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Rockford Fosgate Punch P400-4

4-channel car amplifier
50 watts RMS x 4 (New Stock)

21 Reviews

Item # 575P4004P

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Our take on the Rockford Fosgate Punch P400-4

Rockford Fosgate continues to develop progressive sound technologies. Their aim — to produce a smaller amplifier, with all the power and clarity you expect from the Punch name.

Rockford Fosgate Punch amps

Rockford Fosgate continues to develop progressive sound technologies. Their aim — to produce a smaller amplifier, with all the power and clarity you expect from the Punch name.

High-grade internal components mean high-power output.

Even heat dispersal for longer life

Dynamic Thermal Management

The award-winning "Dynamic Thermal Management" 3-stage cooling system uses forced air to dissipate heat evenly across the amp and out through the heatsink. The internal components in these compact amps stay cooler, resulting in higher efficiency and lower distortion. You get more installation options, without sacrificing wattage or audio quality.

MEHSA cooling process

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.

Maximum Efficiency Heat Sink Application increases heat transfer away from the transistors

P400-4 Punch performance

The P400-4 4-channel amp dispenses 50 RMS watts per channel to your front and rear speakers, or you can bridge it for 200 watts RMS into two channels for your subs. You can tailor the sound with variable-frequency high- and low-pass filters, and use the onboard EQ to add some high- and low-frequency punch to compensate for your car's acoustics. An optional wired remote control lets you tweak the sound from the front seat for quick adjustments while you're on the road.

Product Highlights:

  • 4-channel car amplifier
  • 50 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 (4-ohm stable in bridged mode)
  • CEA-2006 compliant
  • Dynamic Thermal Management cooling system
  • variable high- and low-pass filters (50-500 Hz, 12 dB/octave)
  • variable bass/treble boost (0-18 dB at 45 Hz, 0-12 dB at 12,000 Hz)
  • optional wired remote bass/treble boost
  • Class-AB amplifier design
  • MOSFET power and output stages
  • 4-gauge power and ground leads and an 80-amp fuse recommended — wiring and hardware not included with amplifier
  • no on-board fuses — when installing multiple amps in a system, an additional 80-amp in-line fuse between the distribution block and the amplifier is recommended
  • 13-1/16"W x 2-5/16"H x 8-11/16"D
  • warranty: 1 year
  • Our 60-day money-back guarantee

Powering 2 pairs of Polk db651. Obviously more than enough power. Amp gain is set very, very low. After continuous hours of use it, gets barely warm and I have not experienced any issues.

ED2KSR, Puerto Rico

What's in the Box:

  • Four-channel amplifier
  • Four 1-1/2" Self-tapping screws
  • Installation & Operation manual (English/ French/ Spanish/ German/ Italian)
  • Punch Amplifier Performance Verification Certificate

Rockford Fosgate Punch P400-4 Reviews

Average Customer Review(s):

(21 Reviews)

Outstanding amp, trouble free

AMP from San Diego, CA on 5/13/2013

2006 Subaru Impreza WRX
Crutchfield Customer Review (What's this?)

This amp was easy to install, and has been 100% trouble free. I seriously forget it's part of the system, never have to give it a second thought. It's very sleek, and fit underneath the passenger seat of my 2006 WRX wagon easily with all wiring. Provides clean, solid power to all 4 door speakers. Too bad they've discontinued it, but I'd put solid money on the model RF replaced it with being just as good.

Pros: Slim, powerful, reasonable price, easy to hook up.


Rock Solid

ED2KSR from Puerto Rico on 1/15/2013

Crutchfield Customer Review (What's this?)

Powering 2 pairs of Polk db651. Obviously more than enough power. Amp gain is set very, very low. After continuous hours of use it, gets barely warm and I have not experienced any issues.

Pros: Guaranteed 50 watts x 4.

Cons: Maybe too much power for my Polk db651! Maybe???


BradM from Harrodsburg, Ky on 12/24/2012

Crutchfield Customer Review (What's this?)

