Why Choose Crutchfield?
Great gear and expert advice
Our experts help you pick the ideal gear for your needs.Meet our advisors
Free tech support for the life of your gear.Read about our one-on-one expert help
You may return items that are complete and like new for any reason within 60 days.See the details of our return policy
Earn one point for every dollar you spend and use those points to save on future purchases.Get full details on Crutchfield Rewards
Deep discounts on car installation gear
Trusted since 1974
Our customers have trusted us with their business, and they’ve helped us win awards for our service.Check out our most recent awards
The manufacturer’s warranty always applies.See more details
Power and control that's what you get with Alpine's MRD-M501 mono bass amp. And with 275 watts RMS (at 4 ohms) and Bass Engine digital controls for razor-fine adjustments, outstanding sound is the result. Crank it up, then flip open the top-mount control center and tune your bass to perfection.
The MRD-M501 amplifier includes a built-in digital signal processor for the Bass Engine features, giving you a level of fine-tuning capability previously found only in Alpine receivers. Set the cut-off point for the subsonic filter from 15-50 Hz (in 5 Hz steps) to remove inaudible, energy-wasting low frequencies. The digital parametric EQ allows you to control the width and center point of the equalization curve to improve overall sound.
Need more bass? The Bass Compensator uses Alpine's MediaXpander (found in their receivers to optimize playback of compressed media files) to enhance low-end definition of the amplifier's output. Go hands-on with the optional RUX-4180 dash-mount level control knob.
The MRD-M501 has a set of preamp outputs for easily getting signal to another amplifier for additional power. The extra-large gold-plated wiring terminals will let your bass really hit, since larger-sized power and speaker wires let the power move more efficiently into and out of the amp.Details:
- 275 watts RMS x 1 at 4 ohms (CEA-2006 Compliant)
- 550 watts RMS x 1 at 2 ohms
- 2-ohm stable
- MOSFET power supply and output stages
- STAR Topology for cleaner sound
- Bass Engine® features:
- low-pass digital filter, 30-200 Hz, with a selectable 12 or 24 dB/octave slope
- variable subsonic filter (15-50 Hz in 5 Hz steps)
- parametric EQ variable from 30-160 Hz, ±12 dB
- Bass Compensator enhances low-end definition
- top-mounted digital control center with cover
- preamp outputs
- time correction 0-10 milliseconds in 0.1ms steps
- phase adjustment 0-180°
- turn-on delay
- requires 4-gauge power and ground leads wiring and hardware not included with amplifier
- extra-large gold-plated terminals
- 13-11/16"W x 2-9/16"H x 10-5/8"D
- warranty: 1 year
Alpine MRD-M501 Reviews
Average Customer Review:
Great little amp
I ordered this amp for my girlfriend's car. This is one of the cleanest looking amps I have ever seen. We're running 2 8" JL Microsubs in her hatchback and it sounds incredible. I'm using an Alpine RUX-4280 with the amp that allows me to make adjustments from the driver's seat. The voltage meter on the display helps keep track of the car's charging system. With the system bumping, the car has been at a steady 13.8-9 volts which means the amp is not putting any strain on the alternator. I would definately recommend getting this amp for your subs. It's great for a gadget freak like me who likes to be in control of every little detail in his stereo.
I have 2 of these powering SWR-1221D. One SWR-1221D on each anp and they are wired to this amp as a 4ohm load and they pound. I was amazed how hard they pounded. Never heard of anything like it before. If your looking for power, get one of these or 2 of them. You won't be dissapointed.
Crutchfield Customer Review (What's this?)
The Alpine MRD-M501 a great amplifier with many useful features. The DSP controls take a little getting used to, but it's nothing that can't be figured out after using it a couple of times. Installation was pretty straight forward, with plenty of room under the amp cover for all of the connections. Thanks to the the aluminum cover the installation with this amp looks very clean. I am using a 10" Soundsplinter RL-i10 DVC subwoofer with the amplifier in a sealed enclosure. I am very pleased with the output and sound quality that this amplifier provides.
What's in the box?
- Mono amplifier
- Terminal cover
- 2 Allen head bolts to mount terminal cover
- 3 Allen wrenches
- 4 Self-tapping screws (M4 x 20mm)
- Customer Care Registration/Survey
- Warranty sheet
- Verification Certificate
- Manual correction sheet
V12 AccuClass-D Mono Amplifier: The V12 AccuClass-D amplifier design allows it to deliver massive power without correspondingly huge current draw. This amplifier's true digital design keeps the signal purer and makes the amp extremely efficient. V12 AccuClass-D amps use digital signal processing to provide time correction and other sophisticated controls, all controlled through the Alpine Digital Control Center located under the top-mounted access panel.
Hood: The amplifier has a hinged brushed aluminum hood that flips up to reveal the control panel and LCD display. The control panel consists of six buttons: Display, Mode (up), Mode (down), Enter, <, and >. These buttons are used to navigate the menu that includes all the adjustments on the amp (input level, crossover, EQ, time correction, phase, etc). When closed, the LCD display is visible through the smoked plastic window. Two Allen-head screws (supplied) secure the hood in the closed position.
Display Control: The MRD-M501 features a 5-digit information display that allows you to check the operational status of the amplifier. By pressing the Display button, you can cycle through the following readouts: Voltage (supply), Current (draw), Internal Temperature (Fahrenheit), and Internal Temperature (Celsius).
