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Customer Reviews

JL Audio RD400/4

JL Audio RD400/4 4-channel car amplifier — 75 watts RMS x 4

MFR # 98621

5.0 out of 5 stars
81 reviews
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I love it.

Casey S. from Hustisford, WI on 12/18/2023

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I'm happy I chose this. Im happy to have crutchfield guide me along the way while installing. This amp is very straight forward. Cut the speaker wires atfactory harness or aftermarket stereo harness and route them back to amp. Channel 1 and 2 are front (1) left (2) right. Channel 3 (left) and 4 (right) are rear speakers. RCA follows same concept.

Pros: Nice price. It acts right. It'll only do what you tell it to haha.

Cons: Accepts 4gauge wire and inline for a 40 ANL fuse looks silly. That's about it.

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0 of 4 found this helpful

JL Audio RD400/4

Chris from Castle Rock, CO on 12/3/2023

2021 Jeep Gladiator

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Great sounding amp so far, and Loud. I installed this in my Jeep Gladiator with the stock 7" radio (non alpine), and used the JL speaker cable adapters to provide signal without LOCs. Also replaced the factory speakers with Kicker 46CSS674.this amp brought the kicker speakers to life! Very happy with my purchase and my system sound overall.

Pros: Ability to connect to the speakers without LOC, controls are easy to get to and easy to set.

Cons: The wire terminals are a little difficult to use with higher gauge speaker wires, it took a couple tries to align the speaker wire with the crush down screw.

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JL Audio RD400/4

William from Pearland, TX on 9/24/2023

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Upgraded from entry level jl audio 400/4. Notable difference!

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0 of 0 found this helpful

Clean audio better than pioneer 87

Sukhjit from Greenwood, IN on 9/17/2023

2018 Nissan Maxima

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Love it. Clean sound hooked up to kickers ks components front and 2 way kickers rear. Jl ho w7 12in paired with rd1000. No complaints

Pros: Sounds, connections to hook up

Cons: None

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0 of 0 found this helpful

JL Audio RD400/4

Alfonso from ELMHURST, NY on 5/30/2023

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The sound that this amplifier displays clear and full sound with plenty of power, love it

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1 of 1 found this helpful

LAS VEGAS

Daniel from LAS VEGAS on 5/23/2023

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I'm really pleased with my choice. I choose the RD 400/4 and the RD 500/1. I would say quality value and size were all major factors. I was at first concerned about sound quality as I noticed the S/N ratio was was a little lower than what I was accustomed to. Turned out the ratings were based on the newer 1watt/1 meter method and after some research and the use of an online calculator I was able to convert the S/N ratio to the old standard rated at full power that conversion came out to 104db so I knew that was super clean based on my experience with the old rating method. I later verified this figure in the official JL audio manual. I also l. I'm planning on running the Rd400 in two channel stereo bridged mode to my Morel Virtus components which I hear are a little power hungry. I also have the later option of the 4 channel if I want to power my rear fill externally, but I doubt I will do that. Got the Rd 500/1 mono to power my single 4 ohm sub and it should provide plenty of headroom. I haven't installed any it this yet just designing amp rack and also got the sub enclosure finished. Also I wanted to mention the build quality of both amps are top notch steel chassis very heavy, I like the cover plate, led and input sensitivity indicators as well. Overall it is a little larger in person than what I imagined from the online pics. Only thing I don't like is there is no built in fuse lie chassis fan.

Pros: Great value, lots of power, high quality nice size not too big.

Cons: No built in fuse, no built in chassis fan, remote for rd 500/1 is not but should be included with the amp. Sub remote optional item seems a little cheap compared to the competition. You could use another brand if you want connects via standard 4 pin phone cable

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2 of 2 found this helpful

Excellent amp

R Douglas from Alpine, TX on 5/20/2023

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Great Amp! Replaced a less expensive Amp of the same power and the sound quality improved quite a bit. Cheap amps will increase your volume, but a better quality amp like this JL, will not only increase volume, but will also enhance the sound quality of that increased volume and allow your speakers to shine as they were meant to. This amp is definitely a case of getting what you pay for. Crutchfield, great as always!

Pros: Greatly improved sound quality.

Cons: None...one usually gets what they pay for.

