Monoblock Class-D Subwoofer Amplifier:
The JL Audio XD300/1 is a monoblock amplifier utilizing JL Audio NexD high-speed
switching technology to deliver outstanding fidelity and efficiency. The XD300/1
can be operated with a wide variety of source units and system configurations.
Its frequency response is limited to the range below 1 kHz. Every aspect of its
operation has been optimized for low-frequency amplification.
Note: The XD300/1 is not designed for driving midrange speakers or tweeters.
Amplifier Rating: The JL Audio XD300/1 Class D monoblock, subwoofer amplifier is rated at
200 Watts RMS x 1 channel at
4-ohms (20 Hz to 20 kHz), Signal-to-Noise Ratio 100 dB, 1% THD, 14.4 Volts. At 2
ohms, the rated power is 300 Watts RMS.
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 affordable compact
amplification with superb sound quality.
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 a speaker wire to RCA adaptor (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
- 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 impedance lower than the
optimum load impedance range for the amplifier or a short-circuit in the
- LED Off: The only condition that will shut down an undamaged
XD300/1 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.
Control Panel Cover: The
XD300/1 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 to access the
amplifier's controls. The security cover is secured by two 2.5mm hex-head
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).
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 XD300/1 offers the
following independent crossover adjustments behind a removal cover plate:
- Switchable Slope on Low-pass filter: 12dB/octave Butterworth or
24dB/octave Linkwitz-Riley alignments allowing for more precise integration
of subwoofer and speaker channels.
- Variable Frequency: Fully-variable frequency selection from 50-500 Hz
for low-pass crossover.
Note: The amplifier's low-pass filter can be bypassed in order to
use an external active crossover in your car audio system. With the internal
crossover turned off, the XD300/1's upper frequency response is limited to
This JL Audio XD amplifier features screw clamp terminals for the power, ground, and remote
turn-on connections. A 2.5mm hex-wrench is supplied for tightening or loosening
the set screws.
- Power and Ground:
The amplifier's screw clamp Power and Ground
connections are designed to accept 8 to 4 AWG power wire.
- Remote Turn-On: The amplifier's screw clamp turn-on lead
accept 18 to 8 AWG wire.
Note: The Amplifier is not equipped with a fuse. An
external 30-amp AFS, AGU, or MAXI fuse must be installed on
the power wire. If a wiring kit is used which includes a fuse with a value
other than 30-amps, the original should be replaced with a 30-amp fuse
Speaker Output Terminals: The JL Audio XD300/1 features
four screw clamp speaker terminals for an easy parallel subwoofer connection. The
amplifier's four set-screw speaker terminals will accept 16 to 8 AWG speaker
Preamp Inputs: The
amplifier features one set of differential-balanced RCA jack inputs. The
amplifier features a dedicated Input Sensitivity gain control for these inputs.
These controls are designed to match the input sensitivity of the XD300/1 to the
specific signal source that is feeding it. The amplifier's input level can be
set between 100mV-4V RMS.
Preamp Outputs: The XD300/1 incorporates a pass-through preamp output
sections, so that additional amplifiers can easily be connected to the same
signal feeding the XD300/1. These preamp output signals are buffered to
prevent noise and are always preamp level, regardless of the level of signals
feeding the XD300/1's inputs.
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 the XD300/1 from the driver's seat. If desired, multiple XD amplifiers can be controlled from a single
HD-RLC controller using a simple phone line splitter and multiple phone cables.
Note: All inputs and outputs are located on the
side of the amplifier to make installation of the amplifier simple and neat.