Aiming for ultimate sound quality? Rockford Fosgate knows the feeling. The Power 550X delivers intense multi-channel performance, with 4 channels of ultra-clean 65 watts RMS power. Patented trans•ANA circuitry keeps preamp voltages low and signal paths simple for outstanding audio quality you won't hear in lesser amps.

Use the razor-sharp (24 dB per octave slope) front and rear crossovers to tailor the 550X for different jobs. Switch to high-pass mode to eliminate extreme low bass from full-range speakers or components. Or bridge the amp to 2-channel mode, activate the low-pass crossovers, and drive a pair of subwoofers with 275 watts per side! MOSFET output devices supply the sonic muscle for awesome performance with total accuracy.

In the mood for big bass? The wired remote offers driver's seat control over Punch Bass, with up to 18 dB of bass boost at 45 Hz. If space is tight, you can remove the amplifier's endcaps for a smaller profile.


  • 65 watts RMS x 4 at 4 ohms
  • 137.5 watts RMS x 4 at 2 ohms
  • 275 watts RMS x 2 in bridged mode at 4 ohms
  • 2-, 3-, or 4-channel output
  • Tri-way capable (Tri-Way crossover required)
  • MOSFET power supply and output devices
  • front and rear 50-250 Hz high-pass/low-pass crossovers, 24 dB/octave slopes
  • MEHSA mounting technology increases the heat transfer from the MOSFET output devices to the heat sink, for higher power output, lower operating temperatures, and greater reliability
  • TOPAZ — noise-killing differential inputs that eliminate 80% of ground loop noise
  • Trans•ana circuitry keeps preamp voltages low and signal paths simple for outstanding audio quality
  • NOMAD — advanced protection circuitry for "intelligent" shutdown protection
  • wired remote control included for fingertip control of Punch Bass (for 0-18 dB of bass boost at 45 Hz)
  • preamp-level (RCA) inputs
  • preamp (RCA) outputs
  • 4-gauge power and ground connectors
  • dimensions: 13-7/16"W (9-15/16" 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.

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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
  • 1 Mounting bracket for Remote Punch Bass control
  • 1 Fuse connector
  • One 50-amp fuse
  • 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 7/64" Allen wrench
  • One 3/32" Allen wrench
  • Nine 3/32" set screws
  • Three 1/8" set screws
  • Installation and Operation Manual
  • Manual Addendum sheet
  • Punch Verification Certificate
  • "Team RF" sticker

Product Research

Inputs and Outputs


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.

Trans-ANA (TRANSconductance Active Nodal Amplifier): The 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.

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.

INDIGO (INDexed Ideal Gain Operation): INDIGO is a circuit that maximizes the output power of the amplifier by making better use of the power supplied by the car. As the battery voltage drops, INDIGO tightens up so the amplifier delivers the rated power, resulting in more consistent power coming from the amp.

Internal Crossover: The internal crossover is a 24dB/octave Butterworth filter selectable for high-pass, full range, or low-pass operation variable from 50Hz to 250Hz. The front and rear crossovers work independently.

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 operates for the rear channels only, and 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. The included cable is 15' in length.

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-range signal.

RF Center Badge: For installation flexibility, the RF center badge can be rotated 180 degrees. The LED power indicator is located under the badge and is visible through it when power is supplied to the amp.


Right Side Of Amplifier:

  • Front Crossover Switch: allows you to select high-pass, full range, or low-pass crossover operation for front channels
  • Rear Crossover Switch: allows you to select high-pass, full range, or low-pass crossover operation for rear channels
  • Front Crossover Frequency: the crossover frequency control is variable from 50Hz to 250Hz for front channels
  • Rear Crossover Frequency: the crossover frequency control is variable from 50Hz to 250Hz for rear channels
  • 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 without requiring the use of "Y" adapters

Inputs and Outputs

Right Side Of Amplifier:

  • Front Line Inputs: 1 pair gold-plated RCA jacks
  • Pass-Thru Line Outputs: 1 pair gold-plated RCA jacks
  • Rear Line Inputs: 1 pair gold-plated RCA jacks
  • Rear Remote Punch Bass: RJ-14 jack for use with supplied Remote Punch Bass wired remote

Left Side Of Amplifier:

  • Speakers: 4 pairs of gold-plated set screw terminals (LR, RR, LF, RF) 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" male 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: 275 watts x 2
  • Per Channel Into A 2-Ohm Load: 137.5 watts x 4
  • Per Channel Into A 4-Ohm Load: 65 watts x 4


  • Without Endcaps: H=2.4375", D=9.875", W=9.9375"
  • With Endcaps: H=2.4375", D=9.875", W=13.4375"

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.