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2 of 2 found this helpful

Money well spent.

Daniel B. from CHESAPEAKE, VA on 4/23/2023

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Felt great out of the box. The build quality and attention to detail where superb, the feal and look of it alone justify the price. I'm not a car audio expert and the detailed setup instructions were great.

Pros: The little things like retention clips on the screws for the access plate so they don't fall out, rubber padding on the access plate so it doesn't rattle, and a detailed instruction manual. Sounds awesome and had all the features I was looking for.

Cons: I'm not a fan of the smash the wire connections this amp has. Mounting hardware wasn't included, not big deal.

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2 of 2 found this helpful

JL Audio RD400/4

Kyle from MIDLOTHIAN, VA on 3/15/2023

2018 Toyota Camry

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Sound quality is amazing and the control panel is easy to dial in. For example, the "clipping" LED to set the gain/sensitivity is one of the nicest features I've seen on an amp. This is currently being powered by a Kenwood Excelon Reference DNR1007XR head unit, they compliment each other nicely. Its installed under the passenger seat of a 2018 Toyota Camry and has plenty of room. The only downside is the control panel is not very accessible until the seat is removed. However, this is due to the vehicle layout limitations, not the amp itself.

Pros: Sound quality is amazing and the control panel is easy to dial in. For example, the "clipping" LED to set the gain/sensitivity is one of the nicest features I've seen on an amp.

Cons:

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2 of 2 found this helpful

High Quality

Bradley from RANDLEMAN, NC on 12/30/2022

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High Quality Amp, I've owned JL Audio products in the past, I'm slowly purchasing new stuff for my vehicles. JL Audio and Kenwood Receivers is what I highly recommend

Pros: Features

Cons: None

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2 of 2 found this helpful

JL Audio RD400/4

Mark M from SMYRNA, GA on 12/13/2022

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Had this installed for going on two years. Absolutely love it. The clipping indicators are very convenient for setup and something I really like to see in an amp. Balanced inputs are a great thing to have, too. Previous amp had serious noise issues on 2 out of 4 channels. It's hard for me to say why exactly - could be a problem with the head unit, RCA routing, perhaps damage during installation, etc. However the RD400/4 has been clear and clean since day 1. You get a lot of features for the price and plenty of power, plus a good quality unit beyond the bells and whistles. Would highly recommend.

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2 of 2 found this helpful

JL Audio RD400/4

Boohee from Long Is City, NY on 10/7/2022

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Very good amplifier. Sleek look and easy setup

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1 of 1 found this helpful

JL Audio RD400/4

Crutchfield customer from Houston, TX on 10/2/2022

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Get performance and sounds !

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0 of 0 found this helpful

Good amp, not my sound.

Thomas from PORTLAND, MI on 9/8/2022

2006 Honda Civic

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Its a quality amp to be sure. Its built well, all connections are made on the same side of the amp, and its got plenty of power. My problem seems to be class D and the sound it presents. I tried class D at home with a cambridge evo 150 and returned that. Now Ive tried it in my car and really didnt like it. Ultimately, I went back to class AB in the car and tubes at home and have found the sound I like. To me, this sounds thin, and lacking in fullness I would say. This is how all class D sounds to me. So, i did return this in favor of an AB amp and love that. So, quality amp but whoever says you cant tell the difference between D and AB in a car is hearing something different from what I am. They sound nothing alike unless we are talking subs.

Pros: Solid build. Connections on same side. Good power.

Cons: Not a fan of the sound. Class D sounds thin and not robust to my ears.

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10 of 14 found this helpful

JL Audio RD400/4

Heidi from San Diego, CA on 9/2/2022

1997 Nissan Hardbody

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The quality of the build is so good I went from 2000 watts to 400 watts Without losing sound quality or performance!!!