Awesome amp!! Will NOT let you down. Loud, clear effortless power. GREAT DEAL!!

Pros: Great sound! Will runs subs and or/comps. Great flexibilty.

Cons: None.

Great amp

Pete from Lawrenceville, GA on 10/30/2012

Crutchfield Customer Review (What's this?)

I am very satisfied with this amp. Plenty of clean power. This is my first experience with Fosgate but have known the name for years. Crutchfield reps were great and very helpful



Power for days SQ meh...

Rob from Kona, HI on 4/13/2012

Man I hate to bash this amp because everyone thinks that is sooo great BUT it does have some weaknesses. Power wise this this is super loud I have it running Polk DB tweeters and Boston/Pioneer 5x7/6x8's hit like subs! I have the gain at a tick less than half. I have the Punch EQ turned off it just adds to much distortion for my taste. The unit itself is built like a tank and looks very good.. Size wise it is very compact when compared to other 4 channel amps I've owned. One issue I had with this unit is that it picks up electrical noise very easy. I upgraded to this from another amp using the same exact wires and it introduced a buzz that drove me crazy. Tore my dash up and found that I had to re-route the wiring. Not a big deal but time consuming to find the problem when the Kenwood amp it replaced didnt have any issues using the same wiring. I consider myself an amatuer audiophile on a budget ;) and I concentrate on fine tuning my systems and finding distortion. I try the head unit Crossover vs the amp crossover and tweak it until it sounds just right. The bottom line is this unit just doesnt sound as good as I would like it too. Don't get me wrong its loud and clear and build quality is excellent but it just isnt as natural sounding as I hoped.

Pros: POWER, loud, compact, sleek design

Cons: Sound Quality, Sensitive to electrical noise pickup via RCA's

Rockford Fosgate Punch P400-4

Anonymous from nebraska on 5/10/2011

dont get me wrong my p 400 sounds great with 6 1/2 exceleons and 6x9 explodes but i only had 1 1/2 years life out of my amp. its stunk up my car and had to UPgrade to a better AMP.



Great unit - great price

Andy from State College PA on 2/5/2011

Crutchfield Customer Review (What's this?)

Unit is as advertised and then some. I have a Profiles amp of a higher power rating in a similar car and this one sounds cleaner. Very happy.



Reliable amp

Marek from minnesota on 11/27/2010

Bought the Rockford Punch 400.4 amp about 5 months ago. This amp has never had any problems and blasts the beats as loud as I can handle them. Hooked up to a set of 6x9's and a set of 6 1/2" speakers. Always plays clean and crisp even at max levels.



The Perfect Amp!

Scotty D from Medford, OR on 11/20/2010

Bought this amp to power my old 6.5 components & 2 Rockford Fosgate Series1 10's I had from when I was 19(I'm 35 now) off a JVC head unit. I have the components mounted low in the doors of my 1990 Mitsubishi Mighty Max pickup with the tweeters on low front corners of door panels next to mid woofers. A custom covered sealed box behind the seat houses the 10's with the amp mounted on the front above&between the subs(looks very cool) with 1 farad capacitor(Rockford Fosgate) mounted on 1 side of the subwoofer box. This amp CRANKS loud with no distortion with gains all the way down. The amp is runing the 6.5's off the front chanels stereo. Rear chanels bridged to 1 mono driving the 10's which are wired in series 8 ohm. Amp EQ''s are @25%, crossovers set @80Hz High&Low pass.The P400-4 is PERFECT for my system that keeps me rockin'&boomin' on the road.




