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XM-S400D | 4-channel Class D Amplifier
$159.99
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$159.99
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Est. Delivery Jul 28-29
3 Years Sony Limited Warranty
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- Class-D amplification technology for high power
- 100 W x 4 maximum power output
- Low and high pass filters for accurate sound
Frequently Bought Together
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- 4 Ohms, 20 Hz – 20 kHz, <1 % THD+N
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How much does the Sony XM-S400D 4-channel Class D Amplifier cost?
MSRP is listed as $159.99. Given that, these models can go on sale from time to time, and there are several other opportunities to save on price like through their group discounts for education, healthcare and military/veterans (ID.me & Unidays) along with their free loyalty program that gives up to 5% back in points.
What is the power output of the XM-S400D?
The XM-S400D delivers a maximum of 100 W x 4 and a rated continuous output of 45 W RMS x 4 at 4 ohms over 20 Hz–20 kHz with less than 1% THD+N. It uses Class-D amplification technology for high power in a compact design.
Does the XM-S400D include built-in crossovers?
Yes, it features switchable high-pass and low-pass filters set at 120 Hz with a 12 dB/octave slope. This lets you high-pass the front channels and low-pass the rear channels for accurate sound without external crossovers.
What kind of car audio system is the XM-S400D best suited for?
The XM-S400D is designed to power up to four full-range speakers with significantly more output than a head unit. Its compact Class-D design makes it ideal for small to mid-sized systems that need to fit in tight spaces.
Can I use the XM-S400D to power a subwoofer?
The XM-S400D is not bridgeable and is designed for 4–8 ohm speakers, so it is best used for full-range or component speakers. Using the low-pass filter, the rear channels can be dedicated to bass-focused speakers or a small sub.
Does the XM-S400D work with factory head units that don't have RCA pre-outs?
Yes, it supports both low-level (RCA) and high-level (speaker-level) inputs. Its Hi-Level Sensing Power On feature lets the amp turn on automatically from a factory stereo's speaker outputs without a remote wire.
What speakers can I connect to the XM-S400D?
The XM-S400D is designed to work with 4–8 ohm speakers and provides stable 4-channel output at 4 ohms, making it suitable for most factory or aftermarket car speakers within that impedance range.
How compact is the XM-S400D and where can it be installed?
This "micro" amplifier measures roughly 62.6 x 37.3 x 162.8 mm and weighs about 0.46 kg. Its small form factor makes it easy to mount behind the dashboard, under a seat, or in other tight spaces.
What warranty comes with the XM-S400D?
The XM-S400D includes a 3-year Sony Limited Warranty. Buying directly from Sony also includes free shipping and easy returns.
*FAQ generated on 07/23/2026. Financing, pricing and promotions may no longer apply.