Expert Service 1-877-289-7664 [Hours]

Fall Blow Out Dot Sale

Rockford Fosgate PRIME R300-4

300W Prime Series 4-Channel Amplifier

Discontinued
|

Good news and a little bad...

This item has been discontinued

But you may be interested in the newest model that's available.

r300x4 thumbnail

Rockford Fosgate R300X4

OUR PRICE: $129.99

View item

Get FAST answers from customers ASK a Question See questions answers

  • Prime Series 4-Channel Class A/B Car Amplifier
  • RMS Power Rating:
    • 4 ohms: 50 watts x 4 chan.
    • 2 ohms: 75 watts x 4 chan.
    • Bridged, 4 ohms: 150 watts x 2 chan.
  • MOSFET power supply and output stage
  • LED power and protect indicators
  • Bass Boost/EQ details: selectable bass boost (0, 6, 12 dB at 45Hz)
  • 4/3/2 channel operation
  • 2-Way System Protection circuitry (overload and speaker short protection)
  • Adjustable gain from 150mV to 8V
  • Heavy duty extruded aluminum alloy convection heat sink for extreme heat dissipation
  • Nickel-plated RCA level inputs
  • Nickel-plated screw terminals
  • Variable high-pass filter (80 Hz)
  • Variable low-pass filter (50-250 Hz, 12 dB/octave Butterworth)
  • CEA-2006 compliant amplifier
  • Frequency response: 20-20,000 Hz
  • Dimensions: 17.09"L x 7.67"W x 2.40"H
  • 8-gauge power and ground wiring is required for installation. Contact us for information regarding a discount on select amplifier kits when purchased together with this amplifier.
  • 1-year SonicElectronix.com warranty

Product History:

Rockford Fosgate R300X4 thumbnail
(newest, current model)
Rockford Fosgate R300-4 thumbnail
(previous model, replaced by Rockford Fosgate R300X4)

Power Specifications - Full Range Channels

RMS Power @ 4 ohms

The RMS power rating is the measure of continuous power that an amplifier can output, or a speaker can handle. It is the most accurate depiction of real, continuous power that the industry has so far.

If the final impedance of your speakers or subwoofers equals 4 ohms, this is how much power this amplifier will supply at that ohm level. The higher the RMS wattage, the more clean and loud your music will sound.

50 watts x 4 channels
RMS Power @ 2 ohms

The RMS power rating is the measure of continuous power that an amplifier can output, or a speaker can handle. It is the most accurate depiction of real, continuous power that the industry has so far.

If the final impedance of your speakers or subwoofers equals 2 ohms, this is how much power this amplifier will supply at that ohm level. The higher the RMS wattage, the more clean and loud your music will sound.

75 watts x 4 channels
Bridged RMS Power

Bridging refers to combining two channels on an amplifier to create one channel with double the voltage and an increased power output. A 2-channel amplifier will bridge down to 1-channel and a 4-channel amplifier can bridge to create 2-channels. An amplifier is most commonly bridged to drive a subwoofer.

Remember, once you bridge two channels down to one its final impedance will be 4 ohms unless otherwise specified. This rating lists the RMS power created once an amplifier is bridged.

150 watts x 2 channels

Amplifier Specifications

Amplifier Series
This designates the series of the amplifier. Many amps are available in a litany of different wattage and channel configurations, but maintain consistent features throughout the product line.
Prime (Rockford Fosgate)
Amplifier Class

An amplifier increases the power of the signal being fed to it by taking energy from its power supply and matching the signal but increasing its amplitude. Amplifiers use many different methods for converting these electrical signals and have been categorized into classes.

Class A/B: Greater than 50% of the input signal is amplified while the other percentage is “off”. These amplifiers have a small amount of current flowing through the output transistors all the time which almost eliminates crossover distortion. Class A/B has great sound quality but is not as efficient as class D. These amps are most commonly used to drive speakers.

