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MB Quart RM740.5

740W Max 5-Channel Reference MYKRO Series Hybrid Class D Full-Range Car Power Amplifier

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List price $479.99

$239.99

with warranty

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Arrives by Friday, Aug. 8 to zip 98109

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General Features:

  • Reference MYKRO Series 5-Channel Hybrid Class D Full-Range Car Amplifier
  • Channel 1-4 Max Power Rating:
    • 4 ohms: 75 watts x 4 chan.
    • 2 ohms: 110 watts x 4 chan.
    • Bridged, 4 ohms: 220 watts x 2 chan.
  • Subwoofer Channel Max Power Rating:
    • 4 ohms: 200 watts x 1 chan.
    • 2 ohms: 300 watts x 1 chan.
  • FLUID-FETS MOSFET Circuit maximizing power efficiency while improving sound quality
  • Q-Stasis Pre-amplifier stage for a cleaner signal from the source unit
  • Ultra low ESR high capacity power supply storage bank
  • Hybrid Class D Full range design for small footprint and exceptional 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
  • 5/4/3/2/1 Channel operation
  • Preamp RCA outputs to daisy chain multiple amps
  • 4-way protection circuitry (thermal, overload, and speaker short protection, DC offset)
  • Extruded aluminum heatsink design
  • Input sensitivity:
    • Level: 200mV-6V
  • Variable high-pass filter (50-3000 Hz 24 dB/octave)
  • Variable low-pass filter (Chan 3 & 4 50-3000 Hz 24 dB/octave)
  • Frequency response: 10-20000 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: 6-1/2"W x 10-1/4"D x 1-15/16"H
  • Authorized Internet Dealer
  • 1-year Manufacturer's Warranty

Power Specifications - Full Range Channels

RMS Power @ 4 ohms

The RMS power rating is the measure of continuous power that an amplifier can output, or a speaker can handle. It is the most accurate depiction of real, continuous power that the industry has so far.

If the final impedance of your speakers or subwoofers equals 4 ohms, this is how much power this amplifier will supply at that ohm level. The higher the RMS wattage, the more clean and loud your music will sound.

75 watts x 4 channels
RMS Power @ 2 ohms

The RMS power rating is the measure of continuous power that an amplifier can output, or a speaker can handle. It is the most accurate depiction of real, continuous power that the industry has so far.

If the final impedance of your speakers or subwoofers equals 2 ohms, this is how much power this amplifier will supply at that ohm level. The higher the RMS wattage, the more clean and loud your music will sound.

110 watts x 4 channels
Bridged RMS Power

Bridging refers to combining two channels on an amplifier to create one channel with double the voltage and an increased power output. A 2-channel amplifier will bridge down to 1-channel and a 4-channel amplifier can bridge to create 2-channels. An amplifier is most commonly bridged to drive a subwoofer.

Remember, once you bridge two channels down to one its final impedance will be 4 ohms unless otherwise specified. This rating lists the RMS power created once an amplifier is bridged.

220 watts x 2 channels

Power Specifications - Subwoofer Channel

RMS Power @ 4 ohms
The RMS power rating is the measure of continuous power that an amplifier can output, or a speaker can handle. It is the most accurate depiction of real, continuous power that the industry has so far. If the final impedance of your speaker(s) or subwoofer(s) equals 4 ohms, this is how much power this amplifier will supply at that ohm level. The higher the RMS wattage, the more clean and loud your music will sound. The 5th channel on these particular amplifiers are usually dedicated for driving subwoofers.
200 watts x 1 channels
RMS Power @ 2 ohms
The RMS power rating is the measure of continuous power that an amplifier can output, or a speaker can handle. It is the most accurate depiction of real, continuous power that the industry has so far. If the final impedance of your speaker(s) or subwoofer(s) equals 2 ohms, this is how much power this amplifier will supply at that ohm level. The higher the RMS wattage, the more clean and loud your music will sound. The 5th channel on these particular amplifiers are usually dedicated for driving subwoofers.
300 watts x 1 channels
Peak Power Output
This form of power rating refers to the maximum amount of power an electronic device can handle or output in an instant without damage. Often times this maximum is achieved during a brief musical burst, such as a drum accent or low bass hit. Some manufacturers display peak power ratings on the face of their products to increase the appeal to consumers. The RMS power rating is more accurate, and we recommend using it for product comparison. This is the peak power output for the amplifier's 5th channel.
600 watts x 1 channels

Amplifier Specifications

Amplifier Series
This designates the series of the amplifier. Many amps are available in a litany of different wattage and channel configurations, but maintain consistent features throughout the product line.
Reference MYKRO (MB Quart)
Amplifier Class

An amplifier increases the power of the signal being fed to it by taking energy from its power supply and matching the signal but increasing its amplitude. Amplifiers use many different methods for converting these electrical signals and have been categorized into classes.

