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Rockford Fosgate Punch P400X4

4-channel car amplifier — 50 watts RMS x 4

Item # 575P400X4

Rockford Fosgate's Punch P400X4 amplifier can put out 50 watts RMS to each of your front and rear speakers, plenty...

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Rockford Fosgate's Punch P400X4 amplifier can put out 50 watts RMS to each of your front and rear speakers, plenty...

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About the Rockford Fosgate Punch P400X4

Buck Pomerantz

Big power for your speakers or subwoofers

Rockford Fosgate's Punch P400X4 amplifier can put out 50 watts RMS to each of your front and rear speakers, plenty of power for clean music even at high levels. You can use the amp's high-pass filter to remove low bass from your speakers so they'll play more efficiently. You can also switch this amp into 2-channel mode to drive a couple of subwoofers with up to 200 watts RMS each. The amp's low-pass filter comes in handy for getting the right sound from your sub/enclosure combo. The Punch EQ2 includes bass and treble boosts, in case you want to add some boom and sizzle back into the mix.

Big power for your speakers or subwoofers

Rockford Fosgate's Punch P400X4 amplifier can put out 50 watts RMS to each of your front and rear speakers, plenty of power for clean music even at high levels. You can use the amp's high-pass filter to remove low bass from your speakers so they'll play more efficiently. You can also switch this amp into 2-channel mode to drive a couple of subwoofers with up to 200 watts RMS each. The amp's low-pass filter comes in handy for getting the right sound from your sub/enclosure combo. The Punch EQ2 includes bass and treble boosts, in case you want to add some boom and sizzle back into the mix.

Easy to set for optimum performance

P300X2 control panel shown as example

P300X2 control panel shown as example

Once again, Rockford Fosgate steps away from the crowd with their C.L.E.A.N. technology (Calibrated Level Eliminates Audible Noise) — a setup system that ensures your music will sound as clean and powerful as possible. It works like this: first download the setup tones from Rockford Fosgate, then play the tone, adjust the receiver volume until a red clip light on the amp goes out, then turn the amp gain up until a blue light comes on. It's that simple — your amplifier will be perfectly set to match your receiver's output. When your receiver reaches maximum clean volume, you'll get maximum clean power from your Power amp. At quiet listening levels, you'll hear less background noise and more of your music.

Keeps an eye on things while playing

If that blue light turns solid red while you're playing music, the amp's telling you that your source is distorting and you should turn it down, or risk damage to your gear. The amp's built-in computer keeps tabs on the output current, ensuring that plunging speaker impedances (they change during play) or even a short circuit won't hurt anything.

Maintaining coolness raises efficiency and lowers distortion

Rockford Fosgate's Dynamic Thermal Management system uses forced air to dissipate heat evenly across the amp and out through the high-mass heatsink, efficiently drawing heat away from vital internal parts. Their proprietary MEHSA cooling process maximizes the heat transfer from the MOSFET devices to the heatsink, allowing the heat to escape more readily, so the transistors stay cooler and work better.

Rockford Fosgate P400X4

                                                     P400X4 connection panel and input clip light


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 at 4 ohms (4-ohm stable in bridged mode)
  • CEA-2006 compliant
  • variable high- and low-pass filter filter (50-250 Hz, 12 dB/octave)
  • variable PEQ2 bass/treble boost (0-18 dB at 45 Hz and 0-14 dB at 12.5K Hz)
  • C.L.E.A.N. gain setup system includes clip lights and link to Rockford Fosgate's setup tones
  • Class-AB amplifier design
  • frequency response: 20-20K Hz
  • Dynamic Thermal Management and MEHSA MOSFET cooling systems
  • MOSFET power and output stages
  • preamp and speaker-level inputs (speaker wire to RCA adapter required for speaker-level input)
  • signal-sensing turn-on with speaker-level inputs eliminate need for remote turn-on lead
More Info:
  • 4-gauge power and ground leads and an 60-amp fuse recommended — wiring and hardware not included with amplifier
  • no onboard fuses — when installing multiple amps in a system, an additional 60-amp in-line fuse between the distribution block and the amplifier is recommended
  • 11-1/8"W x 2-7/16"H x 8-13/16"D
  • warranty: 1 year
  • MFR # P400X4

What's in the box:

  • 4-Channel amplifier
  • Four 1-1/2" Self-tapping screws
  • 2.5mm Allen wrench
  • Quick setup instructions
  • Certificate of Performance

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More details on the Rockford Fosgate Punch P400X4

Mark G.

