Introduction

The PowerBass PowerSport MX Amplifier XL-4255MX is a robust audio amplifier designed specifically for outdoor and off-road applications. This high-efficiency Class D amplifier delivers up to 900 watts of peak power, ensuring that your sound system performs at its best in challenging environments. Featuring a compact design, it includes adjustable settings for optimal sound tuning and is built to withstand the rigors of outdoor use. The cost of the XL-4255MX is approximately $249.99.

SPECIFICATIONS

REQUIRES EXTERNAL FUSE!

Important Notes:

• Due to continuing improvements these specifications are subject to change without any notice.
• Do not attempt to fix or repair this unit. Unauthorized repairs will void the manufacturer’s warranty.

TECHNICAL FEATURES

• IPX 67 Water Resistant Sealed Design
• Aluminum Diecast End Caps with Integrated Input/Output Connections
• FRD (Full Range Class-D) Multi-Channel Technology
• International Rectifier Chip Set
• Conformal Coated PC Board to Resist Moisture, Dust and Extreme Heat
• AUX Input Accepts MP3, iPod or Portable Source Device
• Wrap-around Aluminum Heatsink Shell
• Ultra Low Current Draw
• High Damping Control Circuit
• High Efficiency SMD Circuit Technology
• 4-Layer Copper Plated PCB
• Digital Sound Optimization Circuitry
• Quiet Switching
• Bass EQ Circuitry Centered at 45Hz (+/- 18dB)
• High Current Voltage Ripple Rejection Circuitry
• Virtual Silence Turn On/Off Mute Circuit
• Advanced Protection Circuitry
• Low-Level RCA and High-Level Speaker Inputs
• Wired Remote Level Control (XL-2305M)
• AUX Output (3.5mm)

*iPod is a registered trademark of Apple

FRD-FULL RANGE CLASS D TECHNOLOGY

This amplifier represents the very latest in Class D technology. The XL Series uses the new IR (International Rectifier) platform which has been under development for the past several years. IR®, a leader in PWM circuit design, has worked in conjunction with PowerBass engineers to produce more stable power output, minimal RF interference and improved sound quality.

The benefits of this cooperative effort are many and include improved temperature, frequency, voltage regulation and drive capability to name a few.

The PC board features a conformal coating that resists moisture, dust and extreme heat. Combine that plus their small size and these amplifiers are perfect for many Powersport applications including UTV, golf cart and motorcycle and Watersport vessels.

The result to the user is a all around improved product that will provide years of listening enjoyment.

Description

The PowerBass PowerSport MX Amplifier XL-4255MX is designed with the user in mind, offering a compact and lightweight design that makes it easy to install in various powersport vehicles. The amplifier features a sleek and rugged exterior that not only looks good but also withstands the elements. Inside, it boasts high-quality components that ensure clear and powerful sound output. The XL-4255MX supports a wide range of input sources and comes with adjustable crossover settings, allowing for precise tuning to match your audio system.

The amplifier’s durability is further enhanced by its aluminum heat sink, which efficiently dissipates heat to prevent overheating. This makes it reliable for continuous use in demanding environments. With its versatile mounting options and comprehensive wiring kit, the installation process is simplified, making it accessible to both DIY enthusiasts and professional installers.

INSTALLATION EXPERIENCE

Installation of PowerBass mobile amplifiers requires detailed knowledge of electronics wiring and proper speaker impedance. We strongly recommend installation by an authorized PowerBass dealer. This Owners Manual only provides general installation and operation instructions. If you have any reservations about your installation skills, please contact your local PowerBass dealer for assistance.

IMPORTANT: This amplifier is designed for operation in vehicles with 12-volt Negative ground electrical systems only.

