Rockford Fosgate's engineers took it to the limit with the Power Series amplifiers, building in huge reserves of power, incredible performance, and serious tune-tweaking features. Let the Power 400.4 4-channel amplifier open up vast musical vistas for you, bringing unheard-of depth and clarity to your car's audio system.

Built-in variable (50-210 Hz) crossovers feature steep slopes (24 dB per octave) for precise sonic sculpting. Punch Bass pumps up your low frequencies with up to 18 dB of boost at 45 Hz — the included wired remote gives you driver's seat control over your bass.

And if space is an issue in your vehicle, you can remove the amp's endcaps for a wider range of installation options.


  • 2-, 3-, 4-channel or Tri-Way output
  • 200 watts x 2 in bridged mode
  • 100 watts x 4 at 2 ohms
  • requires 8-gauge power and ground leads — wiring and hardware not included with amplifier
  • variable 50-210 Hz high-pass/low-pass crossover, 24 dB/ octave
  • TOPAZ noise-killing differential inputs eliminate 80% of ground loop noise between the head unit and the amp
  • NOMAD advanced protection circuitry monitors amplifier and provides "intelligent" shut-down protection without limiting system performance
  • TRANS·ana circuit designs keep voltages low and signal paths simple in the pre-amp section, for minimum distortion and maximum musicality
  • MEHSA provides more efficient transfer of heat from MOSFET output devices to the heatsink for cooler operation
  • preamp outputs for convenient daisy-chaining of amplifiers
  • Punch Bass boosts bass up to 18 dB at 45 Hz (wired remote control included for fingertip control)
  • dimensions: 13-7/16"W (9-13/16" without endcaps) x 2-7/16"H x 9-7/8"D
  • 3-year warranty

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
  • RF center badge
  • Remote Punch Bass control
  • 15' Remote Punch Bass cable
  • In-line fuse holder
  • AGU 50-amp fuse
  • Remote Punch Bass mounting bracket
  • Two 3/8" self-tapping screws
  • Self-adhesive Remote Punch Bass control decal
  • Remote Punch Bass control knob
  • Four 3/4" self-tapping screws
  • One 1/8" Allen wrench
  • One 9/64" Allen wrench
  • One 3/32" Allen wrench
  • Nine 3/32" set screws
  • Three 1/8" set screws
  • Installation and Operation Manual
  • Punch Verification Certificate
  • "Team RF" sticker

Product Research

Inputs and Outputs


TRANSana (TRANSconductance Active Nodal Amplifier): The TRANSana 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.

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.

MEHSA (Maximum Efficiency Heat Sink Application): 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.

TOPAZ (Tracking Operation Pre-Amplifier Zone): TOPAZ is a circuit that simply eliminates noise. The TOPAZ circuit allows the amplifier ground to move with the source unit ground, creating a "noise elimination" zone just before the preamp section. If there is any noise in the ground coming down the RCA line to the amplifier, TOPAZ amazingly tracks it down and eliminates it. The result is a 30-40dB improvement of the isolation between input ground and chassis ground. 

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.

DSM (Discrete Surface Mount): In the manufacturing process high speed robotics are used to place 0% tolerance resistors and large board traces providing greater reliability and efficiency.

Internal Crossovers: The front and rear internal crossovers are 24dB/octave Butterworth filters selectable for high-pass, full range, or low-pass operation variable from 50Hz to 210Hz.

Remote Punch Bass: The Punch Bass helps correct for acoustical deficiencies in the listening environment by helping reproduce full range sound without adding excessive boost. The Punch Bass control has a narrow band adjustment centered at 45Hz, variable from 0dB to +18dB. Using the mounting bracket, the supplied Punch Bass wired remote can be mounted in any convenient location under your vehicle's dash. The wired remote is 2.317" wide, 1.523" tall and 2.035" deep. Note: On this amplifier, the Punch Bass adjustment only affects the rear channels.

RCA Pass-Thru Jacks: The pass-thru jacks provide a convenient source for daisy-chaining an additional amplifier without running an extra set of RCA cables from the front of the vehicle to the amplifier location. The pass-thru jacks output a full signal.

RF Center Badge: For installation flexibility, the RF center badge can be rotated 180 degrees.


Left Side Of Amplifier:

  • Front Crossover Switch: Allows you to select high-pass, full range, or low-pass crossover operation
  • Rear Crossover Switch: Allows you to select high-pass, full range, or low-pass crossover operation
  • Front Crossover Frequency: The front crossover frequency control is variable from 50Hz to 210Hz
  • Rear Crossover Frequency: The rear crossover frequency control is variable from 50Hz to 210Hz
  • Front Gain: This variable gain control allows you to adjust the output level of the front channels
  • Rear Gain: This variable gain control allows you to adjust the output level of the rear channels
  • 4/2 Input Switch: Allows the amplifier to be driven with either 1 pair or 2 pairs of preamp inputs

Inputs and Outputs

Left Side Of Amplifier:

  • Front Input: Gold-plated RCA jacks
  • Rear Input: Gold-plated RCA jacks
  • Pass-Thru: Gold-plated RCA jacks
  • Rear Remote Punch Bass: RJ-45 jack for use with supplied Remote Punch Bass wired remote

Right Side Of Amplifier:

  • Speakers: Gold-plated set screw terminals that will accept up to 8 gauge speaker wire
  • GND: Gold-plated set screw terminal that will accept up to 4 gauge ground wire
  • B+: Gold-plated set screw terminal that will accept up to 4 gauge power wire
  • REM: Gold-plated 0.250" quick-slide for remote turn-on lead. Note: A female quick-slide is not supplied.


Dynamic Power Rating (measured at 14.4V):

  • Bridged Into A 4-Ohm Load: 232 watts x 2
  • Per Channel Into A 2-Ohm Load: 127 watts x 4
  • Per Channel Into A 4-Ohm Load: 84 watts x 4

Continuous Power Rating (measured at 13.8V):

  • Bridged Into A 4-Ohm Load: 200 watts x 2
  • Per Channel Into A 2-Ohm Load: 100 watts x 4
  • Per Channel Into A 4-Ohm Load: 50 watts x 4

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 open the box, verify contents, 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.

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