The KMA360.4 and KMA600.4 are both 4-channel Kicker marine amps, both accept the same flexible high-level or low-level input, and both carry the identical 1-year warranty. At $299.99 and $349.99, they're close enough in price that the decision isn't really about budget. It comes down to one real, concrete difference: amplifier class and the certification that goes with it.
Side-by-Side
| Spec | KMA360.4 | KMA600.4 |
|---|---|---|
| Price | $299.99 | $349.99 |
| Class | A/B | D |
| Power @ 4-Ohm (4-ch) | 65W RMS x 4 | 75W RMS x 4 |
| Power @ 2-Ohm (4-ch) | 90W RMS x 4 | 150W RMS x 4 |
| Bridged Output | 180W RMS x 2 | 300W RMS x 2 |
| Dynamic Power | 500W | 725W |
| ABYC/NMMA-Compliant Connections | Yes | Not stated |
| Warranty | 1 Year | 1 Year |
Key Takeaways
- Both accept high-level (speaker-level) input directly, so either works with a head unit that has no RCA preamp outputs, that's not a differentiator between them.
- Both carry the same 1-year warranty, shorter than the 3-year warranty on Kicker's KM speaker lineup, worth knowing regardless of which amp you pick.
- The KMA600.4 delivers meaningfully more power at every configuration, 75W vs. 65W RMS per channel at 4-ohm, and a notably bigger gap at 2-ohm (150W vs. 90W).
- The KMA360.4's real distinguishing feature is explicitly stated ABYC/NMMA-compliant power connections, a specific marine electrical certification the KMA600.4's own listing doesn't claim.
- Neither amp is a strictly better version of the other, the choice is Class A/B with certified connections versus Class D with more power, not a straightforward upgrade path.
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What Actually Separates These Two
It would be easy to assume the $50 price gap between these amps maps to a straightforward "better amp costs more" story, but that's not quite what's happening here. The KMA600.4 is a Class D design, more power-efficient, generates less heat per watt of output, and that efficiency is part of why it delivers meaningfully higher output at every configuration, especially at 2-ohm where the gap widens to 150W vs. 90W RMS per channel. The KMA360.4 is Class A/B, generally considered to deliver cleaner sound character at moderate volumes, though less efficient and lower-powered by comparison.
The other real difference: the KMA360.4's own listing explicitly states REAL MARINE® ABYC/NMMA-compliant power connections, a specific certification for marine electrical standards. The KMA600.4's listing doesn't make that same claim. If that certification matters for your build, whether for a survey, insurance requirement, or just wanting documented compliance, that's a real point in the KMA360.4's favor independent of the power difference.
What Doesn't Actually Differ
It's worth being explicit about what's identical between them, since it's easy to assume more separates two amps at different price points than actually does. Both accept the same flexible input design, low-level RCA or high-level speaker-level, so neither requires a specific head unit type to work. Both carry Kicker's standard 1-year amplifier warranty, not the 3-year warranty on the KM speaker lineup, a detail worth knowing regardless of which one you choose. Neither advantage is exclusive to one amp over the other.
Which One Actually Fits Your Build
If raw output per channel is the priority, especially for 2-ohm speaker loads where the gap is largest, the KMA600.4's 150W RMS per channel at 2-ohm meaningfully outperforms the KMA360.4's 90W. If documented ABYC/NMMA-compliant connections specifically matter for your build, whether for a new boat survey or just wanting that certification on file, the KMA360.4 is the amp that states it. For a straightforward build where neither of those specific factors is a hard requirement, the $50 difference and the power gap are the main practical considerations, and either amp comfortably covers a standard 2-speaker or bridged-subwoofer setup. See our receiver-to-amp pairing guide if you're also deciding which KMC receiver to build around.
Heat and Mounting Location, a Second-Order Difference
Class D amplifiers like the KMA600.4 are inherently more power-efficient than Class A/B designs like the KMA360.4, which means less wasted energy converted to heat for the same electrical input. In practice, that can matter for mounting location choices on boats with tight, poorly-ventilated compartments, a Class D amp running hard generates less heat to manage than a Class A/B amp delivering comparable output. This isn't usually the deciding factor for most builds, both amps are designed to handle normal marine mounting conditions, but if you're working with a genuinely enclosed, low-airflow mounting spot, it's a real secondary consideration alongside the power and certification differences above.
Honest Cons
Neither amp carries the 3-year warranty Kicker's speaker lineup gets, both are 1-year, factor that into the total cost of ownership regardless of which one you choose.
"Not stated" on the KMA600.4's ABYC/NMMA compliance doesn't necessarily mean it fails that standard, it means the listing doesn't claim it, if that certification is a hard requirement for your build, confirm directly rather than assuming either way.
The power gap matters most at 2-ohm loads specifically, if your speakers are wired at 4-ohm, the practical difference between 65W and 75W RMS per channel is real but smaller than the headline numbers suggest.
A Realistic Example of Each Pick
A build running a bridged subwoofer channel at 2-ohm is the clearest case for the KMA600.4, the 150W RMS per channel at 2-ohm versus the KMA360.4's 90W is a real, usable power gap at that specific load, not a marginal spec-sheet difference. A build where the owner specifically wants ABYC/NMMA-documented connections on file, whether for an insurance requirement, a survey, or just personal preference for certified marine wiring standards, is the clearer case for the KMA360.4, even accepting the lower power ceiling. Most builds fall somewhere between these two clear cases, which is exactly why the comparison above matters more than defaulting to "the pricier one is probably better."
Frequently Asked Questions
Is the KMA600.4 just a better version of the KMA360.4?
Not strictly, it offers more power and Class D efficiency, but the KMA360.4 has the stated ABYC/NMMA-compliant connections the KMA600.4's listing doesn't claim. Which matters more depends on your build.
Do both amps work with a head unit that has no RCA outputs?
Yes, both accept high-level (speaker-level) input directly, this isn't a differentiator between them.
Which has the longer warranty?
Neither, both carry the same 1-year warranty, shorter than the 3-year warranty on Kicker's KM speakers.
Which amp should I pick if I'm not sure which factor matters more?
If you don't have a specific need for documented ABYC/NMMA compliance, the KMA600.4's higher power output across the board makes it the more broadly capable pick for the same rough price range.
Does the heat difference between Class A/B and Class D actually matter in practice?
For most mounting locations, no, both are built for normal marine installation conditions. It becomes a real factor specifically in tight, low-airflow compartments where heat has nowhere to go.
Bottom Line
These aren't a budget-vs-premium pair, they're two different engineering approaches at a similar price. KMA360.4 for stated ABYC/NMMA-compliant connections, KMA600.4 for meaningfully more power, especially at 2-ohm. Match the choice to whichever of those two factors actually matters for your build, not to which one happens to cost more.