Pros: 2022 best class D

Cons: Can't find one

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1 of 1 found this helpful

JL Audio RD400/4

Omar from Dolton, IL on 7/21/2022

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Solid amp but in my honest opinion for myself I believe my hertz 4 channel amp appears to be a better amplifier

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3 of 5 found this helpful

Upgraded to this Amp & JL C2 6x9's

Ryan from Orlando, FL on 7/15/2022

1972 Chevrolet C Series

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We put this in a '72 Chevy C10. Previously had a 2 channel Kenwood amp but felt we needed more. So we had Focal ISS 6.5 components with the Kicker Hideaway. We added this amp in with the JL C2 6x9's and what an amazing difference. The Ty ability of this amp was super easy. Even after tuning the gain with the sine wave, we had to turn the gains back some more. Love the ability of having the crossovers for the front & rears. Such a fantastic difference. Adding this and the 6x9's made much more of a difference with the Kicker Hideaway subwoofer that I wish we would have started with this initially. It's more expensive for this amp, but I feel it was worth it. Very, very nice features and I'm glad we did it.

Pros: Packed with features. Worth the extra $$ vs the same JL Audio amp at $130 less. Worth it. Kind of a "treat yourself" situation. Do it.

Cons: None really.

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1 of 1 found this helpful

Compact Amp and Outstanding SQ

Michael from Macon, GA on 7/13/2022

2016 Toyota Tundra

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Easy to install and setup. JL Audio sound quality is next to none. I am amazed about how compact it is. This amp is replacing a 1st gen JL Audio 300/4 that will need to be repaired.

Pros: Easy to install, set up, and compact. The sound quality of JL amps are awesome!

Cons: None

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1 of 1 found this helpful

JL Audio RD400/4

Steven from Waikoloa, HI on 3/18/2022

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Fit perfectly

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0 of 0 found this helpful

Fantastic amp! Sounds great.

Jamshed (Jim) from GRAYSLAKE, IL on 3/11/2022

2020 Honda Accord EX-L

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Wow! I'm impressed. This is my first JL Audio product and it's a fantastic amp. Very clean, clear and powerful sound. I'm hearing a lot more detail in my music as well. Also I've only got my gains at about 50% each, plenty of power to spare. I'm very happy with this product.

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0 of 2 found this helpful

JL rockin' my Focals

DOC from Arlington, TX on 1/23/2022

2019 Toyota Sequoia

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Great little amp, clean power, really brought by Focal Flax 3 ways to life.

Pros: Small size, clean power, easy adjustment.

Cons: None that I can find

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2 of 2 found this helpful

JL At It's Finest

Cody from Perryville, MO on 1/20/2022

2020 Toyota Corolla

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I thought my older RF power series amp was good until I hooked this thing up in its place. Amazing amp with amazing features.

Pros: Clipping LED Build and sound quality Small size Price

Cons: None

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2 of 2 found this helpful

Taylor

Antonio from Taylor on 1/12/2022

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Awesome amp had the kenwood 4 channel just didn't have the clean power but this one rock's what a difference .thanks Crutchfield

Pros: Good clean power

Cons: None so far

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2 of 2 found this helpful

JL Audio RD400/4

Louis from Nipomo, CA on 1/9/2022

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This is nearly the only amp that allowed me to configure my system for mid bass. Great versatility, high quality at a reasonable price. The amp has been installed and it sounds excellent. Awesome product

Pros: High quality. Versatility. Compact/good power

Cons:

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3 of 3 found this helpful

JL Audio RD400/4

Crutchfield customer from Holualoa, HI on 12/12/2021

1998 Toyota Tacoma

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Awesome amplifier. Paired up well with the jl c2650 components

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3 of 3 found this helpful

JL Audio RD400/4

Crutchfield customer from Bradenton, FL on 10/24/2021

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Lo mejor lo Recomiendo CRUTCHFIELD

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1 of 1 found this helpful

Tried and True JL performance

Crutchfield customer from Wyoming, MI on 10/16/2021

1999 Chevrolet Silverado

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Clean sounding and plenty of power. JL is tried and true and lives up to their reputation. Great look. I've been wanting to install one of these and I was able to for my friend and I love everything about this amplifier.

Pros: Great build quality Fresh look from the JL line Clean sound Plenty of power Great price

Cons: I really tried to think of a con but I can not come up with one. That says a lot for the product and it's performance.

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2 of 2 found this helpful

Perfect!

Crutchfield customer from Columbia, MD on 10/16/2021

2005 Toyota Camry

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Slaps!

