Garage
Shop
Account Icon
Account
Box Icon
Track
order
Telephone Icon
Call
Help Icon
Help
Door with Arrow Icon
Sign In

2004 Audi S4

Change vehicle | Remove vehicle

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 S4

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.

Filters
Amplifiers with a wiring kit ✕
Clear Filters
Reset Done
Product Type
Amplifiers with a wiring kit,
Price Range
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.
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.
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.
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.
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.

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.
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.
Deals
Promotions we have offer More Ways to Shop for items that are on clearance, last chance, special offer and sales, Made in America, and more!
Availability
filter-icon Filters & Sort

NVX NBA201 with Amplifier Wiring Kit

1400W Peak (700W) RMS N-Series Class A/B 2-Channel Amplifier

NBA201, BAK42BK big
Go to item page Right Arrow Icon of Right Arrow

NVX NBA201 with Amplifier Wiring Kit

1400W Peak (700W) RMS N-Series Class A/B 2-Channel Amplifier

• 200 watts x 2 channel @ 4 ohm
• 350 watts x 2 channel @ 2 ohm
• Bridged: 1400 watts x 1 channel @ 4 ohm
• Total RMS Power: 700 watts
• CEA-2006 Compliant
• Includes Amplifier Wiring Kit

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

74
List price $309.98
-60% $124.48

In stock

Only 2 Left!

Add to Cart

• 200 watts x 2 channel @ 4 ohm
• 350 watts x 2 channel @ 2 ohm
• Bridged: 1400 watts x 1 channel @ 4 ohm
• Total RMS Power: 700 watts
• CEA-2006 Compliant
• Includes Amplifier Wiring Kit

Lowest price in 30 days

NVX NBA201 Amplifier + NVX 4 Gauge Premium Amp Wiring Kit

700W Total RMS N-Series Class-AB 2-Channel Amplifier Package (Includes Amplifier and Amp Wiring kit)

NBA201, XKIT42 big
Go to item page Right Arrow Icon of Right Arrow

NVX NBA201 Amplifier + NVX 4 Gauge Premium Amp Wiring Kit

700W Total RMS N-Series Class-AB 2-Channel Amplifier Package (Includes Amplifier and Amp Wiring kit)

• 200 watts x 2 channel @ 4 ohm
• 350 watts x 2 channel @ 2 ohm
• Bridged: 1400 watts x 1 channel @ 4 ohm
• Total RMS Power: 700 watts
• CEA-2006 Compliant

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

132
List price $400.97
-55% $179.07

In stock

Only 2 Left!

Add to Cart

• 200 watts x 2 channel @ 4 ohm
• 350 watts x 2 channel @ 2 ohm
• Bridged: 1400 watts x 1 channel @ 4 ohm
• Total RMS Power: 700 watts
• CEA-2006 Compliant

Alpine HDA-V90 with NVX 4 Gauge Amp Kit

900W RMS Status Series Class-D 5-Channel Car Amplifier

HDA-V90, XKIT46 big
Go to item page Right Arrow Icon of Right Arrow

Alpine HDA-V90 with NVX 4 Gauge Amp Kit

900W RMS Status Series Class-D 5-Channel Car Amplifier

• 75 watts RMS x 4 + 300 watts RMS x 1 at 4 ohm
• 100 watts RMS x 4 + 500 watts RMS x 1 at 2 ohm
• 200 watts RMS x 2 bridged at 4 ohm + 500 watts RMS x 1 at 2 ohm
• Total RMS Power: 900 watts
• Quick-connect power and speaker connectors
• Class D 2 ohm Stable 5-Channel Amplifier
• Includes Amplifier Wiring Kit

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

45
List price $1499.99
-27% $1,099.95

In stock

Only 1 Left!

Add to Cart

• 75 watts RMS x 4 + 300 watts RMS x 1 at 4 ohm
• 100 watts RMS x 4 + 500 watts RMS x 1 at 2 ohm
• 200 watts RMS x 2 bridged at 4 ohm + 500 watts RMS x 1 at 2 ohm
• Total RMS Power: 900 watts
• Quick-connect power and speaker connectors
• Class D 2 ohm Stable 5-Channel Amplifier
• Includes Amplifier Wiring Kit

Rockford Fosgate Power T1000-4AD with Amplifier Wiring Kit

1000W 4-Channel Class AD Power Series Constant Power Amplifier

T1000-4AD, XKIT44 big
Go to item page Right Arrow Icon of Right Arrow

Rockford Fosgate Power T1000-4AD with Amplifier Wiring Kit

1000W 4-Channel Class AD Power Series Constant Power Amplifier

• 1000W RMS
• 250W x 4-Chan @ 4 Ohm
• NOMAD Real Time Computer Protection
• 50-500 Hz LP/AP/HP Crossovers
• Constant Power

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

93
List price $1255.98
-12% $1,099.99

In stock

Only 1 Left!

