-on voltage drops below 10-volts. The amplifier will turn back on when voltage climbs back above 11-volts.

Cooling System: The outer shell of the JL Audio amplifier is designed to remove heat from the amplifier circuitry. For optimum cooling performance, this outer shell should be exposed to as large a volume of air as possible.  Enclosing the amplifier in a small, poorly ventilated chamber can lead to excessive heat build-up and degraded performance.

Controls

Control Panel Cover: The XD400/4 features a Control Panel Security Cover which protects and hides the amplifier's controls. When installed, the cover ensures that the amplifier's settings are not accidentally changed while creating a clean aesthetic look for the amplifier and your installation. The control panel security cover is pre-installed at the factory and must be temporarily removed for access the amplifier's controls. The security cover is secured by two 2.5mm hex-head screws.

Simplified Gain Setting: The XD Series amplifier makes setting the gain level of the amp via the input sensitivity control very simple. All you need is Digital AC Voltmeter (142TK12V, sold separately) and a Test CD Disc (503CD104, sold separately) with a sine-wave test-tone recorded at 0 dB reference level in the frequency range to be amplified for that set of channels (50 Hz for subwoofer channels, 1 kHz for a midrange application).

Note: The XD400/4 is equipped with a independent gain controls for the Front (1&2) and Rear (3&4) channels.

Flexible Input Section And Active Crossover Network: The JL Audio XD amplifier provides a flexible input section and a comprehensive crossover network to fine tune your system effectively and accurately. The variable filter design employed in the JL Audio XD amplifier crossover sections allow you to seamlessly switch slopes, easily change filter frequencies and address what frequencies the preamp inputs will pass. The XD400/4 offers the following independent crossover adjustments for the front and rear channels along the unit's top panel, behind a removal cover plate.

  • Input Mode: This switch allows operation of all four amplifier channels with only one pair of input signals (2-CH Input Mode) or with independent front and rear input signal pairs (4-CH Input Mode). You will only need to connect the front RCA inputs when placing the amplifier in 2-CH input mode.
  • Filter Mode: The amplifier allows you to select either a Low Pass, High Pass or Full-Range operation of the amplifier's 1 & 2 channels and 3 & 4 channels.
  • Variable Frequency: You can set the amplifier's Low Pass or High Pass crossover from 50 to 200 Hz for channels 1 & 2 and channels 3 & 4.

Connections

Power/Ground/Turn-On Terminals: The amplifier features set-screw terminals for the power, ground, and remote turn-on connections.

  • Power and Ground: The JL Audio amplifier's set-screw Power and Ground connections are designed to accept 8 to 4 AWG power wire. A 2.5mm hex-wrench is supplied for making connections.
  • Remote Turn-On: The JL Audio XD amplifier's set-screw turn-on lead will accept 18 to 8 AWG wire. The same 2.5mm hex-wrench is supplied for making connection.

Note: The Amplifier is not equipped with a fuse. An external 40-amp AFS, AGU, or MAXI fuse (not included) must be installed on the power wire. If a wiring kit is used which includes a fuse with a value other than 40-amps, the original should be replaced with a 40-amp fuse

Speaker Output Terminals: The XD400/4 amplifier's eight set-screw speaker terminals will accept 16 to 8 AWG speaker wire. A 2.5mm hex-wrench is supplied for making connections.

Preamp Inputs: The amplifier features two sets of differential-balanced RCA jack inputs. The amplifier features a dedicated Input Sensitivity gain control for the front and rear channels of the amplifier. These controls are designed to match the input sensitivity of the XD400/4 to the specific signal source that is feeding it. The amplifier's input level can be set independently for the front and rear channels between 100mV-4V.

Preamp Outputs: The XD400/4 incorporates a pass-through preamp output sections, so that additional amplifiers can easily be connected to the same signal(s) feeding the XD400/4. These preamp output signals are buffered to prevent noise and are always preamp level, regardless of the level of signals feeding the XD400/4's inputs. The amplifier's set of preamp outputs can be configured two different ways.

  • Front (1&2): The preamp output delivers the same signals that is connected to the XD400/4's front RCA inputs. This mode is useful for feeding a subwoofer amplifier when the XD400/4 is being used to drive front and rear speaker system. In this mode, the preamp output level will track with the signal level of the front input signals, allowing you to fade the rear channels in and out, without affecting the subwoofer level.
  • Sum (F+R): This mode delivers a sum of the signals being fed to the front and rear RCA inputs of the amplifier. When the XD400/4 is being used to drive front and rear speaker systems, this preamp output mode will deliver a summed front/rear signal to the subwoofer amplifier, while permitting fading of the front and rear speaker system from the source unit.

Remote Level Control: The amplifier features a standard telephone connector for adding an optional wired remote level control. With the addition of the optional wired Remote Level Control (136HDRLC, sold separately), you can control the volume of one or both channel pairs of the XD400/4 form the front of your vehicle. This is useful for subwoofer level control or even as a master volume control for your system. If desired, multiple XD amplifiers can be controlled from a single HD-RLC controller using a simple phone line splitter and multiple phone cables (all sold separately).

Note: All inputs and outputs are located on the rear side of the amplifier to make installation of the amplifier simple and neat.

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1 question already asked

If you purchased the product from Crutchfield, feel free to contact our Tech Support team. They can walk you through the settings on the product and see if there may be a fix. Our toll-free Tech Support number is printed on your invoice, and is also available under the "My Orders" tab in the "My Account" section of our website. If you did not purchase the unit from Crutchfield, then you may want to contact the manufacturer. You can also post your question in our forums: http://community.crutchfield.com. Or try our online support center: http://crutchfield.custhelp.com/app/answers/list/kw/. [ Krissy  Mar 30, 2014 ]  Staff
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