Power 400 Watt Class-ad 4-Channel Amplifier T400X4ad

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Power 400 Watt Class-ad 4-Channel Amplifier T400X4ad

The Power T400X4ad is an ultra-compact, high efficiency 400 Watt 4-channel amplifier. Features multi-impedance Constant Power, input/output clip detection, top mounted controls and dual fan forced induction cooling. Perfect for hybrid, electric, small cars, trucks, motorcycles, and side-by-side UTVs.

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The Power T400X4ad 400 Watt 4-channel ultra-compact, amplifier is built on Rockford Fosgate’s proprietary Class-AD technology, featuring Constant Power to produce the same output at both 4-Ohm and 2-Ohm impedances. Flexible vehicle integration enabled through low-level and high-level inputs with auto turn-on. Top mounted controls allow easy access to built-in crossover and C.L.E.A.N. input/output clip detection circuits. The 3-stage thermal lock extrusion with dual fan forced induction keeps everything cool while real-time thermal/protection schemes safeguard the amplifier.


  • Rockford Fosgate proprietary Class AD technology
  • 8 AWG power/ground connector w/ upgraded RCA connectors
  • 4/2 Ohm muti-impedance Constant Power
  • Remote-Out feature when using high level inputs
  • C.L.E.A.N. input/output clip detection and indicator LEDs
  • 4 Ohm bridged capable
  • 2/4 channel input switch
  • Top mounted controls
  • Differential inputs with high level auto turn-on feature
  • Dual extruded heat sinks
  • Dual fan cooled
  • Real time thermal sensing
  • Discrete surface mount technology
  • 2-Year Warranty
3-Stage Airflow

3-stage airflow method effectively exhausts heat and ensures your amplifier runs cooler for optimum performance.

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C.L.E.A.N. Set-Up

C.L.E.A.N. (Calibrated Level Eliminates Audible Noise) is a patented circuit with in/out clip LEDs to help ...

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This technology allows the amplifier to produce more power with less current draw from the vehicle's ...

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Constant Power

Constant Power is a patented circuit topology that provides instantaneous delivery of output power over varying ...

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CTA-2006 Compliant

Power ratings on Rockford Fosgate amplifiers conform to CTA-2006 industry standards. These guidelines mean your amplifier's ...

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DSM utilize 1% tight-tolerances improving efficiency of the circuit, decreases cross-talk from other discrete components and ...

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Engineered In The USA

These Avatars are a personal signature from the Rockford Fosgate team member(s) who designed and engineered ...

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CE Compliant

This product fulfills all essential safety and environmental requirements as defined in the European Directives (768/2008 ...

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Differential Inputs

Differential inputs eliminate noise picked up by signal cables resulting in clean signal transfer.

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Cta-2006 Compliant
Number of Channels
Total Power
(Sum of Rated Power)
400 Watts
Rated Power
(RMS Continuous Power)
100 Watts x 4 @ 4-Ohm
100 Watts x 4 @ 2-Ohm
200 Watts x 2 @ 4-Ohm Bridged
Dynamic Power
128 Watts x 4 @ 4-Ohm
152 Watts x 4 @ 2-Ohm
290 Watts x 2 @ 4-Ohm Bridged
Front Terminals: Left (+) Right (-)
Rear Terminals: Left (+) Right (-)
Frequency Response
20Hz-20kHz +/-1dB
Input Sensitivity
150 mV to 12 V
Circuit Topology Class
Class AD
Efficiency (average)
Total Harmonic Distortion (THD+Noise)
4-Ohm: <1.0%
2-Ohm: <1.0%
Signal Input
Front High/Low Level Input: 4-Pin harness
Rear High/Low Level Input: 4-Pin harness
Signal Output
Tone Controls
Treble: 0 to +14 dB @ 12.5 kHz
Bass: 0 to +18 dB @ 45 Hz
Crossover Controls
High-Pass: 50Hz - 250Hz @ 12dB/Octave Butterworth
Low-Pass: 50Hz - 250Hz @ 12dB/Octave Butterworth
All-Pass: Yes
Remote Controls
Visual Indicators
Power: Blue LED
Protect: Red LED
Input Clip: Red LED3
Output Clip: Blue/Violet/Red LED1,2,3

LED Color Legend:
1BLUE: <0.5% THD
3RED: 10%+ THD
Power Wire Gauge
Power Input Connector
Detachable Compression Terminal
Replacement 1040-57997
Speaker Wire Gauge
16 AWG
Speaker Output Connector
Front: 4-Pin Harness
Rear: 4-Pin Harness
Dual Fan Cooled
Extruded Aluminum
Operating Voltage
9 - 16 VDC
Recommended Fuse
(not included)
60 A
Average Current Draw (13.8V Music)
28 A
Max. Current Draw (13.8V Sinewave)
55 A
Suggested Alternator
75 A
Included In The Box
Dimensions (H x W x D)
1.6 x 4.3 x 8.3 (in.)
4.1 x 10.8 x 21.1 (cm)
Shipping Weight
3.4 Lbs. (1.54 Kg.)

