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.

Shipping
We ship worldwide from the United States. Rates are calculated at checkout based on destination and package weight. Some items include free shipping, which will show automatically. Not every product is eligible for international shipping; checkout will confirm eligibility. We do not ship to PO Boxes except through USPS, and not all packages qualify.

Processing and dispatch
Most orders are verified, packed, and handed to the carrier within 1 to 2 business days. Some products may need extra handling time or ship directly from the manufacturer. For certain international orders, inventory transfers between warehouses may add time. If any delay is expected, we will let you know the dispatch date.

Delivery and tracking
Deliveries are handled by trusted carriers such as USPS, UPS, FedEx, and DHL. Estimated arrival times appear at checkout and depend on your location and the service you choose. These are estimates and can be affected by customs or carrier disruptions. A shipping confirmation with a tracking link is emailed when your order ships, and tracking may take up to 24 hours to update. You can also view tracking in your account.

Duties, taxes, and support
International customers are responsible for any customs duties, taxes, and fees charged by the destination country. If these charges are refused and a shipment returns to us, the carrier’s return cost and any re-entry customs fees will be deducted from the refund. If your order is late or you need help, contact cs@qualityboatparts.com and we will assist you.

Quality Boat Parts is a reseller. Many items include a manufacturer’s warranty, and all warranty service is handled directly by the manufacturer. We do not manage or administer warranty claims on behalf of customers.

Warranty terms, coverage, and duration are set by each manufacturer. Issues involving defects, repairs, or replacements must be addressed with the manufacturer’s support team. When available, the warranty period is listed on the product page. If it is not shown, contact us or the manufacturer for details before purchasing.

To start a claim, the customer must contact the manufacturer and follow their process. Keep your proof of purchase and original packaging, and register the product if the manufacturer requires it, as these are often needed for warranty service.

We are happy to help you find the right contact or documentation, but we cannot decide outcomes or intervene in claim resolutions. For guidance, email cs@qualityboatparts.com.