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2004 Audi A4

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Use our shopping filters to find the right 2/3/4-channel amp to power upgraded speakers properly.

Overview Upgrade your Stereo Upgrade your Speakers Add a Subwoofer Add an Amplifier Digital Sound Processors Audio Installation & Accessories Add a Backup Camera Dads & Grads Sale

Amps for Adding Speakers for 2004 Audi A4

Some vehicles require an amp bypass module, a line-output converter like the NVX XLCA2 or AudioControl LC2i, or a DSP to integrate with your factory radio and avoid bass roll-off. Bass roll-off occurs when a factory radio's crossover is designed only for the original equipment speakers, resulting in a not complete signal being sent to your new aftermarket amp.

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Amplifiers,
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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.
Amplifier Key Features
Amplifiers can offer a diverse array of features. If you select more than one feature, then you will view amplifiers that have ALL features selected. These include speaker-level inputs that facilitate seamless integration with factory audio systems, Bluetooth connectivity suitable for ATV/UTV or Classic vehicle setups, built-in DSPs that provide enhanced control over your audio signal, and a host of other functionalities to explore.
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.
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.
Total Peak Power Output
The total peak power output is measured as the wattage per channel multiplied by the number of channels, and is calculated at the lowest level of operating impedance.

It is measured during a brief musical burst, such as a sudden drum accent. Some manufacturers display peak power ratings on the face of their products to increase the appeal.

The RMS power rating is more accurate, and we recommend using it for product comparison.
Series
Many brands group their products into series or lines of products to help customers know the level of quality (good, better, best for example). You can filter by series and the brand using our guided browsing.
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Minimum Impedance Unbridged
The lowest impedance the amplifier will handle when it is not bridged.
Minimum Impedance Bridged
The lowest impedance the amplifier will handle when it is bridged.
Remote bass/level controller
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.
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.
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.
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.

Amp Bluetooth Connectivity
This feature will tell you if the amplifier has the capability to connect to a Bluetooth device.
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PRV Audio MDX2000.4 2 Ohm

2000W RMS Class D MDX Series 4-Channel Compact Car and Motorsport Amplifier

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PRV Audio MDX2000.4 2 Ohm

2000W RMS Class D MDX Series 4-Channel Compact Car and Motorsport Amplifier

• 330 watts x 4 channel @ 4 ohm
• 500 watts x 4 channel @ 2 ohm
• Bridged: 1000 watts x 2 channel @ 4 ohm
• Total RMS Power: 2000 watts
• Class D 2 ohm Stable 4-Channel Amplifier

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• 330 watts x 4 channel @ 4 ohm
• 500 watts x 4 channel @ 2 ohm
• Bridged: 1000 watts x 2 channel @ 4 ohm
• Total RMS Power: 2000 watts
• Class D 2 ohm Stable 4-Channel Amplifier

Rockford Fosgate Power T600-4

600W RMS Class AB Power Series 4 Channel Car Amplifier

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Rockford Fosgate Power T600-4

600W RMS Class AB Power Series 4 Channel Car Amplifier

• 100 watts x 4 channel @ 4 ohm
• 150 watts x 4 channel @ 2 ohm
• Bridged: 300 watts x 2 channel @ 4 ohm
• Total RMS Power: 600 watts
• Class A/B 2 ohm Stable 4-Channel Amplifier

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AudioControl EPICFOUR

800W RMS Class D Epic Series 4-Channel Car Amplifier

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AudioControl EPICFOUR

800W RMS Class D Epic Series 4-Channel Car Amplifier

• 100 watts x 4 channel @ 4 ohm
• 200 watts x 4 channel @ 2 ohm
• Bridged: 400 watts x 2 channel @ 4 ohm
• Total RMS Power: 800 watts
• Class D 2 ohm Stable 4-Channel Amplifier

