Customer Ratings & Reviews

Poor fidelity

The product is OK for a kid, or for a very noisy environment, but not OK for a discriminating ear. I tried this route because I was trying to put the amps under a cover, I thought they would stay cooler. Nope. This guy gets hot. I would recommend to some, but not others.

great

This is my first amp of d class, but once tuned with scope or whatever It is this amp Gets it.

Good

I have had this for a couple months now and it works great. I had to send it back for replacement after a week of owning it, not really sure what happened. Rockford fosgate is a reliable product usually but the first one started smoking after I had been using it for a while. Sonic electronix replaced it and it works great now. I do recommend buying a amp fan to go with it because it does get very hot after long periods of time. Sounds great though.

Good amp

Great highs amp for powering small speakers. That's all I use it for and it's not even at the 12 o clock position. I would recommend it. Also I like the fact that it's compact in size.

Awesome amp! Rockford all the way!

I have been wanting to build an all Rockford system for a while, I knew I wanted to run a sub and four new speakers (All Rockford) but didn't want to buy two amps. This amp was the answer, pushing 500 RMS @ 2 ohms (according to the birth sheet) this thing rocks. I have two pairs of 4-ohm Rockford 6.5s running at 2-ohms bridged. So they are getting a good 65 RMS each, and they produce great highs and mid. For the lows, I have a DVC 10" Rockford sub that's being pushed a good 250 RMS. The sound is amazing, highs, lows, mids, everything all in perfect crisp harmony. This amp is absolutely amazing, not to mention its a perfect size. All my friends find it hard to believe that this little amp pushes so hard. Worth every penny!

Like you need me to tell you to buy this amp

Mated the Rockford Fosgate R400-4D to a Pioneer head unit. Wow! Amazing sound. Loud. Crisp. Clear. Everything you want in a sound system. Fits perfectly under the front driver's seat. It sounded great out of the box but is absolutely superb now that I've been able to tweak it a little bit. Installed the amp using an NVX Audio XKit44 with 4 gauge wire 4 channel connection kit. Stop reading reviews and buy this amp.

small with a lot of power!!

This amp is great.. I bough it to wire 4 Rockford Fosgate PPS8-6 to wire them at bridge 4ohms (2 speakers at each channel bridge) let me tell you..WOW!! This amp gives power to the speakers and I'm happy with that..I recommend this amp and for the price..NICE!!

Good Amp!

Fast shipping, never have problems with the amp, & puts out more than it says.

Excellent Amplifier

Got this amplifier to power my six speakers in my '99 Camaro; it does an excellent job! Ran the two rear pair in parallel and made a custom MDF rack to mount both this amp and the sub amp on the trunk deck just behind the back seat. My only frustration with the amplifier is the angle that the wires have to enter into the terminals at; they wires have to bend upward. It's just less convenient than having terminals coming straight out of the amplifier.

As far as sound quality goes, this amplifier brought my Rockford Fosgate Punch speakers to life! The clarity is brilliant and the crossovers work splendidly. I am very pleased with my purchase and will always look to Rockford for car audio components.

Great Bang for the buck!

Awesome power for such a small size. Fits in small space.

great amp

All around a great amp , good sound quality, really lacks in the midrange area but still good quality well built

rockford r400-4d

this rockford amp is a great product. works well,looks good and stays cool.

702 LOUDNESS

Great little amp, the crossovers built into this amp are outstanding, I can dial any music from thrash to rap, and a great price, thanks sonic electronix

Right size for compact installs, but lacks in sound quality

This amp is great if you're in a budget and looking for a small footprint for a compact install. But it significantly lacks in sound quality. For its size it's puts out gobs of power (birth sheet claims 514 burst power) but the sound is very... Flat. Midbass lacks clarity, highs became harsh relatively low in volume. I tried everything but I was disappointed from the get go. The old school (90's) Orion amp it replaced had MUCH better sound than this amp, much more "musical" really. It's not that this amp is terrible, it's just not great.
Maybe it would be a different story when powering a sub, but if you're looking for great sound quality look elsewhere or at least a higher end RF amp.

outstanding performance

this is my second Rockford product and I am very happy with the amp performs great and matches with the MB Quart speakers better than any other set up I have owned

YES

These are powering my NVX v-series speakers very well. There is not much to say - this amp can work like a slave without dying from the heat, literally. The sound quality is excellent (maybe since it's a Class D amp) and the features are good too. I have absolutely no regret purchasing this amp.

