Sundown Audio SDX-400.1 Mono Class D Amplifier, 400W x 1 RMS, Weatherproof 1-Ohm by Sundown Audio - Used condition

Sundown Audio SDX-400.1 Mono Class D Amplifier, 400W x 1 RMS, Weatherproof 1-Ohm — Open-Box, 11% Off

Name: Sundown Audio SDX-400.1 Mono Class D Amplifier, 400W x 1 RMS, Weatherproof 1-Ohm
Brand: Sundown Audio
SKU: awhd-us-b0fdh7svlz
Price: 80.00 USD
Availability: InStock

Brand: Sundown Audio

Condition: Used - Mint

$80⁰⁰

$89⁹⁵

-11% Save $9⁹⁵

Updated: 9 days ago

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Description

Weatherproof Mono Design: The SDX-400.1 Class D amplifier suits car, UTV, powersports, and open-air vehicle audio systems, with a water-resistant build for changing conditions 1-Ohm RMS Power: Delivers 400 x 1 at 1 ohm RMS, 300 x 1 at 2 ohms RMS, and 175 x 1 at 4 ohms RMS for compact mono subwoofer setups Bass Tuning Control: Variable low-pass filter from 50Hz to 250Hz and variable 12dB bass boost help shape low-frequency output for subwoofer systems Protected Control Layout: A removable audio control cover keeps settings covered, with DC auto-sensing turn on, wired remote, and thermal, voltage, speaker short, and DC-offset protection Compact Aluminum Housing: Heavy cast aluminum heat sink supports heat control, while 11.5V to 15V operation, 40A fuse, 90dB S/N ratio, and 5.75 x 4 x 2.125 in size fit tight builds The Sundown Audio SDX-400.1 is a compact mono weatherproof Class D amplifier made for car, UTV, powersports, and open-air vehicle audio systems. Its water-resistant design helps keep the amp ready for changing conditions while giving your setup controlled single-channel power for subwoofer use.

This amplifier delivers flexible RMS output for mono bass layouts, including 400 x 1 at 1 ohm, 300 x 1 at 2 ohms, and 175 x 1 at 4 ohms. A sealed control area and removable cover keep the tuning section protected, and the badge can be removed with an allen key to access audio settings.

Built-in tuning controls give installers room to shape the system with a variable low-pass filter from 50Hz to 250Hz and variable 12dB bass boost. DC auto-sensing turn on, wired remote control, and protection circuitry help support dependable daily use.

Technical Highlights:
Amplifier Type: weatherproof mono Class D car audio amp
Power Output: 400 x 1 at 1 ohm RMS, 300 x 1 at 2 ohms RMS, 175 x 1 at 4 ohms RMS
Voltage And Fuse: 11.5V to 15V operation with 40A recommended fuse
Size: 5.75 x 4 x 2.125 in with heavy cast aluminum heat sink
Controls: Removable audio control cover with wired remote control

This SDX-400.1 amp is suited for car stereo builds, UTV systems, powersports audio, and open-air vehicles where compact mono power, tuning control, and weatherproof construction matter. Its aluminum housing, water-resistant build, and low-pass control make it a practical choice for subwoofer-focused installations.

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Product Details

SKU:: awhd-us-b0fdh7svlz
Model:: A-SDX400
Country:: US
ASIN:: B0FDH7SVLZ
GTIN:: 00810111130516
UPC:: 810111130516

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Common questions about buying open-box and refurbished.

Why buy refurbished or open-box?

Refurbished and open-box products offer the same performance as new at a fraction of the price. You're already saving $10 on this listing. They've been inspected, tested, and are ready to use — the only difference is the price tag. Buying refurbished also reduces electronic waste, extending product life cycles and keeping functional devices out of landfills.

What's the difference between open-box and refurbished?

Open-box products are customer returns that have been inspected and confirmed functional. They may show little to no use — often the item was returned simply because the buyer changed their mind. Refurbished products have been professionally repaired or restored by technicians, tested to meet or exceed manufacturer specifications, and sometimes come with a warranty. Both are a smart alternative to buying new.

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