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• 100 watts x 4 channel @ 4 ohm
• 200 watts x 4 channel @ 2 ohm
• Bridged: 400 watts x 2 channel @ 4 ohm
• Total RMS Power: 800 watts
• Class D 2 ohm Stable 4-Channel Amplifier

Kenwood eXcelon X803-5

1600W Peak (800W RMS) Class D eXcelon Series 5 Channel Car Amplifier with Bass Remote

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Kenwood eXcelon X803-5

1600W Peak (800W RMS) Class D eXcelon Series 5 Channel Car Amplifier with Bass Remote

• 50 watts x 4 channel + 300 watts x 1 channel @ 4 ohm
• 75 watts x 4 channel + 500 watts x 1 channel @ 2 ohm
• Bridged: 150 watts x 2 channel @ 4 ohm + 500 watts x 1 channel @ 2 ohm
• Total RMS Power: 800 watts
• Class D 2 ohm Stable 5-Channel Amplifier

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NVX XQA16005

1600W RMS Class D XQ-Series 5-Channel Car Amplifier with X-Boost (Hi-Res Audio Capable)

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NVX XQA16005

1600W RMS Class D XQ-Series 5-Channel Car Amplifier with X-Boost (Hi-Res Audio Capable)

• 125 watts x 4 channel + 300W x1 @ 4 ohm
• 200 watts x 4 channel + 500W x 1 @ 2 ohm
• Bridged: 400 watts x 2 channel @ 4 ohm + 800W @ 1 ohm
• Total RMS Power: 1600 watts
• Class D 1 ohm Stable 5-Channel Amplifier

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NVX XKIT06

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NVX VADM4 Version 2 (VADM4v2) (Open Box, Great)

500W RMS V-Series Micro Full-Range Class D 4-Channel Amplifier Car/Marine/Powersports Amplifier

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NVX VADM4 Version 2 (VADM4v2) (Open Box, Great)

500W RMS V-Series Micro Full-Range Class D 4-Channel Amplifier Car/Marine/Powersports Amplifier

• 80 watts x 4 channel @ 4 ohm
• 125 watts x 4 channel @ 2 ohm
• Bridged: 250 watts x 2 channel @ 4 ohm
• Total RMS Power: 500 watts
• Class D 2 ohm Stable 4-Channel-Channel Amplifier

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JBL Stage GT 60041 (JBLSTAGEGT60041AM)

1240W Peak (360W RMS) Class D Stage GT Series 4-Channel Car Amplifier

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JBL Stage GT 60041 (JBLSTAGEGT60041AM)

1240W Peak (360W RMS) Class D Stage GT Series 4-Channel Car Amplifier

• 65 watts x 4 channel @ 4 ohm
• 90 watts x 4 channel @ 2 ohm
• Bridged: 180 watts x 2 channel @ 4 ohm
• Total RMS Power: 360 watts
• Class D 2 ohm Stable 4-Channel Amplifier

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List price $279.95
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Rockford Fosgate Punch P400X4

400W RMS Class AB Punch Series 4 Channel Car Amplifier

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Rockford Fosgate Punch P400X4

400W RMS Class AB Punch Series 4 Channel Car Amplifier

• 50 watts x 4 channel @ 4 ohm
• 100 watts x 4 channel @ 2 ohm
• Bridged: 200 watts x 2 channel @ 4 ohm
• Total RMS Power: 400 watts
• Class A/B 2 ohm Stable 4-Channel Amplifier

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Rockford Fosgate Power T400-4

400W RMS Class AB Power Series 4 Channel Car Amplifier

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Rockford Fosgate Power T400-4

400W RMS Class AB Power Series 4 Channel Car Amplifier

• 60 watts x 4 channel @ 4 ohm
• 100 watts x 4 channel @ 2 ohm
• Bridged: 200 watts x 2 channel @ 4 ohm
• Total RMS Power: 400 watts
• Class A/B 2 ohm Stable 4-Channel Amplifier