Amazing amp

Once again Rockford does its stuff. This amp is a monster and runs my Power 6x9s and 5 1/4" components extremely well. They aren't monster speakers by any means, but this amp keeps them perfectly fed at 75w to the components and 100w to the rears...very, very loud! Keeps the music as loud as and clear my subs keep their bass, which is nice because now I can actually hear the music rather than bass alone.

Great amp

Came 514w out the box gain is matched to the deck at 1 and never gets hot.

Amazing amp

If this is what the new prime series is offering I couldn't imagine what the new power series is going to offer. Got this amp pushing a set of t2 components and a set of 6x8 primes and wow sounds way better now. Had a Rockford PBR300x4 but it messed up? Sonic was quick and great on the return if you plan on getting the PBRx4 just spend the extra $15 and get this great choice on my part.

great amp!

i bought this amp to power my t2-652s and spr-17c. this amp delivers and then some. for the price and power this amp puts out i def. recommend this product. i have been a fan of rockfords amps and speakers since i started building my audio system. they deliver top quality products. especially there prime amps. the size is another plus in my book. i have not have any problems with this amp or any of rockfords products. to put the icing on it all ,sonicelectronix prices are especially why i keeping coming back to buy more products!! thanks!!

702 LOUDNESS

I got this amp because my 50 x4 four channel was out,sure glad I did,75 x 4 ,much nicer ,could not believe my ears,an for the price,also john was very helpful helping match the watts to the speakers I have thanks again sonic electronix

Excellent amp for the money!

I bought this amp to replace a PPI P600.2 because I needed 2 more channels to run an active front stage. I'm powering a JBL P660C component set ran active from a MiniDSP. After I adjusted my gains the noise floor was basically nonexistent and my speakers have never sounded better. They get louder than I would ever want and sound great doing it.

The amp is tiny, even smaller than I expected, and fits under my driver's seat with plenty of room around it. It never gets even warm to the touch, even after playing music for over an hour on hot summer days with the windows down. The birthsheet said it produces almost 550 watts and I believe it. If you need a small 4 channel amp that has plenty of power for not much money, you can't do much better than this!

Also, I own the Rockford Fosgate R1200-1D that powers my 2 Polk MM1240 subs and all of the same things hold true for it as well.

good

has the power, quality and runs cool, but it lacks in the mid-low range frequencies.

and to the guy who says he was only using about 15% of amp power u need to learn the gain is not a volume, it is used to tune the amp to the radio outputs, higher voltage = lower settings, lower voltage = higher settings

Small and Powerful

I'm so happy I finally decided to add an amp to power my Polk db series speakers in my truck; it makes a world of difference in the sound quality, especially in the amount of bass added to my front stage. I went with this amp because I needed a small amp in the 50-75w rms range that would fit under my seat. This amp does not disappoint! I knew it would be small, but I wasn't prepared for how compact this little thing would be. Even with this amps small size, heat is not a problem. This amp is Class D, so it runs very efficiently, and therefore very cool. It just gets warm to the touch and has plenty of power for pretty much any system. The amp sounds great, although there is slight distortion at zero volume, but once music is playing this sound is inaudible (this distortion is probably more noticeable because I have 2v preouts and have to turn the gains a little higher than if I had 4v ones). Build quality is extremely solid and I expect this amp to last forever, my only gripe is that controls on top are a little flimsy, but this isn't a big deal at all. Overall this is a great little amp. If you're in the market for a small and powerful amp look no further than the R400-4D.

ford ranger

i need a small amp to fit under my seat that does not get hot and This the one

Not too bad

Handles everything and can push T1675-S's and T165's quite nicely. After not using the gain as a volume control and setting it properly i could push the speakers to there limits with clear highs and lows and no distortion.