PREPARING FOR INSTALLATION

NOTE: The tools listed below may be required for basic installation

• An electric drill with bits
• Philips head and standard screwdrivers
• Wire strippers
• Crimping tool
• VOM (electronic volt ohm meter)
• Heat shrink tubing and heat gun
• Soldering iron
• Electronic (Rosen not Acid Core) Solder

INSTALLATION PRECAUTIONS

NOTE: Proceed only if you are a qualified installer, otherwise; see your Authorized PowerBass Dealer to professionally install this amplifier. Always wear protective eyewear when using tools.

• Turn off all stereo and other electrical devices before you begin.
• Disconnect the negative (-) lead from your vehicles battery.
• Locate all fuel lines, brake lines, oil lines, and electrical cables when planning the install.
• Make sure there is at least 2-inches (5 cm) around the air vents on the amplifier.
• When connecting ground points, make sure all paint is carefully scrapped away from the auto body and contact is made with bare metal.
• Use a utility knife to trim away fabric from hole locations before drilling or cutting.
• When running power cables through sheet metal, be sure to use grommets to properly insulate the metal edges from the wire insulation.
• If possible, use tubing through grommets.

WARNING: Check your vehicle’s owner’s manual before disconnecting the battery. Disconnecting the battery on some vehicles may require an anti-theft code when reconnecting the battery and require the on-board computer to be reset at the dealership. Check with your local dealer if you are uncertain.

MOUNTING THE AMPLIFIER

To keep your PowerBass Xtreme amplifier running at top performance, choosing the proper location is of utmost importance. Both Thermal and Overload protection are built in.

In the event of overheating, the amplifier will turn off and only restart when cooled. For this reason the amplifier should be mounted in a location which will allow air to circulate freely. The compact size of the PowerBass XL Series amplifier allows greater flexibility in mounting.

MOUNTING LOCATION

The XL Series amplifiers are IPX67 rated and feature a conformal coating applied to the PC board. This coating makes them resistant to water, dust, and quick submersion. Care should still be taken to protect the amplifier from water and find a mounting location that is not likely to get wet. Take care not to mount in a vehicle/vessel where it can cause interference with the factory installed electronic devices.

The unique wrap around outer shell (heatsink) allows the XL Series amplifiers to be mounted in spaces with minimal air flow. It is important that whatever location is selected the amplifier must be mounted securely in a manner keeps the unit intact even during rough jolts that can occur to the vehicle/vessel.

You may use the amplifier as a template and mark the four screw locations with a felt tip pen. Set the amplifier aside before drilling. Use caution to make sure there are no objects behind the installation surface that may become damaged during drilling.

If mounting under a seat, make sure there is at least 1-inch (2.5 cm) of space above the amplifier’s heatsink to permit proper cooling.

The best places to mount your amplifier are: The floor of the trunk, under a seat, on the back of the rear seat or a storage compartment will air can circulate. For alternate installation locations, please consult your authorized PowerBass Dealer.

NOTE: Do not use a drill with driver bit to mount the amplifier. Excessive force could cause the mounting feet to crack.

WARNING

• Do not install in a place where it could injure the driver or passengers if the vehicle stops suddenly.
• Try to avoid mounting the amplifier on a subwoofer enclosure, as extended exposure to vibration may cause malfunction of the amplifier.
• Don’t mount the amplifier so that the wire connections are unprotected or are sub-ject to pinching or damage from nearby objects.
• The DC power wire must be fused at the battery positive (+) terminal connection. Before making or breaking power connections at the amplifier power terminals, disconnect the DC power wire at the battery end.
• The battery of the car audio system must be disconnected until the entire wiring and installation is completed.

XL-4255MX CONTROL PANEL LAYOUT

NOTE: Panel Layout and Controls may differ by model.

