NexD™ Switching Technology
NexD™ amplifier technologies produce exceptional audio quality, unsurpassed total efficiency and high power from very compact amplifier designs.
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.
Advanced Rollback Protection
JL Audio's exclusive Advanced Rollback Protection circuit monitors the amplifier's thermal condition and adjusts amplifier operation to eliminate annoying amplifier shut-down events.
Should a JL Audio amplifier equipped with Advanced Rollback Protection reach an unsafe operating temperature, a special circuit rolls back peak power output, without changing gain, until the amplifier cools down to a safe operating temperature. The red "Thermal" LED will light to indicate this condition has been reached. Once the amplifier cools down, the circuit restores full peak power output and the red "Thermal" indicator reverts to its normal state. The operation of Advanced Rollback Protection is inaudible in most cases, but it ensures that your music keeps on playing, even under the most demanding conditions.
v2 Spec (XD & M-Sereies Amplifiers)
An enhanced set of features added to XD and M-Series amplifiers that bear the "v2" designation make these models more versatile than ever.
Automatic Turn-On - Automatic turn-on detects a signal from virtually any audio source to turn on the amplifier. This feature gives the user greater flexibility in installations where the amplifier may be connected directly to a digital media players such as an iPhone or iPod. The amplifier will also turn on via the traditional remote turn-on lead from a switched +12 V power source from your head unit. Audio signal sensing from the amplifier's inputs or electrical signal sensing from the amplifier's remote lead... Automatic turn-on means you only have to concern yourself with hitting "play".
Dual-Range Differential Balanced Input Section - The realities of today's installations mean the input section of the amplifier could be connected to a variety of audio sources, which is precisely why the input section of the v2 Spec amplifiers has been intelligently designed to give the user maxium flexibilty. Whether your installation needs require connecting higher powered Speaker-Level Inputs or lower powered Line-Level Inputs, the amplifier will permit either and ensure the high fidelity amplifier output you've come to expect from JL Audio without the need for messy line-output converters and other devices.
SpecificationsRated Continuous (RMS) Power @ 14.4 V
- @ 4 Ω 400 W RMS x 1
- @ 3 Ω 500 W RMS x 1
- @ 2 Ω 600 W RMS x 1
- @ 1.5 Ω N/A
- @ 4 Ω 300 W RMS x 1
- @ 3 Ω 400 W RMS x 1
- @ 2 Ω 500 W RMS x 1
- @ 1.5 Ω N/A
- Frequency Response 7 Hz - 500 Hz (+0, -1dB)
- S/N Ratio, referred to highest rated power >87 dB below rated power (A-weighted, 20 Hz - 20 kHz noise bandwidth)
- S/N Ratio, referred to 1 W >67 dB (A-weighted, 20 Hz - 20 kHz noise bandwidth)
- Damping Factor @ 4 Ω >1000 / 50 Hz
- Damping Factor @ 2 Ω >500 / 50 Hz
- THD+N @ Rated Power <1% @ 2 Ω per Ch.
- Input Voltage Range @ RCA Inputs Switchable from 200 mV - 2 V RMS (Low) to 800 mV - 8 V RMS (High)
- Min Copper Power / Ground Wire Gauge 4 AWG wire
- Fuse Rating 50 A (AFS, AGU or MaxiFuse™)
- Filter Slope (dB/Octave) 12 dB or 24 dB
- Filter Frequency Range 50-500 Hz
- Detented, Calibrated Filter Freq. Potentiometer Yes
- Filter Defeatable? Yes
- Filter Modes Low-Pass only
- Pass-Through Preamp Output Buffered
- Bass Boost EQ No
- Output Polarity Switch No
- Remote Subwoofer Level Control Optional (HD-RLC)
- Remote Bass EQ Boost Control No
- Infrasonic Filter 30 Hz, defeatable
- Height (H) 2.05 in / 52 mm
- Width (W) 8.52 in / 216 mm
- Depth (D) 7.09 in / 180 mm
- Net Weight 6.3 lb / 2.86 kg