Add to Cart

• 1000W RMS
• 250W x 4-Chan @ 4 Ohm
• NOMAD Real Time Computer Protection
• 50-500 Hz LP/AP/HP Crossovers
• Constant Power

DS18 SXE-1200.4/BK (Black) with Belva 4 Gauge Amp Kit

1200W Peak (400W RMS) Class AB SXE Series 4-channel Car Amplifier

SXE12004BK_BAK44 big
Go to item page Right Arrow Icon of Right Arrow

DS18 SXE-1200.4/BK (Black) with Belva 4 Gauge Amp Kit

1200W Peak (400W RMS) Class AB SXE 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-Channel Amplifier (Black)
• Includes Amplifier Wiring Kit

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

62
List price $235.94
-19% $190.94

In stock

Only 2 Left!

Add to Cart

• 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-Channel Amplifier (Black)
• Includes Amplifier Wiring Kit

Hertz HCP 4M with Free Premium NVX 4 Gauge Amp Kit

Class-D 4-Channel 2 Ohms Marine Stereo Amplifier

HCP4M, XKIT44 big
Go to item page Right Arrow Icon of Right Arrow

Hertz HCP 4M with Free Premium NVX 4 Gauge Amp Kit

Class-D 4-Channel 2 Ohms Marine Stereo Amplifier

• 65 Watts RMS x 4 @ 4 ohm
• 95 Watts RMS x 4 @ 2 ohm
• CEA-2006 Compliant/Preamp Outputs/LPF
• Corrosion Protection
• Water jet tested
• Dimensions: 12.40" x 7.48" x 1.97"

Save 15% Off Package Deals at Checkout!
shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

80
List price $625.99
-18% $514.16

In stock

Only 1 Left!

Add to Cart

• 65 Watts RMS x 4 @ 4 ohm
• 95 Watts RMS x 4 @ 2 ohm
• CEA-2006 Compliant/Preamp Outputs/LPF
• Corrosion Protection
• Water jet tested
• Dimensions: 12.40" x 7.48" x 1.97"

Limited time!

NVX VADM2 Amplifier with Amplifier Wiring Kit

440W RMS Full Range Class D 2-Channel Car/Marine/Powersports Amplifier

VADM2, BKA82 big
Go to item page Right Arrow Icon of Right Arrow

NVX VADM2 Amplifier with Amplifier Wiring Kit

440W RMS Full Range Class D 2-Channel Car/Marine/Powersports Amplifier

• 440 Watt True RMS Output!
• Marine Certified 2-Channel Micro Class D Amplifier
• 150W x 2-Chan. @ 4 ohm
• 220W x 2-Chan. @ 2 ohm
• 440W x 1-Chan. @ 4 ohm
• 3-Way System Protection
• 8 Gauge Power and Ground Inputs
• Extremely Small Footprint

Dads & Grads Sale! Save 15% at Checkout!
shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

77
List price $335.98
-30% $236.77

In stock

Add to Cart

• 440 Watt True RMS Output!
• Marine Certified 2-Channel Micro Class D Amplifier
• 150W x 2-Chan. @ 4 ohm
• 220W x 2-Chan. @ 2 ohm
• 440W x 1-Chan. @ 4 ohm
• 3-Way System Protection
• 8 Gauge Power and Ground Inputs
• Extremely Small Footprint

Kenwood KAC-D8105 with NVX 4 Gauge Amp Kit

1600 Watts Max Power 5-Channel Class D Amplifier

KACD8105_XKIT46 big
Go to item page Right Arrow Icon of Right Arrow

Kenwood KAC-D8105 with NVX 4 Gauge Amp Kit

1600 Watts Max Power 5-Channel Class D Amplifier

• Kenwood KAC-D8105 5 Channel Amplifier
• Peak Power: 1600 watts
• 50 watts RMS x 4 + 300 watts at 4 Ohm
• 75 watts x4 + 500 watts at 2 Ohm
• Dimensions: 9"W x 2-3/16"H x 7-3/8"D

• Includes Amplifier Wiring Kit

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

46
List price $699.99
-27% $511.64

In stock

Only 1 Left!

