JL Audio RD400/4, RD Series Class D Full Range 4-Ch Amplifier, 400W
Not Available for Shiping Outside the United States
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866-859-0896 ChatEmail UsUtilizing our exclusive NexD™ high-speed switching technologies, the ultra-compact RD400/4 amplifier is engineered to deliver loads of audio output power, with incredible efficiency and low distortion. Don’t let its modern styling and small size fool you though, this little powerhouse churns out 100 watts of crystal-clear audio from each of its four channels into 2 ohms (14.4V, 1% THD) and is fully bridgeable, so it can be used as a 3-channel amplifier, or as a 2-channel amplifier producing a whopping 200W x 2 into 4 ohms.
For your convenience, the RD400/4’s controls can be found on top of the amplifier, beneath a protective cover, with all connections located along one side of its chassis. Studio-grade signal processing features include high or low-pass 12 dB / octave filters (defeatable) for each channel pair, with continuously variable frequency selection from 50-500 Hz, and dual-range, differential-balanced inputs capable of accepting most input voltage levels. Automatic turn-on capability (via signal sensing or DC-offset sensing) is standard equipment, along with all-new input type switches for bridging of stereo output channels without needing to use Y-adaptors.
Onboard LED-clipping indicators are also included with your RD400/4. This all-new, innovative feature lets you easily set your amplifier’s input sensitivity settings, quickly and accurately, with no special equipment needed. You’ll also find a set of preamp outputs on-hand, so you can pass signals to another amplifier, almost effortlessly. The RD400/4 features a durable, black powder-coated finish and a top-mounted, dual-color LED light strip that reports the overall status and condition.
NexD™ Switching Technology
NexD™ amplifier technologies produce exceptional audio quality, unsurpassed total efficiency and high power from very compact amplifier designs.

Differential-Balanced Inputs
JL Audio’s Differential-Balanced Inputs are engineered to combat induced cable noise, which is a common problem in car and marine audio installations. This technology allows for the use of conventional RCA cables, while delivering many of the benefits of a true balanced connection and accepting a wide range of input signal levels.

Number of Channels |
4 |
Class |
D |
Peak Power Rating (Watts) |
|
RMS Power Rating (Watts x Channels) - 4 Ohms |
75 x 4 |
RMS Power Rating (Watts x Channels) - 2 Ohms |
100 x 4 |
RMS Power Rating (Watts x Channels) - 1 Ohm |
N/A |
RMS Power Rating - Bridged | 200 x 4 |
Minimum Impedance Unbridged (Ohms) |
2 |
Minimum Impedance Bridged (Ohms) |
4 |
THD at Rated RMS Power |
1% |
Bulit-in Crossover - Low Pass |
Yes |
Built-in Crossover - High Pass |
Yes |
High Pass Crossover Frequency (Hz) |
50-500hz |
Low Pass Crossover Frequency (Hz) |
50-500hz |
Signal-to-Noise Ratio |
84dB |
Bass Boost |
No |
Bass Remote Included |
No |
Fuse Rating | 40A |
CEA-2006 Compliant | Yes |
Maximum Power Wire Gauge Size | 4 Gauge |
Warranty | 1 Year |
Returns Policy
You may return most new, unopened items within 60 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund much quicker. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the 'Complete Orders' link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Shipping
We can ship to virtually any address in the world. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.
When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.
Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.