Class A/B: Greater than 50% of the input signal is amplified while the other percentage is “off”. These amplifiers have a small amount of current flowing through the output transistors all the time which almost eliminates crossover distortion. Class A/B has great sound quality but is not as efficient as class D. These amps are most commonly used to drive speakers.

Class D: Also known as switching amplifiers, class D amps have output transistors that are completely turned “on” or “off”. This means that when the transistors are on, there is almost no voltage across them but when they are off there is significant voltage but no current flowing through it which makes these amplifiers very efficient at the cost of sound quality. These amps are most commonly used to drive subwoofers.

Other Classes: You may see classes such as GH, bD, X, FD, etc. by some manufactures. These amplifiers tend to be either class A/B, D or a hybrid of the two but with improvements to their designs that can make them more efficient or offer better sound quality.

D
Number of Channels
Each channel on an amplifier will power one speaker using a positive and negative cable. There are various types of amplifiers, each designed to power a certain number of speakers. Monoblock amplifiers, also known as single channel, are designed to power one or more subwoofers. These amplifiers often have very high power ratings. On the other hand, multi-channel amplifiers power multiple speakers, usually at lower power ratings. 2-Channel and 4-Channel amplifiers can power car speakers or low powered subwoofers. Occasionally you might see a 5 or 6-channel amplifier that can power speakers and subwoofers at the same time. The most common setup is a monoblock amp to run subwoofers and a 4-channel amp to run door speakers. Check out our Knowledge Base for more information.
5
Total RMS Power Output
Total RMS power is measured by multiplying RMS power per channel by the number of channels, and is calculated at the lowest level of operating impedance.

RMS power is the amount of continuous power, measured in watts, that an amplifier produces is called RMS power. The higher the RMS figure, the louder and cleaner your music sounds.

The RMS output figure is much more accurate than the peak rating when comparing products.

740 watts
Maximum Input Gauge Size
This is the largest gauge wire that will fit into the power and ground terminals of this device. The lower the gauge number, the thicker the wire is. For example, a 4 gauge wire is thicker than an 8 gauge wire and thus has higher current carrying capacity. Always do your best to get this size wire to reduce the risk of damage to your components.
4 AWG
Minimum Impedance Unbridged
The lowest impedance the amplifier will handle when it is not bridged.
2 ohms
Minimum Impedance Bridged
The lowest impedance the amplifier will handle when it is bridged.
4 ohms
THD at Rated RMS Power
The amount of change in harmonic content of the signal as it is amplified. A lower figure indicates less change and a more accurate amp. THD below 0.10% is inaudible.
0.02%
Speaker Level Inputs
Speaker level inputs are commonly referred to as high-level inputs and vice versa. This input type allows you to get your audio signal directly from the speaker wire in your vehicle, instead of using RCA cables. The advantage of this is factory integration, as most stock radios do not have RCA outputs to run amplifiers.
No
Preamp Outputs
Many amplifiers are equipped with RCA preamp outputs which pass the original music signal from the source to additional amplifiers. This is known as daisy chaining because the source connects to the first amp, and the first amp connects to the second amp, etc. The advantage to daisy chaining is you only need one 2-channel RCA cable to transfer the signal from the head-unit to the amplifier, and then one additional cable for each amp being daisy chained.
1 pair
Built-in Crossover

A crossover is a type of filtering system that permits only certain frequencies to play. A Low-Pass (LP) crossover allows only frequencies below its setting to get through which is good in the case of some subwoofers. A High-Pass(HP) filter allows frequencies above its setting to pass through, this is normally used on speakers.

When a crossover is set to FULL it means no filtering is added and the full frequency spectrum is allowed through the amplifier. Filtering is important because feeding a speaker frequencies it cannot reproduce effectively creates distortion.

