MB Quart NA540.6 Nautic Amplifier – Complete Review

An amplifier improves a weak signal. It increases the voltage, current and power of the signal. In sound systems, an amplifier can dramatically enhance the quality of the audio. It helps the soundtrack rise above the surrounding noise and be more audible. It also brings out the true quality of the music and gives it the delivery it deserves.

A lot of sound systems nowadays come with built-in amplifiers. While it offers a comprehensive solution, factory-installed amps can seldom compete with dedicated external amplifiers. The slim housings of soundbars and speakers often lack the space needed for a powerful amplifier. Hence, they make do with low-capacity amps which go a good job at a basic level, but are in no way equipped to handle full-range multi-channel applications.

In this article we are going to talk about marine amplifiers. The first is a 6 channel marine amp known for its high-intensity output. It is the MB Quart NA540.6 nautic amplifier. It is a leading marine amp product in the 6-channel category and has a peak power of 540 watts. It belongs to the Nautic Series of marine amps by MB Quart. MB Quart is a world-class sound systems and audio components maker.

Let Us Take A Closer Look At The NA540.6 And Analyze Its Amplification and Design :

Sound Amplification :

The MB Quart NA540.6 is a force to reckon with. It supports 6 channels and boasts a max power of 540 watts. It counters wind, water and engine distortions, and elevates the music without breaking it. The device is a Class A/B amplifier.

Its RMS power rating is as follows : Power at 4 ohm: 60 watt x 6 channel; power at 2 ohm: 90 watt x 6 channel; mono bridged at 4 ohm: 180 watt x 3 channel. The amp is designed to drive speakers and subwoofers on the decks of boats and yachts. The 6 channel configuration offers ample bandwidth for speakers as well as subs. The channels are all full-range. The NA540.6 has an integrated active electronic crossover. It consists of high, low and full-pass crossovers. Crossover frequency range for the 1st, 2nd, 3rd and 4th channels are : High pass filter – 250 Hz to 4 kHz. Low pass filter – 40 Hz to 250 Hz. Crossover type is electronic 12 dB per octave. The MB Quart amplifier has Pulse Width Modulated MOSFET power supply. It has 0 dB to 9 dB adjustable bass boost at 45 Hz. The input sensitivity is also adjustable. The variable level is 200mV to 6V. The system has a frequency response of 10 Hz to 45 kHz. It is therefore capable of processing very low and very high frequencies. The signal-to-noise ratio is greater than 93 dB. Tone control is bass EQ 0~9 dB at 45 Hz while voltage gain is 0.2V~6.0V. Overall, the MB Quart NA540.6 gets full points for amplification quality. It is a good marine amplifier for multiple channel systems.

Let us now study the physical design of the product.

Product Design :

The MB Quart NA540.6 is a marine-grade amplifier. It is built as per the marine electronic standards of the American Boat and Yacht Council (ABYC) and the American Society for Testing and Materials (ASTM) International. It comes with a Life Shield Badge which means it is protected against water, impact, snow, dust and mud. It has UV and salt water-resistant silk screen and paint. The PC boards are conformal-coated to prevent corrosion. Sea water has salt which can be extremely corrosive. Combined with atmospheric moisture, it can cause extensive damage to your circuit board. The anti-corrosion coating is very critical and ensures your amplifier lasts for years. The enclosure of the device is made of a tough alloy of aluminum. It has a heatsink design to minimize internal heating. The amplifier has 4 types of protection – overload protection, short circuit protection, thermal protection and DC protection. In short, the NA540.6 is fully fortified and can stand up to any weather. For connectivity, the system has RCA audio inputs and full-range preamp RCA audio outputs for daisy chaining with other amps. All input and output ports are gold-plated to prevent corrosion. It includes power, speaker and ground connections, and RCA inputs and outputs. The amp has LED indicators to show various statuses. It has soft start turn-on which safeguards the electronic parts from sudden spikes in current. The amp is easy to set up. It needs 4 gauge power and ground wiring. Wire gauge 12V/GND is 4-GA, wire gauge speakers is 10-GA. Dimensions of the NA540.6 are: 17 inches x 9.4 inches x 2.2 inches. It weighs 11.1 lbs. Warranty period is one year.

Let us quickly summarize the top features of the MB Quart NA540.6 nautical amplifier.

Key Features :

  • 6 channel marine amp, max power 540 watts.
  • Gold-plated terminals, aluminum heatsink, conformal-coated circuitry.
  • Class A/B amp, Pulse Width Modulated MOSFET power supply.
  • Active high, low, full pass crossovers.
  • Built as per ABYC and ASTM specifications, Life Shield Badge.


A marine grade subwoofer can add the much needed boost to the musical experience in boats and yachts. Read our recommendations.


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