Ruthless Audio

Ruthless Audio Micro 400.4 – 4-Channel 400W Compact Full-Range Amplifier

Name: Ruthless Audio Micro 400.4 – 4-Channel 400W Compact Full-Range Amplifier
Brand: Ruthless Audio
Price: 179.99 USD
Availability: InStock

$179.99 USD

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Ruthless Audio Micro 400.4 – 4-Channel 400W Compact Full-Range Amplifier

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The Ruthless Audio Micro 400.4 – 4-Channel 400W Compact Full-Range Amplifier is a Ruthless Audio four-channel amplifier for customers building a louder, cleaner speaker system in a daily driver, custom door build, motorcycle or powersports installation, or demo-style front stage. The published ratings below make it easier to match the amplifier to full-range speakers, component speakers, midrange drivers, midbass drivers, or other suitable loads.

Use the continuous power ratings at the intended impedance—not the largest number in the model name—to choose speakers and wiring. The amplifier's crossover ranges, operating voltage, fuse requirement, and physical dimensions also matter when planning the installation.

400micro Specifications

Amplifier type: Compact Class-D four-channel amplifier
RMS power at 2 ohms, 14.4 volts: 100 watts x 4
RMS power at 4 ohms, 14.4 volts: 60 watts x 4
Frequency response: 20 Hz–8 kHz
High-pass filter: 20 Hz–8 kHz
Low-pass filter: 50 Hz–8 kHz
Fuse rating: 60 amps
Operating voltage: 9–16 volts
Overall length: 7.25 inches
Heatsink length: 6.375 inches
Width: 4.7 inches
Height: 2.2 inches

What This Ruthless Audio Amplifier Is For

This four-channel model can power a stereo speaker system, multiple door speakers, an active or semi-active front stage, or bridged loads when the final impedance and published ratings are followed.

Match the Amplifier to the Speaker System

A four-channel amplifier should be chosen around the speakers' RMS power handling, impedance, number of channels, crossover requirements, signal source, and intended listening level. Confirm the final load on every channel before installation, and use bridge mode only with loads the amplifier is designed to support.

Shop Ruthless Audio Amplifiers and Installation Parts

Compare the full Ruthless Audio collection, browse more 4-channel car audio amplifiers, or shop all car audio amplifiers. Complete the installation with a correctly sized car audio amplifier wiring kit and the electrical support required by the system.

Helpful Amplifier Setup Guides

Use the Ruthless Audio amplifier selection guide to compare models. Before powering the system, review how to set amplifier gain for mids and highs, the car audio wire-gauge and fuse guide, the amplifier grounding guide, and the car audio wiring-diagram guide.

For reliability and troubleshooting, read the Ruthless Audio reliability and electrical guide and the amplifier protect-mode guide.

Frequently Asked Questions

How should I choose the final impedance?

Use the number of subwoofers or speakers, their voice-coil or nominal impedance, and the series or parallel wiring plan. The final load must stay within the exact amplifier specifications and warranty conditions.

Does the amplifier include everything needed for installation?

No. Plan for suitable power and ground wire, fusing, signal cable, speaker wire, mounting hardware, battery and charging support, and any vehicle-specific integration parts.

What matters most for reliability?

Stable voltage, correct fusing, low-resistance grounds, properly sized conductors, safe impedance, adequate cooling, and a clean gain setting all matter.