JL Audio MHD900/5: marine 5-channel amplifier, 900 W
The MHD900/5 is the marine 5-channel amplifier, 900 W in the JL Audio MHD series: very compact amplifiers with plenty of power and carefully designed signal processing. It delivers 100 W RMS on each of the four main channels at 4 ohms and 500 W RMS on the subwoofer channel.
A single chassis drives the whole system, speakers and subwoofer. It comes in two versions, for 12 V and for 24 V systems.
Key features
- 5 channels: 100 W RMS x 4 at 4 ohms (75 W at 2 ohms) plus 500 W RMS for the subwoofer
- Frequency response: main channels 12 Hz-28 kHz, subwoofer 12 Hz-10 kHz
- 12 V (11-14.5 V) and 24 V (22-29 V) versions
- Weight 3.11 kg
- Class D amplifier with Single Cycle Control plus the R.I.P.S. supply
- Filters switchable between 12 and 24 dB per octave
- Switchable RCA inputs: 200 mV-2 V or 800 mV-8 V RMS
- Footprint 273 x 199 x 49 mm
Single Cycle Control plus R.I.P.S.
The Single Cycle Control circuit corrects the output more than 400 thousand times a second: sound benefits while current draw and heat go down. The regulated R.I.P.S. supply keeps full power into loads between 1.5 and 4 ohms per channel, whatever the supply voltage within the intended range.
Filters and inputs
The main channels have a defeatable high-pass between 50 and 500 Hz, the subwoofer channel a low-pass; the input switches between 2, 4 and 6 channels, and the optional remote level control acts on the subwoofer alone. Slopes are 12 dB per octave Butterworth or 24 dB per octave Linkwitz-Riley, with calibrated potentiometers to blend subwoofers and component systems precisely. The differential-balanced inputs also accept the high-level signal from speaker outputs, with no converter, and reject noise. Alternator whine stays out.
Protection and cooling
If temperature climbs too high, the protection circuit lowers power instead of shutting the amplifier down: music carries on even in the toughest conditions. The chassis sheds heat with no fans and, with the optional kit, lets one amplifier sit on top of another without losing cooling capacity.
Build and installation
The chassis is all aluminium, powder coated, with hardware chosen not to corrode, and a waterproof safety door shields the controls. Every MHD model has the same footprint, which simplifies laying out several units. Power and speaker connectors unplug, a help in tight spaces. The 12 V version runs on 11 to 14.5 V with a 60 A fuse indicated, the 24 V one on 22 to 29 V with a 30 A fuse; the types foreseen are AFS, AGU or MaxiFuse. The power and ground cable indicated is 4 AWG copper at least.
What's in the box
- The amplifier
- Plug-in power connector
- Plug-in speaker connectors
- Four fixing feet
- 2.5 mm and 4 mm hex keys
- Four set screws
- JL Audio badge
