Rockford Fosgate's Power Series Amplifiers

Rockford Fosgate has a well-deserved reputation for building high-quality mobile audio products. Their Power Series amps occupy the top of the amplifier food chain, with fine-tuned audio controls, extreme durability, and proprietary technologies that deliver stronger, more reliable performance than most other amplifiers on the market today.

High-grade internal components mean high-power output.

Even heat dispersal for longer life

Dynamic Thermal Management

Power Series amps use Rockford Fosgate's patented, award-winning "Dynamic Thermal Management," a 3-stage cooling system that uses forced air to dissipate heat evenly across the amp and out through the large heatsinks. This results in cooler internal components, higher efficiency, and lower distortion.

MEHSA cooling process

Maximum Efficiency Heat Sink Application increases heat transfer away from the transistors MEHSA is a Rockford Fosgate proprietary process that increases the heat transfer from the MOSFET devices to the heatsink. This allows the heat to escape more readily from the amplifier, so that the transistors stay cooler.

Extra-quiet inputs

Differential Inputs prevent noise from entering "Differential Input" circuitry helps eliminate any electronically induced noise or hum that could be picked up by the input cables, allowing only clean signals to enter the amplifier. You get more music with less heat and noise in a stylish package that's up to 40% smaller than previous models.

T400-4 Power performance

The T400-4 amplifier puts out 60 watts RMS into each of its four channels — more than enough to drive your front and rear speakers to their musical peaks. Or you can bridge your T400-4 to blast 200 watts each to a pair of subwoofers. Either way, you can depend on clean, powerful sound from your Power Series amp.

T400-4 connections

Product Highlights:

  • 4-channel car amplifier
  • 60 watts RMS x 4 at 4 ohms (100 watts RMS x 4 at 2 ohms)
  • 200 watts RMS x 2 bridged output at 4 ohms (2-ohm stable in bridged mode)
  • CEA-2006 compliant
  • Dynamic Thermal Management cooling system
  • Differential Input circuitry eliminates hum
  • variable high- and low-pass filters (50-500 Hz, 24 dB/octave)
  • variable bass/treble boost (0-18 dB at 45 Hz, 0-12 dB at 12k Hz)
  • optional remote bass/treble boost (available soon)
  • Class-AB amplifier design
  • MOSFET power and output stages
  • preamp inputs
  • 4-gauge power and ground leads and a 100-amp fuse recommended — wiring and hardware not included with amplifier
  • no on-board fuses — when installing multiple amps in a system, an additional 100-amp in-line fuse between the distribution block and the amplifier is recommended
  • 13-5/8"W x 2-1/4"H x 9-5/8"D
  • warranty: 90 days
  • Our 60-day money-back guarantee

My system has plenty of power. Who needs an amp?

You might think you don't need an amp because you have a 400-watt system in your car, or because your new stereo puts out 50 watts a channel. But those are peak wattage ratings, which may boil down to 15 or 20 watts per channel, using the more realistic RMS rating. An amp sends your speakers the power they need to deliver your music with clarity and impact, whether you're using factory speakers or high-performance components. And low-frequency reproduction requires lots of power, so an amp is an absolute must if you're adding a sub to your system.

Hands-on research

What's in the box?

Download owner's manual

  • 4-channel amplifier (refurbished)
  • Four 1-1/2" Self-tapping screws
  • Installation & Operation manual (Eng / Fren / Span / Ger / Ita)
  • Factory Refurbished Warranty sheet

Product Research

Inputs and Outputs Notes


Factory Refurbished: This Rockford Fosgate FRT400-4 is a factory refurbished version of the Power T400-4. It was engineered and assembled in Tempe, AZ, using domestic and globally-sourced components. The warranty on RF factory refurbished products is 90 days parts and labor.

Cast Aluminum Heatsink: The cast aluminum heatsink dissipates heat generated by the amplifier's circuitry. The inherent advantage of casting provides a 30% improvement of cooling over conventional extrusion heatsink designs.

Dynamic Thermal Management (DTM): DTM Evenly distributes excess heat across entire amplifier heatsink.

MEHSA³ (Maximum Efficiency Heat Sink Application-Third Generation): MEHSA is a Rockford Fosgate proprietary process that increases the heat transfer from the MOSFET devices to the heatsink. The multi-layer insulated metal MEHSA substrate operates with minimal thermal resistance, spreading heat both downward and outward to quickly dissipate heat from each device across the heatsink. This allows greater power output, enhanced thermal stability, and maximum reliability.