Pros: Thumps

Cons: None

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1 of 2 found this helpful

JL Audio RD400/4

Crutchfield customer from Holt, MI on 7/19/2021

2018 Ford F-150 XLT

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It's a great, compact amp with lots of power. It brought my Hertz Mille Pro's to life!

Pros: Size, Power, Affordable

Cons:

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2 of 2 found this helpful

Simply perfection from JL

Keith from Omaha, NE on 7/1/2021

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This amp is as amazing as it is beautiful. I have a $90 oscilloscope and the distortion LED is PERFECTLY on point. Going from a 50 watt rms amp to this, my Hertz CK 165 components sounds incredible. You'll want this amp for your setup it's perfect.

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2 of 2 found this helpful

Small but powerful.

Crutchfield customer from Las Vegas, NV on 6/13/2021

2014 Lincoln MKX

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A nice small compact amp. Powering all 4 of my door speakers and tweeters... matching the subwoofer amps power.

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5 of 5 found this helpful

Jl quality I expected

Crutchfield customer from Granite Falls, NC on 5/13/2021

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Powers my 4 c2-600 jl speakers without any issues

Pros: Small All wire hook ups on same side Powerful

Cons:

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2 of 2 found this helpful

Excellent Amp

Jeffrey from Indiana on 5/1/2021

2021 Subaru Crosstrek

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For me JL is the gold standard in car audio amps. The price to quality/clarity/power/reliability cannot be beat. I have this amp pushing Kicker KSC 3.5" and KSC 6x9 coaxials (in parallel) up and front, Polk DB 6.5 coaxials in the rear. I also added a Jensen CAR1000 head unit. This amp absolutely screams. The louder you crank it, the better it sounds. I only have a 8 band graphic equalizer on my headunit, but if I was able to make more adjustments, it would sound even better. I would highly recommend this amp, just make sure you have some decent speakers to do it justice. My only regret is not getting the 5 channel version so I could easily add a subwoofer.

Pros: Reasonably priced small foot print excellent sound Jl qaulity Feature rich

Cons: Zero

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5 of 5 found this helpful

So far so good!

Crutchfield customer from Phoenix, AZ on 2/8/2021

2017 Honda Civic SI

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Great name and great amp. I have this amp running my new Focal setup in my 10th gen Si. To be exact, I have the Focal Performance PS 165FX fronts and ICU 100's in the rear deck rounded out with a RE 12. Only around 5 hours on these speakers/amp so far, getting better every time I get in. I don't suspect I will have ANY issues with this amp, reason I went with JL Audio. Clean and crisp power is all I have heard so far. Hopefully many years to come!

Pros: Small footprint and large sound

Cons: Pricier than other amps

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2 of 2 found this helpful

JL Audio RD400/4

Crutchfield customer from Hanover, NH on 12/22/2020

2020 Honda CRV

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Perfect match for Alpine 6.5 Rs. Life is much easier when the consultants ask the right questions , it makes them truly helpful .

Pros:

Cons: None

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4 of 4 found this helpful

Look no further!!

Kevin from Lamoni, IA on 9/13/2020

2003 Kia Spectra

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Was having bad luck with a Kenwood Excelon 4 channel amplifier So I went and got this one. This thing blows the Kenwood out of the water! I really can't describe how much better it really is and the clipping indicator is spot on. I tested it with my O-scope and it 100% passed for me. I will recommend people buy this one and I'm also looking into buying one of JL Audio's mono amps for subwoofer!

Pros: does 100% everything that it says in description.

Cons: none

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5 of 5 found this helpful

JL Audio RD400/4

Crutchfield customer from Ottumwa, IA on 9/3/2020

2011 Nissan Maxima

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Looks good does what he says easy to set up

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0 of 0 found this helpful

JL Audio RD400/4

Crutchfield customer from Jeffersonville, IN on 8/23/2020

2014 Lincoln MKS

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I purchased this RD400/4 amplifier to run my 2 pairs of C2570X 5X7's. I also purchased RD1500/1 to run my subwoofer. Unfortunately I can't find the Q Class L7 15 inch 2 ohm sub that I want for my project. These amplifier and speakers were packed exceptionally well. I have purchased JL Audio amplifier before. I am not worried about the quality or performance of these amps. Once I can get my sub I will do another review.

