JL Audio JD250/1 Monoblock Amplifier
230,00 €
The JL Audio JD250/1 is a monoblock car amplifier designed for a passive subwoofer. It delivers up to 250 W RMS at 2 ohms and 14.4 V. Line-level and speaker-level inputs make it easier to connect different sources, while the adjustable 50-500 Hz filter helps integrate the subwoofer with the vehicle’s main speakers.
The JL Audio JD250/1 amplifier is a Class D monoblock car amplifier designed to power a passive subwoofer. With a 14.4 V supply and a 2-ohm load, it delivers 250 W RMS. With the same load at 12.5 V, the output is 200 W RMS.
What this amplifier is designed for
This model suits a car audio system in which one subwoofer requires its own dedicated amplification channel. NexD switching technology is used in the amplifier’s power stage.
Inputs and system expansion
Differential-balanced inputs accept either line-level or speaker-level signals. This allows the amplifier to be connected to car audio sources with different types of outputs.
The RCA inputs have switchable ranges. Low mode covers 200 mV-2 V RMS, while High mode covers 800 mV-8 V RMS. Select the range that matches the source signal.
Automatic turn-on can be triggered by signal sensing or DC offset sensing. This is useful when the source does not have a dedicated remote turn-on output. Buffered preamp outputs pass the signal to another amplifier.
Sound adjustment
The built-in low-pass filter operates from 50 to 500 Hz. Its 12 dB-per-octave slope helps restrict the higher frequencies sent to the subwoofer. The filter cannot be bypassed, so it always remains in the signal path.
The frequency control has no detents or calibrated positions. Adjust it by listening carefully so that the subwoofer and main speakers do not overlap excessively or leave an audible gap between their frequency ranges.
A variable bass boost equaliser provides adjustable low-frequency enhancement. Use it moderately, because additional boost increases the system’s power demand.
An LED clipping indicator surrounds the input sensitivity control. It helps with sensitivity adjustment without requiring specialised measuring equipment. Do not set the control so that the clipping indication remains continuously illuminated.
Installation and control
The controls are positioned on the input side. The power and speaker connections are located at the opposite end of the extruded-aluminium chassis. During installation, leave access to both ends and sufficient room for the cables.
The power and ground connections require at least 8 AWG copper cable. A 30 A AFS, AGU or MaxiFuse-type fuse is specified for the power circuit.
The optional RBC-1 remote level controller allows the subwoofer level to be adjusted from the driver’s seat. It is sold separately and does not remotely control the bass boost equaliser.
Technical specifications
| Type | Monoblock Class D car subwoofer amplifier |
|---|---|
| Switching technology | JL Audio NexD |
| Continuous RMS power at 14.4 V | 150 W × 1 at 4 ohms; 200 W × 1 at 3 ohms; 250 W × 1 at 2 ohms |
| Continuous RMS power at 12.5 V | 115 W × 1 at 4 ohms; 150 W × 1 at 3 ohms; 200 W × 1 at 2 ohms |
| 1.5-ohm load | Continuous RMS power not specified |
| THD+N at rated power | <1% at 2 ohms per channel |
| Frequency response | 7-500 Hz, +0/-1 dB |
| Signal-to-noise ratio | >80 dB below rated power; A-weighted, 20 Hz-20 kHz noise bandwidth |
| Signal-to-noise ratio at 1 W | >60 dB; A-weighted, 20 Hz-20 kHz noise bandwidth |
| Damping factor | >1000 at 4 ohms and 50 Hz; >500 at 2 ohms and 50 Hz |
| Signal inputs | Differential-balanced; accept line-level and speaker-level signals |
| RCA input voltage range | 200 mV-2 V RMS in Low mode; 800 mV-8 V RMS in High mode |
| Automatic turn-on | Signal sensing or DC offset sensing |
| Outputs | Speaker output and buffered pass-through preamp outputs |
| Filter mode | Low-pass only; no bypass function |
| Filter slope | 12 dB per octave |
| Filter frequency | Continuously adjustable from 50 to 500 Hz |
| Filter-frequency control | No detents or calibrated positions |
| Infrasonic filter | None |
| Bass boost equaliser | Included, variable |
| Output-polarity switch | None |
| Clipping indicator | LED ring around the input sensitivity control |
| Remote level control | Optional RBC-1, sold separately |
| Remote equaliser control | None |
| Minimum power and ground cable size | 8 AWG copper cable |
| Fuse | 30 A, AFS, AGU or MaxiFuse type |
| Chassis | Extruded aluminium |
| Connection layout | Controls and inputs at one end; power and speaker connections at the other |
| Dimensions | 53 × 242 × 190 mm (height × width × depth) |
FAQ
What kind of subwoofer is suitable for this amplifier?
Choose a subwoofer according to its final impedance and permitted RMS power. At 14.4 V, the amplifier delivers 250 W RMS at 2 ohms, 200 W RMS at 3 ohms and 150 W RMS at 4 ohms. At 12.5 V, it delivers 200, 150 and 115 W RMS respectively. Continuous RMS power is not specified for a 1.5-ohm load.
Which input should I use with my car audio source?
Use a line-level signal if the source has a suitable output. The speaker-level option is intended for sources without a line-level output. Select the input-voltage range to match the level of the signal being supplied.
How should I set the input sensitivity?
Begin with lower sensitivity and increase it gradually. Watch the LED clipping ring around the control while making adjustments. Input sensitivity is not intended to serve as an everyday volume control.
Where should the amplifier be installed?
Choose a secure location that provides access to both ends of the chassis. The controls at one end must remain accessible for adjustment. At the other end, allow enough room for the power and speaker cables.
Can I adjust the subwoofer level from the driver’s seat?
Yes. This requires the optional RBC-1 controller, which is sold separately. It adjusts the subwoofer level but does not control the bass boost equaliser.
