JL Audio MHD 600/4 question

[viking]

Ok you audio experts (ie..........dave, phil, brian). I am running 2 of these amps for my system. 1 runs the bow speakers and towers (new bullethollowpoints - awesome by the way and a big "shoutout" to Dave at Earmark). The other running the 4 cockpits and Sub. All details listed in my signature.

Anyway - was out pounding the system yesterday and enjoying the tunes. After a while of sitting and enjoying the music (at times pretty loud), I started the boat and when underway noticed that the cockpits and sub quite working. I checked the amp and the LED was blinking green/red. I read the manual and sounds like the amp went into protect mode. I'm assuming it was because of low voltage from the batts or something but then wouldn't both amps go into protect mode?? Why just the one?

I ended up shutting the stereo main breaker off at the dash and waiting about 5 minutes.........turned the system back on and all good.

Is this normal or do I need to be worried?

[Brianinpdx]

Viking

I think Mandley is right on the money here about what happend. Quick suggestion is contact earmark (assuming you got the amps from them) and have him walk thru trouble shooting).

Like I always preach.. There is no magic, just physics. It's great that your amplifier was able to engage it's protection circuit and shut things down. If it didn't it would have destroyed itself.

So, should you be worried? No, not at all. Think it's time to look at a fan or two in the cubby and get some venting happening.

If you need more help, shoot me a pm

Brian
Exile audio

[EarmarkMarine]

There are countless reasons why only one of two identical amplifiers would go into protection. Connections. Tuning(crossovers,EQ,etc). Low frequencies
drawing down the terminal voltage to a greater degree. Subwoofer with an inordinately low impedance or its voice coil has incurred some thermal damage. For starters you can redistribute the load more evenly by placing the most demanding draw (sub) with the least demanding draw (single pair of bow coaxials).

David
Earmark Marine

[viking]

Thanks ALL -
maybe I was just taxing the system too hard? I figured with the Class D amps and second dedicated battery that I should be able to anchor and jam the system for at least a few hours? It's not often that I float and keep it that loud the whole time but there are going to be every now and then.

I'll keep you posted on my findings!

[EarmarkMarine]

Viking,
Also keep in mind that this particular amplifier is strictly regulated so it works a little harder to maintain the same output level as the voltage supply declines.

David
Earmark Marine

[viking]

OK -
So I think the culprit is it's just getting too hot. Was out again tuesday and 95degree day. Played the stereo all afternoon and didn't pound it at all. Just did a few pulls and some coving and same issue (the lower mounted amp went into protect) after about 3 hours.

Opened the cubby and it's warm as hell as you can imagine and the amps were hot to the touch.

What are the best solutions to provide some venting and/or air in the cubby?
I thought about possibly adding a fan of some sort in there wired to an accessory switch on the dash?

[EarmarkMarine]

Viking,
Anytime you add a fan its many more times effective if you use it on a shroud so that the fan is circulating air over the entire heatsink rather than just around the fan.
A fan can be automatically turned on/off by the same relay that operates the amplifier remote turn-on circuit. Or, you can add a manual switch at the helm. Or, you can add an adjustable thermister for auto operation.
If you are wanting a fresh exchange in the locker then use a molded louvered vent in the pass-thru (in white or black to best match your gelcoat). To the interior of the vent you will use an ABS adapter plate to facilitate the fan. You will not need a second intake vent because there will be plenty of flow through the open gunnel cavity. Btw, we have these parts prefabricated.
A fan is a band-aid on a core heat issue that may still need to be addressed (redistribution of load, etc). I don't like the fact that the amplifier is generating that much heat to begin with, especially from a fullrange Class D, an issue that we don't see with that amplifier. But, its nice to see the circuit doing its job by protecting the amplifier.

David
Earmark Marine

[viking]

Thanks David.
Can you email me the price and possibly picture of the louvered vent?
I might also discuss why it's working so hard with you as well and possible solutions other than fan/venting.

[email protected]

[cab13367]

How do u recharge the batteries after a day on the water? Or do you?

[viking]

How do u recharge the batteries after a day on the water? Or do you?

Sometimes I do - sometimes I don't.

When I do, I just hook a battery charger to one of them and let them charge. I will alternate between which battery I hook the charger too. The charger will automatically go into trickle mode when they are full. I talked to Blue Seas about isolating them to charge each individually and they advised that it's the ACR's job to sense the charge and go to work so no real need to change it. Been good so far!