Skar Audio SA-125.4D: 720W 4-Channel Class D Car Amplifier

Meet the Skar Audio SA-125.4D — compact power for your car audio system

The SA-125.4D is a 720-watt, four-channel Class D amplifier designed to bring clear, efficient power to a multi-speaker setup. With RMS ratings of 180W x 4 at 2 ohms and 125W x 4 at 4 ohms, it delivers confident performance for front, rear, or a combination in mid-sized cars and trucks. The ability to bridge channels to 285W x 2 at 4 ohms adds versatility for pairing with a subwoofer or a high-power mid/high duo, depending on your goals.

Flexibility is built in, starting with a broad operating voltage range of 8.5V to 16V to accommodate different vehicle electrical systems. Crossover controls include HPF, Full-Range, and LPF, with independently adjustable gain and crossover frequencies for the first pair of channels and the second pair. This setup lets you sculpt the sound stage—whether you’re aiming for crisp highs, punchy mids, or a balanced, full-range experience across the cabin.

Key features at a glance

• 720 Watt, four-channel Class D amplifier for efficient performance
• RMS power: 180W x 4 (2Ω) | 125W x 4 (4Ω) | Bridged: 285W x 2 (4Ω)
• Flexible voltage 8.5V–16V to match vehicle electrical systems
• Crossover options: HPF / Full-Range / LPF with per-pair gain and frequency control
• Frequency response from 10 Hz up to 25 kHz for wide musical content
• 4 AWG power/ground input for sturdy, reliable wiring

Why choose this amp?

• Class D design helps keep heat manageable while preserving audio fidelity
• Compact footprint supports installation under seats or in tight trunks
• Dedicated controls for tuning give you room to optimize your system without sacrificing space

Practical setup tips: plan your wiring with a clean layout, ensure adequate ventilation, and pair the SA-125.4D with compatible speakers that match your desired impedance. This description highlights the data-driven capabilities without promising specific results for every vehicle.