JL Audio JD500/1 (D class) power amplifier (mono).

JL Audio JD500/1 (D class) power amplifier (mono).

Monoblock Class D Subwoofer Amplifier, 500 W x 1 @ 2 Ω / 250 W x 1 @ 4 Ω - 14.4V
Designed to produce a whopping 500 watts into 2 ohms (14.4V, 1% THD), the JD500/1 amplifier is a great solution for powering subwoofers in a cost-conscious system. 
Our proprietary NexD™ switching technology delivers large amounts of real-world power output with excellent efficiency and ultra-low distortion.
The JD500/1’s controls are located on the input panel. while the power and speaker connections can be found along the opposite end of its extruded aluminum chassis. 
Signal processing features include a 12 dB / octave low-pass filter, with continuously variable frequency selection from 50-500 Hz, and a variable bass boost EQ. 
Dual-range, differential-balanced inputs are also on-hand, capable of accepting line-level and speaker-level signals. 
Automatic turn-on capability (via signal sensing or DC-offset sensing) is standard, along with a set of preamp outputs so you can easily pass signals to another amplifier. 

The JD500/1 is also equipped with an onboard LED-clipping indicator ring, surrounding the input sensitivity control. 
This useful feature lets you set your amplifier’s input sensitivity, quickly and accurately, without special equipment. 
With the addition of an RBC-1 remote level control (sold separately), you can control the subwoofer level from the driver’s seat.