UGH NEED HELP WITH AMP IN PROTECT MODE!

[GR8WHITE]

Bear with me here lol. I recently installed a MB Quart NAU460 4 channel amp, Zapco AG360, 4 MB Quart 6.5"speakers, and 2 polk 10" subs. Had the MB on the subs temporarily and the Zapco on the interior speakers. After one day of use the subs stopped playing and the MB amp is in protect mode. I hook the Zapco up to the MB wiring and the subs work once again so something must be toast in the MB amp. So I exchange the amp for another one and go to install last weekend and switch the amps so the MB is running the interior speakers and the Zapco is running the subs. As soon as I hook up the "new" MB amp it goes directly into protect mode again, WTF? So I have a really really old school alpine amp and I hook it up and it runs the interior speakers fine and the system works great, hook up the MB again and nothing. So I get back from the river and decide this morning to first hook the amp directly to the battery and no protect mode, WTF? Hook up RCA's and some speakers and it works. Anyone have any idea why I would be having this problem? Why would my Zapco and Alpine amps work but not the MB in the boat but the MB works outside of the boat.:bash: Only thing I can think of is could it have anything to do with the fact I am running both amps off one remote wire from the head unit? Also why would it work before and not now. I need help, I am getting so frustrated.:grumble: Thanks guys.

 

[bunkrepair]

How big is your power and ground? Could also be a week remote and what are your grounded to?

 

[paradise]

You've got a short somewhere in your speaker wiring. Bust out a tester and check the resistance on each pair of speaker wires. Most should read ~4 ohms, one will probably read substantially lower.

Just reread that its powering the subs. What ohm load are you putting to the amp? If it is just a speaker amp it will probably go into protect at a higher ohm rating than a sub amp. The reason the alpine and zapco are working is because they are stable to lower ohm load.

 

[GR8WHITE]

How big is your power and ground? Could also be a week remote and what are your grounded to?

Power is 4ga and ground is 6ga. Amps are powered and grounded directly to the battery. Would a weak remote power 2 amps and not the other?

 

[GR8WHITE]

You've got a short somewhere in your speaker wiring. Bust out a tester and check the resistance on each pair of speaker wires. Most should read ~4 ohms, one will probably read substantially lower.

Just reread that its powering the subs. What ohm load are you putting to the amp? If it is just a speaker amp it will probably go into protect at a higher ohm rating than a sub amp. The reason the alpine and zapco are working is because they are stable to lower ohm load.

Without connecting the amp to anything but the power, ground and remote in the boat the amp is in protect mode.

 

[paradise]

...hmm, Usually protect mode is polarity, short, low ohm, or temp. I'd throw a multimeter on the power ground and remote and see if anything looks funny.

 

[GR8WHITE]

...hmm, Usually protect mode is polarity, short, low ohm, or temp. I'd throw a multimeter on the power ground and remote and see if anything looks funny.

How would a speaker lose ohm's and go from say 4ohms on a multimeter to 2ohms?

Sometimes I get irritated having my boat 250 miles away.

 

[paradise]

Have you tried the amp back in the boat after it worked on the bench? IMHO a single remote should work fine but jumpering it off the power would be a good test.

How would a speaker lose ohm's and go from say 4ohms on a multimeter to 2ohms?

If the speaker failed/is failing

 

[ka0tyk]

Possible. 3 might be pushing it. Try a bosch relay or hit the amp power with +12v direct and see if it works.

yeh just take a little jumper wire right off the 12v+ to the remote to turn em on. i dont think remote power is the problem here.

does it go into protect with no speakers or inputs on it? try one thing at a time. take a speaker you know is good, could be some little home speaker. wire it up to left side, hook up an ipod with a RCA cable to the inputs. its something input/speaker wise shorting thats making it trip.

 

[GR8WHITE]

yeh just take a little jumper wire right off the 12v+ to the remote to turn em on. i dont think remote power is the problem here.

does it go into protect with no speakers or inputs on it? try one thing at a time. take a speaker you know is good, could be some little home speaker. wire it up to left side, hook up an ipod with a RCA cable to the inputs. its something input/speaker wise shorting thats making it trip.

