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JBL MS-A1004

400W True RMS, 4-Channel MS Class D Amplifier w/ Digital Input Mixer and Graphical Status Display

Discontinued
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This item has been discontinued

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General Features

  • MS Series 4-Channel Class D Car Amplifier
  • RMS Power Rating:
    • 4 ohms: 100 watts x 4 chan.
    • 2 ohms: 100 watts x 4 chan.
    • Bridged, 4 ohms: 200 watts x 2 chan.
  • Digital signal processing amplifier
  • Pulse Width Modulated MOSFET power supply
  • Wireless Remote bass level input (JBL MS-WBC remote level control sold separately)
  • Built-in display shows tone and gain settings
  • Soft Start Turn-on
  • 4/3/2 channel operation
  • "Hi2" input setting provides factory system amps with output loads, eliminating "speaker disconnected" error messages
  • Speaker-level inputs with signal sensing for automatic turn-on
  • Preamp RCA outputs to daisy chain multiple amps
  • 3-Way System Protection circuitry (thermal, overload, and speaker short protection)
  • Digital input-mixer control eliminates the need for Y adapters
  • Heavy duty aluminum alloy heatsink for extreme heat dissipation
  • CD for system setup included
  • Gold-plated RCA level inputs
  • Gold-plated screw terminals
  • Input sensitivity:
    • Level: 100mV-15V
  • Variable high-pass filter (20-20,000 Hz, 6, 12, or 24 dB/octave)
  • Variable low-pass filter (20-20,000 Hz, 6, 12, or 24 dB/octave)
  • CEA-2006 compliant amplifier
  • Frequency response: 20-27,000 Hz
  • Dimensions: 8-13/16"L x 7-1/4"W x 2-13/16"H
  • 8-gauge power and ground wiring is required for installation. Contact us for information regarding a discount on select amplifier kits when purchased together with this amplifier.
  • 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.

100 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.

100 watts x 4 channels
RMS Power @ 1 ohm

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 1 ohm, 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.

Not Stable
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.

200 watts x 2 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.
MSA (JBL)
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.
4
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.

400 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.
8 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.
1%
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.
Yes
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)
Full (AP)
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.

20 - 20,000 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.

20 - 20,000 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.
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.
Optional (Accessory required and sold separately)
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.
30A 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.

Yes
Sonic Certified Amplifier
Sonic Certified amplifiers have been tested by the experts at Sonic Electronix to meet or exceed the wattage ratings provided by the manufacturer. If this is marked as Yes, then you can trust the wattage ratings. If marked as No, then we have tested the amplifier and it did not meet the advertised wattage ratings. If marked as Not Tested, then the Sonic Electronix experts have not yet been able to test the amp.

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
60%
4 Star
30%
3 Star
10%
2 Star
0%
1 Star
0%

Average Attribution Rating

Durability
4.4
Value
4.5
Features
4.9
Design
4.7
Usability
4.7
Dee

, FL

Overall
Durability
Value
Features
Design
Usability
Unmatched Versatility!

December 16, 2014

Never before has an amp of this size existed with so much function & versatility in application! Though not a full blown DSP (which would include time alignment), they would make a mediocre headunit that has time alignment & decent EQ, but lacks widely varying crossovers, more usable than could be. That in itself opens up doors to choosing more headunits than normal. The fact that any channel can be not only high or low passed, but band passed as well which makes up for lack of a subsonic filter or controlling midwoofers and midranges for whatever configuration you desire. All without adding an extra piece in the signal chain!

Power is true at normal operating voltages ... slightly less @ 12.6 volts according to Pasmag. If you can keep a steady 14.4 then there is a bit more power although insignificant in audible difference. However, the amp is underrated in 2 ohm stereo & bridged mode. It is actually almost double the power (200 x 4 @ 2 ohm stereo & 400 x 2 @ 4 ohm bridged... 14.4 volts) vs JBL ratings. More than enough power for a SQ system.

These amps will be missed long after they're gone from the market unfortunately. They're just too ahead of their time!

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cita wong

China

Overall
Durability
Value
Features
Design
Usability
Great Value!

August 21, 2014

WORK GREAT, A1004 WORK WITH A5001 IS VERY GREAT, THE MUSIC IS BEAUTIFUL, AND THE SIZE IS SO SMALL

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Troy

altoona, PA

Overall
Durability
Value
Features
Design
Usability
the first addition to any system

August 11, 2014

This thing is small, powerfull, and very easy to take control of your speaker output. Very versitile amp that would clean up the sound on any system. Wide variety of crossover points and super easy to adjust. I power a set of jbl 608c and a gt5 in my 77 ford standard cab and it is so clear and loud that everyone has got to ask where its coming from. Great amp

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DC

Lake Charles,La

Overall
Durability
Value
Features
Design
Usability
Excellent deal

July 22, 2014

The first one I received didn't have any output on all four channels. I sent it back and got another one and I am sure glad I did because this is a excellent amp for the sales price.I am using this amp to push a set of Focal 6.5'' components(70 RMS) and a set of Polk tweeters. The amp gives plenty of clean power to the components and tweeters.The sound quality is very good even with the 80db signal -to- noise ratio. The gain setting is so easy and the digital processing has a unbelievable amount of set-up options, which comes in handy in many different systems.I have only had the amp installed for a couple months now so I don't know the durability of it yet.

