The Kicker KMA600.4 ($349.99) delivers 75W RMS per channel at 4-ohm. The JL Audio MX500/4 ($529.99) delivers 70W RMS per channel at 4-ohm, actually slightly less. Both are 4-channel amps within 5 watts of each other on the spec most shoppers check first, and JL Audio costs $180 more for it.
The real differences are in bridged output, water rating, and input flexibility, not raw per-channel power.
Head-to-Head
| Spec | Kicker KMA600.4 | JL Audio MX500/4 |
|---|---|---|
| Price | $349.99 | $529.99 |
| RMS @ 4-Ohm | 75W per channel | 70W per channel |
| RMS @ 2-Ohm | 150W per channel | 125W per channel |
| Bridged Output | 300W x2 @ 4-ohm | 250W x2 @ 4-ohm |
| Water Rating | Not numbered on this listing | IPX7 |
| Input Type | Preamp (RCA) and speaker-level input | Preamp (RCA) input |
Key Takeaways
- Kicker actually delivers slightly more per-channel RMS power at both 4-ohm and 2-ohm, and a higher bridged output, at $180 less.
- JL Audio's clear advantage is a documented IPX7 water rating, genuine protection against temporary submersion, versus no numbered rating on the Kicker listing.
- Kicker's KMA600.4 accepts speaker-level input directly, useful if your head unit has no RCA preamp outputs; JL Audio's MX500/4 requires a preamp-level signal.
- On documented specs alone, Kicker is the stronger per-dollar choice for raw power; JL Audio's premium buys water resistance and brand-specific NexD efficiency engineering.
- Neither amp is bridgeable down to a level matching Kicker's own flagship KXMA800.4 (100W RMS/channel at 4-ohm), if you need more power than either delivers, that's the next step up.
Why the Spec Sheet Doesn't Explain the Full Price Gap
If you're comparing purely on RMS output, bridged power, and price, the Kicker KMA600.4 wins on every published number here. JL Audio's case rests on its documented IPX7 water rating and NexD efficiency technology, real differentiators, but not ones that show up in the per-channel wattage figure most people compare first. If your amp will be mounted somewhere genuinely exposed to water, that rating matters regardless of the power numbers. If it's going in a dry, protected compartment, the case for paying $180 more is harder to make on specs alone.
Check the Kicker KMA600.4 → | Check the JL Audio MX500/4 →
Feature Walkthrough
Power Output
Kicker: 75W RMS per channel at 4-ohm, 150W at 2-ohm, 300W x2 bridged. JL Audio: 70W RMS per channel at 4-ohm, 125W at 2-ohm, 250W x2 bridged. Kicker leads on every published power figure here.
Water Resistance
JL Audio's MX500/4 carries a documented IPX7 rating. Kicker's KMA600.4 listing doesn't publish a numbered IP rating, don't assume it matches JL Audio's submersion protection without confirming directly.
Input Flexibility
The KMA600.4 accepts both preamp (RCA) and speaker-level input, meaning it can pull directly from a head unit with no RCA outputs at all. The MX500/4 requires a preamp-level RCA signal, a real consideration if your source unit is speaker-output only.
Who Each One Is For
Choose the Kicker KMA600.4 if you're optimizing for documented power output and per-dollar value, or if your head unit lacks RCA outputs and you need direct speaker-level input. Choose the JL Audio MX500/4 if a documented IPX7 water rating for an exposed mounting location is worth the premium to you.
Honest Cons
Kicker's lack of a numbered IP rating on this listing is a real documentation gap next to JL Audio's IPX7, even if Kicker's amp is still marketed and built for marine use.
JL Audio's premium isn't explained by power output, Kicker actually delivers more per the published specs.
Neither amp is speaker-level-input AND IPX7-rated, you're choosing one advantage or the other here, not both.
Frequently Asked Questions
Is the JL Audio MX500/4 more powerful than the Kicker KMA600.4?
No, per the published specs, Kicker delivers slightly more RMS power at both 4-ohm and 2-ohm, plus a higher bridged output.
Why does JL Audio cost more if it has less power?
Its documented IPX7 water rating and NexD efficiency technology are the stated differentiators, not raw output.
Can I use either amp with a head unit that has no RCA outputs?
Only the Kicker KMA600.4 accepts speaker-level input directly for that scenario; the JL Audio MX500/4 requires a preamp-level RCA signal.
Which amp should I choose for more power overall?
Neither, if you need meaningfully more power than either delivers, see our Kicker KXMA800.4 review for a 100W RMS per channel option, or our JL Audio amplifier buying guide for JL's higher tiers.
Bottom Line
On documented specs, the Kicker KMA600.4 wins on power and price. JL Audio's MX500/4 wins specifically on water resistance. Choose based on which of those two factors actually matters for your install.