Class D: Also known as switching amplifiers, class D amps have output transistors that are completely turned “on” or “off”. This means that when the transistors are on, there is almost no voltage across them but when they are off there is significant voltage but no current flowing through it which makes these amplifiers very efficient at the cost of sound quality. These amps are most commonly used to drive subwoofers.

Other Classes: You may see classes such as GH, bD, X, FD, etc. by some manufactures. These amplifiers tend to be either class A/B, D or a hybrid of the two but with improvements to their designs that can make them more efficient or offer better sound quality.

AB
Number of Channels
Each channel on an amplifier will power one speaker using a positive and negative cable. There are various types of amplifiers, each designed to power a certain number of speakers. Monoblock amplifiers, also known as single channel, are designed to power one or more subwoofers. These amplifiers often have very high power ratings. On the other hand, multi-channel amplifiers power multiple speakers, usually at lower power ratings. 2-Channel and 4-Channel amplifiers can power car speakers or low powered subwoofers. Occasionally you might see a 5 or 6-channel amplifier that can power speakers and subwoofers at the same time. The most common setup is a monoblock amp to run subwoofers and a 4-channel amp to run door speakers. Check out our Knowledge Base for more information.
4
Total RMS Power Output
Total RMS power is measured by multiplying RMS power per channel by the number of channels, and is calculated at the lowest level of operating impedance.

RMS power is the amount of continuous power, measured in watts, that an amplifier produces is called RMS power. The higher the RMS figure, the louder and cleaner your music sounds.

The RMS output figure is much more accurate than the peak rating when comparing products.

300 watts
Maximum Input Gauge Size
This is the largest gauge wire that will fit into the power and ground terminals of this device. The lower the gauge number, the thicker the wire is. For example, a 4 gauge wire is thicker than an 8 gauge wire and thus has higher current carrying capacity. Always do your best to get this size wire to reduce the risk of damage to your components.
8 AWG
Minimum Impedance Unbridged
The lowest impedance the amplifier will handle when it is not bridged.
2 ohms
Minimum Impedance Bridged
The lowest impedance the amplifier will handle when it is bridged.
4 ohms
THD at Rated RMS Power
The amount of change in harmonic content of the signal as it is amplified. A lower figure indicates less change and a more accurate amp. THD below 0.10% is inaudible.
1%
Speaker Level Inputs
Speaker level inputs are commonly referred to as high-level inputs and vice versa. This input type allows you to get your audio signal directly from the speaker wire in your vehicle, instead of using RCA cables. The advantage of this is factory integration, as most stock radios do not have RCA outputs to run amplifiers.
No
Preamp Outputs
Many amplifiers are equipped with RCA preamp outputs which pass the original music signal from the source to additional amplifiers. This is known as daisy chaining because the source connects to the first amp, and the first amp connects to the second amp, etc. The advantage to daisy chaining is you only need one 2-channel RCA cable to transfer the signal from the head-unit to the amplifier, and then one additional cable for each amp being daisy chained.
No
Built-in Crossover

A crossover is a type of filtering system that permits only certain frequencies to play. A Low-Pass (LP) crossover allows only frequencies below its setting to get through which is good in the case of some subwoofers. A High-Pass(HP) filter allows frequencies above its setting to pass through, this is normally used on speakers.

When a crossover is set to FULL it means no filtering is added and the full frequency spectrum is allowed through the amplifier. Filtering is important because feeding a speaker frequencies it cannot reproduce effectively creates distortion.

Low-pass (LP)
High-pass (HP)
Full (AP)
High-Pass Crossover Frequency
The high-pass crossover frequency can be a fixed crossover point or a variable crossover range. A variable high-pass crossover allows you to select a specific crossover point which allows frequencies above the set crossover point to pass, while making frequencies below the set point gently or harshly roll-off, depending on the steepness of the slope.

The steepness of the roll-off slope is measured in dB/octave and refers to the rate of attenuation (lowering of volume) outside their pass bands.

80 Hz
Low-Pass Crossover Frequency
The low-pass crossover frequency is typically used for subwoofers. It can be a fixed crossover point or a variable crossover range. A variable low-pass crossover allows you to select a specific crossover point which allows frequencies below the set crossover point to pass, while making frequencies above the set point gently or harshly roll-off, depending on the steepness of the slope.

