JL Audio JX400/4D #99401 4-Channel Car Amplifier
The JL Audio JX400/4D is a four-channel, full-range amplifier utilizing Class D technology. The JX400/4D can be operated with a wide variety of source units (aftermarket or factory) and system configurations (4-channel, 3-channel, or 2-channel).
MOSFET Switching Power Supply
The amplifier employs a rugged MOSFET power supply for outstanding reliability and operational stability.
JL Audio JX400/4D’s protection circuitry automatically shuts the amplifier down if thermal limits are exceeded, a short-circuit is detected in the speaker wiring, or if a dangerously low impedance is connected to the amplifier. Once the problem is corrected, the amplifier will return to normal operation.
Status Indicator Lights
There are two status indicator lights on the right side of the amplifier.
Power (Green): This LED lights green to indicate that the amplifier is turned on and operating normally.
Protect (Red): The Protection LED lights Red to indicate the amplifier’s protection circuitry has been activated.
The four-channel amplifier’s Input Sensitivity Control is used to match your source unit’s output voltage to the input stage of the amplifier for maximum clean output.
You can send four discrete channels of input into the amplifier, or feed all four channels with only two channels of input. The Input Mode switch has two positions: 4 Ch. for discrete 4 channels of input or 2 Ch. for feeding four channels with the inputs to Channels 1 & 2.
The JL Audio JX400/4D has a defeatable 12dB/octave filter for each channel bank. The crossovers can be configured as a low-pass or high-pass filter with a continuously variable cutoff frequency from 50 to 200 Hz.
Filter Mode: The amplifier has independent 3-way switches that allow you to select either a Low Pass (LP), High Pass (HP) or Full-Range operation (Off) for Channels 1&2 and Channels 3&4.
Filter Frequency: Separate rotary dials let you set the cutoff frequency between 50 to 200 Hz for each channel bank.
The JL Audio JX400/4D features set-screw terminals for the power, ground, and remote turn-on connections:
Power and Ground: The set-screw Power and Ground connections are designed to accept up to 4 AWG wire. A 2.5mm Allen wrench is supplied for tightening/loosening connections.
Remote Turn-On: The set-screw turn-on lead will accept 18 to 10 AWG wire. The same 2.5mm Allen wrench is supplied for making the connection.
Note: The Amplifier is not equipped with a fuse. An external 40-amp fuse (not included) must be installed on the power wire within 18″ of the positive battery post. 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 JX400/4D amplifier’s eight set-screw speaker terminals will accept 16 to 8 AWG speaker wire. The amplifier’s speaker terminals can be wired in a four-channel or bridged two-channel configuration. The 2.5mm Allen wrench is supplied for making connections.
The amplifier features two sets of stereo RCA input jacks. The amplifier features a dedicated Input Sensitivity gain control for each pair of inputs. These controls are designed to match the input sensitivity of the JX400/4D to the specific signal source that is feeding it. The amplifier’s low-level input can be set between 200mV-4V RMS.
Speaker Level Inputs
The JL Audio JX400/4D also accepts speaker level signals, including those from factory systems (without the need for a line-output converter), via the supplied supplied speaker-level harness. The head unit’s speaker wires should be spliced to the speaker-level harness. The amplifier’s high-level input can be set between 2V-10V RMS.
The JL Audio JX400/4D incorporates a pass-through preamp output sections, so that additional amplifiers can easily be connected to the same signal(s) feeding the amplifier. These preamp output signals are buffered to prevent noise and are always preamp level, regardless of the level of signals feeding the amplifier’s inputs.