Kenwood KAC-M1804 Review – Mini Motorcycle Amplifier

If you are in search of a car audio system that can double the power without consuming a lot of space, the Kenwood KAC-M1804 amplifier is a great choice. The class D digital amp has four channels that work with four speakers or two subwoofers and it does not just suit cars but ATVs, motorcycles and marine vehicles as well.

Specifically designed for the Powersports line of Kenwood products, the amplifier supports higher volumes demanded by open vehicles and withstands extreme conditions.

Let us discuss the features, offerings, pros and cons of the Kenwood KAC-M1804 amplifier to find out whether it suits your requirements.

Popular as the marine amp, the Kenwood KAC-M1804 is one of the best models available in the market today. It can pump up the car’s audio system with 45 watts RMS per channel which is more than twice the power of regular car stereos. The small, compact amp adds a new level of clarity and impact to any basic sound system in different types of land and water vehicles.

Specifications & Highlights

  • 4-channel, compact amplifier
  • 45watts RMS x 4 at 4 ohms
  • Class D amp technology
  • Conformal-coated circuit board for marine applications
  • Dimensions – 6 ½”W x 1 3/8”H x 3 9/16”D
  • Frequency Response – 20-20,000Hz
  • Signal to noise ratio – 74dB
  • Preamp and speaker level inputs
  • Warranty – 90 days


Designed to suit a large number of land and water vehicles, the Kenwood KAC-M1804 is a small, compact amp that fits small spaces easily with a weight of just 1.4 pounds.

It features a conformal coated circuit board that protects its electronic assembly from dust, moisture, corrosion and salt in extreme environments.

This design also ensures long-life and durability of the unit. The plastic covering makes the amp resistant to various environmental factors like moisture and heat. It also avoids damage caused due to poor handling and installation.

Apart from this, the amplifier also features an extruded aluminum heatsink to provide better scope of natural convection. Such technology ensures you need not worry about the amp getting hot after usage.


Compact Construction – The class-D amplifier is designed to boost the clarity and output of any car stereo. The special coating allows using the amp for marine vehicles, all-terrain vehicles and others. It is especially suitable for space-restricted applications due to its compact design.

Signal-Sensing Turn-On – On connecting the amp to a factory radio or an aftermarket receiver, it uses the signal-sensing technology to turn itself on. While it comes with RCA cable to connect an aftermarket head unit, it can also handle speaker-level signals so that you can get input from a radio without using RCA outputs.

Protection Circuitry – This amp comes with protection circuitry for DC offset, short circuits and thermal overload. It stops operating automatically as it goes into the protection mode.

No Crossovers or Controls – The Kenwood amplifier does not have any integrated controls or crossovers. To connect the amp to the smaller speakers, one should use the crossovers of the head unit or use bass blockers on the outputs.

Kenwood Amplifier KAC-M1804 coverage at CES 2014


Featuring a total of four channels, the KAC-M1804 amplifier can connect to up to four speakers. As different channels are used for each speaker, there is less possibility of the device heating up.

Also, the chances of sound distortion are reduced. The amp can supply about 180 watts at 4 ohms, giving 45 watts for each of the channels. It has a signal to noise ratio of 82dB that results in clearer sound as compared to other amplifiers.

User reviews suggest that its design is the most liked of all the amp features. Installing the amplifier is quick and easy and as it is compact, there is no problem of finding a space where it can fit. Anybody interested in powering up the car’s audio system can rely on this powerhouse for a louder and clearer sound.


Kenwood KAC-M1804 Installation

The Kenwood KAC-M1804 amplifier ships with an instruction manual that describes the step-by-step procedure to install the unit.

While the installation requires some technical skills, it can be done easily by following the instructions.

Click Here To Learn How To Install An Amplifier – An In Depth Guide

The amp comes with a 22-pin DC connector and 5’ DC harness that plugs into the connector. It also has wires for ground, battery power, power control and speakers.

The +12V power wire can be connected to the fuse box or battery of the car. The ground wire should be connected to an un-painted chassis area near the unit.

The power control wires should be connected to the remote turn-on lead when using an aftermarket head unit. The DC harness comes with eight wires to connect four speakers to the amplifier. Two stereo RCA patch cables are also included.


  • Compact, lightweight design
  • 4-channel amplifier for car, boat or motorcycle
  • MOSFET power supply and class D technology
  • Conformal circuit board suits marine applications
  • Preamp as well as speaker level inputs
  • Signal-sensing turn-on feature
  • Manufacturer warranty of 90 days


  • Sound is not so loud as expected
  • An insulation pad should be included in the package

What’s In the Box

  • Kenwood 4-channel amplifier
  • 5’ power and speaker output harness
  • Two RCA stereo patch cables
  • Self-tapping screws
  • Plastic wire ties
  • Warranty sheet
  • Instruction manual


Kenwood KAC-M1804 Review

The design, features and performance of the Kenwood KAC-M1804 amplifier are perfect for music enthusiasts who like to move about a lot. This amp allows for enjoying quality sound anywhere, anytime.

Built to handle rough handling, you need not worry about the durability of this unit. It is simple to install and comes with a warranty. It is certainly one of the best choices for a powerhouse!