Product Research



CEA-2006 Compliant: CEA-2006 is a system of testing and measurement methods for mobile audio amplifiers. This voluntary standard advocates a uniform method for measuring an amplifier's RMS power output and signal-to-noise ratio. The criteria for measuring power uses a DC input voltage of 14.4 volts and the RMS power output is measured with 1% or less Total Harmonic Distortion plus noise (THD+N) over a frequency range of 20 Hz to 20 kHz (for full range amplifiers). Signal-to-Noise ratio is measured in weighted absolute decibels (dBA) at a reference of 1 watt into 4Ω. CEA-2006 allows consumers to compare car amplifiers and receivers on an equal basis. Using CEA-2006 criteria, the Rockford Fosgate P400X4 is rated as follows:

  • Power Output:
    • 4Ω: 50 watts x 4-channels
    • 2Ω: 100 watts x 4-channels
    • Bridged: 200 watts x 2-channel (into 4Ω)
  • Signal to Noise Ratio: 85 dBA (105 dB at rated power)

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

Dynamic Thermal Management (DTM): DTM evenly distributes excess heat across the amplifier's entire heatsink.

MEHSA³ (Maximum Efficiency Heat Sink Application-3rd 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 amplifier is protected without limiting sound output unless needed.

DSM (Discrete Surface Mount): High speed robotics are used in the manufacturing process 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.

CLEAN Set-Up: Rockford's integrated level setting technology, CLEAN (Calibrated Level Eliminates Audible Noise), replaces sophisticated test equipment with input/output clip LEDs, allowing you to match the source unit's output to the amp's gain, and optimize the amp's output. The input clip indicator works in conjunction with the audio source volume, illuminating red when the source reaches it's clipping point. The output clip indicator works in conjunction with the input level dial on the amp, illuminating the appropriate color depending on the audio content used for the setup.

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.

Balanced Differential Inputs: Differential inputs eliminate noise picked up by signal cables by measuring the voltage of both the (+) and (-) input signal, then subtracting the voltage common to both conductors (noise), resulting in only the clean signal entering the amplifier.


Input Level: The front and rear sections of the amplifier have separate input level controls. To accommodate the varying range of signal levels from today's factory and aftermarket radios, the input levels are adjustable from 150mV to 12V.

Crossover: The amplifier's internal crossovers are also independent for the front and rear channels. The slope is 12 dB/octave and both can be set to high-pass, all-pass (full range), or low-pass operation. The crossover points are variable from 50 Hz to 250 Hz.

Punch EQ: Both the front and rear amplifier sections have Punch EQ circuits, the function of which changes 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, 0-14 dB at 12.5 kHz. When the crossover is set to all-pass, both the bass and treble boost circuits are active.

Input Switch: With the input switch in the 2-channel position, connecting only the front inputs will send the signal to both the front and rear sections of the amplifier. In the 4-channel position, both front and rear inputs must be used.


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 60-amp fuse (not included) must be installed on the power wire. The remote turn-on terminal will accept up to 12-gauge wire. A Phillips or flat-head screwdriver (not supplied) is required to tighten/loosen the terminals.

Speaker Connections: The four pair of speaker output terminals are also nickel-plated captive c-clamps and will accept up to 8-gauge wire. A Phillips or flat-head screwdriver (not supplied) is required to tighten/loosen the terminals.

Signal Input: The front and rear RCA inputs will accept either a line-level or speaker-level input. A speaker-level signal can be connected using a Speaker Wire to RCA adapter (sold separately). When using a speaker-level input signal, the auto turn-on feature is active and the remote turn-on terminal becomes a 12 volt output to turn on/off up to two additional amplifiers or other components.