Brandon from Maine on 11/19/2010

This is amp is heavy. The heat sinks are very well made, solid and they always stay cool, amp does not overheat even while driven rather hard. Mine was a refurb so actual power is unknown to me. As far as connections go, my 09PK4 Kicker wire barely fits in the power/ground terminals which required a 4 gauge wire. The screws that they use are plastic as far as I can tell, which is fine. The controls were hard to read, you need to find the dot on the dial, and not use the line that your flat head would fit into as a guide line which led me to mis-tune my amp for several days before I found out. As far as quality? It is very nice, details seem to appear when they need to be, it has the power to go extremely loud if turned up, I keep the gain turn down more than usual due to this fact. The power draw of this amp seems to be a fair amount, it appears to be fairly efficient but does draw power when turned up. If I were to choose again based on what I know now, I think I honestly would. The price I paid was good, the customer service I received while getting the price was excellent. If you asked me to recommend this amp I would do it in a heart beat. It is a solid performer for the price, but as with anything there is always something better if you are willing to pay more. All in all, efficient, delivers when you need it to, price if slightly fair for the watts give, the biggest factor for me though; the clean look. Gives a wow factor both in appearance and performance.



Small and powerful

madsen from Madison, WI on 10/22/2010

I have this amp discretely mounted under my front seat. It is powering 5 1/4 inch JL components in the front and bridged running 1 Boston Acoustic 10 inch sub. I kind of built my system around this amp. I LOVE IT!!!! Runs very cool and was WAAAAY underated in power. Mike was the guys name that tested it from the factory and it tested at 77 watts rms x 4 and 272 watts rms bridge x 2. I love that all of the connections and adjustment features are on 1 side. I love the clam like connections into the amp and I love how small it is. I don't even use the eq on my Sony dvd player. I adjusted everything directly from the amp. I paid quite a bit more than this outlet price, but don't mind a bit. I LOVE EVERYTHING ABOUT THIS AMP.



exceeded my expectations!

Stefan from Spokane, WA on 7/29/2010

when i got this amp i knew it was going to improve the quality of the sound in my truck a lot, but what i heard when i got this thing hooked up was amazing u could feel the music in you and this amp made my speakers work harder than ever....i have Focal's in the front and pioneers speakers in the back and this amp complements them perfectly. if your looking to add some much needed energy to your car or truck don't hesitate and buy this amp if you can afford it, and if you can't you better start saving right now!



Most amazing amplifier out there.

Anonymous from Greenville, SC on 4/12/2010

Highly underrated (mine was 77x4 rms). I have it powering 6.5" and 6x9" type-r's. At 50% gain I feel like there is a vice on my forehead from the midbass...lows, highs, and mids are clear and undistorted--this amp is a miracle to car audio.



Couldn't ask for me

Cmac06 from Alabaster, AL on 1/23/2010

Crutchfield Customer Review (What's this?)

Paid for 50Wx4, and got 75Wx4. Extremely clean sound. I have this amp running Focal mids and tweeters from Focal Access 165A1 component set in a QLogic kick panel enclosure. The amp is great. The tweeters are crystal clear without any harshness, and the mid woofers are nice and clear. Brings a great new experience to listening to live recordings.



Unmatched Amplifier

John from Collinsville, IL on 9/12/2009

I bought a Rockford Fosgate P400-4 in May 2008 and paired it with Boston Acoustics SX60 components and SX65 coaxials. Let me get straight to the point: I design amplifiers for a living, and this is the best car amplifier I have had the pleasure of hearing. Because it's a class A/B design, sound quality is brilliant. As everyone says, Rockford Fosgate has severely underrated this amp. Mine was rated 75x4W RMS. In fact, the output was so clean and powerful that I kept the gains turned all the way down (matched to my head unit's 4V RCA's was overkill). Buy the P400-4. You won't be disappointed.



A Great RF Amp

Stephen from Lincoln, NE on 8/27/2009

As always RF has put out a great amp. I have this pushing a set of 2 punch 6.5 components and 6.5 coax and I can hardly put the volume past 25%. And that is with the gain all the way down. It is very a clean sound, and this series of Amps looks tons better than any of the previous models.



Simply Rocks!

Dave from Bay Area, CA on 7/17/2009

2009 Chevrolet Cobalt
Crutchfield Customer Review (What's this?)

In usual Fosgate PUNCH fashion: LOUD, clean and built like a tank!



Awesome amp!

Kyle from Monticello, UT on 5/16/2009

Crutchfield Customer Review (What's this?)

