Hifonics ZD-1750.5D 5-Channel Class D Car Amplifier

The Hifonics ZD-1750.5D is a compact five-channel Class D car audio amplifier designed to power a complete speaker-and-subwoofer system from one chassis. It provides dedicated channels for front and rear speakers plus a subwoofer channel, helping simplify an upgrade that would otherwise require separate amplifiers. Its universal vehicle fitment makes it suitable for custom installations in a wide range of cars, trucks, and SUVs.

This amplifier is intended for listeners building a full-range system with amplified door speakers and a separate subwoofer. The four full-range channels can be used for component or coaxial speakers, while the dedicated subwoofer channel supports low-frequency duty. Variable crossover controls allow the installer to divide frequencies between speakers and subwoofer for a more appropriate system setup.

Hifonics specifies output ratings of 4 x 225 watts plus 1 x 450 watts at 2 ohms, or 4 x 100 watts plus 1 x 225 watts at 4 ohms. The subwoofer channel is rated at 850 watts at 1 ohm, while the full-range channels can be bridged to 2 x 450 watts at 4 ohms. These options provide flexibility for systems using conventional speakers, bridged channel pairs, or a dedicated subwoofer.

The ZD-1750.5D uses a PWM MOSFET power supply with Hifonics' Simpatico Coil Design to maintain voltage through its output devices. Its aluminum heat sink is designed to dissipate heat, while the Class D topology helps keep the amplifier compact. A low-noise preamplifier circuit is also included to pass low-voltage source-unit signals with minimal distortion.

For integration convenience, the amplifier accepts speaker-level audio inputs and has a DC Signal Sense auto turn-on function for RCA-input installations. It also includes a wired bass remote, allowing adjustment of bass level from the driver's seat. This makes the amplifier a practical central power stage for an aftermarket head unit or a compatible factory-audio upgrade.

Key Features

• Five-Channel Configuration: Powers four full-range speaker channels and one dedicated subwoofer channel from one amplifier.
• Class D Topology: Delivers high-efficiency amplification in a compact chassis.
• Variable Electronic Crossovers: Helps tailor frequency ranges for speakers and subwoofer.
• DC Signal Sense: Can turn on from a signal at the RCA inputs.
• Wired Bass Remote: Provides convenient bass-level adjustment from the front seat.
• LED Protection Diagnostics: Illuminated indicators monitor overload and speaker-short protection.

Design & Installation

The ZD-1750.5D has a black finish, an aluminum heat sink, and nickel-plated, high-temperature, impact-resistant RCA connections. Its molded power, ground, and speaker terminals are angled to improve access and help maintain an orderly wiring layout. The amplifier measures 14.8 inches long, 5.75 inches wide, and 2.16 inches high.

Mount the amplifier securely in a dry location with adequate ventilation and plan wiring before final installation. The power and ground terminals accept 4 AWG cable, speaker terminals accept 12 AWG cable, and the amplifier requires external 100A fusing. Match connected speaker loads to the specified channel configurations, use the adjustable crossover controls during setup, and use the included bass remote only after system gain and subwoofer level are properly adjusted.