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Customer Q&A

14 questions already asked

Can this Rockford Fosgate Punch P400X4 take one component set speaker Rockford Fosgate P1675-S and a 2 way speaker -Rockford Fosgate P1692 without having to be bridged ?
e  Apr 19, 2023
1 answer
Absolutely, E.Z. The Rockford Fosgate Punch P400X4 amp delivers 50-watts RMS x 4 and would be an excellent choice to drive the P1675-s components up front and the P1692 6x9's in the rear. You do not need to worry about bridging at all! The Rockford setup is an excellent choice, as the amplifiers have great power and a clean sound and are extremely reliable.
bo  Apr 19, 2023 (Staff)
Hi, I'm putting together a system for my Escalade I have A Pioneer dmh-WT7600 NEX with two pair of Polk Audio 6502 components with 2- 8" basstubes... my question is does this amp. have enough power to run both pair of the Polk Audio 6502's or should i use the DMH-WT7600?
vmbn1900  Mar 15, 2021
2 answers
This amp has plenty of power to run two pairs of component speakers
iver  Mar 16, 2021
I am running two 12 inch Infinity subs and the clarity and detonation of the bass is amazingly clear! Great amp. Spec sheet is even better than guaranteed specs.
brian  Mar 15, 2021
I plan on installing this into my system which consists of two dash tweeters and four door speakers. Each speaker is rated at 4 ohms. If I were to connect the tweeters to the front channel, and wire the door speakers on each side in parallel down to 2 ohms, and connect them to the rear channel, would each speaker get 50 watts nominal?
seth andrew  Oct 13, 2018
2 answers
The tweeters would each get the 50 watts nominal, but the door speakers would share the 50 watts of the rear channels. You should make sure the tweeters can handle more than the nominal power because the amplifier will provide more than rated power.
michael donald  Oct 14, 2018
Basically yes,the amplifier would be pumping out 100w on each rear channel which would be divided in half between the 2 speakers on each of those channels.
john g  Oct 14, 2018
could I set up 4 speakers and 1 subwoofer with this amp?
griselda  Jun 14, 2018
4 answers
No. You need a 5 channel amp
james bradley  Jun 20, 2018
Punch 400 Watt 4-Channel Amplifier P400X4 The Punch P400X4 is a 4-channel amplifier producing 100 Watts into all four channels at 2-Ohm. The P400X4 is perfect for a 4-way full-range system or a 3-way system having a front stage with subwoofers on the rear channels, so two front and using the bridged rear connection for a sub. You would not be able to connect 4 speakers and 1 subwoofer.
franz  Jun 20, 2018
Yes, as long as you mind the loads(ohms).Stereo should go down to 2 and bridged down to 4 max.You'll roast the amp otherwise.
john g  Jun 20, 2018
This is a mono amp used to push sub speakers, You would be better off getting a four channel amp
tracy  Jun 20, 2018
Amp went into protect after 2 hours straight of high output listening.Seemed fine after cool down.Whats the deal?
john g  Mar 31, 2018
1 answer
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.
kristina  Apr 09, 2018 (Staff)
If I bridge this amp to 2 channels(2x200) and want to keep stereo separation,would I need a set of Y-splitters and set the input switch to 4ch or could I just use a single pair of RCA's and set the input switch to 2ch? Would either way work?I will be powering the mid woofers on my front stage so this is why stereo separation is important.
john g  Jun 19, 2017
2 answers
I don't see why you could not just hook it the way your thinking you would.... For it does not hert to try it... That's what I am thinking... Since I try things to see if it works...??
kent  Jun 24, 2017
And still use the other channel for stereo regular separation just change your frequencies for each chanel. Run your gains about 1/2
hector  Jun 23, 2017
Can i use this rf p400x4 amp to power 3 pair of speaker i.e using the front two channels to power the components in the front and the rear channels in parallel at 2ohm to power 1 pair of components in the rear door and 1 pair of coaxial on the rear parcel shelf. I am using focal ps 165 fx in the front and focal access 165 as in the rear door. Is it possible to add a pair of focal 690ac to the rear parcel tray?