Terminal Cover: The amplifier is equipped with a silver brushed aluminum terminal cover that can be attached to the front panel to improve appearance after the amplifier has been installed. The terminal cover hides power, signal and speaker wires, and secures to the amplifier via two Allen-head screws (supplied).
Verification Certificate: The amplifier comes with a certificate that informs you of the total RMS output of the particular amplifier. It lists the model number, serial number, test date, and the test conditions (voltage, impedance).
Bass Engine DSP: The MRD-M501 uses digital signal processing to offer several sophisticated Bass Engine controls without signal loss or sound degradation. The Bass Engine features include:
- Digital Time Correction: Time correction allows you to time align this amp with others in the system. This is particularly useful to maximize SPL if there are multiple subs and sub amps. The adjustment range runs from 0-10ms in 0.1ms steps.
- Digital Parametric Equalizer: A fully adjustable parametric EQ is built into this amp. The center frequency is adjustable from 30 to 160Hz in 1/12 octave steps. The Q value of the EQ curve is selectable between 0.5, 1, 2, 3, 4, and 5. The EQ level is adjustable from -12dB to +12dB in 1dB steps.
- Built-in Variable Crossover: The built-in low-pass crossover is adjustable from 30 to 200Hz in 1/12 octave steps with a selectable slope of 12dB/octave or 24dB/octave.
- Subsonic Filter: The subsonic filter is used to filter out low frequencies that you cannot hear but can "rob" power from the amplifier. The crossover point is variable between 15Hz and 50Hz in 5Hz steps, and can be switched on or off.
- Bass Compensation: The Bass Compensation circuit is used to enhance low-end bass definition. When engaged, the Bass Compensation circuit provides bass with sharp auditory impact, even with a small diameter woofer. Once turned on, you can select the Bass Compensation level that best suits your desired results: Bass Comp 1, Bass Comp 2 or Bass Comp 3.
- Phase Control: The phase is selectable between 0 and 180 degrees.
Gain Factor: Gain Factor is a unique and patent-pending digital processing technology that allows more audible power to be delivered even when pushing the amplifier to its limit. Unlike all analog compensation techniques, Gain Factor interpolates and modifies the signal at the individual digital data level, enhancing smaller signals more and larger signals less without driving the amplifier into hard clipping. The result is more clean power, sooner on the volume knob. You can select a gain factor of 0dB, +6dB or +9dB.
Multi-Amp Installation: Because the above Bass Engine adjustments are all digital and discrete, two of these amplifiers can be used to power the two voice coils of a DVC woofer. Note: Technically this is true of any amp, but with analog adjustments an oscilloscope is needed to ensure the outputs are identical.
Amplifier ID: Alpine's RUX-4280 Remote Amplifier Control Center (RACC) will control up to eight V12 AccuClass-D amplifiers. For this reason each amp needs its own ID when more than one amp and the RACC are used.
Optional Remote Level Control: This amplifier's level can be controlled remotely with the optional RUX-4180 Subwoofer Level Control. Note: The RUX-4180 can only control one amplifier. For multiple amplifiers, the RUX-4280 Remote Amplifier Control Center should be used.
Turn On Delay: The amp's turn-on time is adjustable from 0 to 2 seconds in 0.2 second steps. This is useful for eliminating the loud "thump" that occurs when multiple amplifiers are turned on simultaneously.
Output Disable Mode: The Output Disable Mode turns off the power output of the amp while leaving the control functions active. This should be used when adjusting the DSP function. Only the power of the DSP circuit is on and in the current saving state. After making adjustments, the output disable mode should be turned off.
Memory: The settings on the amp can be stored in one of two memory slots to make it easy to return to your preferred values.
3-Way Protection Circuitry: This amplifier has a 3-way protection circuitry to guard against accidents and undesired operations. It includes protection for Short circuit, Over-voltage, and Thermal overload. When the amplifier goes into protection mode, the LCD display will show a Error code explaining the cause of the failure.
Remote (turn-on): The remote terminal is combination gold-plated screw terminal that will accept a spade connector up to .35" wide on top of the terminal, or set-screw terminal that will accept up to 10 gauge bare wire into the front of the terminal. A Phillips-head screwdriver (not supplied) is required to tighten/loosen the set screw.
Speaker Output: The speaker terminals are gold-plated set-screw terminals that will accept up to 8 gauge wire. A 2.5mm Allen wrench is included to tighten/loosen the set screw.
RCA Input/Output: The amplifier includes gold-plated RCA line input jacks (there is no speaker-level input) and gold-plated RCA pre-out jacks.
Controller: The amp has a 7-pin female DIN jack for connection to the RUX-4280 Remote Amplifier Control Center (RACC) or the RUX-4180 Subwoofer Level Control.
CEA-2006 Compliance: The specifications given by Alpine for the MRD-M501 amplifier comply with the new CEA-2006 Amplifier Power Standard from the CEA (Consumer Electronics Association). All manufacturers who comply with the standard can display the CEA-2006 logo on their product.
RMS Power Rating (measured at 14.4V):
- Into a 4-Ohm Load: 275 watts x 1
- Into a 2-Ohm Load: 550 watts x 1
RMS Power Rating (measured at 12.0V):
- Into a 4-Ohm Load: 225 watts x 1
- Into a 2-Ohm Load: 425 watts x 1
Note: Minimum impedance is 2 Ohms.