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MB Quart RA640.4

640W 4-Channel Reference Series Class SQ Bridgeable Power Amplifier (RA6404)

MB Quart
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• 80W x 4-Chan. @ 4 ohms
• 160W x 4-Chan. @ 2 ohms
• 320W x 2 Chan. @ 4 ohms
• 3-Way System Protection
• 4/3/2/1 Channel Operation
• 4 Gauge Power and Ground Inputs
• FLUID-FETS Circuit for Smooth Sound Quality

Learn more about the ra6404

We apologize

This item has been discontinued

Product Highlights


• 80W x 4-Chan. @ 4 ohms
• 160W x 4-Chan. @ 2 ohms
• 320W x 2 Chan. @ 4 ohms
• 3-Way System Protection
• 4/3/2/1 Channel Operation
• 4 Gauge Power and Ground Inputs
• FLUID-FETS Circuit for Smooth Sound Quality

Description


MB Quart brand icon

Authorized dealer

General Features:

  • Reference Series 4-Channel Class SQ Car Amplifier
  • Max Power Rating:
    • 4 ohms: 80 watts x 4 chan.
    • 2 ohms: 160 watts x 4 chan.
    • Bridged, 4 ohms: 320 watts x 2 chan.
  • FLUID-FETS MOSFET Circuit maximizing power efficiency while improving sound quality
  • LED power (green) and protect (red) indicators
  • Variable Bass Boost (0 to +12 dB bass boost)
  • Built-in system diagnostics and top-mounted controls
  • 4/3/2/1 Channel operation
  • Preamp RCA outputs to daisy chain multiple amps
  • 3-way protection circuitry (thermal, overload, and speaker short protection)
  • Black reference aluminum alloy heat-sink with illuminated MB Quart design
  • Input sensitivity:
    • Level: 200mV-6V
  • Variable high-pass filter (60-13,000 Hz)
  • Variable low-pass filter (30-250 Hz)
  • Frequency response: 30-45,000 Hz
  • 4 gauge power and ground wiring is required for installation. Contact us for information regarding a discount on select amplifier kits from our website when purchased together with this amplifier.
  • Dimensions: 8-1/4"W x 15-1/2"D x 2-3/8"H
  • Authorized Internet Dealer
  • 1-year Manufacturer's Warranty

Specifications & Details


Power Specifications - Full Range Channels
RMS Power @ 4 ohms
80 watts x 4 channel
RMS Power @ 2 ohms
160 watts x 4 channel
Bridged RMS Power
320 watts x 2 channel
Amplifier Specifications
Series
Reference Series
Amplifier Class
SQ
Number of Channels
4-Channel
Total RMS Power Output
640 watts
Maximum Input Gauge Size
4 AWG
Minimum Impedance Unbridged
2 ohms
Minimum Impedance Bridged
4 ohms
THD at Rated RMS Power
0.05%
Speaker Level Inputs
No
Preamp Outputs
No
Built-in Crossover
Low-Pass (LP)
High-Pass (HP)
High-Pass Crossover Frequency
60 - 13000 Hz
Low-Pass Crossover Frequency
30 - 250 Hz
Signal-to-Noise Ratio
92 dB
Channel Separation
80 dB
Bass Boost
0 - 12 dB
Remote bass/level controller
No
Fuse Rating
30A x 3 
Strappable
No
Warranty and Return Policy
Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider
Manufacturer

Item Details


Manufacturer:

Model Number:

RA640.4

Weight:

9.00lbs

Internal SKU:

ra6404

Internal Product ID:

67883

Product and How-to Videos


Customer Ratings & Reviews



5 star
73%
4 star
18%
3 star
0%
2 star
9%
1 star
0%



Durability
4.4
Value
4.8
Features
4.5
Design
4.5
Usability
4.8

Customer Reviews

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Excellent sound Quality

If anyone have a question of how good is MbQuart RA640.4, I can honestly say It's excellent. I had JL 300/4 original and JBL Px300.4 and all I can say is, it sound if not the same, better than the JL. It kills the JBL. I replace the JL with JBL because it died after 8 year and I could tell the the sound quality went down, then I replaced the JBL Px300.4 one week ago with Mb Quarts RA640.4 and WAW incredible sound difference, it also took away some engine noise that I was getting with the Jbl. To be totally honest WAW, WAW, WAW and it does not get hot. " I have it under my car seat pushing 4 JL C-5s and could not be happier. I don't write reviews but this was an excemption. I was researching for over a month and I could not get a stright answer, so I hope this can help someone.