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Nafsusekale

San Gabriel CA

Overall
Durability
Value
Features
Design
Usability
Small compact

June 9, 2014

Easy to install, small compact and very powerfull. Highly recommended

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John

Palmer, TX

Overall
Durability
Value
Features
Design
Usability
Very good amp

May 27, 2014

I have 3 of these up front and 2 of the matching 500s on subs. I've had to send a few back for exchanges for various quality control reasons (pass through on a couple...channels 3 and 4 on at least one). That has been a hassle, but Sonic is pretty good about returns. When you get one that works, it is great. The digital crossovers are sooooo much more convenient and precise than a dial. SQ is very good, especially compared to other full range class D's I've owned. The noise floor is very low...maybe a result of the ease of setting gains with the included CD. Only time I have hiss is when I bridge and turn gains high as they will go before clipping. Not sure I buy pasmags RMS claims (400 x 2 bridged) but the JBL ratings seem honest. These are my keepers after trying MANY setups over the past year. Test for defects and then enjoy!

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Bill

Gonzales, LA

Overall
Durability
Value
Features
Design
Usability
Great amp, nice features, super easy

May 20, 2014

This amp replaced a Planet Audio amp that took up twice the footprint. Installation was simple and straight forward. The independent gain for input and output allowed for great flexibility. I'm using this amp without any of the crossover settings, just a straight pass through to 2 sets of Infinity Kappa component speakers. (Plus separate amp and 2 10" subs). My music has never sounded so alive. Everything is clean, clear, and extremely punchy and strong. There is also a warmth that wasn't there in my PA amp. I highly recommend this amp. I was also able to install it in my 2013 GMC Sierra Crew Cab behind the rear seat and have easy access through the rear seat armrest/cup holder. (removing the seats is a GIANT PAIN) The front control panel is sharp! I can't speak highly enough of this product.

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Rudy

Houston, TX

Overall
Durability
Value
Features
Design
Usability
OK but not the best

January 13, 2013

I have some issue with MS-A1004 amplifier. I used in a higher level audio system. And it makes whistling sound, even with the engine off, and even with radio off. I even unattached the input signal from it but the whistling still exist.
And there is other thing that makes it even stranger for me. I have two other amplifiers in this system, which are working perfectly. The other two are a DLS 3 channel class A/B amplifier (DLS CA 31) and JL Audio 500/1v2: Mono block Class D Amplifier.

I have done any checks you think of, which include isolation of power wires and signal wires, measuring the input voltage of power supply (battery), checking the speakers, checking the RCA wires,…

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Joar

Norway

Overall
Durability
Value
Features
Design
Usability
Great amplifier

December 20, 2012

Great amp.. Perfect for use in a small car like mine. Does not take a lot of space.

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ebk

dover, de

Overall
Durability
Value
Features
Design
Usability
sq amp

June 9, 2012

I would say it's one of the best amps out for sound quality.

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Accessory Tools and Products

Accessories added

NVX XKIT84 4-Channel 8-Gauge Wiring Kit

In case you didn't know, NVX has top notch wire and this kit has everything you need!

Your Price $69.99

Kicker PK8 8-Gauge Wiring Kit

Great wire for your awesome new amp! Don't forget the RCA's!

Your Price $29.95

NVX XBG3PK 1/0 Gauge OFC Big 3 Upgrade Kit

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

Your Price $59.99

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 $151.99

Belva BBG3KT CCA 1/0 Gauge Big Three Kit

Features everything needed to upgrade factory power and ground wire.

Your Price $39.99

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

NVX XIV45 4-Channel RCA Audio Interconnect Cable

5 Meters (16.4 ft.) 4-Channel RCA Audio Interconnect Cable with Dual Twisted Pair Hyper-Flex Technology

Your Price $23.99

NVX XIX45 X-Series RCA Interconnect Cable

16.4 ft. of 4-Channel X-Series RCA Cable with Dual Twisted Pair Hyper-Flex Technology

Your Price $34.99

StreetWires ZN9 Series Interconnect Cable

16.4 ft. of 4-Channel RCA Cable with Rhodium-plated contacts and ZeroNoise construction for clear signal transfer!

Your Price $99.95

Kicker 4-Channel RCA Audio Interconnect Cable

4 Meters (13 ft.) 4-Channel K-Series RCA Audio Interconnect Cable

Your Price $19.95

NVX XWS1225 12 AWG Speaker Wire

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

Your Price $39.99

NVX XWS1250 Speaker Wire

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

Your Price $29.99

NVX XWS1625 16 AWG Speaker Wire

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

Your Price $13.99

Belva BBSW167 16 AWG Speaker Wire

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

Your Price $12.99

The Install Bay IB-CAP1F

True 1.0 Farad Car Audio Capacitor for up to 1000W Max

Your Price $37.99

e2 ECAP1 by Scosche - Mid-Level 1 Farad

Digital 1.0 Farad Car Audio Capacitor for up to 1000W Max

Your Price $49.99

Rockford Fosgate RFC1D - Top of the Line 1 Farad

Digital 1.0 Farad Car Audio Capacitor for up to 1000W Max

Your Price $99.99

Scosche SPL Meter SPL1000F

Handheld boomSTICK measures your SPL range from 60 to 135 dB

Your Price $21.99

Browse 1 question and 4 answers
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Why did you choose this?
Sonic Electronix Store
Compact size, good power, reputable brand, excellent OEM deck compatibility.
Matthew F on Sep 4, 2014
Ratings and price
Jose O on Aug 26, 2014
at this price, I want to try this digital technology
Carlos R on Aug 26, 2014
Great reviews. Flexible installation option
Johann N on Aug 19, 2014

Product Summary

Manufacturer

Model Number

MS-A1004

UPC

050036931021

Weight

8.00lbs

Internal SKU

msa1004

Internal Product ID

29471

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: JBL MS-A1004

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