Hifonics ZTH-1525.1D Mono Class D Car Amplifier

The Hifonics ZTH-1525.1D Zeus Theta is a compact mono car amplifier designed for powering a subwoofer system. It provides a dedicated single-channel platform for adding low-frequency output without requiring a large amplifier footprint. Its Class D design is intended for efficient operation in vehicle audio installations.

This amplifier is a practical choice for listeners building or upgrading a bass-focused system with a compatible subwoofer load. It is rated for 1 x 1,500 watts at 1 ohm, 1 x 750 watts at 2 ohms, and 1 x 375 watts at 4 ohms. Matching the final speaker impedance and power handling to these published ratings is important for system setup.

The ZTH-1525.1D gives the installer useful bass-system adjustments at the amplifier. A variable low-pass crossover, subsonic filter, bass boost, phase control, and built-in bass control allow the subwoofer channel to be tailored to the vehicle and the rest of the audio system. The included bass remote provides convenient level adjustment from the listening position.

Hifonics equips this model with a PWM MOSFET power supply and an aluminum heat sink. These elements support stable power delivery and heat dissipation in a compact chassis. The amplifier also uses a low-noise preamplifier circuit and offers both RCA and speaker-level audio inputs for integration flexibility.

For a complete installation, the ZTH-1525.1D is paired with a properly wired subwoofer system, a compatible source signal, and correctly sized vehicle power wiring. Its angled molded terminals help simplify cable routing, while illuminated protection indicators monitor overload and speaker-short conditions. With its 9.45-inch length, it can suit installations where amplifier mounting space is limited.

Key Features

• Mono Class D Design: Provides an efficient single-channel platform for a dedicated subwoofer system.
• Published 1-Ohm Output: Rated at 1 x 1,500 watts at 1 ohm.
• Variable Low-Pass Crossover: Adjusts the subwoofer frequency range from 40 Hz to 300 Hz.
• Subsonic Filter: Offers adjustment from 10 Hz to 40 Hz for system tuning.
• Included Bass Remote: Allows convenient bass-level adjustment from the front of the vehicle.
• Protection Diagnostics: Illuminated indicators monitor overload and speaker-short protection conditions.

Design & Installation

The ZTH-1525.1D uses a silver aluminum heat sink, a PWM MOSFET power supply, and a compact chassis measuring 9.45 x 5.75 x 2.5 inches. Its power, ground, and speaker connections use secure molded terminals positioned at an angle for easier access and cleaner wire routing. Nickel-plated, high-temperature, impact-resistant RCA input connections are designed for secure signal connection.

Mount the amplifier on a secure surface with adequate ventilation and do not mount it upside down. The manufacturer installation guide specifies 4 AWG power cable and an external 80A fuse for this model; the main power cable should be fused within 18 inches of the battery terminal. Connect a compatible source through the RCA or speaker-level inputs, set the level control conservatively before final tuning, and match the connected subwoofer system to one of the published impedance ratings.