The steepness of the roll-off slope is measured in dB/octave and refers to the rate of attenuation (lowering of volume) outside their pass bands.

50 - 250 Hz
Signal-to-Noise Ratio
This spec compares the strength of the signal to the level of background noise. A higher value indicates less background noise.
70 dB
Bass Boost
The objective of the bass boost is to get more kick out of your subwoofer. It is a circuit that emphasizes the lower frequencies at a given point. The bass boost should always be set first before setting the gain. This feature is known for destroying subwoofers and is commonly used incorrectly, so be cautious.
0, 6, 12dB
Bass/Gain Remote
If the amp comes with a bass/gain remote you will be able to control the level of your bass from your dashboard. Typically bass remotes also include a 16-20 ft. wire for installation.
No
Fan Cooled
A great feature to have if an amp generates a large amount of heat. Cooling fans can help regulate the temperature to prevent the amp from overheating (burning).
No
Fuse Rating
The amperage and the number of fuse(s) an amp requires.
25A x 2 
CEA-2006 Compliant
Amplifiers that have been tested to meet specific standards. When a car amplifier meets these standards, you can be sure that it will be able to produce the amount of power specified by the official CEA-2006 rating. Usually, these rating consist of the following items:
  • RMS Power
  • Signal-to-Noise Ratio

This rating applies to both external car amplifiers, as well as the amplifiers inside of in-dash stereos.

Yes

Specials with this Item

Promotions
Promotions we have offer More Ways to Shop for items that are on clearance, last chance, special offer and sales, Made in America, and more!
On Sale

Warranty and Return Policy

Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider
Sonic Electronix

Summary of Customer Ratings & Reviews

Rating Distribution

5 Star
78%
4 Star
22%
3 Star
0%
2 Star
0%
1 Star
0%

Average Attribution Rating

Durability
4.8
Value
4.9
Features
4.6
Design
4.6
Usability
4.9
John

Lebanon, PA

Overall
Durability
Value
Features
Design
Usability
GOOD AMP

December 23, 2010

I don't have a whole lot of experience with car amps, but my home systems have always been the envy. My friends would spend twice as much as me, and would eventually just have to concede that my system had the best sound. I know what I'm doing. My electronics background, and years as a musician with perfect pitch hearing is my gift. I feel I hit it right on the mark again in building my relatively inexpensive car system, starting with this amp!!! The amp is clean, and loud. Plenty loud for the little Nissan I have it in. In a larger sedan, I might want to step up the watts, but I like it loud. I have this pushing the two front, and two rear speakers, with a separate powered sub. It was stinking hot this summer, and it's stinking cold now!!! I had no problems what so ever. I didn't wait till the car cooled down any before I cranked it up, and the amp handled all that heat in my black car.

2 of 2 found this helpful

Help our customers find the most helpful reviews

Maxwell

carmichael, CA

Overall
Durability
Value
Features
Design
Usability
r300.4

June 10, 2010

I have this amp powering all my pioneer door speakers, i play it loud for extended amounts of time and no overheating at all, great sturdy amp at a unbeatable price.

2 of 2 found this helpful

Help our customers find the most helpful reviews

AJ

Sacramento, CA

Overall
Durability
Value
Features
Design
Usability
Great amp

February 7, 2014

I purchased this amp back in 2009 from my local car audio shop. at first i had some Memphis 6x9 and some 4x6 kickers. They sounded amazing. I later hooked up some 4x6 JBL power speakers and they sounded like 6.5 great mid-bass and clarity. anyways long story short i have hooked up different speakers to this amp and they all sounded great i currently have some 6x9 kickers and 6.5 PRV audio and some soundstream tweeters and it sounds fantastic. Pros: its loud, clear, and reliable, I have taken 3 hour drives and had been bumping it almost non stop. (I did had to stop and put gas) the controls are easily accessible. easy to mount and you dont have to worry about the mounting feet breaking easily. doesn't get scratched up very easily eatheir. cons: its somewhat bulky. on the instruction manual it says that it takes 4 gauge wire for power and ground but i could never get 4 gauge to fit unless you have some spades. it doesn't have high level inputs. overall a great product and reliable.

