JL Audio MHD Marine Amplifier, Class D

Overview

The JL Audio MHD marine amplifier is a compact Class D marine audio amplifier range offered in 1-channel, 4-channel, and 5-channel configurations, with both 12V and 24V negative-ground options. Depending on the configuration, rated output ranges from 750 W x 1 (monoblock) to 150 W x 4 (4-channel) and 100 W x 4 plus 500 W x 1 (5-channel).

These amps are built for real onboard installs where salt, UV, and constant vibration are part of the deal. The chassis uses a powder-coated aluminum housing with stainless hardware, and the controls sit behind a gasketed cover so settings stay protected once the system is dialed in.

Use the channel count to match how your boat is zoned and how you want to run a subwoofer. The voltage option matters just as much: the 24V versions are meant for 24V systems, and the non-24V versions are meant for 12V systems.

Key features

• Class D marine amplifier platform available as 1-channel, 4-channel, or 5-channel depending on configuration
• Monoblock configuration rated at 750 W x 1 into 1.5 to 4 ohms, and it can be used full-range or for a dedicated subwoofer channel
• 4-channel configuration rated at 150 W x 4, with the ability to bridge to 300 W x 2 for higher output on two channels
• 5-channel configuration rated at 100 W x 4 plus 500 W x 1 to run four full-range channels with a dedicated subwoofer channel
• 12V versions are for 12 volt, negative-ground electrical systems; 24V versions are for 24 volt, negative-ground electrical systems
• Powder-coated aluminum housing with stainless hardware and a gasketed control cover to help resist corrosion around saltwater
• Removable power and speaker plug connections that make wiring easier when the mounting space is tight

Variants

This product is offered in multiple configurations that change the channel count and whether the amplifier is intended for a 24V electrical system.

The channel layout affects how many speaker zones and subwoofer channels you can run from a single chassis. The 24V option indicates a model built for 24V negative-ground power, not a 12V amp that can be switched over.

• 010-03320-00: Channels 1, 24 V No. Monoblock format that fits systems where one amplifier channel is dedicated to a subwoofer or a single full-range run.
• 010-03319-00: Channels 4, 24 V No. Four channels cover two stereo zones, and bridging support helps when you need more output on fewer channels.
• 010-03103-00: Channels 5, 24 V No. Four main channels plus a subwoofer channel to keep a full boat system on one amplifier.
• 010-03104-00: Channels 4, 24 V Yes. 4-channel layout intended for boats with a 24V negative-ground house bank or audio power feed.
• 010-03321-00: Channels 5, 24 V Yes. 5-channel layout for 24V systems, combining four full-range channels with a dedicated subwoofer channel.

Installation and setup

Plan the mounting spot like you would for any high-power marine audio component: a dry location with airflow, away from direct spray and standing water, and not inside an engine compartment. Leave room to route power and speaker wiring without tight bends so the plugs can be removed for service later.

On the electrical side, confirm your vessel system voltage first, then size power and ground cabling for the run length and expected current draw. Use proper fuse protection at the power source, keep power and signal wiring separated where possible, and secure everything so it cannot chafe through under vibration.

Compatibility and system planning

Before ordering, map out how many speaker zones you are powering and whether the subwoofer will be on its own channel or integrated into a multi-channel plan. The 1-channel option fits a dedicated sub amp role, the 4-channel option matches two stereo zones or bridged use, and the 5-channel option covers four full-range channels with a sub channel in the same chassis.

Match the amplifier configuration to your speaker wiring and load expectations, and confirm that the version you select matches your power system (12V negative-ground versus 24V negative-ground). If your boat has both 12V and 24V circuits, keep the amplifier on the correct bank rather than relying on adapters or improvised voltage changes.

Use on board

This range makes sense for boats that need high output in a space that is limited, such as console lockers, helm cabinetry, cabin audio racks, or under-seat installations. It is also a good fit when you want a clean system layout with fewer boxes, especially with the 5-channel setup that can cover a full cockpit and subwoofer system.

Maintenance and care

After installation, recheck fasteners and wiring strain relief after the first few trips, since marine vibration can loosen anything that is not secured. Keep terminals clean, address corrosion early, and avoid directing pressure-washer spray at wiring and connections even if the control area is covered.

