alternator whine/sub shuts off randomly

[noob with an RS 10+ year member]

alternator whine

hey i had an alpine 7995 (which doesn't have an internal amplifier) hooked up to an audiocontrol EQx for the past 2 years. i started noticing low alternator whine through the speakers a couple months back and installed a kenwood DVD player about a month ago. i didn't use the EQx with the dvd unit because it was only one channel input. the alternator whine went away with the kenwood unit so i have reason to believe either the Alpine or Audiocontrol EQx is causing the whine. I sold the kenwood to my friend and have the alpine and EQx back in now and want to solve this problem now.

I know alt whine is usually due to bad ground but can it be a result of boosting frequencies on the EQx too much?? the EQx is grounded directly to the negative terminal of my monoblock amp. and my front stage's amp is grounded directly to the chassis which i took a sandpaper to. the monoblock is grounded the same way except it is at another location.. am i causing ground loop??? i also have another problem...

sub goes out - (amp is a modded mtx 1501d)

every once in a while my sub shuts off because for some reason my amp turns off. i check the voltage when it shuts off and voltage is there so the amp is basically off. i think it may be it's either protecting itself or it's defective and shutting off randomly or ground loop? when i say protecting itself i mean it may be due to temperature? i know its not because of clipping or excessive load because it'll happen with the volume very low too. well actually its more likely to happen at a higher volume but only because the amp is heating up more (modded- running @ 1 ohm) i THINK. and i THINK on hot days it happens all day, every 15 minutes on average. if the ground loop WOULDN'T cause an amp to behave like this, then im sure it must have some thermal protection circuit?

if u have any info to validate anything please share, these minor flaws are getting my anus all anal //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif .

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[azimuth 5,000+ posts]

you have a ground loop on your sub amp?

 

[audiolife 5,000+ posts]

this might sound dumb but the voltage after the fact its shut off doesnt mean that its still not a voltage issue. if it is getting good voltage it will run cooler than if its not. i also started to get noise and alt whine ... all gone after i put my kinetik in. if your battery is old look into it

 

[azimuth 5,000+ posts]

????

 

[azimuth 5,000+ posts]

i've never seen a ground loop isolator on a sub amp before. i've had the problem on front amps, but the low pass filter on sub amps kills the engine noise on every sub amp i've had. if your amp is heating up at low volume, it's either wired to an ohm value it can't handle, or defective. i might be missing something about checking the voltage. a running alternator puts out 14.4 volts max at all times or less, when the engine's hot i think around 13. i'm not as knowledgable as some around here, but unless something is wrong with the alternator or battery, the amp gets between 12 and 14.4 regardless, which is fine. i would guess it's the wiring.

 

[audiolife 5,000+ posts]

under use there is a voltage drop. lack of power is #1 killer of amplifiers. get the electrical system load tested. at most battery places its free to do. a weak electrical system can read a usable voltage level but just goining off that without a serious load doesnt mean that much. my bad battery read 12.3v engine off.

 

[noob with an RS 10+ year member]

under use there is a voltage drop. lack of power is #1 killer of amplifiers. get the electrical system load tested. at most battery places its free to do. a weak electrical system can read a usable voltage level but just goining off that without a serious load doesnt mean that much. my bad battery read 12.3v engine off.

whats a nationwide battery store i can go to to get it checked for free? places like autozone or a store that spcializes specifically in batteries? also, wouldn't BOTH my amps be shutting off if there is lack of power? only my sub amp is cutting off and on.

 

[audiolife 5,000+ posts]

there are alot of factors in that based upon design and what the amp wants to draw off of (that class d wants and needs more power than the rest of the system). on mine it started to (one 4 ch amp) have a slight whine then the sub portion started to make a popping sound. i was in the same boat sorta that you are in because with the car on it read 13.8v and right after i turned it off battery read 12.5-12.3. i talked to soundstream they said was a voltage issue (my battery was only 24 months old or so still should be plenty good) so i went out to my truck without starting it for a few long hours my battery read 11.6v or something like that. also the fact that your amp gets hot when its still within it boundries of daily use is also a sign that the voltage isnt there for the amp. around where i live battery wholesale has an actual load tester and autozone still should give you an idea. there tester has a green stripe telling you if its bad or good but if its barely in the green i would get my alt or battery looked at. not going to say within 100 percent certainty that thats the problem but its one i would look into as it effects everything in your system.

 

[azimuth 5,000+ posts]

would the green bubble on my battery tell me anything?

 

[noob with an RS 10+ year member]

ohhhh i have one of those battery testers you're talking about.. basically, one clamp goes to the positive and one goes to the negative. then you switch LOAD ON on right? my battery checks out to be OK in the green. im at work right now and we have one in our garage (we smog cars). should i run this battery test again before i leave for work in three hours before i crank the car?

 

[audiolife 5,000+ posts]

yuh but it also depends on the load it goes up too. the one the battery place has up here goes to an 800 amp load you are probably wanna know how it does on about a 200-500 amp load