Return Authorization

Contact the Authorized Rockford Fosgate Dealer you purchased this product from. If you need further assistance, call 1-800-669-9899 for Rockford Customer Service. You must obtain an RA# (Return Authorization number) to return any product to Rockford Fosgate. You are responsible for shipment of product to Rockford.

Accessories Wiring Wizard

Available Wiring Diagrams

Please consult your amplifier owner's manual for lowest recommended impedance.

The below diagrams optimize this amp for its lowest recommended BRIDGED/MONO load.

Wiring Diagram #1

Wiring Diagram #2

Wiring Diagram #3

Wiring Diagram #4

Wiring Diagram #5

Wiring Diagram #6

Wiring Diagram #7

Wiring Diagram #8

Wiring Diagram #9

Wiring Diagram #10

Speaker Polarity

Your woofer may use one of the following to identify (+/-) terminals.

Positive +

Red Post

Purple (4Ω)

Red (8Ω)

Negative -

Black Post

No Dot

No Dot

Speaker Polarity

Your woofer may use one of the following to identify (+/-) terminals.

Positive +

Red Post

Purple (4Ω)

Red (8Ω)

Negative -

Black Post

No Dot

No Dot

Wiring Kits


Get a 1-Year extended amplifier warranty when using a matching Rockford Fosgate installation kit.

We want you to get the maximum performance and reliability from your Rockford Fosgate amplifier. We're so certain using the right cables make a difference, we'll give you and additional 1-Year amplifier warranty when using a matching installation kit!

  • 1 Purchase a Rockford Fosgate Punch or Power amplifier.
  • 2 Add the correct amplifier installation kit.
  • 3 Get an additional 1 year amplifier warranty FREE!


Best Amp Ever!!

I upgraded from a P400X4 to my new T400X4ad and I am THRILLED with the sound quality, output, and overall performance.


I have 2 of these bad boys on my Harley and they are destroying everything that I hook up to them.... I LOVE THESE!

Amazing Amp!

I have my T400X4ad powering 2 pairs of 2652-S in my 2009 Honda Fit. The amp was small enough to fit under the passenger seat, and the performance is UNREAL. The setup is very simple and easy to do, and the sound quality surpasses many other amps I have had, including previous Rockfords. It was PERFECT for my application!

Best Out of 6 Different Amps I Tried

I went through 6 different full size amplifiers. class a/b and d. this amp has better sound quality than ALL of them and its tiny. I bought a second one and am using them for a 8 channel active system with minidsp 8x12. All other amplifiers had some issue, noise, low volume humm(noise floor), not enough power, this amp is the closest thing to perfect you can get without having a massive class A/B amp thats super inefficient. The signal to noise ratio is extremely high. I cant believe this is a class D amp, its warm, clean, smooth, and EXTREMELY powerful for its size. I run them hard in the middle of summer and they get warm, but they have active cooling with fans and they have never shut off once. I have bought all Rockford Fosgate amps including my subwoofer amp due to how impressed I was with the quality of these amplifiers. These are overlooked gems in the audiopile HiFi community. These perform slightly better than my second most favorite amplifiers ive owned, my A** Audio X2 1200.6, and my A** audio xdi1200.6. Rockford for life!!! I want to say thank you to the engineers who put in such hard work and design into these amplifiers, it sucks swapping amps in your car because you cant find what you want... once these went in, i found what i was looking for. Class A/B sound quality in a modern class D design and efficiency!! Thanks Guys!!

Arguably The Best 4 Channel Amp Ever

The power you get out of this tiny amplifier is incredible. Put this amp on some high quality component speakers that have metal tweeters and prepare to make your ears bleed. This amp has lots of dynamic headroom. I highly recommend.

Good quality

I have this T400X4ad powering 4 Focal speakers and tweeters. Man, my truck is a concert on wheels with the sound quality crisp clean. Love how it has the built-in clipping indicator.


6 Reviews
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