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3 of 5 found this helpful

I like it

Lael from Mount Olive, AL on 6/4/2020

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Excellent amp so far. Vast improvement from the JL JX400 I had prior. Pushes my Infinity Primus line up with ease and clarity.

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3 of 3 found this helpful

JL Audio RD400/4

Crutchfield customer from Berkeley, CA on 5/21/2020

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perfect amp for my JL components

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2 of 2 found this helpful

JL Audio RD400/4

Crutchfield customer from Schertz, TX on 5/11/2020

2013 Toyota Tacoma

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Nice upgrade over the Kicker that it replaced. Adjustment options are straightforward.

Pros: Easy set up. Sounds good.

Cons: Had to go another website to download test tones.

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1 of 1 found this helpful

Great Amp

Crutchfield customer from Mukwonago, WI on 5/5/2020

2012 Toyota FJ Cruiser

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So far it's a great amp more then fit my needs as an addition to my FJ audio upgrade project. Always been a fan of JL and have not installed in years. Getting back in the game with this amp has been fun. Plenty of adjustments and the clipping adjustment is great idea. Ultimately you end up adjusting it to your system but it's a great reference

Pros: Great adjustability

Cons: Non for me

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0 of 0 found this helpful

Sounds awesome

Juan from Brea, CA on 5/3/2020

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Never had it, looking forward to owning it soon. Thanks.

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0 of 14 found this helpful

JL Audio RD400/4

Crutchfield customer from Baton Rouge, LA on 4/28/2020

2004 Dodge Ram 1500

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Great amp! Easy to set inputs/gains, sounds great and looks good!

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1 of 1 found this helpful

JL Audio RD400/4

Crutchfield customer from Selma, TX on 4/28/2020

2007 Porsche Cayman

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Awesome amp. Plenty of power and no added noise. Love it!!

Pros: Great price and excellent quality

Cons: None

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2 of 2 found this helpful

JL Audio RD400/4

Crutchfield customer from Asheville, NC on 4/20/2020

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Very good amp, it's versatile....small size, great punch, easy install, with clear sound. A little more money than compared to other amps in this wattage range, but money well spent. Great addition to my stock head unit.

Pros: Compact size. Accepts low-level and high-level signals from factory head unit.

Cons: None.

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2 of 2 found this helpful

good sound

audio junkie from Eugene, OR on 4/16/2020

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really good amp. sound good, has good power. thats all pretty impressive however alternator whine started happening. cleaned and checked all connections for chassis and power. comes down to would not filter out the noise. replaced with alternate d class amp same location and connections. problem solved. that may not happen for everyone. sound quality is very good

Pros: small, efficient, powerful

Cons: alternator whine.

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8 of 9 found this helpful

JL Audio RD400/4

Crutchfield customer from Ontario, CA on 3/5/2020

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Unbelievably awesome. This thing did a miracle for me

Pros: No wire cutting

Cons:

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1 of 3 found this helpful

Sweet music

Crutchfield customer from Lake Jackson, TX on 1/30/2020

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What a great amp, it's does an excellent job of cleaning up the signal and producing crystal clear sound. A little more money than other units in this watt range, but money well spent.

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2 of 2 found this helpful

After All

Craig from Oak Grove, MO on 1/22/2020

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After all it is JL Audio. Small size, no noise, great punch, easy install, fantastic sound...after all, it IS JL Audio.

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3 of 4 found this helpful

JL Audio RD400/4

Crutchfield customer from Scottsville, KY on 1/14/2020

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Perfect choice for amplifying my stock head unit. Super easy install. Love it!

Pros: Clean sound, power to spare

Cons: None

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0 of 0 found this helpful

JL Audio RD400/4

Crutchfield Customer 4 Life from USA on 11/9/2019

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Small/compact, clean power!!! Smart amplifier that perfectly configures your vehicles audio to be distortion free!!! Protects and ensures that all your components will last during the life of your car!!!

Pros: This Amplifier eliminates the need for Line Output Converters (LOCs) in most installation scenarios. Amplifierc accepts low-level and high-level signals from a variety of factory head unit outputs and amplifiers, including single ended "ground referenced" sources, Balanced or Unbalanced "Bridged or BTL" sources. . Daisy chain multiple amplifiers with ease.