0 of 0 found this helpful

Help our customers find the most helpful reviews

mark

palm coast, FL

Overall
Durability
Value
Features
Design
Usability
amazing!

January 8, 2014

I love all RF products! this cheap amp literally pushes my cars speakers to their limits! i dont have top notch audio, cause im a college student and i cant afford to spend 500 on a pair of mids/highs. But i do have 150/pair speakers in front and back on doors. JBL, to be exact. Great amp!

0 of 0 found this helpful

Help our customers find the most helpful reviews

Eduardo

Centralia wa

Overall
Durability
Value
Features
Design
Usability
Rf

October 11, 2013

I have this bridged to two channels and it's running a pair of 6.5 component type r speakers to complete my 3 speaker system I got a 12 in type x, you'd need an expensive set up to beat the quality and power of this underrated amp, I completely recommend this even tho everything else in my car is alpine you cannot ignore how much amp you get for ur money

0 of 0 found this helpful

Help our customers find the most helpful reviews

Salvador

Ribera, NM

Overall
Durability
Value
Features
Design
Usability
Great Amp, Great Price == Awesome performance

September 17, 2013

I would highly recommend this amplifier for anyone who wants tight, responsive bass. Make sure you have good subwoofers as this amp packs a punch! I would buy this over and over again!

0 of 0 found this helpful

Help our customers find the most helpful reviews

Andrei

Canada

Overall
Durability
Value
Features
Design
Usability
Great Value!

September 17, 2013

Really like it because of its features, power output and the overall quality it offers in terms of built and how it makes the speakers connected to it, have a well balanced sound between low, mid and highs. Long term durability wouldn't be able to give a rating because I only had it for a few months, though I wouldn't be concerned about it and I would recommend it. I have connected 4 JBL speakers. Also at this price, performance and quality I had a hard time finding something similar

0 of 0 found this helpful

Help our customers find the most helpful reviews

Martin

Lawrenceville, GA

Overall
Durability
Value
Features
Design
Usability
Rockford amp R300-4

September 17, 2013

Awesome sound and great price. I replace my old Power Acoustic 400 × 4 with this Rockford amp, and believe me, it sounds like a whole new system. A lot more powerful and stronger mids plus clear highs, what else you can ask.

0 of 0 found this helpful

Help our customers find the most helpful reviews

Lachlan

Portland, OR

Overall
Durability
Value
Features
Design
Usability
Great Sound!

June 25, 2013

I'd highly recommend these speakers. I have them in the back of my Trooper powered from a 300W Rockford amp and they are amazing!!

0 of 0 found this helpful

Help our customers find the most helpful reviews

Dwayne

Canada

Overall
Durability
Value
Features
Design
Usability
Will continue to buy from Sonic!

January 4, 2013

I was looking for an inexpensive amp to run the factory speakers in my 2003 Maxima. -Amp works great -Sonic ships to Canada and takes care of brokerage/duty at a reasonable price -I will continue to use Sonic

0 of 0 found this helpful

Help our customers find the most helpful reviews

jr

tulare, CA

Overall
Durability
Value
Features
Design
Usability
wow

September 19, 2012

wow ok so before this i had a sound storm 4 channel to power all 4 speakers now i have this baby and man does it make a difference!!!! the sound is so clear and loud. Now my 2 12s are in perfect match with my speakers!

0 of 0 found this helpful

Help our customers find the most helpful reviews

c_ooper

akron ohio

Overall
Durability
Value
Features
Design
Usability
great amp for your buck!