Add to Cart

• Kenwood KAC-D8105 5 Channel Amplifier
• Peak Power: 1600 watts
• 50 watts RMS x 4 + 300 watts at 4 Ohm
• 75 watts x4 + 500 watts at 2 Ohm
• Dimensions: 9"W x 2-3/16"H x 7-3/8"D

• Includes Amplifier Wiring Kit

Kicker 46CXA6605 with Amplifier Wiring Kit

360W RMS CX-Series Class-D 5-Channel Amplifier

BAK42BK,46CXA6605T big
Go to item page Right Arrow Icon of Right Arrow

Kicker 46CXA6605 with Amplifier Wiring Kit

360W RMS CX-Series Class-D 5-Channel Amplifier

• 75 Watts RMS x 4 @ 2 ohm
• 2 ohm: 300 watts x 1 chan. Subwoofer Channel
• Total Peak Power: 600 Watts
• Preamp RCA outputs to daisy chain multiple amps
• Variable Low/High-Pass Crossover: 50 - 200Hz 12dB/octave
• Variable Bass Boost: 0 to +12 dB bass boost at 40 Hz
• Includes Amplifier Wiring Kit

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

28
List price $559.98
-20% $449.99

In stock

Add to Cart

• 75 Watts RMS x 4 @ 2 ohm
• 2 ohm: 300 watts x 1 chan. Subwoofer Channel
• Total Peak Power: 600 Watts
• Preamp RCA outputs to daisy chain multiple amps
• Variable Low/High-Pass Crossover: 50 - 200Hz 12dB/octave
• Variable Bass Boost: 0 to +12 dB bass boost at 40 Hz
• Includes Amplifier Wiring Kit

Rockford Fosgate Punch PM600X4 + NVX XKIT44

600W 4-Channel Punch Series Class AB Marine Amplifier + NVX 4 Gauge 4-Channel Amp Kit

PM600X4, XKIT44 big
Go to item page Right Arrow Icon of Right Arrow

Rockford Fosgate Punch PM600X4 + NVX XKIT44

600W 4-Channel Punch Series Class AB Marine Amplifier + NVX 4 Gauge 4-Channel Amp Kit

• RMS: 75W x 4 @ 4 ohm, 150W x 4 @ 2 ohm, Bridged 300W x 2 @ 4ohm
• CEA-2006 Compliant
• Features C.L.E.A.N. Set-up
• Protected against Dust, UV, & Corrosion
• Marine grade two part epoxy coating on circuit boards

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

80
List price $805.98
-12% $705.45

In stock

Add to Cart

• RMS: 75W x 4 @ 4 ohm, 150W x 4 @ 2 ohm, Bridged 300W x 2 @ 4ohm
• CEA-2006 Compliant
• Features C.L.E.A.N. Set-up
• Protected against Dust, UV, & Corrosion
• Marine grade two part epoxy coating on circuit boards

Cerwin Vega B52 with Belva 4 Gauge Amp Kit

1000W Peak Bomber Series 2-Channel Class D Amplifier

B52, BAK42 big
Go to item page Right Arrow Icon of Right Arrow

Cerwin Vega B52 with Belva 4 Gauge Amp Kit

1000W Peak Bomber Series 2-Channel Class D Amplifier

• RMS: 200 Watts x 2 @ 4 ohm, 250 Watts x 2 @ 2 ohm, Bridged: 500 Watts x 1 @ 4 ohm
• Total Peak Power: 1000 Watts
• Class D IR Chipset with DirectFET Power Mosfet Output
• Wired remote bass level control included
• Ultra Compact High-Density Aluminum Alloy Chassis
• Dimensions: 4.02" W x 6.61" L x 1.40" H

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

170
List price $455.98
-28% $329.99

In stock

Add to Cart

• RMS: 200 Watts x 2 @ 4 ohm, 250 Watts x 2 @ 2 ohm, Bridged: 500 Watts x 1 @ 4 ohm
• Total Peak Power: 1000 Watts
• Class D IR Chipset with DirectFET Power Mosfet Output
• Wired remote bass level control included
• Ultra Compact High-Density Aluminum Alloy Chassis
• Dimensions: 4.02" W x 6.61" L x 1.40" H