Trans-ANA (TRANSconductance Active Nodal Amplifier): Trans-ANA is a circuit that allows the audio signal to pass through the amplifier at low voltage. The signal is directly level-shifted to the fixed high voltage rails via a pair of drive transistors. Signal linearity is assured by an active node formed  by the drive transistors at ultrasonic frequencies. The result is crystal clear sound quality.

NOMAD (NOn-Multiplying Advanced Decision): NOMAD is an intelligent protection circuit that uses an analog computer to make real time decisions regarding temperature, voltage, current and impedance. The unit is protected without limiting sound output unless needed.

TO-247 MOSFET: The Power T400-4 utilizes ultra high performance MOSFET output devices, giving the amplifier more power handling capability as well as lower thermal impedance for more reliable operation, even under the harshest load conditions.

DSM (Discrete Surface Mount): In the manufacturing process high speed robotics are used to place 1% tolerance parts and large board traces. DSM improves the efficiency of the circuit, decreases cross-talk from other discrete components and lowers operating temperature.

2/4-Channel Switch: The 2/4-channel switch changes the T400-4 between 4-channel and 2-channel input mode. When operating in the 2-channel mode, the amplifier produces 4-channels of output with connections to only the front channel inputs.

Internal Crossovers: The amplifier's internal front and rear crossovers have a 24 dB/octave slope. Each is independently selectable for high-pass, all-pass (full range), or low-pass operation and is variable from 50Hz to 500Hz.

Punch EQ: Punch EQ works along with the crossover switches. Like the crossovers, the front and rear EQs are independent of one another. When the crossover is set to low-pass, the Punch EQ acts as a variable bass boost; 0-18 dB at 45 Hz. When the crossover is set to high-pass, the Punch EQ acts as variable treble boost, 0-12 dB at 12 kHz. When the crossover is set to all-pass, both the bass and treble boost circuits are active.

Power and Protection LEDs: The LEDs are located on top of the amplifier. A blue Power LED illuminates when the amplifier is turned on. A red Thermal LED illuminates if the amplifier overheats. The yellow Protect LED illuminates if a short circuit or too low an impedance is detected at the speaker connections. When any of the protection circuits engage, the amp automatically shuts down until the problem is corrected.

Inputs and Outputs Notes

Power Connections: The power and ground terminals are nickel-plated captive c-clamp wire connectors and will accommodate up to 4-gauge wire. An external 100-amp fuse (not included) must be installed on the power wire. The remote turn-on terminal will accept wire sizes of 12- to 24-gauge. A Phillips-head or slotted screwdriver (not supplied) is required to tighten/loosen the terminals.

Speaker Connections: The 4-channel nickel-plated clamp wire connectors will accept 8-gauge to 18-gauge wire. A Phillips-head or slotted screwdriver (not supplied) is required to tighten/loosen the terminals.

Remote Punch EQ (PEQ) Connection: An RJ-45 jack is provided for connecting an optional remote PEQ control (item number 575ROCKPEQ). If you use the remote PEQ, the rear Punch EQ control on the amp is disabled, and replaced by the remote. Note: Previous model Punch Bass and Para-Punch remotes will not work with this amp.

Our Product Research Team

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.

Rockford Fosgate Power T400-4 Reviews

Average Customer Review:

8 reviews
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RFFG T400-4

Written By RubenA, Iowa City on Sunday, September 16, 2012

Bought this amp over 4 years ago. Still going strong with NO problems. The Punch EQ Setting can really bring speakers to life. Highly suggest!

Pros: Easy to install, Great build quality, Amazing sound, Ability to do 2 channel OR 4 channel. Light weight.

Cons: N/A

Foskin awesome!

Written By Mike, Las Vegas, NV on Tuesday, July 10, 2012

This thing rocks my chrysler 300...I have fosgate 6.5's in the doors and t1693 6 x9 s in the deck with a jl 300w sub and this amp runs it all! Even tho its not recommended for this setup I sure hope it lasts cuz it is the best I've ever had!

You won't be disappointed

Written By RPC, Streamwood, IL on Thursday, November 18, 2010

Crutchfield Customer Review (What's this?)

I returned a BA GT-475 and got the RF T400-4 instead. See my BA review for details.

Bought the amp for RFA-64 midbass drivers and single Infinity Beta Twelve sub.

