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2003 Harley Davidson FLSTSI Heritage Springer

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

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Amps for Adding Speakers for 2003 Harley Davidson FLSTSI Heritage Springer

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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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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Diamond Audio HXM800.2D with NVX 4 Gauge Amp Kit

800W RMS Motorsport Series Full-Range Class D 2-Channel Marine Amplifier

HXM8002D_XKIT42 big
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Diamond Audio HXM800.2D with NVX 4 Gauge Amp Kit

800W RMS Motorsport Series Full-Range Class D 2-Channel Marine Amplifier

• 300 watts x 2 channel @ 4 ohm
• 400 watts x 2 channel @ 2 ohm
• Bridged: 800 watts x 1 channel @ 4 ohm
• Total RMS Power: 800 watts
• Class D 2 ohm Stable 2-Channel-Channel Amplifier
• Includes Amplifier Wiring Kit

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• 300 watts x 2 channel @ 4 ohm
• 400 watts x 2 channel @ 2 ohm
• Bridged: 800 watts x 1 channel @ 4 ohm
• Total RMS Power: 800 watts
• Class D 2 ohm Stable 2-Channel-Channel Amplifier
• Includes Amplifier Wiring Kit

Belva BXA6404 (Open Box, Good)

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

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Belva BXA6404 (Open Box, Good)

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

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• 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

Lowest price in 30 days

Rockford Fosgate Punch P500X2 + NVX XLCA2 Line-Output-Converter + Amp Kit

500W RMS 2-Channel Amplifier (P500X.2) + NVX 2-Channel L.O.C + 4 Gauge Amp Kit

P500X2, XLCA2, BAK42 big
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Rockford Fosgate Punch P500X2 + NVX XLCA2 Line-Output-Converter + Amp Kit

500W RMS 2-Channel Amplifier (P500X.2) + NVX 2-Channel L.O.C + 4 Gauge Amp 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

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• 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

JL Audio RD400/4 (Open Box, Great)

400W RMS Class D RD Series 4 Channel Car Amplifier

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JL Audio RD400/4 (Open Box, Great)

400W RMS Class D RD Series 4 Channel Car Amplifier

• 75 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 D 2 ohm Stable 4-Channel Amplifier

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• 75 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 D 2 ohm Stable 4-Channel Amplifier

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MB Quart NA3-1000.5 (Open Box, Good)

Nautic Marine 1000 Watt 5 Channel Marine Amplifier with Bass Remote

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MB Quart NA3-1000.5 (Open Box, Good)

Nautic Marine 1000 Watt 5 Channel Marine Amplifier with Bass Remote

• 75 Watts Peak x 4 + 100 Watts x 1 @ 4 ohm
• 150 Watts Peak x 4 + 200 Watts x 1 @ 2 ohm
• Total Peak Power: 1000 Watts
• CEA-2006 Compliant
• NMMA Certified
• Audiophile Marine Standard
• LED system protection circuit diagnostics
• Class SQ & Class Q1

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List price $569.99
-43% $323.99
$291.59 with coupon | Price details

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• 75 Watts Peak x 4 + 100 Watts x 1 @ 4 ohm
• 150 Watts Peak x 4 + 200 Watts x 1 @ 2 ohm
• Total Peak Power: 1000 Watts
• CEA-2006 Compliant
• NMMA Certified
• Audiophile Marine Standard
• LED system protection circuit diagnostics
• Class SQ & Class Q1

NVX NBA201 (Like New (Open Box))

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

NBA201 big
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NVX NBA201 (Like New (Open Box))

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: 700 watts x 1 channel @ 4 ohm
• Total RMS Power: 700 watts
• CEA-2006 Compliant

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

NVX MVPA4 (Open Box, Great)

600W RMS Marine-V Series 4-Channel Class D Compact Marine/Powersports/Motorcycle Amplifier

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NVX MVPA4 (Open Box, Great)

600W RMS Marine-V Series 4-Channel Class D Compact Marine/Powersports/Motorcycle Amplifier

• 4-Channel Micro Class D Amplifier
• 100W x 4-Chan. @ 4 ohm
• 150W x 4-Chan. @ 2 ohm
• 3-Way System Protection
• 4/3/2/1 Channel Operation
• 8 Gauge Power and Ground Inputs

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-35% $249.99

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• 4-Channel Micro Class D Amplifier
• 100W x 4-Chan. @ 4 ohm
• 150W x 4-Chan. @ 2 ohm
• 3-Way System Protection
• 4/3/2/1 Channel Operation
• 8 Gauge Power and Ground Inputs

NVX VAD22008v2 (Open Box, Great)

2200W RMS Full Range Class D 8-Channel Car/Marine/Powersports Amplifier

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NVX VAD22008v2 (Open Box, Great)