Wow! I would not be surprised if this amp produced more RMS per channel than advertised, its hooked up to 2 pairs of 6X9 kenwood 5 ways, and they really pump out the sound. I had another amp that had the same ratings as the fosgate, but it would never have keep up with the fosgate. I got the refurbished version and it comes looking brand new, with a great warranty. The feature i like the most is the clams that hold the wires in, no more butt connectors to worry about, very simple and quick to use. The only con to this amp is the adjustments are all on the side, not the ends, i have very little room inside my dodge ram witch makes using the controls a pain, but in other cars i bet it would be fine.



Awesome Fosgate Amp!

Joseph from Newnan, GA on 5/18/2008

Crutchfield Customer Review (What's this?)

All I must say is WOW what an amp! I just recently got done with a custom install with 2 of these in a 02 Celica. I have one running in 4 channel mode powering a set of Infinity Reference 6.5" Components in the doors and back and then the other running in 2 channel mode powering 2 Sony Xplods 12". Fosgates are some of the best amps out there in my opinon. Clean, crisp crystal clear power for your speakers! Whoever does their homework online & looks at reviews about different products knows that any Fosgates they under rate their amps. Average actual power for these is 73 Watts*4 & 265 Watts*2 @ 4 ohms. But you def can't go wrong purchasing these! No hissing or anything just really super clean power. And always remember the system is only as good as the install! You do the custom box install with the dynamat in the right places it'll come out great. :) Mine was done with a custom box & a sub floor with plexiglass w/ the dynamat in the trunk & my doors. & the 20 farad cap. Some neons to light things up a lil too. You'll pay a little something for that but it will sound soo much better trust me. Also I recommend getting a good cap too cause you don't want to kill your electrical system & the cap also makes the amps have more power too. I got the 20 farad tsunami. Basically it's 2000 Watts per farad so 20 farads is good upto 40000 Watts. So overrall I def recommend getting this amp & always remember never overpower your speakers. All in all my system kicks really nice.




JAMES from BAKERSFIELD CA. on 10/28/2007

Put this amp in my work van and does it BANG!!!I have it hooked to a pair of punch 6.5 two way speakers in the front doors and a 12" p2d212 punch woofer behind the passenger seat. Sounds really good for what it is in a work van ,the amp has lots of power its a good buy.



Totally blown away

Mr. Bill from Skagit Valley, WA on 10/21/2007

Wow, I have to find words to express this amp's performance? I'm just blown away... I didn't expect this much of a difference... Matched up with my Alpine S-series 6 1/2 2-way speakers (a perfect rms match), I can hear every low, mid and high without distortion, even at volumes that make my ears hurt! WOW! Seriously, it's clean & crisp. I played everything from Tool to Breaking Benjamin. Tricky, Sublime and even some Buddy Guy. This amp outperformed any system I have ever had. And I worked it, too... I had an hour and a half commute of it running as loud as my ears could tolerate it. No electronic protection/shutoff at all. I could go much louder but I would cause some serious permanent hearing damage. Maybe I'll do that after I get my sub/amp/capacitor installed later and turn on the high-pass crossovers... I apologize in advance to anyone between my house and my work :p You will definately hear me coming from afar.




Hands-on research

Product Research



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 P400-4 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.

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.


Internal Crossover: The amplifier's internal crossovers have a 12 dB/octave slope. There are independent crossovers for the front and rear channels. Each is 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 switch. 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 Connections: The power and ground terminals are nickel-plated captive c-clamp wire connectors and will accommodate up to 4-gauge wire. An external 80-amp fuse (not included) must be installed on the power wire. If a wiring kit is used which includes a fuse with a value other than 80-amps, the original should be replaced with an 80-amp fuse. 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.

Differential Input: Differential input circuitry measures the voltage of both the positive (+) and negative (-) portions of the input signal, subtracting the voltage common to both conductors (noise); resulting in a cleaner signal. Reducing the noise on the input then improves the sound quality of the output.

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 (575ROCKPEQ, sold separately). If you use the remote PEQ, the Punch EQ control for the rear channels 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.