In-Boat speaker amp cutting out when bass hits
 

Can't figure out why, when heavy bass hits and the volume's pretty load, my in-boat speaker amp cuts off (goes into protect mode). I thought it was too much voltage drop so I upgraded to two brand new Group 31 deep cycle batteries dedicated to the stereo, but it still does it. I'm using 4 GA wire for the JAD800.4, as recommended by the mfr.

Any ideas? how can i troubleshoot this?


System:
Got 2 stereo only deep cycle Group 31 Dekas (brand new), including a perko switch and ASR.

Amp#1: MTX TC4001 Thunder - Class D driving a Kicker L5 Sub.

Amp#2: Planet Audio AC 1600.4, 4-channel mosfet driving the tower speakers.

Amp#3: JAD800.4 (4-channel class D, 800w RMS) driving 6 Exile SX65-M in boats.

Blown speaker? Check the impedance at the amp. Start disconnecting speakers until it quits shutting off.

main power prob not big , and make sure your running 12 gauge speaker wire to the sub

I'd go with Jonyb first assessment...

Your 800.4 should be in the highpass mode.
Temporarily remove the turn-on lead from the sub amp (rendering it inoperative) and check to see if the 800.4 behavior changes when driven hard with the same material. Do the same when completely faded away from the tower speakers. This will lower the current demand and keep the voltage supply higher. When isolated you are also more likely to hear something going on with the in-boat coaxials such as voice coil contact. Then follow jonyb's recommendation if you still have an issue.
If voltage appears to be a problem then triple check every primary positive and negative connection coming from the supply source to the 800.4 amplifier terminals. Voltage is always suspect. Plus, different amplifiers can have different operating thresholds.
Under certain conditions an ASR can keep the stereo batteries from getting a charge from the alternator and will increase your dependency on AC shore charging. A $15 multimeter investment can quickly eliminate speculation and expose a voltage issue.
Hopefully every amplifier and audio source references the same battery and the same respective supply/ground points.

Ok more info. First i unplugged the in-boats, one at a time, and it still cuts out. The I removed power to the amps for both the sub and the tower speaker, and the in-boat amp still goes into protect mode. The 800.4 is indeed in highpass mode. So I started checking voltage...

The full 12.3 volts is coming from the main power wire to the power block. But the next three terminals of the power block only have 10.8V (See image). Also, the main terminal on the right in the picture gets REALLY hot (the plastic cover is melted a little and the nut on the terminal looks like it's been getting hot enough to get discolored).

So is this potentially my problem area?
(not sure if this is related, but the in-boat speakers have some minor annoying static "clicks").

The visual reference could be deceiving but I see several concerns.
Is that really 4-gauge cable feeding all amplifiers individually?
Is that the 'funny' cooper-clad aluminum alloy wire or all copper?
A lite buss bar is no replacement for a proper power distribution block in this application.
Get those nylocks off of the posts and use solid S.S. nuts and lock washers.
No way should you be getting that type of voltage drop (1.5V) simply across a buss. And no way it should be creating substantial heat.

Fix the voltage issue where you can get some meaningful diagnosis.

Don't alloy one true problem to mask a second potential problem. From your comments, the 800.4 amplifier is still suspect. The "clicks" sounds are a definite concern.

Measure the DCR on all the in-boat coaxials individually. The DCR will be somewhat lower than the stated nominal impedance. This is normal. A 5% deviation in DCR is possible. A much larger deviation is trouble. A speaker with a partially burnt voce coil can still play but will cause the amplifier problems. You may have several speakers on the verge of going.

Temporarily get the fuse out of the buss and re-test.

Also, get a real ground distribution block rather than stacking all those lugs on a single post. I recommend limiting three lugs per post maximum even with a large battery 5/16" post or a 5/16" or 3/8" battery switch post.

Looks like 8ga off the switch to that OEM amp BUS. Ditch it and get a proper distribution setup fed with a proper gauge cable. Do the same for the amp grounds.

I think i mis-spoke earlier. Not near my boat right now, but from the pic it looks like i have an 8GA wire powering the in-boat speaker amp. I bet that's the problem right there?

I'll rework the power distribution block. Suppose I should run 4GA wire from the Perko to the block, then 4GA to each amp? Thoughts on this one? : http://www.darvex.com/store/pc/Sting...lock-26p24.htm

School me on the ground distribution block. Is that just a stud wired to the battery? Can you recommend one for me to buy?

This is just an example, there are many more from that manufacturer.

http://stingerelectronics.com/produc...&CategoryID=13

The red wire labeled in-boat amp, looks 12ga, maybe 10. Regardless, that post marked 12.3 is where the root issue is as you've got a 1.5V drop across that BUS bar. The ground is that stud thats about an inch to the left of the left blue arrow. Amp grounds should go directly to the battery. To not have 3 amp grounds going to battery, use a distribution block and trunk line to battery.

What's the ohm load? I had the same problem running at 1ohm with 4 gauge power and ground. Changed both to 2 gauge and shortened the ground. It worked like a charm after that...I also ran 8 gauge to all speakers

Thx for the help all. Problem was the 8GA wire. Swapped in a 4GA, replaced the crappy bus bar with a fused power distribution block and another block for the ground wires and it sounds SICCKKKK with no cutting out!!