2200W RMS Full Range Class D 8-Channel Car/Marine/Powersports Amplifier

• 150 watts x 6 channel + 250W x2 @ 4 ohm
• 225 watts x 6 channel + 400W x 2 @ 2 ohm
• Bridged: 450 watts x 3 channel + 850W x1 @ 4 ohm
• Total RMS Power: 2200 watts
• Class D 2 ohm Stable 8-Channel-Channel Amplifier

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List price $539.99
-17% $449.99

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• 150 watts x 6 channel + 250W x2 @ 4 ohm
• 225 watts x 6 channel + 400W x 2 @ 2 ohm
• Bridged: 450 watts x 3 channel + 850W x1 @ 4 ohm
• Total RMS Power: 2200 watts
• Class D 2 ohm Stable 8-Channel-Channel Amplifier

Lowest price in 30 days

Rockford Fosgate Punch P600X4 with Amplifier Wiring Kit

600W Punch Series 4-Channel Stereo Class AB Car Power Amplifier

P600X4, XKIT44 big
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Rockford Fosgate Punch P600X4 with Amplifier Wiring Kit

600W Punch Series 4-Channel Stereo Class AB Car Power Amplifier

• 75W x 4-Chan. @ 4 ohm
• 150W x 4-Chan. @ 2 ohm
• Built In NOMAD "Real Time" Analog Computer
• 4/3/2/1 Channel Operation
• 4 Gauge Power and Ground Inputs
• MESHA3 Reduces MOSFET Temperatures for Improved Durability

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• 75W x 4-Chan. @ 4 ohm
• 150W x 4-Chan. @ 2 ohm
• Built In NOMAD "Real Time" Analog Computer
• 4/3/2/1 Channel Operation
• 4 Gauge Power and Ground Inputs
• MESHA3 Reduces MOSFET Temperatures for Improved Durability

Alpine HDA-F60 with NVX 4 Gauge Amp Kit

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

HDA-F60, XKIT44 big
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Alpine HDA-F60 with NVX 4 Gauge Amp Kit

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

• 100 watts RMS x 4 at 4 ohm
• 150 watts RMS x 4 at 2 ohm
• 300 watts RMS x 2 bridged at 4 ohm
• Bridged: @ 4 ohm
• Total RMS Power: 150 watts
• Class D 2 ohm Stable 4-Channel-Channel Amplifier
• Includes Amplifier Wiring Kit

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• 100 watts RMS x 4 at 4 ohm
• 150 watts RMS x 4 at 2 ohm
• 300 watts RMS x 2 bridged at 4 ohm
• Bridged: @ 4 ohm
• Total RMS Power: 150 watts
• Class D 2 ohm Stable 4-Channel-Channel Amplifier
• Includes Amplifier Wiring Kit

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
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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

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• 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

Lowest price in 30 days

Rockford Fosgate Punch PBR300X2 + NVX XKIT82 8 Gauge Amp Wiring Kit

300 Watts Punch Series Boosted Rail Compact 2-Channel Amplifier

PBR300X2, XKIT82 big
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Rockford Fosgate Punch PBR300X2 + NVX XKIT82 8 Gauge Amp Wiring Kit

300 Watts Punch Series Boosted Rail Compact 2-Channel Amplifier

• RMS 100W x 2 @ 4 ohm, 150W x 2 @ 2 ohm, 300W x 1 @ 4 ohm Bridged
• Features Rockford Fosgate's Class-BR Topology
• CEA-2006 Compliant
• Ultra Compact Chassis
• Boosted Rail Design
• Dimensions: 6.75"L x 4.25"W x 1.53"H
• Includes NVX XKIT82 8 Gauge Amp Wiring Kit

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• RMS 100W x 2 @ 4 ohm, 150W x 2 @ 2 ohm, 300W x 1 @ 4 ohm Bridged
• Features Rockford Fosgate's Class-BR Topology
• CEA-2006 Compliant
• Ultra Compact Chassis
• Boosted Rail Design
• Dimensions: 6.75"L x 4.25"W x 1.53"H
• Includes NVX XKIT82 8 Gauge Amp Wiring Kit

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Infinity DSP6840 (DSP6840AM) (Like New (Open Box))

1000W Peak (480W RMS) Class D DSP Series 8 Channel Car Amplifier with Digital Signal Processing

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Infinity DSP6840 (DSP6840AM) (Like New (Open Box))

1000W Peak (480W RMS) Class D DSP Series 8 Channel Car Amplifier with Digital Signal Processing

• 40 watts x 8 channel @ 4 ohm
• 60 watts x 8 channel @ 2 ohm
• Total RMS Power: 480 watts
• Class D 2 ohm Stable 8-Channel Amplifier

