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JBL MA4505

5-channel marine amplifier — 45 watts RMS x 4 at 4 ohms + 500 watts RMS x 1 at 2 ohms

Item # 109MA4505

Looking for one amp to power your boat's sound system? Sporting a sleek stealthy profile, JBL's MA4505 marine...

Looking for one amp to power your boat's sound system? Sporting a sleek stealthy profile, JBL's MA4505 marine...

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Item # 109MA4505

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$479.99

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About the JBL MA4505

Space-age power

Looking for one amp to power your boat's sound system? Sporting a sleek stealthy profile, JBL's MA4505 marine amplifier will deliver 45 watts RMS each to four speakers, while delivering up to 500 watts RMS to a subwoofer. For a high-performance system, you can bridge the amp to 3-channel mode to power two speakers with 130 watts RMS each, while still driving a sub with 500 watts. And JBL uses a coated circuit board and stainless steel connectors to ensure that this amp will rock for many seasons to come.

Space-age power

Looking for one amp to power your boat's sound system? Sporting a sleek stealthy profile, JBL's MA4505 marine amplifier will deliver 45 watts RMS each to four speakers, while delivering up to 500 watts RMS to a subwoofer. For a high-performance system, you can bridge the amp to 3-channel mode to power two speakers with 130 watts RMS each, while still driving a sub with 500 watts. And JBL uses a coated circuit board and stainless steel connectors to ensure that this amp will rock for many seasons to come.

Works with almost any system

Speaker-level inputs allow this amplifier to work in almost any system, even if you're keeping your boat's original radio. The separate high- and low-pass filters on both pairs of channels help maximize the performance of your speakers and subs. The sub channel features a low-pass filter, bass boost, and phase switch so you can tune your bass the way you want.

JBL MA4505

MA4505 input and control panel

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Product highlights:

  • 5-channel marine amplifier
  • 45 watts RMS x 4 + 320 watts RMS x 1 at 4 ohms
  • 65 watts RMS x 4 + 500 watts RMS x 1 at 2 ohms
  • 130 watts RMS x 2 bridged at 4 ohms + 500 watts RMS x 1 at 2 ohms
  • Class D amp technology
  • front and rear channels:
    • variable high- and low-pass filters (32-320 Hz, 12 dB/octave)
  • subwoofer channel:
    • low-pass filter (32-320 Hz, 12 dB/octave)
    • bass boost (0-9 dB at 45 Hz)
    • phase switch (0, 180 degrees)
More Features:
  • conformal-coated circuit board and stainless steel connections resist salt water corrosion
  • preamp and speaker-level inputs
    • high-level input adapter included
  • fuse rating: 30A x 3
  • wiring and hardware not included with amplifier
    • 4-gauge marine-rated power and ground leads recommended
  • dimensions: 15-11/16"W x 2-3/8"H x 7-7/16"D
  • warranty: 1 year
  • Our 60-day money-back guarantee
  • MFR # MA4505

What's in the box:

  • 5-Channel marine amplifier with three 30A ATO fuses installed
  • 3 Spare 30A ATO fuses
  • 4 Speaker wire-to-RCA adapters
  • 4 Self-tapping screws (length 2")
  • Quick Connect Guide
  • 2 JBL decals

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JBL MA4505 reviews

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JBL MA4505

Crutchfield customer from Spokane, WA on 8/9/2019

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Solid built amp. I have it installed in a boat pushing 4 6.5's at 4 ohm and a 10" Polk MM sub at 2ohms. Very clear, and more than enough power to be able to clearly hear the music underway. Great upgrade!

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Extremely well built with great looks and small footprint.

Crutchfield customer from Valley City, ND on 8/4/2019

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I needed to drive speakers and a subwoofer from a fuzion head unit that only had one line out and this amplifier took care of that. Using the included adapters I was able to tap into the speaker outputs of the radio and use the one line out for the subwoofer. Tuning was extremely simple and didn't give any trouble and I was extremely happy with the end results.

Pros: Solid amp with features that make it very flexible for difficult installs.

Cons: Included instruction manual was lacking in regards to what settings to use when using two different inputs but JBL's easy to use website has a much more inclusive manual.

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JBL MA4505

Crutchfield customer from Austin, TX on 7/22/2019

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Great product. Great price

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JBL MA4505

Crutchfield customer from Park Hills, MO on 6/20/2019

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An amazing amp! I have a boat where my wife sits up front. She couldnt hear the music from the rear speakers so i had to do something! I saw it on sale and decided to look into what options it had. By the other reviews, it sounded good! So i bought it. Directly out of the box im thinking this thing is too small to be able to do what it says it can, i was WRONG! This amp puts out some power! I bought a pair of speakers as well with it and let me tell you, with the amp turned 1/4 of the way up, she now has NO problem hearing the music, and it sounds great as well! Amp looks great, has all the power i would ever need and more!

