RA1-280.4 Reference 280 Watt Amplifier

MB Quart RA1-280.4 Reference 280 Watt 4 Channel Amplifier.

$ 229.95

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SKU: 806576232667 Category:

MB Quart Reference series four channel car audio amplifier featuring innovative sound quality and power technology. The RA1-280.4 is a 280 watt car audio amplifier. Reference amplifiers feature DC Sensing to allow any amplifier to be easy integrated into an OEM system by simply adapting a RCA cable from the source unit.

Weight 6.3 lbs
Dimensions 15 × 8.5 × 4 in



MB Quart










1 Year

Compatible Vehicles


Amp Class

Class SQ (Class D)

Amp Total Channels


Amp Max Power (watts)


Amp Power @ 2 Ohms (ch x watts)

4 x 70

Amp Power @ 4 Ohms (ch x watts)

4 x 50

Amp Crossover


Amp Variable High Pass Crossover 12dB per Octave

CH1 & CH2: Switched Full/HPF/LPF 50Hz-250Hz, CH3 & CH4: Switched Full/HPF/LPF 50Hz-250Hz

Amp Variable Low Pass Crossover 12dB per Octave

CH1 & CH2: Switched Full/HPF/LPF 50Hz-250Hz, CH3 & CH4: Switched Full/HPF/LPF 50Hz-250Hz

Amp Bass Boost


Amp Subsonic Filter


Amp Variable Voltage


Amp Signal to Noise

> 101dB

Amp Frequency Response


Amp Total Harmonic Distortion (THD)

< 0.09%

Amp Speaker Level Audio Inputs


Amp Power Terminal 12v/GND


Amp Speaker Terminal Wire Gauge

12 AWG

Amp Fusing

40A External

Proposition 65 Notice WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov
Low Noise Preamplifier Circuit

Q-Stasis Pre Amplifier Stage: Maximum low voltage signal from the source unit comes into the amplifier circuit with minimal distortion.

RCA Inputs

Nickel-Plated: High temperature impact resistant with hex screw terminals that allow for secure connections and is erosion resistant.

High Level Inputs

See Auto-Sense Feature.

Operation Mode

2 / 4 Channel

Crossover Type

Variable electronic crossovers allow for complete control of the sound.

Electronic Equalizer

Control of amplifier output with on-board electronic crossover to tailor specific frequencies to speakers and subwoofers. Check specifications for specific frequencies for this amplifier.

Class / Topology

Class SQ: Multi-channel amplifiers utilize the unique MB Quart Class SQ topology. Matched with Q-Stasis the sonic accuracy and clarity exceeds standard Class D amplifiers.

Output Device Technology

FLUID-FETS: MB Quart output devices, FLUID-FETS are painstakingly selected for their ability to efficiently produce power and mimic the sound quality of the highest end home amplifiers.

Heat Sink

Aluminum: Quickly dissipates heat to allow the amplifier to run lower impedance for longer duration.

Power Supply

Rugged MOSFET Pulse Width Modulation power supply: Allows amplifier to produce efficient power without taxing the vehicle electrical system.

Output Connections

Heavy duty connections allow for secure electrical signal to pass into wiring and resist erosion which will add longevity to the amplifier.

Connection Type

Secure connection for all power, ground and speaker connections.

Auto Turn-On

DC SIGNAL SENSE: The DC SIGNAL SENSE switch will allow the amp to turn on when a signal is received on the RCA inputs, so an amplifier remote turn on wire is not needed to turn on the amplifier. This feature can also be turned off.

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MB Quart Reference Amplifiers (RA1) Quick Start Guide (Rev1)