Cons: No bass knob. A bass knob does put more stress on an amplifier. JL AUDIO ensures all audio output is always always flawless. You must configure/tune the bass on the amplifier itself and then rely on your factory head unit or aftermarket head unit to make specific adjustments on your song selection. This amplifier does add the bass you need by increasing the rms power from the head unit. A bass knob is not needed with this amplifier. .

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7 of 14 found this helpful

JL continues to inpress

Crutchfield customer from Hampton, VA on 10/6/2019

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This amp has plenty of power for what I need. The size of it and how clean my speakers sound compared to a cheaper amp I had makes a huge difference. I'm using Hertz Mille 3-way comments in the front and Hertz Mille 6.5" coax in the rear. This amp makes them scream. The build quality is something that can be expected from JL but you can also tell a lot of thought went into it. Nothing on it feels cheap.

Pros: Small foot print, solid build, plenty of power. Well worth the money.

Cons: None that I can think of.

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JL Audio RD400/4

Crutchfield customer from Anchorage, AK on 10/4/2019

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clear sound great amp

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0 of 0 found this helpful

JL Audio RD400/4

Crutchfield customer from Austin, TX on 8/14/2019

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Well designed both hardware and aesthetics

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1 of 2 found this helpful

JL Audio RD400/4

John from Somerset, NJ on 7/21/2019

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Lot of power for a small amplifier excellent sound quality for my Interiors my entire sound system JL Audio

Pros: Never go wrong with Jl

Cons: None

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0 of 1 found this helpful

JL Audio RD400/4

Crutchfield customer from Covina, CA on 7/16/2019

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Great product. Installation was simple and speakers sound great.

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JL Audio RD400/4

Crutchfield customer from Texas City, TX on 6/10/2019

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Awesome sound way better than expected

Pros: Perfect for highs and mids

Cons: None

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2 of 2 found this helpful

Good solid amp

franc23 from Northborough, MA on 12/7/2018

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Good product. First real amp. Controls are easily accessible though best not to play with it much once set. Came away impressed. Tough to fit in a truck, ended up sealing the vent on the passenger side and this went below that seat.

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JL Audio RD400/4

Crutchfield customer from Puyallup, WA on 12/3/2018

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Sounds great liked all connections on one side mounted well also

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1 of 1 found this helpful

JL Audio RD400/4

Crutchfield customer from Mesa, AZ on 11/9/2018

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Great product lots of adjustments Fits in small spaces

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JL Audio RD400/4

Joe from St Augustine, FL on 9/9/2018

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Excellent amp!!!!

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JL Audio RD400/4

Crutchfield customer from Lewisville, TX on 8/29/2018

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Amps sound very nice

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0 of 2 found this helpful

Great 4 channel amp

FrankyG from Bellflower, CA on 8/11/2018

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Awesome 4 channel amp. Worth every dollar. Night and day from previous amp. JL audio might be a little more pricey than other audio equipment but you pay for what you get.

Pros: Compact and packs a punch. More than enough power for my set up

Cons: None

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5 of 5 found this helpful

JL Audio RD400/4

Crutchfield customer from Tucson, AZ on 8/7/2018

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product is as described and works great. I have had no issues at the time of this review. I will add more info if I run into any problems.

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Easy Install

Phil from Wilmington, DE on 6/28/2018

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I used this to replace a dead Infinity Reference amp. The install was easy since I had all the wires run already. The LED clipping lights and the test tone download from the JL website made setting levels easy. The sound is just a bit cleaner than the old amp and it doesn't get hot to the touch even though it is half the size.

Pros: Small and cool to the touch Easy Install

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5 of 5 found this helpful

Woke up my system

George from Richmond, VA on 6/21/2018

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Added this amp with Alpine speakers. Really woke up my system. Very happy how it sounds.

Pros: Fantastic clean sound. Look great mounted too.

