The MB Quart NA4-320.4 is a 320 watt 4-channel Nautic amplifier for powersports and marine audio, with waterproof potted internals and quick release connectors. It is a compact full range Class D design rated IP67, so it can live in a UTV, boat or RV where water and dust reach the electronics.
This marine amplifier is the four channel Nautic. As a 4 channel marine amp, it powers front and rear speakers or a pair of tower speakers plus cabin speakers. As a UTV amplifier it is small enough for tight spaces; MB Quart lists it for marine and powersports use, so it doubles as a boat amplifier or general waterproof amplifier. Among MB Quart amplifier options, this MB Quart amp is the compact 4 channel UTV amp in the Nautic line, a marine amp and powersports amplifier in one.
Key Features
- 320 watt max, 4 channel full range Class D operation
- 4 x 80 watts at 2 ohms
- 4 x 40 watts at 4 ohms
- IP67 waterproof and dustproof with potted internals
- Q-Stasis low noise preamplifier stage
- Quick connection power wires and RCA connections; Molex plug speaker connector
- Protection circuits for thermal, overload, DC and speaker short with lighted indicators
- 2 pair nickel-plated RCA inputs
Built To Solve: Underpowered Speakers in UTVs and Boats
- Speakers running off head unit power that distort over engine and wind noise
- Car amplifiers that fail when water, dust or vibration reach the circuit board
- No room for a large amplifier under a seat or console
- Bulky screw terminals that are slow to service
Best For: UTV, Boat and RV 4 Channel Amplifier Builds
- UTV and side-by-side audio builds that need compact waterproof power
- Boat and wake setups with marine speakers
- RV and outdoor installs where the amp sees moisture
- Not a subwoofer amp: MB Quart builds the NA4-400.1 mono for that
Specifications
- Channels: 4 channel
- Power: 4 x 80 watts at 2 ohms
- Power: 4 x 40 watts at 4 ohms
- Crossover: Fixed high pass 80Hz, switchable OFF / HP
- Signal to noise: > 95dB
- Frequency response: 13Hz-29kHz
- Input: RCA (2 pair)
- Input sensitivity: 0.2-9V
- THD: 1.0%
- Power terminal: 12 AWG quick connector; speaker connection: Molex plug connector
- Fusing: 30A x 1
- IP rating: IP67, potted internals
- Amp dimensions: 6.8 x 3.94 x 1.77 in; amp weight 2.2 lbs
- Color: Black; warranty: 1 year
- Manufacturer Part Number: NA4-320.4
Fitment
MB Quart lists this product as universal: it is not specific to one machine. Fitment is not guaranteed for every mounting location; confirm space, mounting and wiring for your UTV, boat or RV before ordering.
FAQ
Is the MB Quart NA4-320.4 waterproof?
Yes. MB Quart states it meets or exceeds IP67 standards for waterproof and dustproof and uses potted internals that seal the components.
How much power does the NA4-320.4 make?
MB Quart rates it at 320 watts max: 4 x 80 watts at 2 ohms; 4 x 40 watts at 4 ohms.
Will it fit my UTV?
MB Quart lists the Nautic amplifiers as universal. At 6.8 x 3.94 x 1.77 inches it is compact, but confirm a mounting location and wiring path in your machine before ordering.
How do I connect it?
Power uses 12 AWG quick connectors, inputs are nickel-plated RCA, and speaker outputs use a Molex plug connector. MB Quart publishes a Nautic amplifier quick start guide.
What did it replace?
MB Quart lists the NA4-320.4 as the replacement for the NA2-320.4.
Why MB Quart
MB Quart's Nautic and Discus lines are built for open-air use on boats, UTVs and RVs, where sun, spray, dust and vibration are part of every trip. MB Quart backs this product with a 1 year warranty.
Pair the Nautic 4-Channel Amplifier With the Right Speakers
Match the NA4-320.4 to speakers and impedance using MB Quart's ratings, and plan a power kit and fuse for your machine or boat. Dunes 2 Dezert SXS carries MB Quart Nautic speakers, Discus amplifiers and powersports wiring kits to complete the system.