1. POWER/STATUS Indicator
   This clear LED lights Blue when the power is on—or turns Red constantly when the built-in protection circuitry is activated. Red indicates a problem with the system in relation to the amplifier (See Troubleshooting Tips).
2. LOW LEVEL INPUTS/OUTPUTS (from left to right)
   1. FRONT Low Level RCA Inputs
      Low Level RCA input that connects to source units with RCA line level outputs. A source unit with a minimum input of 250mV is required for proper operation. However, this input can accept levels up to 10Vrms.
   2. AUX Input Jack
      This 1/8-inch (3.5mm) mini jack can be used to accept an MP3, iPOD or smartphone as the source unit from that devices headphone (3.5mm) output. When using AUX input, the amplifier must be in 2CH mode.
3. FRONT HPF
   This control is continuously adjustable from 40Hz to 400Hz at 12dB per octave).
4. FRONT GAIN Control
   This control is used to match the input sensitivity of the amplifier to the particular source unit that you are using up to 250mV to 10 volts.
5. LOW LEVEL INPUTS/OUTPUTS (from left to right) 
   1. AUX Output Jack
      This 1/8-inch (3.5mm) mini jack can be used to connect to multiple MX Series Amplifiers.
   2. REAR Low Level RCA Inputs
      Low Level RCA input that connects to source units with RCA line level outputs. A source unit with a minimum input of 250mV is required for proper operation. However, this input can accept levels up to 10Vrms.
6. REAR BASS EQ Control
   This equalization circuit is used to enhance the low frequency response of the vehicle’s interior. With up to 18dB of boost centered at 45Hz, the BASS EQ can be adjusted to meet your own personal taste.
7. REAR HPF/LPF
   This control is continuously adjustable from 40Hz to 400Hz at 12dB per octave when the X-OVER switch is set to LPF (Low Pass Filter) or HPF (High Pass Filter).
8. REAR X-OVER Switch for LPF/FULL/HPF
   Activates the built-in electronic crossover network. Works in conjunction with the LPF and HPF adjustable control. When set to FULL the amplifier runs Full Range and the electronic crossover circuitry is bypassed.
9. MODE Switch
   Matches the input from the Source Unit to that of the amplifier, either 2 or 4 Channel. This eliminates the use of “Y” adapters and provides a cleaner input signal. When the 2-Channel mode is selected, both front and rear outputs will operate with only one pair of low level RCA inputs. In 2CH mode, use front inputs only.
10. REAR GAIN Control
    This control is used to match the input sensitivity of the amplifier to the particular source unit that you are using up to 250mV to 10 volts.
11. REAR SPEAKER OUTPUT / FRONT SPEAKER OUTPUT
    Be sure to observe the correct speaker polarity and follow the speaker wiring diagrams found elsewhere in this owners manual.
    Green Wire = Left Rear +
    Green/Black Wire = Left Rear -
    Purple Wire = Right Rear +
    Purple/Black Wire = Right Rear -
    White Wire = Left Front +
    White/Black = Left Front -
    Grey wire = Right Front +
    Grey/Black = Right Front -
12. POWER AND GROUND INPUT Wires (from left to right)
    1. Red Wire BATT+ (Power Input Connection)
    2. Blue Wire REM (Remote Turn-On Connection)
    3. Black Wire GND (Ground Input Connection)
       1. BATT+ (Power Input Connection)
          This wire is the main power input for the amplifier and must be connected directly to the positive (+) terminal of the car battery.
       2. REM (Remote Input Connection)
          This wire must be connected to a switched +12V source. Typically, remote turn-on leads are provided at the source unit that will turn on and off the amplifier in correspondence with the source. If this lead is not at the source unit, then a switched +12V supply must be used, like the ACC, +12V.
       3. GND (Ground Input Connection)
          A good quality ground is required for your PowerBass Xtreme amplifier to operate at peak performance. A short length of cable the same gauge as your power cable should be used to attach the ground directly to the chassis of the vehicle. Make sure that all of the paint is sanded or scraped away to ensure a quality ground connection. NOTE: If installing in a boat, UTV or motorcycle make sure your ground wire is connected to the negative ( - ) terminal of the battery.