Love the birth certificate - proves it was tested and you know exactly what you're getting. Mine was 74Wx4. Amp feels well built and connections were great. The bass is AMAZING! I can crank my stereo up to my ear's max tolerance and the sound is distortion free. It hits really hard even at the lowest frequencies. I get no engine whine coming through the speakers at all. I considered the RF P400-4 but it only has a 12db/octave x-over. For $80 more the T400-4 gives you a 24db/oct x-over. For my needs it was a must and well worth the money.

3 complaints:
1) Wish the x-over controls were more precise. I can't say if mine is set to 65hz, 70 or 75. The knob is not exact and you have to estimate.
2) Be careful with the gain and x-over knobs. They are made of plastic (think RF should have spent a few cents more here) and you can damage it if you don't use the right tool.
3) Wish it was a little cheaper.

Overall, I'm very happy with this amp.

Rockford! Still Doing It!!

Written By matt, Hawaii on Thursday, July 30, 2009

Crutchfield Customer Review (What's this?)

My experience with R.F. amps goes back to the Punch 75/150 days. R.F.
always made awsome amps that were powerful and punchy. The T400-4
still delivers those aspects no doubt about it.
Currently using the T400-4 pushing my seperates in front and coaxials in
back. It does the job well just like a R.F. amp should. Highly recommended if
you are a average listener or just want SPL. Dont get me wrong, it's an
AWSOME amp I just wish the power deliverence to the seperates were a
little more SMOOTHER or GRACEFUL.
All in all I'm giving it 5 Stars just because this amp "Kicks Butt"! I'm glad R.F.
is CONSISTENT in producing awsome amps.


Written By ryan, Ohio on Wednesday, May 27, 2009

I wanted an amp that could do it all and I found it with the T400-4. I have Infinity 6.5 components in front, Fosgate 6.5 coaxials in back, and a 10" Fosgate Sub all connected. Amazing how this amp can handle all of this. I have the components and coaxials connected to the front channels running at 2ohm and the 8ohm DVC sub running bridged at 4ohm on the rear channels. If you are not looking for ridiculous bass then this is a perfect setup. Have this in my 350z which is hatchback. The sub may not be loud enough in a trunk. I originally connected a 4ohm DVC running at 2ohm and the amp shutoff (protective circuitry kicked in) at high levels. So this amp is not fully 2ohm stable but good enough for me. Buy this amp and get the punch bass remote!!

Great Amp

Written By Joseph, Salinas CA on Sunday, March 01, 2009

Crutchfield Customer Review (What's this?)

I love loud clear music and this amp satisfies my needs. A good JVC head with a Bazooka powered sub with four Infinity speakers and this system is one power house. I went with fosgate because they have been around for a long long time and the technology that they have developed, cooler more powerful amps, A little pricey but well worth it. I was a little concerned if changing my 500 watt Sony amp was going to make a difference but it did. Music just sounds better with this amp. I do recommend it to anyone who cares about great sound. I give it a 10. Make sure you wire it with the proper wiring because this amp is thirsty for power. A power condenser is a must because most likely cranking it up will drain your cars power supply.

Rockford Fosgate Power T400-4

Written By Dmorel, Phenix City, AL. on Wednesday, February 06, 2008

Crutchfield Customer Review (What's this?)

This is one STRONG Amplifier!! I have always used two 2 channel amplifiers in the past. Having never used a four channel, and having heard a few systems with them, I wasnt impressed, until I got THIS Rockford Fosgate T400-4! All I can say is WOW! This thing Rocks! There is more power here than I need, thats for sure. Since I have the rear Channels running in mono on 2 ohms, it really puts it out! and the front side , running in stereo on 4 ohms, is super clean and LOUD! Great Amp.!

rockford forever for me

Written By jeff, conover,nc on Wednesday, April 11, 2007

picked up this amp after my old power 4004a was humming through the front outputs but lasting 7 yrs old sweet music!i liked the screws that secure power...ground and speaker now compared to having to use allen wrenches...only need #2 phillips screwdriver to secure.
makes it sound like a total new system..sound quality like i added new speakers but i didnt.
here is my actual amp certificate:
77x4@4 ohms....128x4@ 2 ohms....256x2@4 ohms bridged.
the amp is very stylish looking but no connector covers to conceal wiring that would have made it better to have but not really important.only installed it today but the sound is rockford amps my old 360a2 is still going strong at 7 yrs old driving a power stage 1 dvc 2 ohm sub...that sub rocks too...check it out if u need a sub!
plus been a customer of crutchfield for going on 20 yrs no other company comparies! buy from them and u will be a customer for life like me!

