Potential Causes for Amp To Cut Off

[Jeff T]

I have a slight problem. It has taken several weekends for me to get my stereo tuned just right. I'm still not quite there, but it has gotten a lot better. The Wetsounds sound incredible. The sub sounds awesome. I love how the deck speakers sound under the 350.4...but here is where my problem lies.

ZX 350.4
-90x4 @ 2ohms
I have the gain turned up just over half way.
I have 4 gauge power running from a distribution block. The power run is only maybe 5-8ft. I can't remember exactly.

Kicker KM 620.2
-4ohm
-195 peak
-65 RMS

I have 5 deck speakers (didn't install the speaker in the kickpanel). Three speakers are on their own channel and 2 speakers are in parallel. When I hit a certain volume on the HU, the deck speakers cut off. The volume setting is 22. (24 is 3/4 volume on the CDM4). When I hit around 21-22, the speakers cut off. I lower the volume back down a few notches and they come back on after a few seconds.

The amp is not getting too hot. I've checked that. It doesn't seem as though the amp should be maxing out and going into protection. The speakers sound great and then just shut off.

Any help is appreciated.

[philwsailz]

Try taking the pair wired in parallel and wire them in series.

I see this occasionally in marine applications; it is a combination of a slightly lower than 4 ohm DCR in the speakers, combined with a battery that is not completely topped off; i.e. voltage is a little low.

Low voltage combined with low DCR is probably causing an over-current sensor to trip, despite ev erything being connected properly.


BEFORE ANYBODY JUMPS ME....

I do not believe you will notice any appreciable loss of output from the two speakers we are moving to series wiring, despite going from a NOMINAL 2-ohm load to a NOMINAL 8-ohm load. Please, just try it before we get into a bunch of Ohm's Law discussions....

Let us know!

[Razzman]

Jeff I'm curious, how many batteries do you have? I'll defer to the experts here but mine was doing the same thing and in my case was low bat charge on the deep cycle due to a wire not connected (loose). Sounds like as the volume raises and the power demand increases your bat(s) can't supply the power required.

[Razzman]

Ahh .. Phil beat me too it as usual!

[Jeff T]

I have two batteries. EDIB system from Tige. Phil, I know you know that I'm just one step above completely ignorant when it comes to wiring. Can you explain the diff between parallel and series?

I have the two bow speakers and the speaker directly behind the driver's seat on their own channels and the 2 main cabin speakers in parallel. Should I change the configuration?

Thanks.

[philwsailz]

Parallel wiring ties both positive leads togeher and both negative leads together. Each speaker has a wire path directly to the amp. In series wiring, we take the wiring THROUGH the speakers as shown below. This raises the overall impedance of the speaker pair, and lowers the amount of the current going through the speakers.

If the two main cabin speakers are wired with each other on a single channel, you are only getting left, or right, but not both in the main cabin. That is the downside I perceive.

****EDIT******

AS I re-read your comment, I will change my statement. You do have stereo in the main cabin, but an odd number of speakers....

[Jeff T]

So is leaving the two primary cabin speakers (the ones that most people will hear) wired in series the best option, or should I wire the bow speakers in series and put the two primary cabin speakers on their own channel?

[philwsailz]

So is leaving the two primary cabin speakers (the ones that most people will hear) wired in series the best option, or should I wire the bow speakers in series and put the two primary cabin speakers on their own channel?

I am not sure it will matter, with a little thought on the subject. The current wiring has the bow speakers probably in stereo, with one speaker getting signal from the left side of the H/U and one speaker getting signal from the right side, (this assumes the RCA's are connected the way most people will connect them). If you wire the bowrider speakers to a single channel, it will only be left, or right, and not both.

In the cabin, you have three speakers, period. Anything you do will still cause two series-wired speakers to carry the same signal, with the other one on another channel to get the other half of the total stereo signal.

Despite saying I do not think it will matter, I think that I would leave it the way it is, and just move to series wiring. that way the bow is stereo, and the cabin area is stereo, (just with one extra speaker, or one missing speaker, depending on how you look at it).

[Jeff T]

Eventually, I may end up installing the last speaker in the kickpanel. I ran the speaker wire for it and just left it hanging on both ends.

Would turning the gain down a little bit alleviate the issue? How about a bigger Deep Cycle that will hold more charge? Any other options?

[philwsailz]

Eventually, I may end up installing the last speaker in the kickpanel. I ran the speaker wire for it and just left it hanging on both ends.

Would turning the gain down a little bit alleviate the issue? How about a bigger Deep Cycle that will hold more charge? Any other options?

I do not think that turning the gain down will help much; it might a little though. That being said, you will end up just turning the stereo up louder to compensate, and you will be in the same place.

Adding another battery is always a good idea, but it is best to install same battery type purchased at the same time to ensure equal charging and best life. It costs money too.

The series wiring I suggest is free....

[Jeff T]

I agree that it is free...but I have been worried about my deep cycle anyway. We anchor and listen to tunes for hours on end. Anyway...the boat is brand new (had it out 4 weekends now). I'm almost willing to be the battery in the boat won't be any older than one off the shelf at a retail store. I was just thinking about it.

[philwsailz]

I agree that it is free...but I have been worried about my deep cycle anyway. We anchor and listen to tunes for hours on end. Anyway...the boat is brand new (had it out 4 weekends now). I'm almost willing to be the battery in the boat won't be any older than one off the shelf at a retail store. I was just thinking about it.

With that in mind, the differences between the new batt and the old should be minimal. JUST BUY THE SAME TYPE AND BRAND IF POSSIBLE...