Hifonics ZTH-2225.1D Mono Class D Car Amplifier

The Hifonics ZTH-2225.1D is a compact mono Class D car amplifier designed for a dedicated subwoofer channel. It provides adjustable low-frequency controls for building or upgrading a bass-focused vehicle audio system. Its compact chassis is suited to installations where available mounting space is limited.

This single-channel amplifier is intended for users matching a subwoofer system to a mono amplifier with selectable crossover, subsonic, phase, and bass-EQ controls. Output is listed at 2,200 watts at 1 ohm, 1,100 watts at 2 ohms, and 550 watts at 4 ohms. Proper subwoofer wiring and impedance matching are important when selecting the final system configuration.

A variable 40-300 Hz low-pass filter lets the amplifier focus on bass frequencies rather than sending full-range content to the subwoofer. The adjustable 10-40 Hz subsonic filter can help tailor the very low-frequency range for the enclosure and system setup. Variable phase control from 0 to 180 degrees can assist with blending subwoofer output with the rest of the vehicle audio system.

The ZTH-2225.1D uses a PWM MOSFET power supply and an aluminum heat sink to support efficient Class D operation and heat management. Its low-noise preamplifier circuit is designed to accept a low-level source signal with minimal added distortion. Illuminated protection indicators provide a visible status reference for overload and speaker-short conditions.

For system integration, the amplifier provides RCA input and output connections, speaker-level audio inputs, and a wired bass remote. Angled molded terminals are designed to make power, ground, and speaker wiring more accessible. It is a practical choice for a subwoofer upgrade when installed with the specified 4-gauge power and ground wiring and external fuse protection.

Key Features

• Mono Class D Design: Efficient single-channel amplification for a subwoofer system.
• Selectable Power Ratings: Supports listed output ratings at 1-, 2-, and 4-ohm loads.
• Variable Low-Pass Filter: Adjusts bass passband from 40 to 300 Hz.
• Subsonic Filter: Adjustable 10-40 Hz filtering helps tailor low-frequency response.
• Wired Bass Remote: Included remote provides convenient bass-level adjustment.
• Protection Indicators: Illuminated LEDs help monitor overload and speaker-short protection.

Design & Installation

The amplifier has a silver compact chassis with an aluminum heat sink for heat dissipation. It uses a PWM MOSFET power supply, nickel-plated high-temperature RCA inputs, and molded angled connection terminals for power, ground, and speaker wiring. The amplifier measures 10.9 inches long, 5.75 inches wide, and 2.5 inches high.

Mount the amplifier securely in a ventilated location and do not install it upside down. The installation guide specifies 4-gauge power and ground cable plus an external 125-amp fuse, with the battery-side fuse installed within 18 inches of the battery terminal. Connect RCA inputs from a compatible source unit or use the speaker-level inputs, set the gain from minimum during setup, and match connected subwoofers to a supported final impedance.