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MB Quart MA1-440.4

4-channel marine amplifier — 75 watts RMS x 4

Item # 049MA14404

MB Quart's MA1-440.4 M-Line amplifier packs a lot of power into a small package that's perfect for boating or...

MB Quart's MA1-440.4 M-Line amplifier packs a lot of power into a small package that's perfect for boating or...

Top seller

Item # 049MA14404

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About the MB Quart MA1-440.4

For boating or backwoods riding

MB Quart's MA1-440.4 M-Line amplifier packs a lot of power into a small package that's perfect for boating or powersports applications. It's small enough to fit almost anywhere, and tough enough to take almost anything. This rugged amp delivers 75 watts RMS per channel in 4-channel mode, or 220 watts per channel when bridged to 2-channel operation.

For boating or backwoods riding

MB Quart's MA1-440.4 M-Line amplifier packs a lot of power into a small package that's perfect for boating or powersports applications. It's small enough to fit almost anywhere, and tough enough to take almost anything. This rugged amp delivers 75 watts RMS per channel in 4-channel mode, or 220 watts per channel when bridged to 2-channel operation.

Runs speakers and/or subs

This versatile Class D amp can run almost any speaker combination — from multiple speakers (including tower and roll bar-mounted speakers) to thumpin' subwoofers. With high-pass and low-pass filters plus bass boost, you'll be able to tune your system to get the sound you want.


MB Quart takes their marine-rated amps seriously, so they build their amps to last. Conformal coating protects the internal circuits from water and dirt, while stainless steel hardware resists corrosion in even the saltiest environments.

More about MB Quart

Three decades of marine and powersports audio expertise goes into MB Quart marine amplifiers. These rugged, high-quality amps provide great sound and rugged, all-weather reliability. The MB Quart "Life Shield" badge means your gear has been designed and tested to stand up to the toughest conditions on the water or off the beaten path.


Product highlights:

  • 4-channel marine/powersports amplifier
  • 75 watts RMS x 4 at 4 ohms (110 watts RMS x 4 at 2 ohms)
  • 220 watts x 2 bridged at 4 ohms
  • Class D amp technology
  • conformal-coated circuit board — suitable for power sports and marine applications
  • variable high- and low-pass filters
    • channels 1 and 2: high-pass 50-300 Hz, 24 dB/octave
    • channels 3 and 4: low-pass 50-3000 Hz, 24 dB/octave
    • channels 3 and 4: high-pass 10-1000 Hz, 24 dB/octave
  • 2 pairs of preamp inputs; one set of preamp outputs
  • variable bass boost
  • frequency response: 20-20,000 Hz
  • 8-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • dimensions: 8-5/16"W x 2"H x 6-15/16"D
  • warranty: 1 year
  • Our 60-day money-back guarantee
  • MFR # MA1-440.4

What's in the box:

  • 4-Channel amplifier
  • Two 25A ATO fuses (installed)
  • 2 Plastic terminal covers
  • 3mm Allen wrench
  • 1.5mm Allen wrench
  • 4 Self-tapping screws (Length 5/8")
  • Installation Manual

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MB Quart MA1-440.4 reviews

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Product Research


Overview: The MB Quart MA1-440.4 is a 4-channel amplifier from the M-Line of Class D full-range amps. The amps are small and powerful, and can be mounted in areas where space is at a premium. The M-Line amplifiers feature a new "marinized" design, with conformal coating and stainless hardware, that make them perfect for marine or powersports applications.

Power Output: The MA1-440.4 has the following power output:

  • 75 watts RMS x 4 at 4Ω
  • 110 watts RMS x 4 at 2Ω
  • 220 watts RMS x 2 at 4Ω bridged

Controls: The amp's controls are located on one side of the amplifier. The rotary controls require a flat-head screwdriver (not included) for making adjustments. There are independent controls for the front (channels 1&2) and rear (channels 3&4).

  • Input Level: The rotary Input Level controls let you match the amplifier to the output of the connected source unit. If the source unit has a strong signal, you can keep the input level turned down. The Input Level control can be set between 0.2V and 6.0V.
  • Input Mode: The Input Mode can be set to 2CH or 4CH via a 2-way switch. If you connect two pairs of RCA inputs from the source unit, you should set the amp to 4CH mode. If you only have one pair of RCA outputs, the amp should be set to 2CH mode, and all four channels will be fed signals from the single pair of inputs.
  • Crossovers: The MA1-440.4 has selectable low-pass and high-pass crossovers for both channel pairs. You can also configure the amplifier for "bandpass" operation, setting the high-pass frequency below the low-pass frequency. In this case, the high-pass crossover can be used as a subsonic filter for driving subwoofers. The 3-way Crossover Mode switch for Channels 3&4 lets you select LP/BP, HP, or Full. For Channels 1&2, you can select Full, HP, or Dupe CH3-4 (which duplicates the settings for Channels 3&4). The frequency controls range from the following:
    • Channels 1&2: High Pass 50Hz to 300Hz (24dB/octave)
    • Channels 3&4: High Pass 10Hz to 1000Hz (24dB/octave)
    • Channels 3&4: Low Pass 50Hz to 3000Hz (24dB/octave)
  • Bass EQ: The Bass EQ circuit boosts the bass response, centered at 45Hz, from 0dB to 9dB.

