1 / 8
Delivers clear, punchy power in a very small footprint—great for driving mids/highs or bridged channels; pay attention to wiring and fuse needs during installation.
Buyer confidence
88%Highlights
- Differential inputs with high level auto turn-on feature
- Remote-Out feature when using high level inputs
- 4 Ohm bridged capable
- Dual fan cooled
Key specs
Full specs- Number of Channels
- 4
- 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 (PVC/PowerCube®)
- 128 Watts x 4 @ 4-Ohm 152 Watts x 4 @ 2-Ohm 290 Watts x 2 @ 4-Ohm Bridged
- Bridgeable
- Yes 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
Key specs
Full specs- Number of Channels
- 4
- 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 (PVC/PowerCube®)
- 128 Watts x 4 @ 4-Ohm 152 Watts x 4 @ 2-Ohm 290 Watts x 2 @ 4-Ohm Bridged
Highlights
Overview- Differential inputs with high level auto turn-on feature
- Remote-Out feature when using high level inputs
- 4 Ohm bridged capable
Review highlights
Based on customer reviewsCompact, clean 4‑channel power that’s easy to hide and tune
Delivers clear, punchy power in a very small footprint—great for driving mids/highs or bridged channels; pay attention to wiring and fuse needs during installation.
What buyers praise
- Very compact — ideal for stealth or under‑seat mounting
- Clean, powerful output that suits mids/highs and bridged use
What to watch for
- Small chassis limits wiring: accepts up to 8 AWG, can be difficult to seat power cable, and won’t accept ferrules
Overview
The Rockford Fosgate T400X4ad is a compact 4-channel amplifier for builds where space and output both matter. It is rated at 400 watts total, uses Class-AD amplifier technology, and is a strong candidate for powering front and rear speakers, a compact active setup, or bridged speaker channels in a tight vehicle, motorcycle, truck, or side-by-side install.
Best for
- Four-speaker systems that need a compact amplifier with real output.
- Motorcycle, truck, hybrid, electric, small-car, and UTV installs where amplifier space is limited.
- Systems that benefit from clip indicators, top-mounted controls, and flexible high-level or low-level input planning.
Key points
- 400-watt Power Series 4-channel amplifier.
- Rated at 100 watts x 4 at 4 ohms or 2 ohms, and 200 watts x 2 bridged at 4 ohms.
- Class-AD design with Constant Power output across common speaker loads.
- C.L.E.A.N. input and output clip indicators help with setup and gain checking.
- Dual fan cooling, top-mounted controls, and 8 AWG power and ground terminals support compact installs.
Fit and use
Confirm speaker impedance, channel count, bridged use, wiring gauge, fuse planning, and the physical mounting location before checkout. This amp is especially useful when a standard full-size 4-channel amplifier is too large for the available space.
What to know
This amplifier is powerful for its footprint, but it still needs clean wiring, ventilation, and proper tuning. Match it with speakers that can use the power safely and plan the install around access to the top controls.
Highlights
Key features
- Differential inputs with high level auto turn-on feature
- Remote-Out feature when using high level inputs
- 4 Ohm bridged capable
- Dual fan cooled
- Real time thermal sensing
- Dual extruded heat sinks
- 2/4 channel input switch
- 4/2 Ohm muti-impedance Constant Power
- Discrete surface mount technology
- 8 AWG power/ground connector w/ upgraded RCA connectors
- C.L.E.A.N. input/output clip detection and indicator LEDs
- Top mounted controls
Technologies
3-Stage Airflow
3-stage airflow method effectively exhausts heat and ensures your amplifier runs cooler for optimum performance.
Patent: 7,994,857
Constant Power
Music and speakers have a dynamic relationship. As the frequency of music varies, so does the impedance of the
CTA-2006 Compliant
Power ratings on Rockford Fosgate amplifiers conform to CTA-2006 industry standards. These guidelines mean your
Class-AD
Rockford Fosgate's AD topology brings out high efficiency bd amplifier design to a full range application.