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Deaf Bonce MFA 4.320

1920W RMS Class D Machete Series 4 Channel Car Amplifier

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Deaf Bonce MFA 4.320

1920W RMS Class D Machete Series 4 Channel Car Amplifier

• 320 watts x 4 channel @ 4 ohm
• 480 watts x 4 channel @ 2 ohm
• Bridged: 960 watts x 2 channel @ 4 ohm
• Total RMS Power: 1920 watts
• Class D 2 ohm Stable 4-Channel Amplifier

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NVX XKIT44

NVX XKIT44

$119.99

$83.99

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PRV Audio MDX1200.4 2 Ohm

1200W RMS Class D MDX Series 4-Channel Compact Car and Motorsport Amplifier

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PRV Audio MDX1200.4 2 Ohm

1200W RMS Class D MDX Series 4-Channel Compact Car and Motorsport Amplifier

• 200 watts x 4 channel @ 4 ohm
• 300 watts x 4 channel @ 2 ohm
• Bridged: 600 watts x 2 channel @ 4 ohm
• Total RMS Power: 1200 watts
• Class D 2 ohm Stable 4-Channel Amplifier

Save 30% off an NVX XKIT44 Amp Kit at Checkout!
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List price $199.89
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NVX XKIT44

NVX XKIT44

$119.99

$83.99

$36 Savings!

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• 200 watts x 4 channel @ 4 ohm
• 300 watts x 4 channel @ 2 ohm
• Bridged: 600 watts x 2 channel @ 4 ohm
• Total RMS Power: 1200 watts
• Class D 2 ohm Stable 4-Channel Amplifier

Limited time!

Belva BXA6404

640W Peak BX-Series Class A/B 4-Channel Car Audio Amplifier

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Belva BXA6404

640W Peak BX-Series Class A/B 4-Channel Car Audio Amplifier

• 80 watts x 4 channel @ 4 ohm
• 160 watts x 4 channel @ 2 ohm
• Bridged: 320 watts x 2 channel @ 4 ohm
• Total Peak Power: 640 watts
• Class A/B 2 ohm Stable 4-Channel-Channel

Save 30% off an NVX XKIT84 Amp Kit at Checkout!
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NVX XKIT84

NVX XKIT84

$79.99

$55.99

$24 Savings!

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Used from: $59.99

• 80 watts x 4 channel @ 4 ohm
• 160 watts x 4 channel @ 2 ohm
• Bridged: 320 watts x 2 channel @ 4 ohm
• Total Peak Power: 640 watts
• Class A/B 2 ohm Stable 4-Channel-Channel

Alpine R-A90S

900W RMS Class D R Series 6 Channel Car Amplifier

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Alpine R-A90S

900W RMS Class D R Series 6 Channel Car Amplifier

• 75 watts x 4 channel + 150 watts x 2 channel @ 4 ohm
• 100 watts x 4 channel + 250 watts x 2 channel @ 2 ohm
• Bridged: 200 watts x 2 channel @ 4 ohm + 500 watts x 1 channel @ 4 ohm
• Total RMS Power: 900 watts
• Class D 2 ohm Stable 6-Channel Amplifier

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AudioControl EPICBIGFOUR

1400W RMS Class D Epic Series 4-Channel Car Amplifier

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AudioControl EPICBIGFOUR

1400W RMS Class D Epic Series 4-Channel Car Amplifier

• 200 watts x 4 channel @ 4 ohm
• 350 watts x 4 channel @ 2 ohm
• Bridged: 650 watts x 2 channel @ 4 ohm
• Total RMS Power: 1400 watts
• Class D 2 ohm Stable 4-Channel Amplifier

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$239.00

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JL Audio RD900/5

900W RMS Class D RD Series 5 Channel Car Amplifier

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JL Audio RD900/5

900W RMS Class D RD Series 5 Channel Car Amplifier

• 70 watts x 4 channel + 225 watts x 1 channel @ 4 ohm
• 100 watts x 4 channel + 500 watts x 1 channel @ 2 ohm
• Bridged: 200 watts x 2 channel @ 4 ohm + 500 watts x 1 channel @ 2 ohm
• Total RMS Power: 900 watts
• Class D 2 ohm Stable 5-Channel Amplifier

