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Stereo cuts out on a beat

Started by _mello92_ , Jun 03 2010 09:09 PM

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39 replies to this topic

#1 _mello92_

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Posted 03 June 2010 - 09:09 PM

Throwing this one out to the lekkies...

Installed a 720W 4chl amp, 1000W sub and 2x 420W 6x9 speakers into the LX about 2-3 months ago, used 4 gauge cable since the amp and battery are at either ends of the car.

Within the past 3-4wks it has started to cut out on a beat, even at 1/4 volume. Turn it down a bit and you can notice all the lights dimming to the beat.

Question is: why? and why now? Why not right from the moment I installed it?

Remedy?

BTW:- Did a bit of a test the other day.

With the stereo up to the point where it cuts out, lights on highbeam, wipers on and the fan on, I get 13-13.3V across the battery.

Turn everything off and I get 13.9V.

Drive around for 4hrs or so without the stereo and I get 5-10mins at half volume.

Alternator buggered?

Cheers for the help.

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#2 _luv the uc_

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Posted 03 June 2010 - 09:35 PM

Is your earth for the amp of comparable size to the power side? Is it getting a good, clean connection? Also check the connections to the sub, may have vibrated loose and are pulling more amps than the amp can produce for a split second? If that fails you may need a capacitor to level out power peaks on the base lines.
My thoughts only, these are based on previous problems I have had.

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#3 _Skapinad_

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Posted 03 June 2010 - 09:38 PM

just pull it out and enjoy the exhaust note !!

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#4 _mello92_

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Posted 03 June 2010 - 09:51 PM

Steve - yeah mate, earth and power are both 4 gauge. Bought a new kit when I installed. Yes I sanded the earth point back to bare metal. Will have to check connections - will do tomorrow.

Adam, dont worry, you can still hear the exhaust over the stereo...cept when it works well.

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#5 _robslxhatch_

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Posted 03 June 2010 - 10:01 PM

if you suspect a dodgy alternator , why dont you get a good set of jumper leads and connect up to a car with a decent size alt and see if that helps .

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#6 _mello92_

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Posted 03 June 2010 - 10:10 PM

Cause I didnt think of that.

See, this is why I ask questions here!

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#7 robd74

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Posted 03 June 2010 - 11:04 PM

Hi, have you checked the earth on the head unit or deck?

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#8 fuzzypumper

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Posted 03 June 2010 - 11:21 PM

What about the earth point from battery to the body.
But I dare say you need to have a look at increasing the alternator to at an 85amp VN type
and check condition of the battery.
If your having these stereo problems , what sort problems if any are you havong trying to start the car?

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#9 _mello92_

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Posted 04 June 2010 - 09:39 AM

Head unit earth is good.

Amp earth connection to the body is fine, I cant see the connection to the amp itself..its in a awkward position, will check that this weekend.

Steve - sub connections were fine mate.

The car starts fine, just a flick of the key and away you go.

And my battery earth is connected to the engine head, not the body. Should I run a lead from the battery neg to body? Why/why not?

Battery condition is good. Its a sealed type with an indicator which tells me its fine.

Archie, yes Ive read heaps about using the 85amp alternators, I understand they are a straight swap? Would I need to change anything else if I were to fit one?

Thanks guys.

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#10 fuzzypumper

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Posted 04 June 2010 - 10:18 AM

Even the factory torana negative lead had a wire connecting from the negative to the body just infront of
battery to the radiator support panel or one of the radiator bolts.
If you think about it the main negative wire goes to engine for supply to the starter motor but the engine, exhaust,
gearbox are all tehnically insulated by rubber mounts and and thereefore the boby doesnt get a good earth.
Somehow some earthing is getting through otherwise your guages would not work and other items the car.
It could be through your gear selector, an exhaust mount hitting the body ar similar.
If your amp or any other extra devices you have added are just connected to body for earth then the connection will
not support the extra current.

There is a thread somewhere I showed what I had to do to put a VN alternator on here.

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#11 _mumstaxi_

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Posted 04 June 2010 - 10:29 AM

Battery condition is good. Its a sealed type with an indicator which tells me its fine.

Think the others are on the right track, but dont rely on those battery indicators as a accurate indication of battery condition,they usually only work on one cell only.

MT

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#12 _mello92_

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Posted 04 June 2010 - 10:48 AM

Hmm yeah I dont like to rely on them either, but what other method have I got of testing a sealed battery?

Cheers Archie, looks like I will be running a lead from battery neg to body then, any particular size cable?

Ahhkk, will go hunting for it, cheers.

