JL Audio M700/5 5-Channel Class D M-Series Marine Amplifier Review

A marine amplifier is not the same as your regular amplifier. It has a weatherproof construction to take on water, salt, wind and dirt abuse. It is also protected against UV rays and physical impact.

If you are looking to invest in a compact marine amplifier for multi-channel applications, we have just the right product for you. It is the JL Audio M700/5, a top-class 5 channel marine amplifier. It can power two pairs of speakers and a subwoofer at the same time. It is a Class D amp with a sophisticated NexD™ super-high-speed switching design. The new design does away with the shortcomings of traditional Class D amps. The M700/5 also has a rugged body for weathering storms and direct sunlight on the high seas. It is designed for rough outdoor use and can take a knock or two.

Let Us Analyze The Performance Of The JL Audio M700/5 :

Sound Amplification :

When it comes to sound quality, the JL Audio M700/5 is a winner. It is the best marine amplifier in market in the 5 channel category. It has a unique NexD™ super-high-speed switching design which eliminates the common disadvantages of conventional Class D amps. For instance, it minimizes distortion and delivers full-bandwidth amplification with great efficiency. The M700/5 is a beefy amp. It delivers a continuous total power of 700 watts into a 2 ohm load @ 14.4 volts, 1% total harmonic distortion. The four front and rear channels deliver 100 watts each while the subwoofer channel has 300 watts. The device can simultaneously support two pairs of coaxial/component speakers with its first four channels and a subwoofer with its fifth. RMS power rating of the JL Audio M700/5 is as follows:

@ 14.4 volts RMS power is :

  • @ 4 ohms: 75 watt x 4 channels + 180 watt x 1 channel
  • @ 2 ohm: 100 watt x 4 channels + 300 watt x 1 channel
  • In bridged mode, 8 ohm: 150 watt x 2 channels
  • In bridged mode, 4 ohm: 200 watt x 2 channels

@12.5 volts RMS power is :

  • @ 4 ohm: 60 watt x 4 channels + 180 watt x 1 channel
  • @ 2 ohm: 90 watt x 4 channels + 300 watt x 1 channel
  • In bridged mode, 8 ohm: 120 watt x 2 channels
  • In bridged mode, 4 ohm: 180 watt x 2 channels

The JL Audio M700/5 has an unregulated MOSFET switching type power supply. It has variable high-pass filter within the range of 50 to 5000 Hz, 12 dB/octave. Variable low-pass filter is 50 to 500 Hz, 12 dB/octave. The filters can be configured like a 3-way crossover with a variable high-pass filter on channel 1 and 2 (50 to 5000 Hz, 12 dB per octave), variable high or band-pass filter on channel 3 and 4 (50-500 Hz, 12 dB per octave), and a low-pass filter for the subwoofer channel (50 to 500 Hz, 12 or 24 dB per octave). The JL Audio M700/5 has preamp RCA level inputs. For daisy chain connections with other amps it has pass-through preamp RCA outputs. It also has optional remote level controls. Frequency response of the front and rear channels is 12Hz to 22 kHz while that of the subwoofer channel is 10 Hz to 1000 Hz. Signal-to-noise ratio of the amp is greater than 104 dB and total harmonic distortion is less than 1%. Input range of the system is 100mV to 4V RMS. Damping factor @ 4 ohm is > 150 and @ 2 ohm is > 75. The manufacturer recommends 4 gauge wire for power and ground connection. Speaker outputs support up to 8 AWG (American Wire Gauge) wire. +12V and ground connections need 4 AWG wire. All in all, the JL Audio M700/5 is a good amp for marine applications. Its advanced NexD™ Switching Technology keeps distortions at bay and offers a more balanced sound output.

The sound amplification section ends here. We now move to the design and construction of the amplifier.

Product Design :

The JL Audio M700/5 is built for sea use. It has a water and salt-resistant housing with a white and grey powder coated finish. The cabinet is made of heavy duty stainless steel to avoid rusting. The control cover is gasketed to prevent water and dust ingress. The amp has Advanced Rollback Protection which safeguards the system from shutting down due to over-heating. If the temperature of the amp becomes too hot, a special circuit reduces the peak power output without affecting the gain. It keeps it at that level till the temperature comes down to normal, at which point full peak power output is restored. All RCA inputs and screw terminals of the M700/5 are nickel-plated. The speaker output connection support up to 8 AWG wire. The device measures 10.25 inches by 2 inches by 7.12 inches.

We have come to the end of our review. Let us now go over the main features of the JL Audio M700/5 marine amplifier.

Key Features :

  • 5 channel marine amplifier.
  • Total power 700 watts.
  • Class D amp with NexD™ Switching Technology.
  • Advanced Rollback Protection, stainless steel cabinet, gasketed control cover.
  • Unregulated MOSFET switching type power supply, high and low-pass filters.


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