Cons: None

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1 of 1 found this helpful

JL Audio RD400/4

Kevin from Upper Marlboro, MD on 6/11/2018

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Great product Easy to install and good sound Stays cool

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1 of 2 found this helpful

JL Audio RD400/4

VERONICA from Fairfield, AL on 5/31/2018

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Love the sound.....no other competitors comes close.... .Crutchfield & JL Audio y'all got people hating on me ....lol

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2 of 5 found this helpful

All you need for mids-highs

Rick from Elk Grove, CA on 4/24/2018

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Awesome amplifier, lots of power. Plenty of parameter settings available. Simple to install; I love the blue LED light! Most importantly it has plenty of power to drive my 6.5" mids. Thanks Sam at Crutchfield for recommending this amp to me!

Pros: Plenty of power, good price point

Cons: None

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3 of 3 found this helpful

JL Audio RD400/4

Crutchfield customer from Louisville, KY on 4/16/2018

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Good amp very easy to install the crossover adjustment are great delivers good power when needed doesn't over heat

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2 of 3 found this helpful

JL Audio RD400/4

Theodore from Midland, MI on 12/8/2017

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No complaints, Easy setup and sound clean. Recommended in this price range.

Pros: Gain adjustment.

Cons: None found

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0 of 2 found this helpful

Takes the guess out of work.

Dave from Cowen, WV on 11/18/2017

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I picked this up to replace a physically larger Infinity Reference 704A. Everything is mounted to the rear wall of my F150 Supercab and needed that extra space. The install was easy, the output clean, and it was no sweat dialing it in. Not that anyone will ever see mine, but it's nice to know that it looks as good as it sounds. The only downside was that I was missing the mounting screws. Fortunately, I had some from a previous amp that I pressed into service and didn't have to resort to using assorted wood screws that were laying in a drawer in my workbench.

Pros: Small footprint and easy to dial in.

Cons: No mounting hardware? What gives?

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4 of 4 found this helpful

Great for the price

Mark from MINNEAPOLIS, MN on 9/3/2017

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I've had this amp for a few weeks running C3's on the front channels and C2's on the rear for fill. Having previously ran the Slash V2 and V3 series 4 channels as well as the J2 Series 4 channel, this amp definitely isn't the BEST in the JL line. I've never seen the HD series in person so I can't comment on that, but I would say the RD is definitely just below the Slash series. Good amp for the price, very compact and efficient, with decent settings and filters for the price. I would recommend for anyone who wants to break away from the entry level amps like Kicker and Pioneer. You definitely won't regret the investment!

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14 of 15 found this helpful

JL Audio RD400/4

Crutchfield customer from Jackson Heights, NY on 6/20/2017

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I love it easy set up and it sounds great! Going deaf already!!!

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2 of 6 found this helpful

JL Audio RD400/4

Crutchfield customer from Clearfield, Ut on 6/1/2017

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Very happy with this product. The Jl audio Rd 400/4 is a awesome product. I'm powering jbl 6.5 components and jbl 6x9 with a pioneer head unit. Very clean sound.

Pros: Great price High end construction Power 75x4 @ 4 ohms Small size

Cons: Can not find any

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4 of 4 found this helpful

JL Audio RD400/4

Glenn from Union, MO on 4/6/2017

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Awesome, need to use the HP filter for regular speakers and tune the filter some or it will eat em' up with bass also used this with the little Kenwood (2 channels) one for 6 channels total. Recommend Rockford Speakers

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1 of 5 found this helpful

Good quality

Bobby from Birdsboro. PA on 4/5/2017

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Great sound and made of high quality material as expected. Service was great as always one of their fellow customer service reps helped me pick the best option in my price range.

Pros: Easy to set up and small size

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4 of 5 found this helpful

JL Audio RD400/4

LUAN h from Atlanta, ga on 1/16/2017

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Fit nicely under the seat and it does what it suppose to

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JL Audio RD400/4

Crutchfield customer from FORESTVILLE, CA on 10/17/2016

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I PURCHASED THIS AMPLIFIER TO REPLACE AN OLDER SOUND STREAM AMPLIFIER. INSTALLATION AND TUNING WAS EASY,.MOST IMPORTANTLY IT SOUNDS GREAT.

Pros: SOUNDS GREAT SMALL IN SIZE

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4 of 5 found this helpful

JL Audio RD400/4

CBR Bob from Hamilton, NJ on 10/14/2016

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Smooth, easy installation. Replacing an old amp... Easy to adjust and set up. Good sound as expected.

Pros: Runs cool

Cons:

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4 of 5 found this helpful

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