DS18 SXE-3000.4D/RD with Amplifier Wiring Kit

1000W RMS SXE Series Class-D 4-Channel Amplifier

SXE-3000.4D/RD, BAK44 big
Go to item page Right Arrow Icon of Right Arrow

DS18 SXE-3000.4D/RD with Amplifier Wiring Kit

1000W RMS SXE Series Class-D 4-Channel Amplifier

• 200 watts x 4 channel @ 4 ohm
• 320 watts x 4 channel @ 2 ohm
• Bridged: 500 watts x 2 channel @ 4 ohm
• Total RMS Power: 1000 watts
• Class D 2 ohm Stable 4-Channel-Channel Amplifier
• Includes Amplifier Wiring Kit

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

63
List price $367.94
-12% $322.94

In stock

Only 3 Left!

Add to Cart

• 200 watts x 4 channel @ 4 ohm
• 320 watts x 4 channel @ 2 ohm
• Bridged: 500 watts x 2 channel @ 4 ohm
• Total RMS Power: 1000 watts
• Class D 2 ohm Stable 4-Channel-Channel Amplifier
• Includes Amplifier Wiring Kit

Lowest price in 30 days

Rockford Fosgate P500X2 with Amplifier Wiring Kit

500W RMS 2-Channel Amplifier (P500X.2) with NVX 8 Gauge Amplifier Wiring Kit

P500X2, XKIT82 big
Go to item page Right Arrow Icon of Right Arrow

Rockford Fosgate P500X2 with Amplifier Wiring Kit

500W RMS 2-Channel Amplifier (P500X.2) with NVX 8 Gauge Amplifier Wiring Kit

• 150W x 2 Chan. @ 4 ohm
• 250W x 2 Chan. @ 2 ohm
• Built In NOMAD "Real Time" Analog Computer
• 2/1 Channel Operation
• 4 Gauge Power and Ground Inputs
• MESHA3 Reduces MOSFET Temperatures for Improved Durability

Save 15% Off Package Deals at Checkout!
shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

62
List price $525.98
-18% $429.98

In stock

Only 3 Left!

Add to Cart

• 150W x 2 Chan. @ 4 ohm
• 250W x 2 Chan. @ 2 ohm
• Built In NOMAD "Real Time" Analog Computer
• 2/1 Channel Operation
• 4 Gauge Power and Ground Inputs
• MESHA3 Reduces MOSFET Temperatures for Improved Durability

Rockford Fosgate Power TM400X4ad with Amplifier Wiring Kit

400W Power Series Class-AD Marine 4-Channel Amplifier

TM400X4ad, XKIT84 big
Go to item page Right Arrow Icon of Right Arrow

Rockford Fosgate Power TM400X4ad with Amplifier Wiring Kit

400W Power Series Class-AD Marine 4-Channel Amplifier

• RMS: 100 watts x 4 chan. @ 4 ohm, 100 watts x 4 chan. @ 2 ohm, 200 watts x 2 chan. @ 4 ohm Bridged
• CEA-2006 Compliant Amplifier
• Rockford Fosgate 4/2 Ohm muti-impedance Constant Power technology
•Differential inputs with high level auto turn-on feature
• C.L.E.A.N. input/output clip detection and indicator LEDs
• 4-layer 2oz. copper circuit board with 2-part epoxy coating

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

43
List price $737.98
-6% $694.99

In stock

Add to Cart

• RMS: 100 watts x 4 chan. @ 4 ohm, 100 watts x 4 chan. @ 2 ohm, 200 watts x 2 chan. @ 4 ohm Bridged
• CEA-2006 Compliant Amplifier
• Rockford Fosgate 4/2 Ohm muti-impedance Constant Power technology
•Differential inputs with high level auto turn-on feature
• C.L.E.A.N. input/output clip detection and indicator LEDs
• 4-layer 2oz. copper circuit board with 2-part epoxy coating

MB Quart RA1-150.2 with Belva 4 Gauge Amp Kit

100W RMS 2-Channel Reference Series Full Range Class D Car Amplifier

RA11502_BAK42 big
Go to item page Right Arrow Icon of Right Arrow

MB Quart RA1-150.2 with Belva 4 Gauge Amp Kit

100W RMS 2-Channel Reference Series Full Range Class D Car Amplifier

• 50 watts x 2 channel @ 4 ohm
• 100 watts x 2 channel @ 2 ohm
• Bridged: 200 watts x 1 channel @ 4 ohm
• Total RMS Power:
• Class D 2 ohm Stable 2-Channel-Channel Amplifier
• Includes Amplifier Wiring Kit

Save 15% Off Package Deals at Checkout!
shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

169
List price $322.49
-10% $288.74

In stock

Only 1 Left!