Get everything you’ll need to enjoy your new Rockford Fosgate Power T400-4

You'll need an amp wiring kit to install your new amplifier, as wiring is not included.
Bring the music from your amp to your speakers.
Patch cables take the music from your stereo to the amplifier. Most amp wiring kits don't include them.
Add a remote and control your amp from the driver's seat.
Get a spare fuse now so you won't be listening to silence later.
For multi-amp systems, you'll need a separate fuse holder.
Helps protect your car's charging system and improves power handling. Required power and ground wires not included with cap.
The right tools will make the installation easier.
Have your new amplifier put in by a qualified professional in your area.
Rockford Fosgate RFK4X

Rockford Fosgate RFK4X

Complete 4-gauge amplifier wiring kit
Includes patch cable and speaker wire

Item #: 575RFK4X


Add to Cart
Rockford Fosgate RFK4

Rockford Fosgate RFK4

4-gauge amplifier power wiring kit

Item #: 575RFK4


Add to Cart
EFX PA4BX Wiring Kit

EFX PA4BX Wiring Kit

4-gauge amplifier wiring kit — includes 2-channel patch cable

Item #: 142PA4BX


Add to Cart
T-Spec 16-gauge Speaker Wire

T-Spec 16-gauge Speaker Wire

Black/white jacket — priced per foot

Item #: 120SW16WB1


T-Spec 12-gauge Speaker Wire

T-Spec 12-gauge Speaker Wire

Black/white jacket — priced per foot

Item #: 120SW12WB1


T-Spec 2-Channel RCA Patch Cables

T-Spec 2-Channel RCA Patch Cables

Available in 7 different lengths (17-foot)

Item #: 120RCA172


Add to Cart
T-Spec 4-Channel RCA Patch Cable

T-Spec 4-Channel RCA Patch Cable

17-foot length

Item #: 120RCA174


Add to Cart
EFX 17-foot RCA Patch Cable

EFX 17-foot RCA Patch Cable

Item #: 142A17C


After $2.00 Savings Add to Cart
EFX 2-Channel RCA Patch Cables

EFX 2-Channel RCA Patch Cables

Reference Series Multi-Core RCA patch cables — available in 5 different lengths (25-foot)

Item #: 142RR25


Add to Cart
EFX 2-Channel RCA Patch Cables

EFX 2-Channel RCA Patch Cables

Elite Series Braided Multi-Core RCA patch cables — available in 5 different lengths (17-foot)

Item #: 142RE17

Add to Cart
EFX 2-Channel RCA Patch Cables

EFX 2-Channel RCA Patch Cables

Core Series Twisted RCA patch cables — available in 5 different lengths (17-foot)

Item #: 142RCT17B


Add to Cart
Rockford Fosgate PEQ Amp Remote Control

Rockford Fosgate PEQ Amp Remote Control

For 2007-up Power and Punch Series amps

Item #: 575ROCKPEQ


Add to Cart
Rockford Fosgate RFFM100 MAXI Fuse

Rockford Fosgate RFFM100 MAXI Fuse

Pair of 100-amp platinum-plated wafer fuses

Item #: 575RFFM100


Rockford Fosgate RFFAGU Fuse Holder

Rockford Fosgate RFFAGU Fuse Holder

Platinum-plated AGU fuse holder
Fits 4- or 8-gauge cable

Item #: 575RFFAGU


Add to Cart
EFX CFHG4 Fuse Holder

EFX CFHG4 Fuse Holder

In-line AGU fuse holder accepts 4- to 8-gauge wire

Item #: 142CFHG4

T-Spec Capacitor

T-Spec Capacitor

1.5-farad capacitor with red LCD meter

Item #: 12015DDC


Add to Cart
S&G Wire Cutter/Stripper Tool

S&G Wire Cutter/Stripper Tool

Cuts and strips 12- to 22-gauge wire

Item #: 18119100


Add to Cart
S&G Tool Aid 87650

S&G Tool Aid 87650

Door Trim and Panel Removal Tool

Item #: 18187650


Skewdriver Pro SPK4042

Skewdriver Pro SPK4042

Ratcheting straight and offset screwdriver set with 40 bits (Skewdriver Pro with ratchet handle, pictured)

Item #: 180SPK4042


Add to Cart
InstallCard: Amp or Equalizer

InstallCard: Amp or Equalizer

Prepaid professional amplifier or EQ installation

Item #: 597421003


Add to Cart