August 18, 2012

I'm basically a rookie in the car audio game workin for a shop with over 20 years in the game and me only 5 . but lemme just say i know my audio and i know how to make it last. but this amp is great by far better than anything else in this price range you cant go wrong unless your not hooked up properly the end great buy, but im ready for more power for my db drive mids and highs got over 18 speakers hooked up off two of these you can hear me way before you see me

0 of 0 found this helpful

Help our customers find the most helpful reviews

JB

Lexington,Ky

Overall
Durability
Value
Features
Design
Usability
Powers the entire system

April 14, 2012

I wrestled for sometime on which amp to go with as I was extremely limited on space, so I went with the fosgate 300-4. Im running a pioneer head unit, cadence 7v line driver as far as high end speakers I choose a pair of kicker 6.5's for the doors and kicker 6x9's for the rear and went with a kicker c124 sub. I am absolutely amazed by the bass and how clear the high end is. If you were in doubt about running "only 150 watts" to your sub(s) have no fear, this amp does a fantastic job. For the money you'll not find better.

0 of 0 found this helpful

Help our customers find the most helpful reviews

RYAN

NEW ORLEANS, LA

Overall
Durability
Value
Features
Design
Usability
Clean Straight up sound

February 17, 2012

I recently bought this amp and the sound, power, and price you cant beat. I am powering some diamond audio 6-1/2" components and factory 6x9s clean & pure sound. I recommend this amp to anyone who is looking for great undistorted sound. Pros- doesn't take up plenty space for the amount of power that it has, Cons-couldn't find any you cant go wrong buy this amp.

0 of 0 found this helpful

Help our customers find the most helpful reviews

mofosta

Amarillo, Texas

Overall
Durability
Value
Features
Design
Usability
Excellent Product

January 26, 2012

I have had several Rockford Fosgate products in the past. My last Rockford amplifier lasted 14 years. I have purchased many of their items from amps to speakers to head units. Very reliable product. I will continue to purchase Rockford products as well as recommend them to others.

0 of 0 found this helpful

Help our customers find the most helpful reviews

SD's Finest

San diego

Overall
Durability
Value
Features
Design
Usability
Great amp for the price great quality

December 22, 2011

Pros- powerful, clear, adjustable for 4 speakers or 2 speakers and a sub. This amp over powers my kenwood speakers and makes them sound crystal clear all my friends are jealous of my vocals and think i payed over 200. Fast shipping from Sonic and the price is awesome. Cons- really long amp for my lil car thats it

0 of 0 found this helpful

Help our customers find the most helpful reviews

James

Detroit, MI

Overall
Durability
Value
Features
Design
Usability
rockford 4 channel

December 17, 2011

The rockford prime 300 is a good amp... Better than stock. I have this thing hooked up to 4 5.25 speakers and 2 3.5 speakers. I thought my car was not loud until I stepped inside my cousins grand prix. My system WAY louder and clearer. I would recommend this to a friend, because I get headaches just off vocals. The only con is that my speakers don't handle bass good enough(but that's whats subs are for). Love the way I can change db's by the flip of a switch.

0 of 0 found this helpful

Help our customers find the most helpful reviews

lil porn

chicago

Overall
Durability
Value
Features
Design
Usability
good amp

November 13, 2011

I bought this amp and put it on a pair of infiniti 6x9 and is sounds amazing. Good amplifier for the price.

0 of 0 found this helpful

Help our customers find the most helpful reviews

Leo

Richmond Hill, GA

Overall
Durability
Value
Features
Design
Usability
Rockford Fosgate still great

November 7, 2011

I am using this amp to power my pillar tweeters and dash 4" speakers. It works great and I like the fact that it has fine tuning controls on the AMP itself.

0 of 0 found this helpful

Help our customers find the most helpful reviews

daniel

Adelanto, CA

Overall
Durability
Value
Features
Design
Usability
Just what I wanted

August 21, 2011

Loud and clear just like the company claims.

0 of 0 found this helpful

Help our customers find the most helpful reviews

Accessory Tools and Products

Accessories added

NVX XKIT84 4-Channel 8-Gauge Wiring Kit

In case you didn't know, NVX has top notch wire and this kit has everything you need!