Pros: Looks good, all the power u would need for 4 speakers and a sub, easy to wire up, easy to adjust

Cons: None that i can find

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Clean and Strong

Crutchfield customer from Waupaca, WI on 5/7/2019

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Great amplifier. Used this on my new stereo build for my classic boat. All channels are clear and STRONG. Would like a few other features like remote gain control and especially larger power/ground wire terminals, but nothing i can complain about.

Pros: Easy to understand, setup, and use. Perfect for several applications. Strong amplifier.

Cons: Power/ground are only sized for 4 awg wire... Though i managed to squeeze in a 2 awg wire. Didn't come with full printed manual, just a quick start guide.

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JBL MA4505

Crutchfield customer from Trenton, SC on 4/12/2019

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Works great, clear, no complaints.

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JBL MA4505

Stephen from Pace, FL on 3/18/2019

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I was able to use this one and to power my highs, mids and Subwoofer. It sounds great!! Thanks Crutchfield for a great product at a great price.

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JBL MA4505

Crutchfield customer from Greenville, MS on 8/1/2018

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Just what I was looking for to power my tower speakers and subwoofer in my Polaris rzr. The color of the amp matches perfect, as well as the design looks. The sound is amazing.

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Product Research

Features

Overview: JBL Marine amplifiers are designed to provide ample power to the speakers and subwoofers on your boat or 12-volt outdoor system. The amplifiers are equipped with conformal-coated circuit boards and other protections to withstand the harsh marine environment, where moisture and water spray may be prevalent. The MA4505 Class D 5-channel amplifier will accept both high-level and low-level inputs. The unit comes with spare fuses, speaker wire-to-RCA adapters, and corrosion-resistant stainless steel mounting hardware.

Power Output: The MA4505 delivers the following power output:

  • Full Range Channels:
    • 45 watts RMS x 4 at 4 ohms (<1.0% THD+N)
    • 65 watts RMS x 4 at 2 ohms (<1.0% THD+N)
    • 130 watts RMS x 2 at 4 ohms bridged (<1.0% THD+N)
  • Subwoofer Channel:
    • 320 watts RMS x 1 at 4 ohms (<1.0% THD+N)
    • 500 watts RMS x 1 at 2 ohms (<1.0% THD+N)

Protection Circuitry: The amplifier features protection circuitry for thermal overload, over- or under-voltage (<9V or >16V), and short circuits. The LED on the top of the amp glows red if the amp goes into protection mode.

Controls: The MA4505's controls are located on one side of the amplifier. The rotary controls require a small screwdriver (not included) to make adjustments. The amp controls include:

  • Gain: The rotary gain controls let you match the amp's input sensitivity to the output of the source unit. There are separate gain controls for the front, rear, and subwoofer channels.
  • Input Level: The Input Level switch lets you select the type of input you are using. For high-level input, there are two settings: Hi1 and Hi2. If the audio system fails to play with an amplifier connected to its output, or you get a "speaker disconnected" message on your factory stereo, set the switch to the Hi2 position. The Hi2 position includes a circuit design to fool this type of factory system into "seeing" a speaker connected to its output.
  • Crossovers: The amp features switchable crossovers for the front and rear channels that can be set to low pass (LPF), high pass (HPF), or Full Range. The subwoofer channel has a non-defeatable low pass filter. You can adjust the cutoff frequency of the crossovers from 32Hz to 320Hz using the independent rotary controls.
  • Bass Boost: You can apply up to 9 dB of bass boost, centered at 45 Hz, using the rotary control.
  • Phase: You can switch the phase of the subwoofer from 0° to 180°.

Connections: The JBL Marine MA4505 uses set screw terminals for the +12V power, ground, turn-on (remote) lead, and speaker outputs. The screws can be tightened/loosened with a Phillips-head or flat-head screwdriver (not provided). The tops of the terminals are covered by a rubber plug to prevent water from entering the amplifier. The amp connections include:

  • Power/Ground: The +12V Power and Ground terminals will accept up to 4-gauge wire. It is recommended that you use a minimum of 4 AWG power wire to the battery, with an in-line 100A fuse installed no more than 18" from the battery terminal. A 4 AWG ground wire (minimum) is also recommended, and attached to a metal area close to the amplifier.
  • Remote Turn-On: The Remote terminal will accept up to 8 AWG wire. Typically, an 18 AWG turn-on lead is included in an amplifier wiring kit.
  • Speaker Outputs: The amp features screw terminals that accept up to 8 AWG wire for connecting five speakers. There are markings on the terminals for bridging the amplifier.
  • Speaker-Level Input: The amp includes four bare wire-to-RCA adapters for connecting the amp to a factory radio or aftermarket head unit without preamp outputs. You should attach each speaker wire from the head unit to an adapter and plug the adapter's RCA plug into the amp.
  • Line-Level Inputs: The amplifier is equipped with three pairs of RCA inputs for connecting stereo RCA patch cables from the head unit to the amp.

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