NA3-750.1

The MB Quart NA3-750.1 is a single-channel Class D amplifier built to power a subwoofer in an open marine environment. It is rated at 750W max power and delivers 1 x 300W at 4 ohms, 1 x 500W at 2 ohms, and 1 x 750W at 1 ohm, so it matches a wide range of marine subwoofer impedances.

The chassis is made for water and spray. It meets or exceeds IPX standards for water and dust resistance, output connections are sealed and grommeted, and the RCA jacks are prewired to the circuit board with covers that close over unused inputs. A gloss white epoxy heat sink rejects heat at the surface and moves it away from the MOSFETs, and marine grade MOSFET power supply design keeps current demand off the boat's electrical system.

Tuning sits under a top-mounted panel: a variable low-pass crossover from 50Hz to 250Hz, 0-12dB bass boost, a subsonic filter set to off or 25Hz, and input sensitivity from 0.02V to 9V. High-level inputs and DC signal sense let the amplifier switch on from an RCA signal alone, so a remote turn-on wire is optional when you are working with a factory head unit. The included bass remote puts subwoofer level within reach at the helm.

Performance holds up: greater than 99dB signal to noise, less than 0.01% THD, 10Hz-250Hz frequency response. Surface mount construction inside stands up to the shock and vibration a boat sees at speed, and LED indicators flag overload and speaker short conditions. Power and ground terminals accept 10 AWG wire, speaker terminals 12 AWG.

At 10 x 6 x 2.5 in and 6.05 lb, it mounts under a console, helm or seat in a center console boat, pontoon or wake boat, and fits powersports builds such as side-by-sides and golf carts.