FUSE-IMPORTANT
Due to the limited space on the XL amplifier chassis they do NOT come with internal fusing! Instead we have included an in-line fuse holder that can be con-nected directly to the BATT+ input on the amplifier. Please note the proper ampere fuse for each model are listed below. Never replace a fuse with a higher rating then what is listed. (XL-2305MX uses 60A, XL-4255MX uses 80A)

POWER WIRING AND SIGNAL CONNECTIONS

WARNING
Disconnect the negative (-) battery terminal before you start any wiring work! The battery of your car audio system must be disconnected until the entire wiring installation is completed.

• Use rubber grommets when running cables through any metal or sharp plastic, to prevent accidental shorting or shearing. Make sure the cables do not interfere with normal operation of the vehicle.
• The audio signal cables (RCA interconnects) should be kept far away from any potential sources of electrical interference such as electronic vehicle management systems (relays, engine computers etc.), wiring harnesses, fuel pumps etc.

These amplifiers are designed to work within a 10 to 16 volt DC range. Before any wires are connected, the vehicles electrical system should be checked for correct voltage supply with the help of a voltmeter.

First, check the voltage at the battery with the ignition in the OFF position. The voltmeter should read no less than 12V. If your vehicles electrical system is not up to these specifications, we recommend having it checked by an auto electrician before any further installation. Once the vehicle is checked, make certain the correct cable gauge is used. The XL amplifier is capable of accepting up to 8 gauge power and ground cable. We recommend using as large a gauge cable as possible, use the Power Cable Selection Chart to calculate the correct power wire size for your application.

PowerBass PowerSport MX Amplifier XL-4255MX POWER WIRING

BATT+ (Power) - Red Wire

• This amplifier should be wired directly to the vehicle battery using the appropriate size cable. Start at the vehicle battery and run the power cable through to the amplifier.
• Avoid running the power cable over engine components and near heater cores. The use of an inline fuse or circuit breaker is a must; this will prevent the risk of a potential fire caused by a short in your power cable.
• Connect the fuse holder or circuit breaker as close to the battery positive (+) terminal as possible (within 18” from the battery).
• You may now connect the cable to the battery, but remember to leave the fuse out or circuit breaker “off” until all other cable connections are made.

GND (Ground) - Black Wire

• When grounding your amplifier, locate a metal area close to the amplifier that is good source of ground (preferable the floor pan).
• Use a short length of cable the same gauge as your power cable. Once again, investigate the area you wish to use for electrical wires, vacuum lines, and brake or fuel lines.

• Use either a wire brush or sandpaper to eliminate unwanted paint for better contact of the ground. NOTE: If installing in a boat, UTV or motorcycle make sure your ground wire is connected to the negative ( - ) terminal of the battery. See Fig. 7

  

• Secure the ground cable to the body using a bolt, star washer and nut. Spread silicon over the screw and bare metal to prevent rust and possible water leaks.
• For Power Sport applications such as UTVs, motorcycles and boats it is highly recommended to wire both the Ground (GND) and Positive (BATT+) cables from the amplifier directly to the battery. 

NOTE: The Ground must be capable of carrying the same amount of current as the positive wire.

REM (Remote Trigger) - Blue Wire
This wire must be connected to a switched +12V source. Typically, remote turn-on leads are provided at the source unit that will turn on and off the amplifier in correspondence with the source. If the source unit does not have a remote turn-on lead, then a switched +12V supply must be used, like the ACC, +12V.

FUSE REQUIREMENTS

Due to the small size of the PowerBass XL series amplifiers, no fuses are incorporated into the panels that normally protect the unit from excessive current. Instead we have included an in-line fuse holder and fuse for this purpose.

• XL-2305MX 60A
• XL-4255MX 80A

It is absolutely vital that the main power lead to the amplifier(s) in the system be fused within 18-inches (45cm) of the connection to the battery. The value of this fuse (or circuit breaker) should be no greater than the fuse rating above.

Proper Ground Connection For UTVs, Motorcycles or Boats

SOURCE INTERCONNECT

Choose the correct length and style of RCA interconnects for your needs. Always use high quality RCA audio cables (not supplied) for signal connections—those with multiple layers of shielding or a twisted pair variety for better noise rejection.

