JBL MS-A5001

Mono subwoofer amplifier — 500 watts RMS x 1

  • JBL MS-A5001


  • JBL MS-A5001

  • JBL MS-A5001

  • JBL MS-A5001

  • JBL MS-A5001

  • JBL MS-A5001

  • JBL MS-A5001

  • JBL MS-A5001

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Item #: 109MSA5001
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Our take on the JBL MS-A5001

by Buck Pomerantz

My system has plenty of power. Who needs an amp?

You might think you don't need an amp because you have a 400-watt system in your car, or because your new stereo puts out 50 watts a channel. But those are peak wattage ratings, which may boil down to 15 or 20 watts per channel, using the more realistic RMS rating. An amp sends your speakers the power they need to deliver your music with clarity and impact, whether you're using factory speakers or high-performance components. And low-frequency reproduction requires lots of power, so an amp is an absolute must if you're adding a sub to your system.

JBL's Tiny amps

JBL's stylish MS Series "Tiny" amps measure only 7" by 8" so you can tuck one into virtually any hiding place that has adequate ventilation. Or you can mount one in a prominent spot to show off the bright digital display with its tone and gain settings. These unique amps come with a setup CD and include built-in indicators that help you set the input level perfectly. They also feature preamp and speaker-level inputs so you can hook them up to almost any system.

MS-A5001 display

Digital signal processing

The MS-A5001 sends 500 watts RMS to your sub at either 2 or 4 ohms. Digital processing makes tuning this amp virtually a snap. It offers a wide selection of crossover points and gives you a choice of three filter slopes to get just the right tone to your music's bass.

Sophisticated circuitry

An optional remote bass controller does much more than just turn this amp up and down. This wireless controller works with multiple MS Series amps at the same time, coordinating the low frequencies of all the amps to blend smoothly so you don't get a bunch of mud when you boost the bass. A signal-sensing turn-on circuit eliminates the need for a separate lead from your receiver, and a special input mode allows this amp to work even when there's a factory amplifier in your car's system.

MS-A5001 inputs MS-A5001 power and speaker connections
See more info on this item


  • mono subwoofer amplifier
  • 500 watts RMS x 1 (2 to 4 ohms)
  • CEA-2006 compliant
  • selectable high- and low-pass filters (20-140 Hz; 6, 12, or 24 dB/octave)
  • optional wireless remote bass controller (automatically pairs with multiple JBL MS Series amps)
  • Class-D amplifier design
  • digital signal processing — settings stored in non-volatile memory, no settings lost if power is disconnected
  • speaker-level inputs (RCA adapters included)
  • "Hi2" input setting provides factory system amps with output loads, eliminating "speaker disconnected" error messages
  • CD for system setup included
  • preamp inputs and outputs
  • output level controls
  • fuse rating: 40A x 2
  • 8-gauge power and ground leads and an 80-amp fuse recommended — wiring and hardware not included with amplifier
  • 7-1/4"W x 2-13/16"H x 8-13/16"D
  • warranty: 1 year
  • Our 60-day money-back guarantee

Hands-on research from the Crutchfield Labs (what are the Labs?)

Features and Specs
RMS Power Output (Watts x Channels) 500 x 1
Peak Power Output (Watts x Channels) N/A
Power at 2 Ohms (Watts x Channels) 500 x 1
Bridged Power (Watts x Channels) N/A
Minimum Impedance Bridged N/A
Minimum Impedance Unbridged 2
Best Frequency Response 20-270 Hz
THD at Rated RMS Power 1%
Signal to Noise Ratio 80 dB
Input Voltage 14.4v
Amplifier Class D
Low-Pass Crossover Frequency 20-140 Hz
Low-Pass Slope (dB/octave) 6, 12, 24 dB/oct
High-Pass Crossover Frequency 20-140 Hz
High-Pass Slope (dB/octave) 6, 12, 24 dB/oct
Bass Boost Optional remote only
Bass Boost Frequency N/A
Fan Cooled No
Fuse Rating 80
Speaker Level Inputs RCA
Preamp Outputs 1 pair
Width (inches) 7-1/4
Height (inches) 2-13/16
Depth (inches) 8-13/16
Parts Warranty 1 Year
Labor Warranty 1 Year
Product Research
What's in the box?