Low-pass (LP)
High-pass (HP)
High-Pass Crossover Frequency
The high-pass crossover frequency can be a fixed crossover point or a variable crossover range. A variable high-pass crossover allows you to select a specific crossover point which allows frequencies above the set crossover point to pass, while making frequencies below the set point gently or harshly roll-off, depending on the steepness of the slope.

The steepness of the roll-off slope is measured in dB/octave and refers to the rate of attenuation (lowering of volume) outside their pass bands.

50 - 3000 Hz
Low-Pass Crossover Frequency
The low-pass crossover frequency is typically used for subwoofers. It can be a fixed crossover point or a variable crossover range. A variable low-pass crossover allows you to select a specific crossover point which allows frequencies below the set crossover point to pass, while making frequencies above the set point gently or harshly roll-off, depending on the steepness of the slope.

The steepness of the roll-off slope is measured in dB/octave and refers to the rate of attenuation (lowering of volume) outside their pass bands.

50 - 3000 Hz
Signal-to-Noise Ratio
This spec compares the strength of the signal to the level of background noise. A higher value indicates less background noise.
90 dB
Channel Separation
Also referred to as crosstalk. The amount of interference on one stereo channel caused by the leaking of the other stereo channel. The higher the rating in decibels (dB), the better the Channel Separation.
80 dB
Bass/Gain Remote
If the amp comes with a bass/gain remote you will be able to control the level of your bass from your dashboard. Typically bass remotes also include a 16-20 ft. wire for installation.
No
Fan Cooled
A great feature to have if an amp generates a large amount of heat. Cooling fans can help regulate the temperature to prevent the amp from overheating (burning).
No
Fuse Rating
The amperage and the number of fuse(s) an amp requires.
40A x 2 
CEA-2006 Compliant
Amplifiers that have been tested to meet specific standards. When a car amplifier meets these standards, you can be sure that it will be able to produce the amount of power specified by the official CEA-2006 rating. Usually, these rating consist of the following items:
  • RMS Power
  • Signal-to-Noise Ratio

This rating applies to both external car amplifiers, as well as the amplifiers inside of in-dash stereos.

No
Strappable
Some amplifiers can be "strapped" together in order to increase the output of a single audio channel. These amplifiers feature RCA preamp outputs, allowing you to pass the signal directly from one amp to the other to ensure consistency.
No

Warranty and Return Policy

Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider
Manufacturer

Summary of Customer Ratings & Reviews

Rating Distribution

5 Star
0%
4 Star
33%
3 Star
67%
2 Star
0%
1 Star
0%

Average Attribution Rating

Durability
2.0
Value
4.0
Features
3.7
Design
4.3
Usability
4.0

LO

Canada

Overall
Durability
Value
Features
Design
Usability

Realibility ?????

October 24, 2013

I bought this amp and i had to return it two month later because the amp overheated. They replace it ,no question ask, but the new one output distortion when cold :-(

0 of 0 found this helpful

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theDogger

CDA, ID

Overall
Durability
Value
Features
Design
Usability

MB Quart RM740.5 - Shipped with DEAD Sub Channel

September 1, 2013

Bought this amp to power a new install into a 2006 Ford F-250 Super Duty. This was to match to two sets of MB Quarts 6.5 Comp and a MB Quarts 12" Shallow mount sub. So after getting everything wired up to do the initial test before closing everything off found that the sub channel was dead! So two days of re-wiring, cust. subbox creation we only have for channels. To make it worse the amp is on back order! Pretty disappointed in MB Quarts quality control, really makes me weary of the quality that MB Quarts has become from what they once were!