Be extra careful when routing your RCA audio interconnect cables. Car environments are notorious for poorly insulated wires. This means that hiss, engine noise, and fan noise can easily be picked up through RCA cables if run incorrectly.

Make sure that the cables for power and audio signal are not on the same side of the vehicle and that they do not cross each other; this will help reduce any noise that may radiate from the power cable and the signal cable. If an audio cable is too close to a power cable, it may pick up the magnetic field generated by the power cable, which could lead to a loss of quality in your signal.

NOTE: AUX Input is for use with portable MP3 players or an iPod* Use of this input will over-ride (defeat) the RCA low level inputs.

HIGH INPUT PLUG

The balanced input of this XL series amplifier can receive either low RCA or high speaker lead level signals from the source unit (radio). A high level signal can be run from the source units speaker lead outputs to the low level RCA amplifier inputs via the PowerBass HL-AD2 wiring harness (available separately as shown below).

3.5mm AUX INPUT/OUTPUT WIRING

Typical 2 amplifier setup

MP3 or Portable Device as a Source

The XL Powersport Series amplifiers all feature a AUX source input. This allows you to substitute a portable music device such as an iPOD, Smartphone, MP3 Player, etc instead of a traditional radio as your music source. Above is a typical two amplifier system—using AUX Input and AUX Output.

You will need to use a quality shielded 1/8-inch (3.5mm) stereo male to male audio cable for this type of set up. Route the shielded audio cable using the same care as you would with the RCA interconnect for a traditional source unit.

NOTE: An AUX Input is for use with portable MP3 players or an iPod* Use of this input will override (defeat) the RCA low level inputs.

SET UP ADJUSTMENTS

INPUT Gain Adjustment

This control allows you to match the input level of the amplifier to the output level of your head unit. Matching the input can be accomplished in three simple steps:

1. Set the volume of GAIN on the amplifier to Min (completely counter clock wise).
2. Turn on the head unit and adjust volume to 2/3 maximum, and set the BASS and TREBLE to zero.
3. Adjust the GAIN control clockwise until the sound just begins to distort, then back off slightly to cut distortion and operate at optimum gain.

Remember, the GAIN control is not a volume control. Ignoring the three steps above may leave you with damaged speaker and/or a damaged amplifier.

BASS EQ Control
This special feature is designed to provide you more powerful sound quality, and it allows you to increase the bass output up to +18dB at 45Hz. Keep in mind more is not always better. Setting the control to the max (18dB) may stress the amplifier and woofer and could result in damage. Bass EQ only works in Low Pass Mode (Rear Channel only on XL-4255MX).

NOTE: More is not always better. By turning the BASS EQ all the way up to 18dB you can overwork the amplifier and send the unit into thermal protection.

LPF (Low Pass Filter) Adjustment
Using this volume, adjust the LPF frequency for your subwoofer speaker(s) operation. Using the LPF control, adjust the Low Pass Frequency to limit the amount of midrange going to your speakers. The X-OVER switch position should be at “LPF”.

HPF (High Pass Filter) Adjustment
When you are using coaxial or component speaker system, this allows you to adjust high-pass X-over frequency from 40Hz to 400Hz. To get better sound quality from coaxial or component speaker system, we recommend the frequency should be higher than 80Hz. Make sure the X-OVER switch is positioned at “HPF”. NOTE: The HPF circuit is always active on the front channels of the XL-4255MX.

SPECIAL CONTROLS FOR THE XL-4255MX
The following instructions apply to the model XL-4255MX only. You will not find these controls on the other models in this series.

MODE Switch 
Matches the input from the Source Unit to that of the amplifier, either 2 or 4 Channel. This eliminates the use of “Y” adapters and provides a cleaner input signal. When the 2-Channel mode is selected, both front and rear outputs will operate with only one pair of low level RCA inputs. Must use front inputs.

