Crutchfield Customer Review (What's this?)
So far this is everything I could want in a 4 channel amp
Our experts help you pick the ideal gear for your needs.Meet our advisors
Free tech support for the life of your gear.Read about our one-on-one expert help
You may return items that are complete and like new for any reason within 60 days.See the details of our return policy
Earn one point for every dollar you spend and use those points to save on future purchases.Get full details on Crutchfield Rewards
We offer vehicle-specific installation instructions, dash kits, wiring harnesses, and speaker accessories at deeply discounted prices with car stereo and speaker purchases. Available for most vehicles.Learn more
Our customers have trusted us with their business, and they’ve helped us win awards for our service.Check out our most recent awards
The manufacturer’s warranty always applies.See more details
Item # 575R4004D | MFR # R400-4D
$219.99 Earn up to 220 Rewards points
Rockford Fosgate packs more power per square inch into their Prime Class D amps than almost any other amplifier made, so you can put more music power in your vehicle's limited space. Your music will play loud and clear with one of these reliable and cool-running amps.
The R400-4D 4-channel amp puts out 75 watts RMS to each of your full-range speakers or components, giving them plenty of juice to rock. You can also use the front channels of the R400-4D for your front speakers while using the rear channels bridged to run a sub with up to 200 watts RMS. And, of course, you can bridge the amp to 2-channel mode to drive a pair of subs.
Clean power, extensive controls
Rockford Fosgate designed Prime amps to deliver Power Output Without Excessive Regulation (POWER), which means they'll respond quickly to the peak demands that you may throw at your system. High- and low-pass filters, along with Rockford Fosgate's famous Punch bass boost, let you tune your speakers for maximum performance, so your driver's seat will become your favorite place for listening.
So far this is everything I could want in a 4 channel amp
wesley, reading, pa
Average Customer Review(s):
So far this is everything I could want in a 4 channel amp
Great amp for the price. Easily powers my RF 5x8's and tweeters. Makes the system sound complete and has plenty of power. Been running this amp for about 4 weeks powering 4 5x8's and a set of tweeters, clean highs, powerful mids. Great amp!!!
Pros: Lots of clean power. Great price.
Cons: None to speak of at the moment
I love the features, power is good, installation easy. The first unit I received heated up and shut it self off after about 15-30 minutes of play. The second unit quality was lacking. I read reviews on this unit and experienced a lot of the complaints I read in the reviews , I would buy with caution.
Pros: nice features
Cons: Overheats and shuts off
Amazing little amp. Rated at 75W x 4. Factory cert rating was 549W RMS. Gain set at 2. Stays cool every day on my hour commute to work.
Pros: Price Size POWER
Cons: No high level line input clip
Rated at 4 by 75 watts. Certified by Rockford at 549 watts. That's a lot of bang for the buck! Sounds great with the Rockford speakers.
Pros: Power Size
Cons: No high level inputs.
Great amp for the price. I used to run RF wayyyyyyyyy back in the day of Punch 45,75 & 150. They were kind of dirty little amps but got the job done. The new amps are nice, clean, efficient, solid and have well thought out hookups, dials and switches. This amp far exceeded my expectations. Great clearance for behind the back seat of a 2011 ford f150 extended cab. It's a D class amp so it's efficiency means it runs at a much cooler temp than the old school A/B class amps. Currently running a pair of Polk Audio MM5251 component speakers up front and Pioneer 6x8 4ways in the back doors. This amp runs all of them with with the gain only up about 1/2 way. Even at this level, the volume on the stereo set at 10 will blow your doors off. No regrets.
Pros: Well priced, quality feel, easy to reach dials and switches
I love this amplifier I have it powering 2 sets of Rockford fosgate t1650 coaxial speakers and it sounds amazing the only problem is that the amplifier has only one set of rca's out but it would be nice to have 2 sets.
Pros: Awesome product.
Cons: Only one set of rca's out.
Over the years I have used nothing but RF amps in any of my cars, and never once have I been disappointed. The quality is amazing and the sound they put out is awesome. Easy install, love the small size can fit it almost anywhere. Excellent controls to set up the amp just right. Cant go wrong with RF.
Pros: Same RF quality as always, small size huge output. High quality great price. If you want to do it onxe and do it right yoy will not be disappointed with RF.
Product was endorsed by Crutchfield for my application. The instructions to install were right on. It was a very happy ending and a SUPERB upgrade. Thanks for all the product support.
Pros: Great sounding product that was easy to install. Thank-you for all the product support.
Cons: None so far that I can see.
Speakers are great! They fit perfect in my 2004 Jeep Wrangler roll bar... There being powered by a Rockford fostgate prime amp.. I am very impressed with the sound quality crisp highs! And very good mids in the stock Jeep Wrangler pods. They screw right it and fit perfectly.
Pros: Sound quality is great! Crisp highs and very good mids. Fit right in my jeep wranglers speaker pods.
Cons: Absolutely none
I've setup with AVH x5750BT Head Unit, with Focal 165F and JL Audio 12" W1 v3 Subs! Great sound and clarity! feel all the bass and power !
