Memphis MM500.4V 4-Channel Marine Amplifier

The Memphis MM500.4V is a four-channel marine amplifier designed to add dedicated power to boat, powersports, and outdoor audio systems. It delivers up to 125 watts RMS to each of four channels at 2 ohms, making it suitable for driving multiple marine speakers from one compact amplifier. Its bridgeable configuration also supports systems that need higher output for two 4-ohm speaker loads.

This amplifier is intended for installations where water exposure, vibration, and changing weather are practical concerns. Its IPX5-rated construction, sealed chassis, conformal-coated circuit boards, and protected connections help support use in demanding marine environments. The sealed top-mounted controls keep key adjustments accessible while helping maintain the enclosure's weather-resistant design.

With 80 watts RMS per channel at 4 ohms or 125 watts RMS per channel at 2 ohms, the MM500.4V provides useful flexibility for matching common marine speaker loads. Its frequency response extends from 10 Hz to 25 kHz, while a signal-to-noise ratio greater than 80 dB supports a clean signal path. Adjustable gain, crossover settings, and bass boost let an installer tailor the amplifier to the speakers and system layout.

The onboard crossover section includes selectable high-pass, low-pass, and full-range operation for each appropriate channel pair. A 12 dB-per-octave Butterworth crossover can help protect smaller speakers from low bass or focus channels on midbass and subwoofer duties. The variable bass boost is adjustable from 0 to 12 dB and centered at 45 Hz.

The MM500.4V fits well as the main amplifier for a four-speaker marine system, or as a two-channel bridged amplifier for higher-power applications. It supports low-level and high-level input sensitivity ranges, allowing integration with a variety of source units. Memphis recommends its 8GKIT amplifier kit for installation, with properly sized wiring, fusing, and secure battery connections especially important in marine applications.

Key Features

• Four-Channel Output: Powers four speakers with up to 125 watts RMS per channel at 2 ohms.
• IPX5-Rated Housing: Helps protect the amplifier from water exposure in marine and outdoor installations.
• Bridgeable Channels: Provides up to 250 watts RMS per bridged pair at 4 ohms.
• Sealed Connections: Removable sealed signal connectors and waterproof quick-disconnect outputs support marine-focused installation.
• Variable Crossovers: High-pass, low-pass, and full-range settings help match the amplifier to speaker roles.
• Protection Circuitry: Includes overload, short-circuit, thermal, and reverse-polarity protection.

Design & Installation

The MM500.4V uses a sealed chassis with conformal-coated boards, sealed top-mounted controls, removable power terminals, and an extruded aluminum heat sink. Its marine-oriented construction is designed for water-resistant operation, but it is not intended for submersion. An integrated LED light strip adds visual accent lighting to an installation.

Mount the amplifier where it has adequate ventilation and is protected from excessive direct water contact. Use the recommended 8GKIT wiring kit, connect marine ground directly to the negative battery terminal, and install the battery-side fuse within 7 inches for marine applications. Maintain at least a 2-ohm stereo load or 4-ohm bridged load, and set gain and crossover controls after confirming speaker wiring and impedance.