AUX INPUT NOTE: The MODE switch must be in the 2-Channel position in order to use the 3.5mm AUX input

Rear X-OVER Switch 
Activates the Low Pass Filter (LPF). The LPF is variable from 40Hz-400Hz. FULL runs the rear channels full range without any filter

REMOTE LEVEL Controller Connection (XL-2305MX)
Your PowerBass Xtreme amp includes a Remote Level control module. To connect the Remote Level Control to the amplifier, simply insert one end into the REMOTE LEVEL port. Plug the other end into the remote module. Install the module within easy reach on or under your dash.

NOTE: The remote level controller works with all settings HP, LP, FULL.

SPEAKER WIRING AND CONFIGURATIONS

Speaker Load
Keep in mind your PowerBass Xtreme amplifier is a high power amplifier and not a high current amplifier. In other words The amplifier's minimum impedance is 2 ohms STEREO and 4 ohms bridged to operate trouble free. Lower impedance will send the amplifier into protection and possibly damage the electronics inside and void the waranty.

NOTE: Know your total impedance load before you make any connections.

Speaker Wiring
Choose the correct speaker wire for your application. Most applications will require a minimum of 16 gauge wire. At the amplifier end, splice the speaker wires to the properly marked output leads from the amplifier. Route these using the same precautions as you did when you ran the power cable. Check to make sure you’ve maintained proper polarity and balance.

CAUTION:
Maintaining proper impedance is critical when wiring the Full Range Digital model amplifiers. Improper wiring can cause severe damage to BOTH the speakers and the amplifier. Detailed wiring diagrams are supplied with all PowerBass woofers.

IF YOU ARE NOT EXPERIENCED OR UNCOMFORTABLE READING THE WIRING DIAGRAMS CONSULT YOUR AUTHORIZED POWERBASS DEALER BEFORE YOU ATTEMPT TO WIRE THE SYSTEM.

Speaker Output Connections 4 Channel Model (XL-4255MX)

4-Channel Speaker Output Connection

3-Channel Stereo/Mono Speaker Output Connection

XL-4255MX Wiring Layout

RECOMMENDED WIRE SIZES

PowerBass makes several types of amplifier wiring kits to assist with the installation of your PowerBass amplifier. Consult your local PowerBass dealer for details. For more information about recommended power wire check out our website at https://www.powerbassusa.com 

TROUBLESHOOTING TIPS

NOTE: After using all the troubleshooting tips above, if the Status L.E.D. is activated and glows RED with no speak-ers connected to the amplifier, and all the power connections are correct, this would indicate an internal problem with the amplifier. Contact PowerBass USA or your local dealer.

Pros & Cons

Pros

• High Power Output: Delivers up to 425 watts RMS, ideal for loud environments.
• Rugged Construction: IPX67 certified, making it perfect for marine and powersport use.
• Compact Design: Easy to install in various vehicles due to its compact size.
• Adjustable Crossover: Allows precise tuning to match different speaker configurations.
• Comprehensive Protection Features: Overheat, short circuit, and overload protection ensure reliability.

Cons

• Higher Cost: While competitive, it may be more expensive than some other amplifiers on the market.
• Installation Complexity: Requires careful wiring and setup, which may be challenging for beginners.
• Heat Dissipation: Requires proper ventilation to prevent overheating during extended use.

Customer Reviews

Customers have praised the PowerBass PowerSport MX Amplifier XL-4255MX for its robust build quality and impressive sound performance. Many have noted its ease of installation and the comprehensive wiring kit provided. However, some users have mentioned that the amplifier can run hot if not properly ventilated, emphasizing the need for careful placement.

Common complaints include the higher price point compared to other amplifiers and the complexity of the setup process for novice users. Despite these, the overall feedback is positive, with many recommending it for its reliability and performance in harsh environments.

WARRANTY POLICY

PowerBass Xtreme Amplifiers are to be free of defects in material and workmanship for a period of one (1) year.