This amp makes me wish I'd never started this upgrade in the first place. I'm sure some people have had good luck with it, but I got my whole install done, hooked up the last RCAs to it, and they slipped right off. They are Stinger 6000 interconnects, and I've read a hundred reviews saying how great they are, and how tight, but on this RF amp, they come right off. I was just doing a first test of the system, engine off, listening, and the speakers cut out. The plugs had vibrated off in a matter of a couple of minutes, with just the sound causing it. When I told Crutch about it, they naturally said it was the interconnects (which I bought locally, instead of from them). Nobody I've talked to on several forums, and Amazon have had this problem. I guess the only solution is to rip out everything and start over with different RCAs. I think I'd rather just not bother, drive the car off a cliff.
Pros: The expectation of it working was great.
Cons: The reality sucked.
Produces amazing sound quality when paired with Rockford subs and speaker setup
Pros: Extremely good quality and sound
Cons: Could use a little more tuning capabilities
used to power 4 speakers, had it professionally installed. 2 of the speakers didn't work at all and the problem was traced back to the amp. Ended up just buying a different one from the instaler
Bought this amp 2 years ago. It is an awesome amp when it worked. It is hooked up with all professional wiring. I only had the front channels hooked up and were running at half gain. It is hooked up to a infinity kappa component system and sounded awesome at just half gain. Just recently it stopped working. Power light on but no sound. For this price point, with half gain, 1 channel ever used, and in a vehicle that is rarely driven this amp should not be broke. Ive had RF amps that lasted years longer at max power for extended periods of time. Purchase a different amp or get a extended warranty. Tried to get it fixed but for $150 not worth it.
Pros: Sounds great when working.
Cons: Broke after minimal use. Guess thats why its only a year warranty. Just like a car, they know how long to do the warranty because after its out you will have problems.
Worth the price for amplifier.
Pros: Can install underneath driver's seat.
What a great amp! First amp I've personally boughten and I've been very pleased so far! Had it for almost a year now. Love how small it is and easy to hook up. I have mine mounted to the back of my seat and it looks great! Definitely recommend!
Pros: Small Plenty of power Easy to install
This is a great amplifier. I used this and underrated my speakers that were able to handle 100W rms a piece. Let me tell you what, 75W a channel is perfect. Plenty of power going to my speakers, no distortion at all. Plus the high pass filters are real convenient when paired with a pair of subwoofers. Great amplifier. Crutchfield is definitely the quickest supplier you'll find, but unfortunately not the cheapest.
Pros: Easy installation All the inputs(positive and negative, power, ground, etc) are all nicely separated. Lots of power And of course, its Rockford Fosgate quality.
Cons: None that I can think of.
Purchased this amp to simplify my system in newer car, i.e. going from two amp system to one 4 channel amp. Installed along with new JVC KD-X80BT head unit, driving JBL GTO938 in rear and old Infinity reference components in the front. This amp has plenty of power. Besides breathing new life into the old Infinities, provides ample power to provide me with all the base I need from the JBLs. The small size allowed me to install under rear deck. Love the various controls and set screws for wiring.
Pros: Great Amp
Installed the R400-4D in a 2009 F150 along with 4 Kenwood KFC-680C speakers. Also replaced the headunit with a Pioneer AVH 8400H receiver. The amp was easy to install and sounds great. 100% improvement over the factory radio. I've always liked the Rockford Fosgate products.
Pros: Small footprint Easy install
Cons: Should have done this sooner.
Great amp ive used rockford amps since the 90s and absolutely love them especially with their new style amps that have no more external fuses...
Pros: Does the trick plenty of power with a small footprint
|RMS Power Output (Watts x Channels)||
75 x 4 |
|Peak Power Output (Watts x Channels)||---|
|Power at 2 Ohms (Watts x Channels)||100 x 4|
|Bridged Power (Watts x Channels)||200 x 2|
|Minimum Impedance Bridged||4|
|Minimum Impedance Unbridged||2|
|Best Frequency Response||20-20k Hz|
|THD at Rated RMS Power||1%|
|Signal to Noise Ratio||90 dB|
|Low-Pass Crossover Frequency||50-250 Hz|
|Low-Pass Slope (dB/octave)||12 dB/oct|
|High-Pass Crossover Frequency||50-250 Hz|
|High-Pass Slope (dB/octave)||12 dB/oct|
|Bass Boost||0-18 dB|
|Bass Boost Frequency||45 Hz|
|Speaker Level Inputs||No|
|Preamp Outputs||1 pair|
|Parts Warranty||1 Year|
|Labor Warranty||1 Year|
Overview: The Rockford Fosgate Prime R400-4D is a 4-channel full-range Class D amplifier. It is optimized to power a full-range front/rear speaker system. You can also bridge the front and/or rear channels to run a subwoofer or two. The Class D design is very efficient with a cast aluminum heatsink to keep it in a small footprint.
