Products by Car

Vehicle Specific Upgrades
Product Code: Sony XM-S400D
Availability: In Stock
£149.99 £179.99
DescriptionReviews (0)

Sony XM-S400D 4 Channel 400w Compact Amp

The Sony XM-S400D is a very compact amplifier, designed for moderately sized mobile audio systems. It is ideal for amplifying front and rear speakers in a vehicle with a factory or aftermarket stereo. You can also drive small subwoofers instead of full range speakers on the rear channels. The XM-S400D is a Class D 4-channel stereo amplifier that outputs 45 watts per channel RMS at 4 ohms. It comes with RCA and high-level input harnesses, and a power/speaker output harness.

Sony knows that many vehicles just don't have space for a big amplifier, so they've created the XMS400D 4-channel amp. This tiny powerhouse will blow your mind — blasting your front and rear speakers with 45 watts RMS each from a chassis that's the size of a big candy bar.

You can't bridge this amp, but you can use the onboard switchable high- and low-pass filters to run small subs with the rear channels and full-range speakers with the front channels. The amp will accept preamp or speaker-level signals, so it'll hook up to just about any system.

You also get High-level Sensing when the speaker-level input is used, the amplifier can sense when an audio signal is present on the input and will turn on the amplifier. The amp will automatically turn itself off when no audio signal is detected. This eliminates the need for connecting a remote turn-on wire.

Product Review

Note: HTML is not translated!


The XM-S400D is equipped with a 120Hz high-pass filter (HPF) for the front channels, and a 120Hz low-pass filter (LPF) for the rear channels. The HPF will filter out low frequencies from the front channels to eliminate distortion. The LPF will filter out voices and higher frequencies from the rear channels when they are used for driving subwoofers. (The LPF should be turned off when full range speakers are connected to the rear channels.) Both crossovers have a 12dB per octave slope, and are controlled with separate on/off switches.

Input Select:

The Input Select switch lets you set the amplifier to match the input connection. If you have connected the amp to one pair of inputs, the switch should be set at "2CH." All four outputs are fed the signal from the 2-channel input. If you have connected the amp with two pairs of inputs, the switch should be set to "4CH".


The Sony XM-S400D features harnesses for all power and signal connections:

Power/Speaker Outputs Harness: The 40" main harness has connections for power, ground, and amp turn-on, as well as the outputs for front and rear speakers. The speaker outputs follow the industry standard color coding. The wires connected to the power and ground wires should be at least 14-gauge.

Fuse: The amplifier has a 15A ATM (mini-blade-type) fuse installed next to the power/speaker harness plug.

Input Harnesses: The amp has a 10-pin Molex receptacle for either the line-level or speaker-level input harness. The line-level harness has two pairs of female RCAs. The 39" speaker-level input harness has wires for connecting the speaker output wires from the head unit. The wires follow the industry standard color coding.

RMS Power Output (Watts x Channels) 45 x 4
Peak Power Output (Watts x Channels) 100 x 4
Power at 2 Ohms (Watts x Channels) N/A
Bridged Power (Watts x Channels) N/A
Minimum Impedance Bridged N/A
Minimum Impedance Unbridged 4
Minimum Impedance 4
Best Frequency Response 20-20k Hz
THD at Rated RMS Power 1%
Signal to Noise Ratio 83 dB
Input Voltage 14.4v
Amplifier Class D
Low-Pass Crossover Frequency 120 Hz
Low-Pass Slope (dB/octave) 12 dB/octave
High-Pass Crossover Frequency 120 Hz
High-Pass Slope (dB/octave) 12 dB/octave
Bass Boost No
Bass Boost Frequency N/A
Fan Cooled No
Fuse Rating 15
Speaker Level Inputs Harness
Preamp Outputs No
Width (inches) 7-1/4"
Height (inches) 1-1/2"
Depth (inches) 2-1/2"

We recommend that you have your installation carried out by a qualified car audio and security installer. Our experienced installation team can take care of all kind of car audio and security installations.

  • Car Stereo
  • Andriod Screens
  • Apple Carplay / Andriod Auto Integration
  • Multimedia Audio Visual (Sat/Navs, Headrest Screens, Roof Screens etc.)
  • Speakers/ Subwoofers / Amplifiers
  • OEM Adapters Installation (DAB, iPod, iPhone, USB, Bluetooth, Aux)
  • Dash Cameras
  • Bluetooth Hands Free Car Kit Installation
  • Vehicle Alarm Systems
  • Vehicle Tracking Systems
  • Vehicle Immobilisers
  • Reversing Camera / Parking Sensors
Other than vehicle immobiliser and tracking systems all other installations are carried out at our London based Car Audio and Security Installation Centre