Orders are processed within 2 business days, which includes verification, packing, and dispatch. Orders of $100 or more qualify for free shipping when eligible. For orders under $100, shipping costs are calculated at checkout based on destination, package weight, and selected service. International shipping is available for eligible products, and certain items may require additional handling, warehouse transfers, or may ship directly from the manufacturer, which can affect processing time.

Deliveries are handled by preferred carriers such as USPS, UPS, FedEx, DHL, and others depending on your location and selected service. Estimated delivery times are displayed at checkout and may vary due to customs processing, carrier delays, weather, postal disruptions, or other circumstances beyond our control. Once your order ships, you'll receive a confirmation email with tracking information. Tracking may take up to 24 hours to update on the carrier's website and is also available through your account when applicable.

We ship throughout the United States and to most international destinations for products eligible for international shipping. International orders may be subject to customs duties, taxes, brokerage charges, or other import fees, which are the customer's responsibility and are not included in the product or shipping price. PO Boxes are accepted only when shipping through USPS, and not all packages qualify for this option. If your order does not arrive within the estimated delivery window, please contact us at info@apollolighting.com or +1 (954) 375-0100 so we can assist with locating your package.

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Returns may be requested within 30 days of receiving your order. Items must be unused, uninstalled, unaltered, and returned in their original packaging with all tags, packing materials, blank warranty cards, manuals, instructions, accessories, and included items. Certain products, including installed or used electronics, electrical components, lighting, consumables, custom or special-order items, cut-to-length products, safety equipment, and merchandise exposed to water or marine conditions, may not be eligible for return.

To request a return, sign in to your account and select the applicable order and items, and submit your request for review. Eligible unfulfilled items may also be submitted for cancellation within 1 hour of placing the order. Returns or cancellations are not considered approved until you receive confirmation from Apollo Lighting. Please do not ship or drop off merchandise before receiving return approval and instructions.

Customers are responsible for arranging and paying for return shipping unless the return is due to an error by Apollo Lighting or the item is verified as defective, damaged, or incorrect. Missing, damaged, defective, or incorrect items must be reported within 2 business days of delivery, and photos or other documentation may be required for review. If the issue is verified, Apollo Lighting may provide or reimburse return shipping and issue a replacement or refund depending on the circumstances. International customers are responsible for return shipping, duties, taxes, customs charges, brokerage fees, and other costs associated with an international return.

After your return is received and inspected, approved refunds are issued to the original payment method and may take 5-7 business days to appear after processing. Original shipping and handling charges are nonrefundable, and the value of any included free items that are not returned may be deducted from the refund. Apollo Lighting does not charge a standard restocking fee on eligible returns. Returns that are incomplete, damaged, installed, used, altered, improperly packaged, or otherwise do not meet the eligibility requirements may be refused. We recommend using a trackable and appropriately insured shipping service for all customer-arranged returns.

For assistance, contact info@apollolighting.com or call +1 (954) 375-0100.

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Many products sold by Apollo Lighting include a manufacturer's warranty covering defects in materials or workmanship. Warranty terms vary by brand, product category, and model, so eligibility, coverage duration, exclusions, and available remedies are determined by the applicable manufacturer. We recommend reviewing the warranty information provided with your product before installation or use, especially for marine electronics, navigation equipment, lighting, electrical systems, pumps, safety equipment, and other specialized marine products.

If you need warranty service, the claim must follow the process established by the manufacturer, authorized service center, or designated warranty provider. You may be asked for proof of purchase, a serial number, product registration, photos, maintenance or installation records, or other documentation. Apollo Lighting does not determine or modify a manufacturer's warranty coverage or final claim decision, but we are happy to help provide purchase information and direct you to the appropriate manufacturer or warranty resource.

Keep your receipt, product documentation, serial number information, and original packaging when practical. Damage caused by normal wear, misuse, improper installation, insufficient maintenance, corrosion, impact, unauthorized modifications, electrical issues, or operation outside the manufacturer's specifications may not be covered. Warranty claims are separate from standard returns, so a product that has been installed, used, or exposed to marine conditions may no longer qualify for return while still remaining eligible for evaluation under the manufacturer's applicable warranty.

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