By Vic on February 7, 2014

23

found this helpful.

A real amp

This is the best buy I've ever had from sonic I'm telling you when I have a hertz energy setup in my car and this amp isn't even turned up a quarter of the way man this amp has some serious power and sound's clean to the bone and looks so nice.

By Lc on October 12, 2013

19

found this helpful.

Music to my ears!

Ordered amp, and it arrived two days later, installed that evening after I removed the Alpine MRP-F300 that was running my mids and highs, dont get me wrong, the Alpine was a great amp, just not strong enough for me. Got the MB up and running and WOW is all i can say,the clarity, the subtle details in the music, the warmth, and the power, this amp is rated 80W x 4 and I'm sure it's underrated, very clean and quite, midbass,midrange and highs soar with this amp, very very happy with purchase

By Havolia on May 16, 2013

18

found this helpful.

Not what I expected from a "SQ" amp

I had this amp installed for a couple of weeks powering two sets of MB Quart QSD213's (the last handmade in Germany components sets from MB). I expected the reference amps to be in the same class as the prior equipment before Maxxsonics bought the MB Quart name. I was not impressed. From the plastic mounts and end caps to the cover that was drilled incorrectly, this amp felt as cheap as it is made. Clean power was not an option with this amp. Crossovers were still letting the low end through even after setting it higher than I usually would on other amps. I had Sonic cross-ship me a JBL 4 channel and the sound quality is in a different league than the RA640.4. I thought maybe my components were starting to show the wear and tear of 7 years of playing, but it was just a poorly designed amp that was the issue.

By Aaron on December 16, 2013

16

found this helpful.

info

great amp for the price. has the power to drive your speakers to loud levels with decent clarity. if you are on a budget this amp works. crossover setup doesn't work like regular crossovers so look into that to see if it will work for you

By Jonathan on December 11, 2014

16

found this helpful.

Good Deal: Loud with Good Sound Quality

I have had my RA640.4 powering a set of polk component speakers and infinity 6x9's for about a month now. All the speakers ask for about 90wrms at 2 ohms, each, and this amp does the job. In fact, it does the job better than my old infinity 4 channel amp (I think it was the 360.4) which is significantly pricier than this amp. Although I would say that this amp does not push 640 wrms, but hey, it is a little more powerful than the infinity and sounds just as good. Overall I would recommend this amp for anyone looking for a budget bang-for-your-buck amplifier.

By Dan on December 4, 2014

16

found this helpful.

Great amp

Have this wired to push my mids/highs. Plenty of power and looks great next to my 1000w MB amp.

By Joshua on March 22, 2015

12

found this helpful.

best amp for the price

It will be hard for one to find an amp that is as powerful as this one and as cheap. The best part is you are getting a quality amp. Everyone who knows me, knows that I buy what I want. If the amp i want is very expensive, ill wait and get it when i can. i wont settle for something else. So after doing my research and being content with buying a product that is cheap (which was a first for me in car audio) i am very pleased. For the money, you aren't taking a risk.

By Kyle on September 18, 2013

14

found this helpful.

Clarity, Power, Value. Concert in a Car...

Installed the MB Quart RA640.4 with 0 AWG and a 1.2F Cap and I am impressed!
I installed the amp in a '76 Ventura with 6x9" (Eclipse) in the rear deck and 6.5" (Alpine) in the kick panels.
The subtle parts of music don't get lost as the music becomes complex.
A friend asked if I had a subwoofer, because of the clarity and extension of the bass.
Thinking of buying another for my Silverado.
Great Amp for the $$$.

By Bill_ventura on August 26, 2013

14

found this helpful.

Great sounding amp

I'm running this amp pushing two sets of mb quarts 5 1/4 in a boat. It sounds great and gets loud, really loud

By Ryan on September 17, 2013

13

found this helpful.

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