Your Price $69.99

Rockford Fosgate RFK8 Wiring Kit

Get a matching Fosgate wiring kit for your new Fosgate amplifier! Don't forget the RCA's!

Your Price $47.99

Kicker PK8 8-Gauge Wiring Kit

Great wire for your awesome new amp! Don't forget the RCA's!

Your Price $29.95

NVX XBG3PK 1/0 Gauge OFC Big 3 Upgrade Kit

Comes with everything you need to upgrade your power and ground wire.

Your Price $59.99

Kicker Big 3 Package 1/0 Gauge Big 3 Upgrade Kit

Get all you need including wire cutters to upgrade your power and ground wire.

Your Price $149.99

Belva BBG3KT CCA 1/0 Gauge Big Three Kit

Features everything needed to upgrade factory power and ground wire.

Your Price $39.99

Small Universal Remote Level Bass Control

The Scosche RLC is a smaller universal bass remote that connects via RCA inputs.

Your Price $11.99

StreetWires FB8

8 Gauge Firewall Bushing

Your Price $6.95

NVX XDBU4 - Top of the Line!

Distribution Block with Two 1/0 or 4 AWG Inputs and Four 4 or 8 AWG Outputs

Your Price $17.99

NVX XIV45 4-Channel RCA Audio Interconnect Cable

5 Meters (16.4 ft.) 4-Channel RCA Audio Interconnect Cable with Dual Twisted Pair Hyper-Flex Technology

Your Price $23.99

Kicker K-Series RCA Interconnect Cable

19 ft. of 4-Channel RCA cable with dual twisted-pair conductors, hyper-flex technology, and gold plated contacts for maximum signal transfer!

Your Price $29.95

StreetWires ZN7 RCA Interconnect Cable

16.4 ft. of 4-Channel RCA Cable with hyper twist construction, oxygen free copper, and precision machined tips.

Your Price $59.99

Kicker 4-Channel RCA Audio Interconnect Cable

4 Meters (13 ft.) 4-Channel K-Series RCA Audio Interconnect Cable

Your Price $19.95

NVX XWS1225 12 AWG Speaker Wire

25 ft. of True 12 Gauge 100% Copper EnvyFlex Speaker Cable/Wire

Your Price $39.99

NVX XWS1250 Speaker Wire

50 ft. of True 12 Gauge 100% Copper EnvyFlex Speaker Cable/Wire

Your Price $29.99

Belva BBSW127 12 AWG Speaker Wire

12 Gauge 7 Meter (23 Ft) Speaker Wire (CCA)

Your Price $14.99

Belva BBSW167 16 AWG Speaker Wire

16 Gauge 7 Meter (23 Ft) Speaker Wire (CCA)

Your Price $12.99

The Install Bay IB-CAP1F

True 1.0 Farad Car Audio Capacitor for up to 1000W Max

Your Price $37.99

e2 ECAP1 by Scosche - Mid-Level 1 Farad

Digital 1.0 Farad Car Audio Capacitor for up to 1000W Max

Your Price $49.99

Rockford Fosgate RFC1D - Top of the Line 1 Farad

Digital 1.0 Farad Car Audio Capacitor for up to 1000W Max

Your Price $99.99

Scosche SPL Meter SPL1000F

Handheld boomSTICK measures your SPL range from 60 to 135 dB

Your Price $21.99

Hide answersShow all answers | Sort by
No questions have been asked about this item. Be the first!

Product Summary

Manufacturer

Model Number

R300-4

UPC

780687328801

Weight

9.00lbs

Internal SKU

r3004

Internal Product ID

19566

Sonic Electronix Wiring Guide

Wiring Diagram Legend

Warning: The image depicted shows the resistance change when wiring multiple subwoofer terminals. Please refer to your subwoofer's owner's manual for the proper wiring of its terminals. Sonic Electronix, Inc. is not responsible for damage caused to your audio system or vehicle due to improper installation. Please call tech support at 1-877-289-7664 if you require additional assistance.

Product Name: Rockford Fosgate PRIME R300-4