Pioneer GM-DX871 Class D Mono Subwoofer Amplifier

The Pioneer GM-DX871 is a Class D mono amplifier designed to add dedicated subwoofer power to a vehicle audio system. It provides a single amplified channel for bass reproduction and supports loads from 1 to 8 ohms. It is suited to systems that need a compact amplifier for one subwoofer or a parallel-wired pair of subwoofers.

With continuous output ratings of 300 watts RMS at 4 ohms, 500 watts RMS at 2 ohms, and 800 watts RMS at 1 ohm, the GM-DX871 offers flexible power matching for compatible subwoofers. Its Class D design is intended to deliver substantial bass power in a relatively compact chassis. The amplifier is CTA-2006 compliant for its published power ratings.

A variable low-pass filter lets the installer select a cutoff point from 40 Hz to 240 Hz. This helps keep low-frequency duties focused on the subwoofer while allowing the bass blend to be tailored to the vehicle and speaker system. The filter uses a -12 dB/octave slope.

The GM-DX871 supports both RCA-level and speaker-level signal connections. Its supplied speaker-input wire with RCA pin cord can help integrate the amplifier with factory radios that do not provide RCA preamp outputs. Automatic input-signal detection selects between RCA-level and speaker-level input modes.

A wired bass boost remote is included for convenient adjustment from the listening position. The remote controls bass boost from 0 to 18 dB at 50 Hz, while the amplifier's gain controls support a range of source-output levels. Gold-plated RCA terminals and high-current electronic components support its role as a dedicated bass amplifier in an upgraded car audio system.

Key Features

• Mono Class D Design: Delivers dedicated power for a subwoofer system in a compact amplifier format.
• 800W RMS at 1 Ohm: Supports high-output compatible subwoofer configurations at 14.4 volts.
• Variable Low-Pass Filter: Adjusts the bass cutoff frequency from 40 Hz to 240 Hz.
• Wired Bass Remote: Allows accessible adjustment of bass boost from the front seat.
• Speaker-Level Input: Enables connection to many factory radios without RCA outputs.
• Protection Monitoring: Helps protect the amplifier during overheating, DC output, or speaker short conditions.

Design & Installation

The GM-DX871 uses a compact chassis measuring 252 mm wide, 60 mm high, and 215 mm deep. It incorporates high-current electronic components, gold-plated RCA terminals, a POWER/PROTECT status indicator, gain control, and low-pass filter control. The protection system indicates abnormal conditions through the POWER/PROTECT indicator and can mute or shut down output when necessary.

Use properly sized power and ground wiring, with the same gauge for both; Pioneer specifies 6 AWG for runs under 3.6 m and 4 AWG for runs under 6.4 m. A separately sold 100 A fuse should be installed within 30 cm of the battery's positive terminal, and speaker wire should be 8 to 16 AWG. Mount the amplifier securely in a ventilated location, keep it clear of carpeting, and match the connected subwoofer configuration to the amplifier's 1 to 8 ohm allowable load range.