Download owner's manual

  • Mono subwoofer amplifier
  • Two 40-amp ATO fuses (installed)
  • 2 Speaker wire to RCA adapters
  • 4mm Allen wrench
  • 2.5mm Allen wrench
  • Setup CD
  • Owner's manual

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team — they open the box, verify contents, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.



Digital Signal Processing: The MS-A5001 is a mono subwoofer amplifier with a digital signal processor (DSP) built in to control input mixing, crossover settings, and output level. Once the gain is adjusted for the incoming signal, it is converted from analog to digital and routed through the DSP, then to the Class-D amplifier.

Setup Disc: The included setup CD is used to correctly adjust the input gain. With the amp in setup mode, a test tone is output from the disc with the radio at full volume (the amplifier output is muted) and the amp measures the line voltage, guiding you with arrows on the display as you adjust the gain controls.

Signal Sensing: The MS-A5001 has a remote turn-on terminal that activates the amp with an input between +5 and 12+ volts DC. If the connected radio has no remote lead, or you prefer not to use it, turn on the signal sensing turn-on circuit and the amp will turn on whenever an audio signal is present at the inputs.

Crossovers: There are independent high-pass and low-pass crossovers; they can be used individually or both can be used together as a band-pass crossover. The slope of each is adjustable (6 dB/oct, 12 dB/oct, and 24 dB/oct) and the crossover point has 98 options:

  • 20 Hz to 110 Hz in 1 Hz steps
  • 115 Hz to 140 Hz in 5 Hz steps
  • Off

Subsonic Filter: The high-pass crossover can be adjusted to act as a subsonic filter (20 Hz, 21 Hz, etc).

Audio Input: If your radio has no line-level outputs, use the included adapters to convert the speaker wires to RCA and plug them into the amplifier's inputs. The differential inputs will accept any signal from 100mV to 20.0V; set the input selector switch to Hi when using speaker-level inputs. The input selector switch also has a Hi2 position, used to present a speaker load to factory radios equipped with a circuit that turns the radio off when an amp is connected.

Wireless Bass Control: An optional MS-WBC wireless bass control (item number 109MSWBC, sold separately) is available to remotely adjust the bass output. The MS-WBC communicates via RF signal and requires no physical connection to the amp; it's also battery powered, but has an optional power wire if you prefer not to replace the battery periodically. When adjusting the bass output, the DSP also adjusts the crossover, so the tonal quality of the bass (and its apparent location) doesn't change.



  • Input Gain: rotary knob
  • Input Selector: three position switch; Lo (line-level RCA), Hi (speaker-level), or Hi2 (used only with factory radios having a circuit that turns the radio off when it sees no speaker load)
  • Input Mixer: one or two inputs can be used with no need for a Y-adapter; select 1 (mono input), 1/2 (stereo input is summed to mono)
  • High-Pass Crossover Slope: 6 dB/oct, 12 dB/oct, or 24 dB/oct
  • High-Pass Crossover Frequency: choose from 97 options from 20 Hz to 140 Hz, or off
  • Low-Pass Crossover Frequency: choose from 97 options from 20 Hz to 140 Hz, or off
  • Low-Pass Crossover Slope: 6 dB/oct, 12 dB/oct, or 24 dB/oct
  • Output Level: adjust from 0 to 80; important when matching tweeters and midrange, subwoofer and full range speakers, etc


Inputs and Outputs:

  • Power and Ground Terminals: set screw terminals; accept up to 4 gauge bare wire; requires included 4mm Allen wrench
    • Note: JBL recommends the power and ground cables be 8 gauge minimum. The recommended accessory list for the MS-A5001 includes wiring kits with 8 gauge wire and 60 amp fuses, but the amp has two 40 amp fuses (80 amps total), so if one of these kits is used a replacement fuse (at least 80 amps) must also be added. If a 4 gauge wiring kit is used no additional fuse is necessary.
  • Remote Turn-on Terminal: set screw terminal, accepts up to 8 gauge bare wire; requires included 2.5mm Allen wrench
  • Speaker terminals: two sets of outputs wired in parallel to easily connect two subwoofers; set screw terminals, accept up to 8 gauge bare wire; require included 2.5mm Allen wrench
  • Audio Inputs: 2 female RCA jacks; labeled channels 1 and 2; compatible with a speaker level signal using the included adapters
  • Line Level Outputs: 2 female RCA jacks; no crossover is applied
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