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JL Audio MHX280/4 4 Channel Class D Full Range Marine Amplifier

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JL Audio MHX280/4 4 Channel Class D Full Range Marine Amplifier

In stock
  • Perfect for Marine and Powersport Applications
  • High Power in a Small Footprint
  • NexD™ Switching Technology

JL Audio MHX280/4

4-Channel Class D Full-Range Marine Amplifier SKU 98403

Engineered specifically for limited-space marine applications, the 4-channel MHX280/4 amplifier employs our high-speed NexD™ switching design to deliver lots of clean power, while being kind to small charging systems. Its ultra-compact, cast aluminum chassis is highly resistant to corrosion, with an IPX6 water-resistance rating, making it ideal for applications where moisture would prohibit use of a conventional 12V amplifier.

Delivering a solid 50W x 4 into 4 ohms (14.4V, 1% THD), the MHX280/4 is fully bridgeable, so it can be used as a 3-channel amplifier, or as a 2-channel amplifier producing a potent 140W x 2 into 4 ohms.

Other features include independent front and rear crossovers with selectable full-range, high-pass or low-pass filter controls and a dual-range input section that accepts a wide range of input voltage levels, from line-level all the way to high-power speaker level signals.

This marine amplifier features a white powder-coated finish, a gasketed cover for the controls and stainless steel hardware for durability in the marine environment.


NexD™ Switching Technology

NexD™ amplifier technologies produce exceptional audio quality, unsurpassed total efficiency and high power from very compact amplifier designs.

Detailed Information:

Beginning with the original 'Slash' subwoofer amplifiers, JL Audio has been at the forefront of Class D amplifier design. Today, our flagship Single-Cycle Control™ technology sets the ultimate standard for Class D amplifier performance. The NexD™ amplifiers may be a bit less complex, more compact and more affordable, but they flow from the same minds that have set the trend in mobile amplifier technology for over a decade.

Let's get a little nerdy... A traditional PWM switching amp design uses a fixed switching frequency and varies the pulse width based solely on the audio input signal to the pulse modulator. This basic approach assumes some ideal conditions, like a rock-steady power supply, that do not necessarily occur in a real, in-car installation. Power supply sag with signal causes distortion at all power levels with these designs, even well below clipping. The cure for this is feedback (a corrective signal sent back to the input side), but this becomes impractical as the audio frequency increases, making it a good solution for band-limited (subwoofer) amps, but not for full-range amplifiers.

Taking the above into account when designing the NexD™ subwoofer amplifiers, we have taken the simple fixed PWM approach and enhanced it with a very high switching frequency: 240 kHz, which is about 4x higher than most Class D subwoofer amplifiers. This pushes the amplifier's bandwidth to at least 500 Hz with minimal distortion and improves efficiency, while keeping typically bulky circuity more compact. Your subwoofers will reward you with tight, rock-solid bass performance.

For the full-range NexD™ amplifiers and channels we applied a variable, ultra-high speed version of the NexD™ technology (switching at well over 400 kHz). In these designs, a self-oscillating modulator with "feed-forward" sends information about the instantaneous power supply voltage to the modulator, combining this with the input signal to cancel out any distortion due to supply voltage fluctuation. This reduces distortion prior to applying feedback, simplifying the overall feedback loop design.

The bottom line is simply great audio: clean, powerful and reliable.


Rated Continuous (RMS) Power @ 14.4 V

  • @ 4 Ω 50 W RMS x 4
  • @ 2 Ω 70 W RMS x 4
  • Bridged @ 4Ω 140 W RMS x 2

Rated Continuous (RMS) Power @ 12.5 V

  • @ 4 Ω 36 W RMS x 4
  • @ 2 Ω 52 W RMS x 4
  • Bridged @ 4Ω 100 W RMS x 2

General Specifications

  • Frequency Response 20 Hz - 20 kHz (+0, -1dB)
  • S/N Ratio, referred to highest rated power >89.5 dB below rated power (A-weighted, 20 Hz - 20 kHz noise bandwidth)
  • S/N Ratio, referred to 1 W >70.5 dB (A-weighted, 20 Hz - 20 kHz noise bandwidth)
  • Damping Factor @ 4 Ω >60 / 50 Hz
  • Damping Factor @ 2 Ω >30 / 50 Hz
  • THD+N @ Rated Power <1% @ 2 Ω per Ch.
  • Input Voltage Range @ RCA Inputs Switchable from 250 mV - 4 V RMS (Low) to 750 mV - 15 V RMS (High)
  • Min Copper Power / Ground Wire Gauge 8 AWG wire
  • Fuse Rating 35 A (AFS, AGU or MaxiFuse™)

Signal Processing

  • Filter Modes Low-Pass or High-Pass
  • Filter Slope (dB/Octave) 12dB
  • Filter Frequency Range 35-300 Hz
  • Detented, Calibrated Filter Freq. Potentiometers Yes
  • Filter Defeatable? Yes
  • Remote Level Control No
  • Remote Level Modes N/A
  • Channel Input Mode Switch Yes (2/3/4 ch.)

Physical Specifications

  • Height (H) 1.77 in / 45 mm
  • Width (W) 8.66 in / 220 mm
  • Depth (D) 3.09 in / 78.5 mm
  • Net Weight 3.18 lb / 1.44 kg
More Information
Product Name JL Audio MHX280/4 4 Channel Class D Full Range Marine Amplifier
Manufacturer JLAudio
Manufacturer's Warranty 2 Year Manufacture's Warranty
Manufacture's Warranty 2 N/A
UPC 699440984034
Manufacturer Sku 98403