Add to Cart

• 50 watts x 2 channel @ 4 ohm
• 100 watts x 2 channel @ 2 ohm
• Bridged: 200 watts x 1 channel @ 4 ohm
• Total RMS Power:
• Class D 2 ohm Stable 2-Channel-Channel Amplifier
• Includes Amplifier Wiring Kit

Alpine KTP-445A with NVX 8 Gauge Amp Kit

180W RMS Power Pack Series Class D 4-Channel Compact Amplifier

KTP445A_XKIT84 big
Go to item page Right Arrow Icon of Right Arrow

Alpine KTP-445A with NVX 8 Gauge Amp Kit

180W RMS Power Pack Series Class D 4-Channel Compact Amplifier

• 45 watts x 4 channel @ 4 ohm
• 100 watts x 4 channel @ 2 ohm
• Total RMS Power: 180 watts
• Class D 2 ohm Stable 4-Channel-Channel Amplifier
• Includes Amplifier Wiring Kit

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

49
List price $507.99
-25% $380.31

In stock

Add to Cart

• 45 watts x 4 channel @ 4 ohm
• 100 watts x 4 channel @ 2 ohm
• Total RMS Power: 180 watts
• Class D 2 ohm Stable 4-Channel-Channel Amplifier
• Includes Amplifier Wiring Kit

JVC KS-DR2104DBT with NVX 8 Gauge Amp Kit

600W Peak (200W RMS) DRVN Series Class-D 4-Channel Amplifier with Bluetooth Remote

KSDR2104DBT_XKIT84 big
Go to item page Right Arrow Icon of Right Arrow

JVC KS-DR2104DBT with NVX 8 Gauge Amp Kit

600W Peak (200W RMS) DRVN Series Class-D 4-Channel Amplifier with Bluetooth Remote

• 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-Channel Amplifier
• Includes Amplifier Wiring Kit

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

40
List price $546.79
-27% $399.00

In stock

Add to Cart

• 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-Channel Amplifier
• Includes Amplifier Wiring Kit

Pioneer GM-DX874 with NVX 4 Gauge Amp Kit

1200W Peak (600W RMS) GM Series Class-FD 4-Channel Amplifier with Remote Bass Knob

GMDX874_XKIT44 big
Go to item page Right Arrow Icon of Right Arrow

Pioneer GM-DX874 with NVX 4 Gauge Amp Kit

1200W Peak (600W RMS) GM Series Class-FD 4-Channel Amplifier with Remote Bass Knob

• 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 1 ohm Stable 4-Channel Amplifier
• Includes Amplifier Wiring Kit

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

94
List price $455.99
-38% $284.99

In stock

Add to Cart

• 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 1 ohm Stable 4-Channel Amplifier
• Includes Amplifier Wiring Kit

Infinity Reference 7005A (AMPRF7005AAM) + Free NVX Premium Amp Kit

Reference Series High Performance Class AB+D 5-Channel Amplifier + XKIT46

AMPRF7005AAM, XKIT46 big
Go to item page Right Arrow Icon of Right Arrow

Infinity Reference 7005A (AMPRF7005AAM) + Free NVX Premium Amp Kit

Reference Series High Performance Class AB+D 5-Channel Amplifier + XKIT46

• 5-Channel Amplifier
• Phase Switch on Sub Channel
• Full Board Protection
• Variable High and Low Pass Filter
• Class AB + D Technology

shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

47
List price $709.94
-31% $489.95

Available

Ships in 10-14 days

Add to Cart

• 5-Channel Amplifier
• Phase Switch on Sub Channel
• Full Board Protection
• Variable High and Low Pass Filter
• Class AB + D Technology

Crunch DR-1325.4D with Belva 4 Gauge Amp Kit

1325W Peak Class D V-Drive Series 4-Channel Full Range Car Amplifier

DR13254D_BAK44 big
Go to item page Right Arrow Icon of Right Arrow

Crunch DR-1325.4D with Belva 4 Gauge Amp Kit

1325W Peak Class D V-Drive Series 4-Channel Full Range Car Amplifier

• 165 watts x 4 channel @ 4 ohm
• 330 watts x 4 channel @ 2 ohm
• Bridged: 660 watts x 2 channel @ 4 ohm
• Total peak power output: 1325 watts
• Class D 2 ohm Stable 4-Channel-Channel Amplifier
• Includes Amplifier Wiring Kit

Save 15% Off Package Deals at Checkout!
shipping truck icon Free shipping in USA. Provide zip for delivery date.

