Description
MB Quart NA4-320.4 Nautic 4-Channel Marine & Powersports Amplifier
The MB Quart NA4-320.4 Nautic amplifier delivers reliable multi-channel power in a compact, marine-grade design. Built for harsh environments, this 4-channel Class D amplifier features fully potted internals and IP67-rated protection, ensuring dependable performance in marine and powersports applications where moisture, dust, and vibration are constant challenges.
Key Features
- 320 watts maximum output across four channels
- IP67 waterproof and dustproof construction
- Fully potted internal circuitry for long-term durability
- Q-Stasis low-noise preamp for improved audio clarity
- Quick-release power, speaker, and RCA connections
- Compact footprint for flexible installation
Marine-Grade Protection
Designed to meet or exceed IP67 standards, the Nautic amplifier is fully sealed against water and dust intrusion. Its potted internal components are insulated against moisture, preventing corrosion and electrical failure while enhancing long-term reliability in extreme outdoor environments.
Efficient Class D Performance
The full-range Class D topology provides high efficiency and strong output in a compact chassis. Combined with a PWM MOSFET power supply and Simpatico coil design, the amplifier maintains stable voltage delivery while minimizing heat generation.
Audio Control & Signal Integrity
The integrated Q-Stasis preamplifier reduces incoming noise from source units, improving overall sound quality. A fixed 80Hz high-pass crossover and wide 0.2–9V input sensitivity allow for flexible system integration and cleaner signal management.
Installation & Connectivity
The NA4-320.4 features nickel-plated, corrosion-resistant connections and quick-connect terminals for power, speakers, and RCA inputs. This design simplifies installation while ensuring secure, long-lasting connections in demanding environments.
Specifications
| Amplifier Type | 4-Channel Class D |
| Total Max Power | 320 Watts |
| Power @ 2 Ohms | 4 × 80W |
| Power @ 4 Ohms | 4 × 40W |
| Frequency Response | 13Hz – 29kHz |
| Signal to Noise Ratio | > 95dB |
| Total Harmonic Distortion | 1.0% |
| Input Sensitivity | 0.2V – 9V |
| Crossover | Fixed High Pass 80Hz |
| Inputs | 2 Pair RCA |
| Power Connection | 12 AWG Quick Connector |
| Speaker Connection | Molex Plug Connector |
| Fusing | 30A × 1 |
| IP Rating | IP67 |
| Application | Marine / Powersports |
Used Frequently Asked Questions
- What does used mean? Used products may be unused customer returns that are essentially "new" items, or they may be previously installed products that were returned under warranty or during our return policy period.
- What is the warranty? All of our used items come with a 90-day warranty.
- What's it look like? All of our used items are inspected and graded by our returns team at our facilities. They will test them and grade them to one of four standard gradings: Used Open Box, Used Very Good, Used Good, and Used Acceptable. Please see the following descriptions of each grade - also note that if an item falls under ANY of the criteria for a certain grade, even though the rest of the product is better, we will give it the lowest grade.
- Used Open Box An item in perfect working condition. Original protective wrapping may be missing, but the original packaging is intact and in good condition with minor damage possible. Instructions are included.
- Used Very Good A well-cared-for item with limited use, remains in good working condition. The item may show some limited signs of wear,small scratches,cosmetic blemishes. Item may arrive with damaged packaging or be repackaged and could be missing some accessories.
- Used Good The item shows wear from use, remains in good condition and functions properly. May have damaged packaging or be repackaged. It may be marked, have identifying markings on it, have minor cosmetic damage. It may be missing some parts or accessories.
- Used Acceptable The item is fairly worn but continues to function properly. While repackaged; signs of wear can include aesthetic issues; scratches, dents. The item may have markings on it or show signs of previous use. Item may be missing some parts or accessories.
- Have more questions? Call us, send us a chat, or an email. We'll be able to answer any additional questions you may have.