Yes its in protect mode with no speakers or RCA's hooked up, just power, ground, and remote. Thats why I thought it was the amp. It was in protect with the subs and the interior speakers so what's the chance of a bad ohm load with subs and interior speakers? Other amps turn on and work fine.:grumble:

 

[kevnmcd]

If you are saying that it worked at home with a full 12v to it and not in the boat, then I would say that you are not getting enough voltage to the amp in the boat. The MB amp may go into protect mode at a higher voltage than your other two amps, therefore the protect mode in the boat but not on the bench at home. Check your voltage at the amp location in the boat and see what you are getting. Maybe your not getting a good connection somewhere giving you a full 12v. Just my .02. Good luck.

 

[cruzer]

Firstly, speaker DC resistance can be a lot different than speaker impedance (AC - sound). If you get the same dc resistance on all the speakersthat is good but not the final test.

Secondly, your +/- wires to/from you amp should be the same size and large enough to not drop a lot of voltage when the amp is running. If the voltage drop in the wiring is too much, the amp will shutdown thinking it's saving you from running your battery down.

If it is in protect mode with no inputs or outputs connected I would suspect that the amp isn't seeing full voltage or the polarity is incorrect. Measure this first.

 

[bunkrepair]

I have had this problem before trying to power multiple amps witha a single remote I ended up using a toggle switch and a piece of 10 gauge off of my + and it solved my issues. Are you grounding multiple amps with a single 6 gauge off a distribution block?

 

[ROZ]

A lot of good points made above.

The mb amp power supply may be more sensitive than the alpine amp and the remote turn on may be less sensitive.

As suggested, wire in a Bosch relay in order to get good voltage to the amp's remote turn on. I think this most likely the issue.

Also, how far are your amps from the battery? Long run plus low battery could be enough voltage drop to cause the amp to go in to protect mode. If the run is long, I'd run 2 ga power and ground to their own distribution, and run 4 ga to each amp.

Since its going in to protect before speakers are hooked up, the two suggestions are likely the cause.

If it went in to protect mode while running, I'd make sure the load on the amp isn't too low by insuring your speakers aren't over working your amp.

good luck.

 

[GR8WHITE]

No distribution block, I am running each 4ga power and 6ga ground directly to the battery each with an inline fuse. The batteries are in the rear engine compartment and the amps are in the mid cuddy so that they are open to air. Only thing in commom from where I have both amps hooked up is the remote so I will start there. I am going to jump it off the power wire first and see where that gets me, if all is good then I will just pull off the ignition switch for a remote signal. Length of power wire from battery to the amp is about 8-9 feet on that side.

 

[ROZ]

Cable reference link. http://www.the12volt.com/info/recwirsz.asp

My boat is 21 ultra. Bats in back amp at helm. My run totals 16 ft from battery to the location of my amp rack.(2) 2 ga runs from battery to helm. One is power the other is ground. Distribution power fuse block and std distribution for ground.4 ga from blocks to amp. Currently installing one 700 watt amp but will get another down the road.

Your remote voltage is most likely 2v. I don't know how sensitive your mb quart's remote sensitivity is, but that current divided a long distance through a 14 ga wire will loose voltage. As low.as it may be, it may be enough drop to effect your.amp.


Hopefully I'm accurate, its been a few.years since I messed with this Crap ..lol

One more thing, to ensure good ground, your power and ground should be the same ga.

 

[GR8WHITE]

When I check power and ground with the multimeter what should they be testing good at?

 

[cruzer]

When I check power and ground with the multimeter what should they be testing good at?

Since you say the amps go into protect mode with out a load:
The voltage between the power and ground wires should be almost as much as the voltage at the battery.

There probably is a section in the owners manual for your amp that says what the minimum voltage that must be supplied to the amp is and your measured voltage needs to be > than that when the amp is loaded.

I would check the remote turn on signal first and then the voltage supply polarity and value.