Found it mate, thanks for posting that.

But I have a 6cyl. Is it still a straight swap?

Edited by mello92, 04 June 2010 - 11:00 AM.

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#13 _nial8r_

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Posted 04 June 2010 - 04:11 PM

same thing happened to me yrs ago, do a quick Amp swap ( if you have a spare ) i think you might find the Amp is fullabucked... or have you got the sub to Amp wires bridged ?? is so try un bridging them,how many subs do you have running of the one Amp, some times if there are to many sub + speakers running of the same Amp it will cut in and out, you might need to run 2 Amps one for the subs and one for Speakers !! just my 2 cents worth

[EDIT] you can stilll try all that^^^^ but i just seen that you have a 720watt 4 ch Amp, which is 180 watts per channel so the Amp is suffering as it cant keep the watts up when the juice is turned up and the sub is trying to pump, disconnect the sub and see if you have the same problem with just the 6x9;s running off the Amp, then see what happens when you just run the sub without the 6x9's ?? i think you will need to run a seperate amp for the sub, i had the problem in my old 4 runner Posted Image

Edited by nial8r, 04 June 2010 - 04:25 PM.

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#14 _mello92_

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Posted 04 June 2010 - 04:20 PM

Nah, this amp is 2 months old, brand new model. I got the sub bridged across channels 3 and 4. Just one sub mate, the speakers are connected to channels 1 and 2.

Cheers for the input though Posted Image

Im keen on getting a VN V8 alternator...

Edited by mello92, 04 June 2010 - 04:20 PM.

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#15 _nial8r_

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Posted 04 June 2010 - 04:27 PM

Nah, this amp is 2 months old, brand new model. I got the sub bridged across channels 3 and 4. Just one sub mate, the speakers are connected to channels 1 and 2.

Cheers for the input though

Im keen on getting a VN V8 alternator...

i just edited my post mate have a look !! Posted Image

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#16 _mello92_

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Posted 04 June 2010 - 05:28 PM

Yeah, that makes some sense. Posted Image

But I think this may make it worse...

The amp is rated at 180W bridged, so the sub is only getting 180W, speakers are only getting 90W each.

And this amp sucks...............34Amps. Eeek. No wonder the alternator is struggling. Hmm. Posted Image

Remember, 720W is max output, and if its not getting the 14.4V like it supposed to, then that aint gonna happen.

Anyway, will try your elimination method tomorrow arvo. Posted Image

So does a VN V8 series alternator just bolt straight in?? Wiring to suit of course.

Edited by mello92, 04 June 2010 - 05:29 PM.

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#17 _Torrie_Man_

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Posted 04 June 2010 - 06:21 PM

bad earthing

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#18 _mello92_

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Posted 04 June 2010 - 06:40 PM

Why do you say that Johnno?

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#19 davelh

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Posted 04 June 2010 - 08:43 PM

Where abouts are the fuse holders for the amp and stereo?
If they are in the engine bay are they sealed?
I have seen shit fuse bases fill with crap that have caused high resistance joints on the fuse itself, causing voltage issues on stereos, especially when the load increases (read bass/volume)
May be worth a shot to just pull the fuses, have a look and maybe give the contacts a bit of a scrub with some scotchbrite or similar.

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#20 _Gunmetal LH_

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Posted 05 June 2010 - 02:46 AM

Check all of your connections at the speakers. You may find one wire is touching ground at some point?

I'd say your alternator is ok if you have everything on and your reading over 12v across the battery...

Edited by Gunmetal LH, 05 June 2010 - 02:48 AM.

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#21 _mello92_

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Posted 05 June 2010 - 07:12 AM

Righteo, will do a thorough connection check this arvo.

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#22 xu1kid

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Posted 05 June 2010 - 11:11 AM

sound like the amp overload protection cutting in i had a jbl 4 channel amp running 2 12 inch subs and fourspeakers all bridged went well for ages now if i turn it up about 3/4 and have a bit of hard bass hiting the overload protection cuts in,

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#23 _mello92_

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Posted 05 June 2010 - 11:16 AM

Could be, but it does it at different volume levels depending on how long I dont use it for.

For example: drive around for a while without the stereo; cuts out at a higher volume than if I use it all the time.

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#24 _uncleian_

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Posted 05 June 2010 - 12:01 PM

the stereo is trying to tell you something...........................................................your music preference is shit..................................... Posted Image

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#25 _mello92_

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Posted 05 June 2010 - 12:37 PM

99% sure it isnt Joshua, will check again though.

And..................................................................you're shit.

Thanks for the constructive input though, seriously..................................