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 |  JL Audio - MHD600/4-24V Owner’s Manual  

“How do i properly set the input sensitivity on my amplifier”

 

Please  refer to Appendix C (pages 18, 19) to set the input sensitivity 

for maximum, low-distortion output.

“my amplifier doesn’t turn on”

 

Check  the fuse(s), not just visually, but with a continuity meter. It 

is possible for a fuse to have poor internal connections that 
cannot be found by visual inspection. It is best to take the 
fuse out of the holder for testing. If no problem is found with 
the fuse, inspect the fuse-holder. 

 

Check  the integrity of the connections made to each of the 

+24VDC”,  “Ground”,  and “Remote” terminals. Ensure 
that no wire insulation is pinched by the terminal set screw 
and that each connection is tight. 

 

Check  to make sure there is +12V/+24V at the “Remote” connection of 

the amplifier. In some cases, the turn-on lead from the source 
unit is insufficient to turn on multiple devices and the use of a 
relay is required. 

 

“i get a distorted / attenuated sound coming out of the speaker(s)”

 

Check  the speaker wires for a possible short, either between the positive 

and negative leads or between either speaker lead and the 
vessel’s chassis ground. If a short is present, you  
will experience distorted and/or attenuated output. The  

“Status” LED will turn amber (yellow) in this situation. It may 
be helpful to disconnect the speaker wires from the amplifier 
and use a different set of wires connected to a test speaker. 

 

Check  the nominal load impedance to verify that each channel  

of the amplifier is driving a load equal to or greater than  
1.5 ohms in stereo mode (3 ohms bridged). 

 

Check  the input signal and input signal cables to make sure signal 

is present at the “Amplifier Inputs” and the cables are not 
pinched or loose. It may be helpful to try a different set of 
cables and/or a different signal source to be sure.

“my amplifier’s output fluctuates when i tap on it or hit a bump”

 

Check  the connections to the amplifier. Make sure that the 

insulation for all wires has been stripped back far enough to 
allow a good contact area inside the connector plugs. 

 

Check  the input connectors to ensure that they all are making good 

contact with the input jacks on the amplifier. 

aPPendix d:  troublesHooting

Summary of Contents for MHD600/4-24V

Page 1: ...s the training expertise and installation equipment to ensure optimum performance from this product Should you decide to install the amplifier yourself please take the time to read this manual thoroug...

Page 2: ...fier is designed for operation in vessels with 24 volt negative ground electrical systems Use of this product in vessels with positive ground and or voltages other than 24V may result in damage to the...

Page 3: ...jolt or as a result of the repeated vibrations the vessel is prone to during normal operation Stupid Mistakes to Avoid Check before drilling any holes in your vessel to make sure that you will not be...

Page 4: ...stem delivering high passed signals to front and rear speaker systems Preamp outputs permit connection of a separate amplifier to drive the subwoofer system 3 As a 600W full system amplifier in bi amp...

Page 5: ...ttery post Use the same size power wire as the wire connected to the 24V connection minimum 8 AWG 5 Run signal cables RCA cables and remote turn on wire from the source unit or interface processor to...

Page 6: ...tc We do not recommend the use of copper clad aluminum wire or CCA wire because this wire is significantly less conductive than pure copper wire Only use pure copper power wire such as JL Audio Premiu...

Page 7: ...ire and insert the bare wire into the receptacle seating it firmly so that no bare wire is exposed When using smaller wire it may be necessary to strip 1 inch of insulation from the wire and fold the...

Page 8: ...ling any holes in your vessel to make sure that you will not be drilling through a gas tank brake line wiring harness or other vital vessel system ConTROL PAnel SECURITY CoVER The MHD600 4 24V feature...

Page 9: ...n on the Input Mode switch and connect a single pair of input cables to the Front input jacks only In this mode the amplifier will route the signals connected to the Front inputs to the Front and Rear...

Page 10: ...en the Input Range switch is placed in the High position The output increases with the switch in the Low position While this may sound counter intuitive it is correct as described Input Sens Control L...

Page 11: ...h allows you to select from two filter slopes 12dB Configures the filter to attenuate frequencies above or below the selected filter frequency at a rate of 12 dB per octave Butterworth alignment 24dB...

Page 12: ...ecise filter frequency information refer to Appendix B page 18 Bi Amplified System with one MHD600 4 24V in four channel mode and a separate subwoofer amplifier This configuration requires that the se...

Page 13: ...HD600 4 24V is being used to drive front and rear speaker systems In this mode the preamp output level will track with the signal level of the front input signals allowing the user to fade the rear ch...

Page 14: ...r Speaker OUTPUTS The MHD600 4 24V employs JL Audio s exclusive Regulated Intelligent Power Supply R I P S design The operation of the R I P S system is independent for each pair of channels This soph...

Page 15: ...el pair This requires an RCA Y Adaptor sold separately because a bridged pair of channels requires that both amplifier channels of the bridged pair receive input Connection of only one RCA input will...

Page 16: ...he amber LED will light when you connect the section that is experiencing the problem and turn the volume up 4 Alternating Red and Green lights to indicate that the amplifier is experiencing a fault t...

Page 17: ...g power supply Recommended Fuse Value Type 25A AFS AGU or MaxiFuse Rated Power Stereo 150W RMS x 4 1 5 4 22V 29V Rated Power Bridged 300W RMS x 2 3 8 22V 29V THD at Rated Power 0 03 4 per channel Aver...

Page 18: ...ipped output is very predictable This makes setting the gain structure via the input sensitivity controls very simple Following the directions below will allow the user to adjust the input sensitivity...

Page 19: ...ceeding Play a track with an appropriate sine wave within the frequency range to be amplified by each set of channels at 3 4 source unit volume 7 Connect the AC voltmeter to the Front Speaker Outputs...

Page 20: ...the speaker wires for a possible short either between the positive and negative leads or between either speaker lead and the vessel s chassis ground If a short is present you will experience distorte...

Page 21: ...ate test tone is played through the source unit disconnect the input cables from the amplifier prior to this test The frequency used should be in the range that is to be amplified by the amplifier exa...

Page 22: ...22 JL Audio MHD600 4 24V Owner s Manual INSTALLATION NOTES Use this diagram to document your amplifier s switch and control positions...

Page 23: ...23...

Page 24: ...d warranties therefore these exclusions may not apply to you This warranty gives you specific legal rights and you may also have other rights which vary from state to state If you need service on your...

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