Hertz ML Power 4 Mille 4-Channel Amplifier 250W RMS x 4

The Hertz ML Power 4 is a Mille-series Class D 4-channel car audio amplifier rated 150 W RMS x 4 at 4 ohms and 250 W RMS x 4 at 2 ohms (14.4 VDC), bridgeable to 500 W RMS x 2 at 4 ohms, built to power a front-rear Hertz Mille speaker system in any 12-volt vehicle installation. It runs in 4-, 3-, or 2-channel mode and is sold as a single amplifier.

Hertz's Advanced D-Class (ADC) topology packs this output into a 289 mm chassis, and the dual-technology heat sink — extrusion plus aluminium die-casting — sustains continuous full-power operation. Each channel bank carries its own crossover: bank A switches full-range, hi-pass, or lo-pass across 50 Hz - 5 kHz, and bank B across 80 Hz - 3.3 kHz, both at 12 dB/Oct, so a front stage, rear fill, or a bridged subwoofer can all be filtered inside the amplifier. The control section sits under a removable top panel, and a status LED reports thermal, overload, and short-circuit protection.

What's Included

Sold individually — one 4-channel amplifier. The ML Power IN input module accepts RCA connections from aftermarket sources and balanced speaker-level connections from factory (OEM) head units; with speaker-level input, the ART (Automatic Remote Turn On-Off) function switches the amplifier without a remote wire.

Specifications

• Channels: 4 (configurable 4 / 3 / 2 channel modes)
• Output power (RMS @ 14.4 VDC, 1 percent THD): 150 W x 4 @ 4 ohm; 250 W x 4 @ 2 ohm; 3-ch: 150 W x 2 (4 ohm) + 500 W x 1 (4 ohm) or 250 W x 2 (2 ohm) + 500 W x 1 (4 ohm); 2-ch bridged: 500 W x 2 @ 4 ohm
• CEA 2006-A rated power: 120 W x 4 @ 4 ohm
• Crossovers: bank A full/hi-pass/lo-pass 50 Hz - 5 kHz @ 12 dB/Oct; bank B full/hi-pass/lo-pass 80 Hz - 3.3 kHz @ 12 dB/Oct
• Bandwidth (-3 dB): 5 Hz - 55 kHz
• THD (100 Hz @ 4 ohm): 0.08 percent
• S/N ratio (A-weighted @ 1 V): 100 dB
• Damping factor (100 Hz @ 4 ohm): 80
• Inputs: Pre-In 0.2 - 5 V RMS; Speaker-In with ART auto turn-on
• Fuse: 2 x 40 A; supply 11 - 15 VDC
• Dimensions (W x D x H): 170 x 289 x 46.7 mm (6.69 x 11.38 x 1.84 in)
• Weight: 2.45 kg (5.4 lb)

Fitment / Compatibility

The ML Power 4 is a universal 12-volt car audio amplifier with no vehicle-specific fitment; it installs in any vehicle with an 11-15 VDC supply and space for its 289 mm chassis. Hertz positions it as the amplifier for a top-level front-rear Mille speaker system — for example driving an MLK 1650.3 component front stage, or bi-amping one component kit across all four channels. Its speaker-level input with ART supports unmodified factory head units.

FAQ

How much power does the Hertz ML Power 4 make bridged?

In 2-channel bridged mode it delivers 500 W RMS x 2 at 4 ohms. In 3-channel mode it can run a pair of speakers plus one bridged 4-ohm subwoofer at 500 W RMS.

Can the ML Power 4 run speakers and a subwoofer together?

Yes — in 3-channel mode: two channels drive speakers (150 W x 2 at 4 ohm or 250 W x 2 at 2 ohm) while the other pair bridges into a 4-ohm subwoofer at 500 W RMS. For four speakers plus a dedicated subwoofer channel from one chassis, step up to the ML Power 5.

Does the ML Power 4 work with a factory head unit?

Yes. The ML Power IN module's balanced speaker-level input accepts OEM signals, and ART turns the amplifier on and off automatically without a remote lead.

What is the difference between the ML Power 4 and ML Power 5?

The ML Power 4 is a 4-channel speaker amplifier (250 W RMS x 4 at 2 ohms, bridgeable); the ML Power 5 adds a fifth dedicated subwoofer channel (100 W x 4 + 550 W x 1 at 2 ohms) for complete one-amp systems. The mono ML Power 1 is the dedicated subwoofer amplifier of the line.