Patent: 8,712,066
C.L.E.A.N. Technology
Time and sophisticated test equipment have been replaced, with Rockford’s integrated level setting technology
CE Compliant
This product fulfills all essential safety and environmental requirements as defined in the European Directives
DSM
DSM - An industry-leading manufacturing process, DSM utilizes high-speed robotics, high-quality 1% tight-tolerance
Engineered In The USA
[av• uh•tahr -noun] 1. an embodiment or personification, as of a principle, attitude, or view of life 2. a
Differential Inputs
Differential input circuitry measures the voltage of both the (+) and (-) input signal. The circuitry subtracts
Specs
Specifications
29
| Number of Channels | 4 |
| 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 (PVC/PowerCube®) | 128 Watts x 4 @ 4-Ohm 152 Watts x 4 @ 2-Ohm 290 Watts x 2 @ 4-Ohm Bridged |
| Bridgeable | Yes 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) | >75% |
| 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 2VIOLET: 1% THD 3RED: 10%+ THD |
| Power Wire Gauge | 8 AWG |
| 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 |
| Cooling | Dual Fan Cooled |
| Heatsink | 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 |
| 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.) |
Reviews (0)
—
No average rating yet
0 reviews
No written reviews are live yet. Signed-in customers can submit one below.
No written reviews are live for this item yet.
Installation resources
Wiring diagrams
10
Wiring Diagram #1
Source: Rockford Fosgate
Wiring Diagram #2
Source: Rockford Fosgate
Wiring Diagram #3
Source: Rockford Fosgate
Wiring Diagram #4
Source: Rockford Fosgate
Wiring Diagram #5
Source: Rockford Fosgate
Wiring Diagram #6
Source: Rockford Fosgate
Wiring Diagram #7
Source: Rockford Fosgate
Wiring Diagram #8
Source: Rockford Fosgate
Wiring Diagram #9
Source: Rockford Fosgate
Accessories
Rockford Fosgate
RFK4D 4 AWG Complete Dual Amp Installation Kit
4.675 reviews
$379.99CAD
$449.99
In stock
Rockford Fosgate
RFK8X 8 AWG Complete Installation Kit
$189.99CAD
$219.99
In stock
Rockford Fosgate
RFK8I 8 AWG Power & Signal Installation Kit
4.7213 reviews
$159.99CAD
$189.99
In stock
Rockford Fosgate
RFK8 8 AWG Power Installation Kit
4.694 reviews
$109.99CAD
$129.99
In stock
Similar products
Compare nearby options
Rockford Fosgate•Power
T600-4 Power 600 Watt 4-Channel Amplifier
4.527 reviews
$1019.99CAD
$1199.99
In stock
Rockford Fosgate•Power
T400-4 Power 400 Watt 4-Channel Amplifier
4.931 reviews
$689.99CAD
$809.99
In stock
Rockford Fosgate•Punch
P600X4 Punch 600 Watt 4-Channel Amplifier
4.832 reviews
$759.99CAD
$899.99
In stock
Rockford Fosgate•Punch
P400X4 Punch 400 Watt 4-Channel Amplifier
4.757 reviews
$579.99CAD
$669.99
In stock
Rockford Fosgate•Prime
R2-500X4 Prime 500 Watt 4-Channel Amplifier
4.865 reviews
$549.99CAD
$649.99
In stock
Rockford Fosgate•Prime
R2-300X4 Prime 300 Watt 4-Channel Amplifier
5.040 reviews
$459.99CAD
$549.99
In stock
Rockford Fosgate•Power
T1000-4ad Power 1,000 Watt Class-ad Full-Range 4-Channel Amplifier
4.99 reviews
$1619.99CAD
$1919.99
In stock
Boss Elite
BE600.4D 4-Channel Class D Amplifier
$298.99CAD
$379.99
In stock