Kenwood KAC-M1804 Car Amplifier Review

If you are looking for an audio system that would double your amps power without taking a lot of space, the Kenwood KAC-M1804 amplifier is worth looking into. It is a class D, a small digital amp that has four channels which can be hooked up to 2 subwoofers or four speakers. It has a maximum power output of 400 watts and has 4 Ohms RMS power rating.

This amp is ideal for small spaces since it only measures 3 9/16 inches diameter, 5 ½ inches width and 1 5/16 inches height and weighing about 1.4 pounds. The technology used in this amp makes it ideal not just for cars but also for motorcycles, ATVs and even marine vehicles.

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Conformal Coated Circuit Board Built For Durability

Known as a marine amp, the M1804 is one of the best that you can find in the market. It has a conformal coated circuit board which protects the electronic assembly from moisture, dust, salt spray and corrosion due to an extreme environment.

The M1804 has prolonged life operation because of its conformal coated circuit board. The covering makes the amp resistant to outdoor environmental factors like heat and moisture. It also prevents damage from rough installation and handling.

On top of its tough covering, the M1804 also has an extruded aluminum heatsink which means it has a superior scope of natural convection solutions. With this kind of technology, you won’t have to worry about your amp getting too hot after usage which is a very common problem.

Four Channel Amplifiers for Subwoofers and Speakers

Equipped with a total of four separate channels, the M1804 amplifier can connect to four speakers minus the additional impedance to the amp. Since you will use different channels for different speakers, the likelihood of the device overheating is lessened. In addition, there is less possibility of experiencing sound distortion in the speaker.

The car amp can supply around 180 watts at 4 Ohms which gives 45 watts for each of the 4 channels. It delivers 82 dB signal to noise ratio resulting in clearer sound compared to other amplifiers. The signal to noise ratio is one way to measure the quality of the sound coming from the amp.

Kenwood KAC-M1804 Features and Specifications

  • Compact 4-channel amplifier with maximum power output of 400 watts
  • 4 Ohms RMS power rating providing 45 watts each channel
  • With extruded aluminum heatsink for better thermal resistance
  • Has conformal coated circuit making the amp durable even to extreme environments
  • Compact size ( 5-1/2“ width x 3-9/16” diameter x 1-5/16” height)
  • Signal to noise ratio: 82 decibels
  • One year factory warranty

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Kenwood KAC-M1804 Reviews

This miniature powerhouse received an editor rating of 8/10 coming from 143 customer reviews. This marine amplifier has a great design on top of all the other important features.

One customer said that installing the amp only took him 15 minutes, including the soldering of the wires to the receiver harness and the vehicle harness connector. Since the device is compact, he did not have a hard time finding a space where it would fit. He claims that his car audio is now clear without having to use increase the volume to more than 13. According to him, with his old amp, he needed to raise the volume to 25 to get a powerful sound.

Another client said that he purchased the amp to increase the RMS power of his boat speaker. He only hooked 2 speakers to the M1804 and the other 2 he left hooked to the head unit but the difference was obvious. According to him he now got a better quality of sound which is louder and clearer.

Things to Improve

Even with all the rave about the M1804, there are still some things that need to be improved. For instance, a few consumers would want an insulation pad in the package. This is because most of the amps on the market have problems with getting too hot. Another issue is that the sound coming from the device is not as loud as they expect.

Since the M1804 is a small amplifier with a maximum power of 400 watts, it does not give you the loud sound as with others who have higher maximum power. This amp can only perform up to the limit that it has. But given its size, it gives a clear and decent sound. Adding to its performance, this amp is also designed to last for a long time.

The electronic covering and outer casing of the amp ensure that all parts are protected from different environmental factors like moisture and dust.


The features and performance of Kenwood KAC-M1804 are perfect for those audio enthusiasts who love the outdoors. With this amp, you can enjoy quality sound anytime, anywhere. You don’t have to worry about the possible wear and tear because it can withstand rough handling. For more information, check out our best amplifier reviews.

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