Infinity INFPRIMUS50011AAM Mono Class-D Subwoofer Amplifier

The Infinity Primus 50011A is a mono Class-D amplifier made to power a dedicated car subwoofer system. It provides 500 watts RMS at 2 ohms or 300 watts RMS at 4 ohms, giving installers two documented power-match options for compatible subwoofer loads. Its compact dimensions help make a bass upgrade possible when installation space is limited.

This amplifier is suited to listeners building a subwoofer-focused system, whether they are retaining a factory radio or using an aftermarket head unit. It accepts low-level RCA-style signal input as well as high-level speaker input, allowing it to work with a broad range of source units. OEM load-detect compatibility is also intended to support integration with factory audio systems that monitor speaker-load resistance.

The Primus 50011A focuses its output range on bass frequencies, with a 10 Hz to 320 Hz frequency response. Its variable low-pass filter lets the subwoofer hand off cleanly to the vehicle's main speakers within a selectable 32 Hz to 320 Hz range. A variable phase control from 0° to 180° helps align the subwoofer's output with the rest of the system.

For system tuning, the amplifier includes adjustable bass EQ level, frequency, and width controls. Bass EQ can be set from 0 dB to 12 dB, with a selectable center-frequency range of 30 Hz to 100 Hz and a narrow-to-wide width adjustment. A supplied remote bass control gives the driver a convenient way to adjust bass level from the front seat.

Built-in protection circuitry addresses DC, overvoltage, undervoltage, overcurrent, and overtemperature conditions. The amplifier operates on 9V to 16V vehicle electrical systems and is designed for start/stop-equipped vehicles. It is a practical foundation for a single-subwoofer upgrade when paired with a properly impedance-matched subwoofer, appropriate power wiring, and a correctly fused installation.

Key Features

• Mono Class-D Output: Delivers dedicated power for a compatible car subwoofer.
• 500W RMS at 2 Ohms: Supports substantial output with a 2-ohm final load.
• Variable Low-Pass Filter: Sets the subwoofer crossover point from 32 Hz to 320 Hz.
• Adjustable Bass EQ: Tailors bass boost level, frequency, and width.
• High- and Low-Level Inputs: Supports factory or aftermarket source-unit integration.
• Remote Bass Control: Allows accessible bass adjustment from the driver's seat.

Design & Installation

The Primus 50011A uses a compact black amplifier enclosure with Infinity's curved body styling, angular end-cap design, and prominent Infinity logo treatment. Its 9-23/32-inch width, 1-15/16-inch height, and 5-7/32-inch depth are intended to help with placement in tighter vehicle locations. The manufacturer specifies a maximum operating temperature of 70°C.

Install the amplifier with suitable 4-gauge power wiring, a properly fused power connection, secure mounting hardware, and adequate ventilation. Match the connected subwoofer system to one of the documented 2-ohm or 4-ohm power ratings, then set input sensitivity, low-pass crossover, phase, and bass EQ carefully. The package includes a high-level input cable, remote bass control and cable, mounting screws with washers, spare fuses, and Allen keys.