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Alpine R2-A60F

600W RMS Class D R-Series 4 Channel Car Amplifier

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Alpine R2-A60F

600W RMS Class D R-Series 4 Channel Car Amplifier

• 100 watts x 4 channel @ 4 ohm
• 150 watts x 4 channel @ 2 ohm
• Bridged: 300 watts x 2 channel @ 4 ohm
• Total RMS Power: 600 watts
• Class D 2 ohm Stable 4-Channel Amplifier

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-17% $539.95

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Kenwood KAC-M5024BT

600W Peak (300W RMS) Class D M Series 4-Channel Marine and Powersports Amplifier with Bluetooth

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Kenwood KAC-M5024BT

600W Peak (300W RMS) Class D M Series 4-Channel Marine and Powersports Amplifier with Bluetooth

• 50 watts x 4 channel @ 4 ohm
• 75 watts x 4 channel @ 2 ohm
• Bridged: 150 watts x 2 channel @ 4 ohm
• Total RMS Power: 300 watts
• Class D 2 ohm Stable 4-Channel Amplifier

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Alpine OPTIM8 PXE-C80-88

900W RMS Class D PXE Series 8 Channel Car Amplifier with Automatic Sound Tuning

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Alpine OPTIM8 PXE-C80-88

900W RMS Class D PXE Series 8 Channel Car Amplifier with Automatic Sound Tuning

• 50 watts x 6 channel + 150 watts x 2 channel @ 4 ohm
• 50 watts x 6 channel + 300 watts x 2 channel @ 2 ohm
• Total RMS Power: 900 watts
• Class D 4 ohm Stable 8-Channel Amplifier

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• 50 watts x 6 channel + 150 watts x 2 channel @ 4 ohm
• 50 watts x 6 channel + 300 watts x 2 channel @ 2 ohm
• Total RMS Power: 900 watts
• Class D 4 ohm Stable 8-Channel Amplifier

Pioneer GM-DX975

2000W Peak (1000W RMS) Class D GM Series 5 Channel Car Amplifier with Bass Remote

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Pioneer GM-DX975

2000W Peak (1000W RMS) Class D GM Series 5 Channel Car Amplifier with Bass Remote

• 75 watts x 4 channel + 350 watts x 1 channel @ 4 ohm
• 100 watts x 4 channel + 600 watts x 1 channel @ 2 ohm
• Bridged: 200 watts x 2 channel @ 4 ohm + 600 watts x 1 channel @ 2 ohm
• Total RMS Power: 1000 watts
• Class D 2 ohm Stable 5-Channel Amplifier

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JL Audio MX600/3

600W RMS Class D MX Series 3 Channel Marine and Powersports Amplifier

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JL Audio MX600/3

600W RMS Class D MX Series 3 Channel Marine and Powersports Amplifier

• 75 watts x 2 channel + 250 watts x 1 channel @ 4 ohm
• 100 watts x 2 channel + 400 watts x 1 channel @ 2 ohm
• Bridged: 200 watts x 1 channel @ 4 ohm + 400 watts x 1 channel @ 2 ohm
• Total RMS Power: 600 watts
• Class D 2 ohm Stable 3-Channel Amplifier

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• 75 watts x 2 channel + 250 watts x 1 channel @ 4 ohm
• 100 watts x 2 channel + 400 watts x 1 channel @ 2 ohm
• Bridged: 200 watts x 1 channel @ 4 ohm + 400 watts x 1 channel @ 2 ohm
• Total RMS Power: 600 watts
• Class D 2 ohm Stable 3-Channel Amplifier

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    FAQ for Multi-channel Amplifiers for Adding Speakers in 2004 A4

    Q: Can I upgrade or change the Multi-channel Amplifiers for Adding Speakers in 2004 Audi A4?

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