0 of 0 found this helpful

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experienced installer

Seattle

Overall
Durability
Value
Features
Design
Usability

Installed and operational

September 23, 2013

I purchased this 5 channel amp for installation into a small car because of its compact profile. The wattage ranges (75 per channel/200 sub)offer many choices for speakers and subs that are capable of filling a small car with a generous level of sound...at a lower price point than other comparable amps with around the same output levels. A word about some inaccuracies in their .pdf manual, page 8: They list the power/ground terminals as "2-ga" or 2 gauge or 2 awg. No...not even close. There is no way a 2 gauge wire fits in that tiny little hole. I know because I ran a 2 gauge power wire and I would have had to snip 30% of the strands to get it to fit. It's closer to a 6 gauge which is what I ran to the amp from a distribution block that I lead the 2 awg into...no biggie, but they should correct that. They list the speaker wire block as able to receive 16 gauge...I ran 14 gauge with no problem and it fit with room to spare. They list the subwoofer block as able to receive 14 gauge, but it is the exact same size as the power/ground block. (so, it's big for any sub that this little thing could ever hope to drive) It's been a week since I installed it and so far I am quite happy with it. I installed the larger gauge power/ground/speaker wire in case it couldn't perform as well as I hoped and I needed to upgrade to a more powerful amp (not doing that job twice) but so far I am happy with the amount of "bump" it has. If you want your car to rattle, this is not the amp, but if you have a small car and want to put in a discreet upgrade, I recommend this little number. Sounds good. Oh and I did contact MB Quart for something regarding this amp and the emails were immediate, friendly and helpful. That matters...to me anyway.

0 of 1 found this helpful

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Accessory Tools and Products

Accessories added

NVX XKIT44 4-Gauge 4-Channel Wiring Kit

4-Channel 100% OFC Complete True 4 Gauge Amp Kit with RCA Cables and Speaker Wire

Your Price $99.99

NVX XBG3PK 1/0 Gauge OFC Big 3 Upgrade Kit

Comes with everything you need to upgrade your power and ground wire.

Your Price $79.99

Kicker Big 3 Package 1/0 Gauge Big 3 Upgrade Kit

Get all you need including wire cutters to upgrade your power and ground wire.

Your Price $149.99

Belva BBG3KT CCA 1/0 Gauge Big Three Kit

Features everything needed to upgrade factory power and ground wire.

Your Price $39.99

Universal Remote Level Bass Control

Controls bass level and frequency via RCA/Interconnect connectors on any amp.

Your Price $7.99

Small Universal Remote Level Bass Control

The Scosche RLC is a smaller universal bass remote that connects via RCA inputs.

Your Price $11.99

StreetWires FB4

4 AWG / 4 Gauge Firewall Bushing

Your Price $6.95

NVX XDBU4 - Top of the Line!

Distribution Block with Two 1/0 or 4 AWG Inputs and Four 4 or 8 AWG Outputs

Your Price $17.99

Professional Installation for your Car Power Amplifier

Covers labor charges through our professional installer network.

Your Price $89.99

Stinger SI4617 4000 Series Interconnect Cable

17 ft. 6-Channel 4000 Series Audio Interconnect Cable

Your Price $41.99

NVX XWS1225 12 AWG Speaker Wire

25 ft. of True 12 Gauge 100% Copper EnvyFlex Speaker Cable/Wire

Your Price $39.99

NVX XWS1625 16 AWG Speaker Wire

25 ft. of True 16 Gauge 100% Copper EnvyFlex Speaker Cable/Wire

Your Price $13.99

Belva BBSW127 12 AWG Speaker Wire

12 Gauge 7 Meter (23 Ft) Speaker Wire (CCA)

Your Price $14.99

Belva BBSW167 16 AWG Speaker Wire

16 Gauge 7 Meter (23 Ft) Speaker Wire (CCA)

Your Price $12.99

Scosche SPL Meter SPL1000F

Handheld boomSTICK measures your SPL range from 60 to 135 dB

Your Price $21.99

AutoSound 2000 CD-102

High Frequency Test CD specifically designed for the set-up and evaluation of sound system imaging and placement.

Your Price $11.99

AutoSound 2000 CD-104

Audiophile reference series test disc for evaluation of all audio components.

Your Price $11.99

XIX2025 Strapping RCA

0.25 Meter (0.86 ft) Hyper-Flex RCA cable w/ Serpentine-Cut Nickel Plated Connectors

Your Price $12.99

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Product Summary

Manufacturer

Model Number

RM740.5

UPC

806576220831

Weight

7.50lbs

Internal SKU

rm7405

Internal Product ID

67886

Sonic Electronix Wiring Guide

Wiring Diagram Legend

Warning: The image depicted shows the resistance change when wiring multiple subwoofer terminals. Please refer to your subwoofer's owner's manual for the proper wiring of its terminals. Sonic Electronix, Inc. is not responsible for damage caused to your audio system or vehicle due to improper installation. Please call tech support at 1-877-289-7664 if you require additional assistance.

Product Name: MB Quart RM740.5

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