Hertz CP 5.1K 5-Channel Car Amplifier

The Hertz CP 5.1K is a compact five-channel Class D car amplifier designed to power front and rear speakers plus a subwoofer from one chassis. It provides a practical upgrade path for systems that need more output, cleaner control, and dedicated bass amplification without using separate amplifiers. Its selectable five- or three-channel operating configurations support a range of active and bridged system layouts.

This amplifier is suited to listeners building a full aftermarket audio system or improving a factory-source setup. It accepts both low-level preamp signals and speaker-level inputs, making it compatible with many aftermarket and factory head units. Automatic remote turn-on from compatible BTL speaker-level radio outputs can simplify integration when a conventional remote lead is unavailable.

The CP 5.1K delivers 80 watts RMS to each full-range channel at 4 ohms and 330 watts RMS to the subwoofer channel at 4 ohms. At 2 ohms in five-channel mode, it is rated for 130 watts RMS per full-range channel and 510 watts RMS for the subwoofer channel. This distribution gives a speaker system and subwoofer dedicated power from a single amplifier.

Hertz equips the CP 5.1K with adjustable front, rear, and subwoofer crossover controls for matching the amplifier to the speakers in the vehicle. The subwoofer channel includes a 50 Hz bass boost, a fixed 25 Hz subsonic high-pass filter, and optional remote level control capability. Hi-Res Audio certification and a wide full-range bandwidth support detailed playback in compatible systems.

The compact aluminum die-cast chassis is intended for installations where available amplifier space is limited. A full-range front pre-out allows signal pass-through to an additional amplifier if the system is expanded later. With its included input and output harnesses, the CP 5.1K is configured for organized integration into multi-speaker systems.

Key Features

• Five-Channel Design: Powers four speakers and one subwoofer from one amplifier.
• Class D Amplification: Delivers efficient power in a compact chassis.
• Hi-Res Audio Certified: Supports extended full-range frequency response for detailed playback.
• Pre-In And Speaker-In: Connects to aftermarket or compatible factory audio sources.
• Adjustable Crossovers: Helps match frequency ranges to connected speakers and subwoofer.
• Optional Sub Level Remote: Enables convenient subwoofer-level adjustment from the driver seat.

Design & Installation

The CP 5.1K uses an aluminum die-cast casing with a low-profile, compact footprint. Its Class D output stage is designed for efficient operation, while the covered control and connection area keeps the installation layout clean. The amplifier weighs 2.27 kg (5 lb).

Mount the amplifier on a solid surface with ventilation and leave access to the adjustment controls and wiring connections. Use the supplied harnesses for speaker-level input, preamp input, speaker output, and remote input/output connections as needed. Match connected speakers and subwoofer to the stated minimum impedance requirements, set the crossover controls for the system layout, and use the optional Hertz HRC 02 when in-cabin subwoofer-level adjustment is desired.