ZD-750.4D [Open Box]

The Hifonics ZD-750.4D is a four-channel Class D amplifier built to add real power to a car audio system without eating up trunk space. It delivers up to 750 Watts total, with 100 Watts per channel at 4 ohms or 175 Watts per channel at 2 ohms, and it bridges to two channels for up to 375 Watts each when you need to power a pair of subwoofers instead of four speakers. A PWM MOSFET power supply with a dual-coil Simpatico design keeps voltage steady under load, while the aluminum heat sink pulls heat away from the board so output stays consistent on long drives. Onboard variable crossovers, tunable from 50Hz to 250Hz, and a built-in bass control let you shape the sound to match speakers, coaxials, or subwoofers without an external processor, and low-noise, nickel-plated RCA inputs keep the signal clean coming from the head unit. DC signal sense turn-on means the amp can power up straight from the RCA signal, so a remote turn-on wire isn't required, though the feature can be switched off if you'd rather wire it the traditional way. LED diagnostics on the end panel flag overload or speaker-short conditions at a glance, which makes troubleshooting a lot faster than pulling the amp to check fuses. At just over 7 inches long and 3.13 lb, it mounts easily under a seat or behind a trunk panel, making it a solid pick for anyone upgrading factory speakers or adding a single subwoofer to a daily driver.