rfguy  Jan 21, 2017
2 answers
Yes, as long as your speakers in the rear equals 2 ohms per side. Give or take a few, 1.8 or 1.7 would be fine. Just remember each speaker that is added cuts your power per speaker down. Say the amp does 100 watts at 2 ohms, 2 speakers on the rear right would be 50 per speaker, if you did 3 speakers on the right, and the ohm load was the same, you only have 33 watts per speaker.
david  Jan 21, 2017
Hello, I used my p400x4 in a Toyota tundra. In my particular configuration I left the front channels untouched and added this amp to power the rear door components I installed, and a JL 8" loaded enclosure under the rear seat. I bridged one side of the amp to run that single voice coil 4 ohm JL sub and set the crossover at @50 hz. I have the gain set about half way. I ran the other side of the amp to power some basic MTX 6.5" components in the rear doors. Here's a problem you might experience, even with the components set at @65 hz (only playing frequencies above that point) and the gain about 75%, the clipping light flickers at higher volumes. The way I have it set up now is the way I like it to sound, so im ok with it clipping a little bit at higher volumes with songs that have a lot of bass. I cant hear any real distortion, but you know if that clip light is flickering, it probably is a little. The bridged sub channel doesn't clip at all. So, with you wanting to run 2 sets of components off one side of the amp, it's probably going to clip. I love your idea though, I've always wanted to try that set up to see how it would sound. Maybe with those higher quality focals they might be more efficient and not cause problems, but you never know till you try. I would try it and see, install everything loosley to tune it, and if it clips too much, maybe come up with a different plan. I like the amp, it sounds good, has decent power and tuning options, usual RF quality. There is always some combination that will work, hope this helps.
joshua s  Jan 21, 2017
I have (4) Infinity Kappa 682.11cf 5"x7"/6"x8" 2-way car speakers (front and rear door). Would you recommend the P400X4 or the P600X4?
kevin  Feb 15, 2015
3 answers
I would recommend the p600x4 to get the most out of the speakers. The p400x4 would work too just wouldn't be as loud or hard hitting as the 600.
trevor  Feb 18, 2015
I like mine. Has plenty of power. I don't have a subwoofer.
bobby  Feb 17, 2015
I replaced factory speakers. I can't compare them to yours but I like them. Just remember that the Twitters are separate and have to be mounted separately.
bobby  Feb 17, 2015
Does this amp include the bass remote?
adam  Jun 17, 2014
2 answers
no. it does not
richard  Jun 22, 2014
No it doesnt
brian  Jun 17, 2014
Can I use this amp in tri mode? I want to run my front door speakers on channel 1 and 2, then bridge 3 and 4 to power my sub.
clint  May 21, 2014
1 answer
Yeah, you can. But honestly I would just go buy the P300X2, and a mono block for your sub. Bridging for the sub on this amp will only give you like 250 watts rms to your sub. And that's like...max. Also I'm not entirely sure if you can make 2 channels high pass, and the other 2 low pass. Just be sure you buy a 2 ohm DVC sub if you're going to bridge it.
luke  May 24, 2014
Why doesn't this give you a max power output? I would like to know so I can pair up the right speakers.
rfproject  Feb 06, 2014
2 answers
If you want to know what an amps real power output is. Multiply the fuse rating by 10. If the amp call for a 25 watt fuse, your looking at a 250 watt amp, (give or take, I know most systems are 14.4 volts, it's easier to multiple by 10 than it is 14.4) even thou it may say 1000 watts on it, Ohm's Law dictates that, now there are a few new amps out there that use capacitors to get around that, but you pay for that technology, Fosgate has a few examples of them.
david  Jan 21, 2017
All of our products display the RMS power ratings. This provides a more real world ideal of the power you will get from the unit and avoids the numbers game that gets played with Peak power. You can find some good tips on choosing speakers here:
jeff  Feb 08, 2014 (Staff)

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