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JL Audio XD300/1 – Monoblock Class D Series Subwoofer Amplifier

James Benchman
Last Updated on
by James Benchman

The JL Audio XD300/1 is definitely among the trusted amp brands that every car audio enthusiast can turn to when then need quality amplification. One of the areas where JL Audio simply excels is compact units that are capable of delivering decent amounts of power. When we say compact, we mean compact.

Other companies make amps of this kind, but the prices are often a bit higher than those of JL Audio’s models. Whether or not that is a good thing is up to you to decide. In our eyes, these amps deserve nothing but praise.

JL Audio XD300/1 is an efficient and compact model that was developed for those who appreciate a stealthy look. The whole idea behind this amp was to increase the power while reducing the size to something that is easily hidden in the boot. Today we are going to take a closer look at this brick of power and talk about how potentials are hidden within its aluminum enclosure.

  • Very portable and can fit anywhere in the car
  • Packs a lot of power
  • Generates little heat
  • No cons yet

JL Audio XD300/1 Review

Amps are shrinking in size each year, but one of the biggest limitations in this effort is still the heat output that needs to be taken care of. Powerful amps require large heat syncs to dissipate the heat efficiently and keep the electronics cool enough to sustain prolonged hours of use.

The only real way to sort that problem is to increase the efficiency of the amps themselves. Class D amplifiers helped a lot in this regard, with their efficiency rating that is often above 80%, but even that was not enough to allow for really compact amps. JL Audio XD300/1 brings a more advanced solution to the table, which helps going a lot further when it comes to size reduction.


If you are looking for an amp that is the size of a 400-page hardcover book, you have just found one. JL Audio XD300/1 is so small and compact that it can even be used on motorcycles. Not a lot of brands can say that about their amps.

The key for this type of size reduction lies within the new NexD high-speed switching design that primarily increases the efficiency of the amp, allowing JL Audio to pack everything up in a much smaller case. With more efficient amps come better thermal properties, meaning that you don’t have to worry about pushing this thing into a glowing hot state.

The back panel of the amp hides your RCA connectors and all the other standard I/O components. The bottom side is a lot more interesting. This is where you will find an adjustable low-pass filter that comes with a 12 dB to 24 dB switch as well as a frequency range of 50 Hz to 500 Hz.

That is a pretty decent amount of boost for a 300 Watt RMS monoblock unit. Speaking of which, you can run this amp at the 300 Watts RMS at 2 Ohms, which we have just mentioned, or you can run it at 200 Watts RMS at 4 Ohms. As expected, JL Audio XD300/1 comes with a remote bass-level control which allows you to directly control the output of the amp from the passenger cabin.

Regarding thermal and surge protection, JL Audio did a pretty excellent job. The circuitry is very robust and is capable of shutting down the whole unit at the first hint of trouble. During most regular use, you won’t have to worry about this. However, once you start pushing things a bit, having this kind of protection is a welcome feature.


For a 300 Watt unit, JL Audio XD300/1 is one loud amp. Paired with a decent quality transducer, you are looking quite impressive amounts of volume combined with an equally remarkable sound definition. The frequency range is somewhat conservative, although even if it doesn’t go subsonic, you are still going to experience some deep bass sounds coming from your subwoofer.

Installing the JL Audio XD300/1 in your car is probably among the easiest amp installations you will ever do. It’s so small that you will quickly find a place for it in your trunk. Whether you want to hide it out of sight, or only keep it somewhere that still allows you to use the boot, JL Audio XD300/1 will fit right in. It’s a versatile amp in all aspects imaginable.

Great sound, excellent power output, surprisingly compact form factor and finally a decent price. These are the things you can count on getting from JL Audio XD300/1.

Our Verdict on the JL Audio XD300/1 AMP:

Having a super-compact amp that is still within a power range that is considered good draws a lot of attention. With JL Audio XD300/1, JL Audio spread their reach outside the car community and entered the territory of lighter vehicles. Even though there is no much practical use for installing one of these amps on a bike, it’s nice to have the option. There are some vehicles out there that can benefit from a design such as this one.

The most surprising thing about JL Audio XD300/1 is the level of performance it brings to the table. JL Audio’s NexD technology pushes the Class D amplifiers to a new level. It’s smaller, but all of the finesse is preserved in a way that is merely practical and attractive to automotive audiophiles.

Not everyone can understand the need for such a small unit, but when you have a compact car, every inch of space counts. In those instances, something like this JL Audio XD300/1 is the perfect solution to a genuine problem. Even if you don’t have a small car, and even if storage space is not an issue for you, there are other reasons why this amp should be on your list.

Its efficiency puts it among the cooler amps out there. That type of thermal performance is something you need to check out if you are serious about car audio.

  • Very portable and can fit anywhere in the car
  • Packs a lot of power
  • Generates little heat
  • No cons yet

About James Benchman
James Benchman
James is an Automotive Mechanic with over 20 years experience and 300+ car repairs. He is an expert with cars and has worked with different models from the biggest brands.James is a Mechanic , Husband , Father of 3 , and head of content at Caraudiologic. Learn more about us
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  2. Does this amp requires extra battery and alternator I have a jl audio 12w7 and ajl audio jx1000d amp and is the second battery that get drained out

    1. Hey Silvestre, it’s really hard to answer that without having more information. Generally speaking, no, it shouldn’t as a requirement. Let me know if you’ve made any progress on this or still having the issue.

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