Outstanding amp

Clean, clear, and loud. Great amp. I'm using it to power 4 infinity 6.5 inch two way speakers in the radar arch of my boat. Factory tested at 502 watts RMS. The only amp I have that is better is the R600 (same amp more power). Definitely go for 2 guage wire and a second battery if your getting more than one.

very strong but maybe something wrong with it

Had this hooked up to 4 rockford fosgate T1675's that say they handle 75 watts rms each. this amp puts out 75rms X 4 but i had the gains on 2. 2 out of 11 and was insanely loud. Anyways, speakers started sounding very bad after about an hour and the amp started smoking really bad. keep in mind that i was only using about 20% of the amp capability so i was only putting around 15 rms to each speaker. i have been hooking up stereo systems for 15 years.

Do not buy

I purchased one of these and had it hooked up to two pair of 6.5 Pioneer components for ABOUT 15 MINUTES and it completely fried itself. I'm not sure what to say about this other than the RF quality control is not the same as it used to be. I have had several RF amps in the past and never been disappointed until now. The up side is that it failed immediately instead of 13 months after purchase. Sonic was great to work with and they hooked me up w/a RMA to get my money back. I replaced this w/the JL XD400 and it blew this thing out of the water; no comparison. However, the JL amp was more. All that said, you get what you pay for. Do not buy this amp *unless your only pushing a pair of tweeters.

Great AMP

AWESOME AWESOME AWESOME AMP!! Produced way more power than it was rated..LOVE the amp...thanks Sonic!!

Works great

Definitely puts out the power and clarity just ground it good

By Anonymous on December 2, 2019 Verified purchase

Fosgate Prime R4004D

Great amp professional sound quality well built with solid terminal connections

By Anonymous on September 6, 2019 Verified purchase

Amazing

This amp is severely underrated mine came with the test sheet and tested at 567 watts! It cleared up my Skar components tremendously

By Anonymous on July 8, 2019 Verified purchase

Amazing

I highly recommend this amp to pair up with door speakers the cross over on the amp really allows you to clear them up and I’m running it at less than half the power !

Great amp

perfect for my highs I would recommend for anyone looking for clean sound.

By Anonymous on April 8, 2019 Verified purchase

Works great!

I would recommend this to anyone who is getting a system it worked really good and gave me the Watts I needed. And it made my set up look good.

Rockford Fosgate Prime R400-4D

It was exactly what I was looking for and work GREAT!!

Big clean power

If your looking for big clean power without all the bulk of a monster size amp then this is the amp for you ,doesn't get hot or shut down

By Rafael on September 7, 2017 Verified purchase

Nice little amp with small footprint.

Very nice little amp! Birth certificate states that is way more powerful than listed. Mine came in at 98 watts rms per channel. Rockford Fosgates amps always put out more power than listed. I paired this amp with 2 sets of Rockford Fosgate P-1683s 6X8s in my Ford Explorer along with a Kicker CX300x1 mono block amp, a single 10 db1040 in a Atrend vented box. I can honestly say that the sound is awesome. You can feel the bass in your chest and the clarity through the 6X8s is clean and clear. You can hear me coming up the road. I have read one other review about the amp getting hot, no such issue here!! He must have the amp set up wrong. This little amp is totally worth the money, money well spent!!! I have had this amp in my truck mow for a period of 9 months now with no issues at all.

By Paul on May 6, 2017 Verified purchase

Loud af

Way louder than my head unit...tons of bass and trebble... got it connected to 4 cresendo symphony speakers.... sounds great... I was worried about class D for mids and highs but rockford know their stuff...

By Kelvin on February 24, 2017 Verified purchase

Fantastic Amp!!

I would not have expected so much from Rockford Fosgate's prime series, but this amplifier puts out the wattage it advertises with phenomenal quality to my T-675 components. Definitely worth $165!