CEA 2006 Compliant: The R400-4D's power ratings are measured according to the strict standards dictated by the Consumer Electronics Association (CEA). These standards allow you to accurately compare the rated power output of all CEA 2006-compliant amplifiers, even different brands. Manufacturers who adhere to the standards can display the CEA 2006 logo on their products and packaging. The RMS power output is as follows (measured with a 14.4 volt input, <1% THD+N, 20 Hz-20 kHz):
LED Indicator: The amplifier is equipped with a top-mounted LED indicator which illuminates blue when the unit is turned on. The LED illuminates red when a protection circuit engages (short circuit or too low an impedance is detected at the speaker connections). The amplifier automatically turns off if this occurs.
Mounting: The amplifier can be mounted vertically, horizontally, or inverted using the supplied mounting screws; horizontal mounting (right side up) will provide the best cooling.
Independent Controls: The R400-4D has independent, top-mounted controls for the front and rear channels. The controls include:
Punch EQ: The rear channel has an independent Punch EQ (bass boost) control that works with the crossover switch. When the rear channel crossover is set to low-pass, the Punch EQ can add a bass boost, centered at 45 Hz, from 0 dB to +18 dB.
2/4 CH Switch: When the 2/4 CH switch is set to the 2 CH position, the inputs are switched to a 2-channel mode. The signal on the front input feeds all four output channels, however, you lose front to rear fading capability. In the 4 CH position, the amp uses both front and rear inputs and fading capability is restored.
Power Terminals: The power and ground terminals are nickel-plated set-screw terminals, and will accommodate up to 4-gauge wire. The set screws can be tightened/loosened with the supplied 3mm hex key.
Fuses: The amplifier does not have on-board fuses. A 40A fuse should be placed on the power wire within 18" of the battery.
Remote Turn-On Terminal: The remote turn-on terminal is a nickel-plated set-screw terminal that will accommodate up to 8-gauge wire. The set screws can be tightened/loosened with the supplied 3mm hex key.
Speaker Terminals: The speaker terminals are nickel-plated set-screw terminals that will accommodate up to 8-gauge wire. The set screws can be tightened/loosened with the supplied 3mm hex key.
RCA Input Jacks: There are two pairs of RCA input jacks for the front and rear channels. They are nickel-plated to resist signal degradation caused by corrosion.
RCA Pass-Thru Jacks: The nickel-plated RCA pass-thru jack provides a convenient source for daisy-chaining an additional amplifier without running an extra set of RCA cables from the front of the vehicle to the amplifier location.
At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.
I have always enjoyed the power and value from Rockford Fosgate equipment. [ Christopher Aug 23, 2017 ]
great power output from such a small amplifier. LOVE IT!!!!!! [ Alfonso Mar 19, 2017 ]
I am using everything Rockford fosgate I need 2 twleves a amp and a box combo [ daniel Dec 17, 2015 ]
Is it what i need [ sergio Dec 11, 2015 ]
Bang for the buck [ Brent Dec 05, 2015 ]
It says to run a #4 wire which can handle 100 amps I believe it just needs capacity for flow of electricity.. I notices if voltage drops amp crackles... [ Greg May 23, 2017 ]
In order to answer this question, there are a few variables that need to be filled in. Everyone's answer may differ ... I'd suggest using an ohms law calculator or amperage draw calculator online to give you the closest possible answer. [ Chris May 23, 2017 ]
Hi. I'm pretty sure it doesn't go by amperage, look at the wattage. If anything, very little amperage. [ eric gorski May 23, 2017 ]
It sure on ohms but I have mine hooked up to 4 pioneer 6 x 9s works fine [ DOUGLAS Jan 06, 2017 ]
It will power them both for sure, the speakers that have the higher resistance will suffer for sure. Great amp for what it cist [ Joseph W. Jan 06, 2017 ]
U won't go wrong with RF amps. I use the prime series. They put out gobs of power!! Plus They're small and don't draw much current. I didn't use a capacitor and I have no problems with lights dimming or bass cutting out and I'm running the R500x1D at 2 ohms. U won't find a better amp for the price imo. [ william Jan 07, 2016 ]
Rockford fosgate is the only option in my opinion, I have never had issues with my amps and when it comes to getting the power from theses amps it s way to easy . Well know and depndable quality unsurpassed . Don't make a mistake and choose a cheaper brand because you won't be happy , to with the best and forget about the rest. Dave [ David Jan 06, 2016 ]
Thanks for your question. For information on selecting the best amp for your speakers and sub I would recommend reaching out to an Advisor by phone (1-800-324-9695) or online chat. They will be able to help determine the differences between the amp models and help you make the best choice for your system. [ Kenny Jan 06, 2016 ] Staff
If you purchased the product from Crutchfield, feel free to contact our Tech Support team. They can walk you through the settings on the product and see if there may be a fix. Our toll-free Tech Support number is printed on your invoice, and is also available under the "My Orders" tab in the "My Account" section of our website. If you did not purchase the unit from Crutchfield, then you may want to contact the manufacturer. You can also post your question in our forums: http://community.crutchfield.com. Or try our online support center: http://crutchfield.custhelp.com/app/answers/list/kw/. [ Krissy May 26, 2014 ] Staff