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List price $539.95
-24% $412.21
$370.99 with coupon | Price details

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Crunch GP-1000.2 (Open Box, Great)

1000W Peak Class AB GP Series 2-Channel Full Range Car Amplifier

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Crunch GP-1000.2 (Open Box, Great)

1000W Peak Class AB GP Series 2-Channel Full Range Car Amplifier

• 250 watts x 2 channel @ 4 ohm
• 500 watts x 2 channel @ 2 ohm
• Bridged: 1000 watts x 1 channel @ 4 ohm
• Total Peak Power: 1000 watts
• Class A/B 2 ohm Stable 2-Channel Amplifier

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List price $89.99
-33% $59.99
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• 250 watts x 2 channel @ 4 ohm
• 500 watts x 2 channel @ 2 ohm
• Bridged: 1000 watts x 1 channel @ 4 ohm
• Total Peak Power: 1000 watts
• Class A/B 2 ohm Stable 2-Channel Amplifier

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NVX VADM2 Amplifier with Amplifier Wiring Kit

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

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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

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• 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

Belva BXA5002 (Open Box, Good)

500W Peak BX-Series Class A/B 2-Channel Car Audio Amplifier with Bass Remote

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Belva BXA5002 (Open Box, Good)

500W Peak BX-Series Class A/B 2-Channel Car Audio Amplifier with Bass Remote

• 125 watts x 2 channel @ 4 ohm
• 250 watts x 2 channel @ 2 ohm
• Bridged: 500 watts x 1 channel @ 4 ohm
• Total Peak Power: 500 watts
• Class A/B 2 ohm Stable 2-Channel-Channel

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-68% $59.99

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Cerwin Vega B54 with Belva 4 Gauge Amp Kit

1200W 4-Channel Bomber Series Class D Amplifier with 4 Gauge Amp Kit

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Cerwin Vega B54 with Belva 4 Gauge Amp Kit

1200W 4-Channel Bomber Series Class D Amplifier with 4 Gauge Amp Kit

• RMS: 80 Watts x 4 @ 4 ohm, 150 Watts x 4 @ 2 ohm, Bridged: 300 Watts x 2 @ 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 8.70" L x 1.40" H

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• RMS: 80 Watts x 4 @ 4 ohm, 150 Watts x 4 @ 2 ohm, Bridged: 300 Watts x 2 @ 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 8.70" L x 1.40" H

NVX NDA6004 with Amp Wiring Kit

1200W Peak (600W RMS) N-Series Class-D 4-Channel Amplifier + NVX XKIT44 4 Gauge 4-Channel Premium Amp Wiring Kit

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NVX NDA6004 with Amp Wiring Kit

1200W Peak (600W RMS) N-Series Class-D 4-Channel Amplifier + NVX XKIT44 4 Gauge 4-Channel Premium Amp Wiring Kit

• 100 watts x 4 channel @ 4 ohm
• 160 watts x 4 channel @ 2 ohm
• Bridged: 320 watts x 2 channel @ 4 ohm
• Total RMS Power: 600 watts
• Class D 2 ohm Stable 4-Channel-Channel Amplifier
• Includes 4 Gauge Amp Wiring Kit

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• 100 watts x 4 channel @ 4 ohm
• 160 watts x 4 channel @ 2 ohm
• Bridged: 320 watts x 2 channel @ 4 ohm
• Total RMS Power: 600 watts
• Class D 2 ohm Stable 4-Channel-Channel Amplifier
• Includes 4 Gauge Amp Wiring Kit

Diamond Audio MICRO4V2 with NVX 1/0 Gauge Amp Kit

600W Peak Series Class-D 4-Channel Compact Amplifier

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Diamond Audio MICRO4V2 with NVX 1/0 Gauge Amp Kit

600W Peak Series Class-D 4-Channel Compact Amplifier

• 80 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
• Includes Amplifier Wiring Kit

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-34% $399.99

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• 80 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
• Includes Amplifier Wiring Kit

Infinity Reference 3004A with NVX 8 Gauge Amp Kit

400W RMS Reference Series Class-H 4-Channel Amplifier

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Infinity Reference 3004A with NVX 8 Gauge Amp Kit

400W RMS Reference Series Class-H 4-Channel Amplifier

• 75 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 H 2 ohm Stable 4-Channel Amplifier
• Includes Amplifier Wiring Kit

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• 75 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 H 2 ohm Stable 4-Channel Amplifier
• Includes Amplifier Wiring Kit

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    FAQ for Multi-channel Amplifiers for Adding Speakers in 2003 FLSTSI Heritage Springer

    Q: Can I upgrade or change the Multi-channel Amplifiers for Adding Speakers in 2003 Harley Davidson FLSTSI Heritage Springer?

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

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