Connections: The MA1-440.4 has stainless connections that are resistant to corrosion when used in harsh environments. Set-screw terminals are used for power and speaker output connections. The set screws can be tightened/loosened with the included 3mm or 1.5mm Allen wrenches. The amp has the following connections:

  • RCA Inputs: Two pairs of RCA inputs are provided for connecting the amp to the source unit via RCA cables. With two pairs of inputs connected, fader control is possible from the source unit. If only one pair is connected, the Input Mode can be set to 2CH, and Channels 3&4 will be fed the signal from Channels 1&2, and fader control is lost.
  • RCA Output: This pair of RCA line outputs allows you to send a full range signal to another amplifier or a powered subwoofer. This allows you to daisy-chain another amp without having to run an RCA cable from the source unit to the second amplifier.
  • Power/Ground: These set-screw terminals for power and ground will accept up to 8-gauge power and ground wire. With a 50A fuse rating, it is recommended that a 50A fuse be placed on the power wire within 18" of the battery.
  • Remote Turn-on: The remote turn-on terminal will accept up to 16-gauge wire. Typically an 18-gauge wire is included in an amp wiring kit.
  • Speaker Outputs: Like the remote turn-on lead, the speaker output set-screw terminal will accept up to 16-gauge wire. Markings on the amp (+ and -) are provided for connecting four speakers, and for bridging the channel pairs.

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Customer Q&A

Crutchfield asked: Why did you buy this?
Best price, Lower THD than other brands, and has an input selector. [ Michael  Jun 26, 2020 ]
I purchased this based on the specs listed and what I was looking for. [ Charles  Feb 05, 2019 ]
This amplifier is going in a Jeep Wrangler so I needed a marine amp that can survive the punishment I am going to put it through. [ Parker  Jan 11, 2019 ]
Reviews [ jose  Aug 31, 2018 ]
Proven brand & RMS Power available is perfect for application. Thanks Crutchfield! [ Robert  Aug 27, 2018 ]
After talking with Lee he made me feel like this would be my best bet for the speakers I have. Looking forward to seeing what this amp can do. [ james  May 22, 2018 ]
Price and wattage per channel at 4 ohms [ Daniel  May 22, 2018 ]
marine grade and price and recommendation from Ember [ Paul  May 14, 2018 ]
Replacing a failed 100W x 4 channel Planet Audio amp. Wanted a quality marine amp with similar specs and a small footprint to fit in same location to drive four 6.5" coaxial JL audio speakers. Reviews were strong and personally I've had good experiences with MB Quart back in the mid 1990's. [ Jimmy  May 10, 2018 ]
Great reviews and a great price point. [ DAVID  May 08, 2018 ]
What happened to 3 day shipping that would mean delivery on the 4th? [ Bucky  May 02, 2018 ]
Past experience with this brand, RMS power per channel at 4ohm and size. [ Marcos  Apr 24, 2018 ]
Hogan recommended it, and after my own research I understood why he did it [ ciprian  Apr 07, 2018 ]
direct recommendation by Crutchfield expert [ eric  Mar 19, 2018 ]
Hi, This amp was recommended by Shawn and Hunter. I tried to buy more items but it turns out Crutchfield won't ship to a freight fowarder. I had to cancel the order, but I did re-order the amp and am having it sent to a friend. I didn't feel comfortable shipping all of the other items to my friend, so I have to get those other items elsewhere. [ Beth  Jan 13, 2018 ]
Suggested by Crutchfield and Grillo [ Floyd Wm  Jan 05, 2018 ]
good specs good price. mb quart has made quality products for years [ shawn  Nov 25, 2017 ]
This amp has very good specs (THD, power and SN ratio), good reviews and reasonably priced. [ Richard  Aug 13, 2017 ]
Looked like a good amp for the price, worth a try [ Cliff  Jul 07, 2017 ]
Mick recommend it for price and quality. [ Russell  Jul 06, 2017 ]
Reviews [ jack  Jun 04, 2017 ]
A combination of the specifications, reviewsand the price! [ Michael  May 07, 2017 ]
Strong reviews. [ Chad  Apr 07, 2017 ]
Small, compact with clean sound. Just what I needed for marine application! [ Alan  Mar 03, 2017 ]
Small size, good power, good SNR and THD, good reviews. [ Rodney  Feb 28, 2017 ]
marine unit [ David J.  Jan 21, 2017 ]
i know it wont be a piece of junk because crutchfield sells it [ phil  Dec 16, 2016 ]
Compact size [ MATTHEW  Aug 06, 2016 ]
Salesperson Brooke recommended it and I took her advice. Brooke's Bio: [ RONALD  Jul 27, 2016 ]
Top of the ratings with best price and warranty. [ Brian  Apr 15, 2016 ]

4 questions already asked

Can this amp be bridged for 2 subwoofers?
[ Daniel  May 27, 2020 ]
1 answer
It can be bridged but you can't use a sub-woofer lower than 4 ohms
[ David  May 27, 2020 ]
What is the voltage of the preamp (mono) outputs on this amp?
[ Bryan  Mar 07, 2017 ]
1 answer
There is no listed voltage for the amplifier's pre-amp output. It can vary based on the signal strength provided to the amplifier's pre-amp inputs. I hope that helps. My Bio:
[ Ryan  Mar 17, 2017 ]  Staff
The manual for this amp sounds like it is recommending a 4 gauge wire, yet crutchfield says 8. Which is correct?
[ Joe  Jan 05, 2017 ]
3 answers
I used 8 gauge wire since I'm running four 6.5 mids. Being a 300 watt Class d amp 4 gauge would be over kill. If you're nervous us 6 gauge.
[ JASON  Jan 07, 2017 ]
In my opinion, it depends on the wire length. I run 25ft from battery to amp and use 8 guage. No problem.
[ MARC  Jan 07, 2017 ]
The input on the amp is for an 8 gauge wire. A 4 gauge will not fit in the holes for the power or ground wires.
[ William  Jan 06, 2017 ]

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