Universal Icon Universal – fits most vehicles.

Shop similar products or Update vehicle

61
List price $216.98
-25% $163.49

In stock

Add to Cart

• 165 watts x 4 channel @ 4 ohm
• 330 watts x 4 channel @ 2 ohm
• Bridged: 660 watts x 2 channel @ 4 ohm
• Total peak power output: 1325 watts
• Class D 2 ohm Stable 4-Channel-Channel Amplifier
• Includes Amplifier Wiring Kit

Prev 2 3 4 5 6 Next

Items per page: 20 40 60

    Clear all
    why-shoping-with-sonic

    We love people and we're ready to help you! See what separates us from our competition.

    Take advantage of our VIP rewards like 10% back on your purchases, free 2-day shipping, extended warranties, and free returns! Gain access to all of these rewards without any membership fees.
    Get great discounted (and possibly FREE) installation accessories with most car stereo purchases. This includes dash kits, wiring harnesses and antenna adapters that you will need to properly install your new car stereo.
    We are an Authorized Dealer for all the brands we sell, including the most premium brands in car and marine audio such as Hertz, JL Audio, NVX, Rockford Fosgate, Kicker, Alpine, Kenwood and many more.
    Shop Deals and get up to 30% off premium brands! Shop Now! We are always looking out for the best products and deals to offer our customers. Don’t pay too much by shopping elsewhere!
    We have information on brands, gear, and more for you to explore! Check out our YouTube Channel for helpful how-to videos, product reviews, and Q&As. For a more detailed look, also visit our Learning Center!
    Our trained experts are here to assist you! They are just a phone call or click away to help you get the right gear for you and your vehicle!
    Why Shop With Us?
    FAQ for Multi-channel Amplifiers for Adding Speakers in 2004 S4

    Q: Can I upgrade or change the Multi-channel Amplifiers for Adding Speakers in 2004 Audi S4?

    A: Yes this page includes all the best Multi-channel Amplifiers for Adding Speakers that work in your S4.

    Save up to 10 different vehicles in your garage
    Vehicle
    Store     Delete

    2004 Audi S4

    Add vehicle Clear all vehicles
    Where to find vehicle info
    Are you sure you want to clear your garage?
    This action cannot be undone. Confirm

    Cancel

    This category was not designed for products.
    If you continue, you will be redirected to a category customized for your vehicle. Continue

    Cancel

    Shop your 2004 S4
    Why Use a Vehicle Fit Guide?
    Change vehicle | Shop without vehicle
    Whoa! Slow down. Add your details below!
    additional information required
    Add vehicle details to confirm fitment
    Ignore fitment details
    Find stereos and more that work -- fast.

    Additional information:

    Remove

    Can't find your vehicle? Click here and we'll help.

    Where to find vehicle info

    Go to Fitment

    Didn't find your car?

    Submit your details and we'll help!
    Please enter the letters as they are shown in the image above. Letters are not case-sensitive.
    Identify your vehicle and submodel details
    • Owner's manual
    • Vehicle's insurance card
    • Vehicle registration
    • Vehicle produced after 2005: Inside driver's side door
    • Vehicle produced before 2005: Rear passenger doorjamb, glove box, center console, or engine compartment
    Car Info Side Door Icon
    Vehicle Registration Icon
    Vehicle Insurance Icon
    Back

    Modern vehicles often require specific brackets, wiring harnesses, and mounting solutions. A fit guide ensures:

    • You see only parts engineered for your exact vehicle
    • You avoid incompatible radios, speakers, or wiring
    • Installation is smoother, faster, and frustration-free
    • You get the correct accessories the first time

    Whether you're replacing a factory stereo or upgrading your entire audio system, the Fit Finder eliminates uncertainty.

    Back
    Track your order
    Call our experts
    Support Center
    Return & Exchanges
    Follow on Instagram Instagram logo
    Subscribe on YouTube YouTube logo