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why is my amp shutting down?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=107478
Printed Date: March 28, 2024 at 8:46 PM


Topic: why is my amp shutting down?

Posted By: snowsoldier
Subject: why is my amp shutting down?
Date Posted: September 16, 2008 at 12:03 AM

i have a pdx 1.1000 alpine amp hooked up to  2-12" Pioneer IMP subs.  when i turn up my stereo to a certain point the amp will shut down and i have to turn the deck off then back on to get it to work again. what is going on? i have read on other fourms about similar problems and some people talk about the voltage drop. which could explain my battery gauge bouncing back and fourth when the bass hits. what can i do to fix it? my buddy who used to install recomended adding a capacitor because my lights dim with the stereo too. is he right?




Replies:

Posted By: jayson33
Date Posted: September 16, 2008 at 12:10 AM
Do the Big 3 and a highoutput altenaitor

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Posted By: i am an idiot
Date Posted: September 16, 2008 at 12:21 AM
A capacitor will not help you at all.




Posted By: snowsoldier
Date Posted: September 16, 2008 at 12:57 AM
just to understand this a little better. the concept of "Big 3" is to replace the wires between the engine ground to the chassis, alternator to battery possitive, and the battery negative to chassis with bigger wire to let more current pass between each point? what is an ideal wire size?




Posted By: jayson33
Date Posted: September 16, 2008 at 1:06 AM
I replaced mine with 4 gage. Even wire from alt. to battery. 0-4 gage should be fine.

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Posted By: snotdobbs
Date Posted: September 16, 2008 at 7:18 AM
how are your subs wired, is the input level selection switch in the right position? just throwing things at you.....




Posted By: megaman
Date Posted: September 16, 2008 at 9:08 AM
There's a few things that could be shutting the amp off.  One is a power problem, whether low voltage or low current.  This can be solved by the correct gauge wiring for your power, big 3 upgrade, and a higher output altenator.  Another is a load issue.  If you're subs are wired for too low of an impedance, as soon as you turn it up, the amp sees too low of a load and shuts off to protect itself.  Another, but less likely, event , would be the deck amp turn-on lead shutting off because of low voltage when your system is taxed by the heavy bass output.  I've seen dozens of Clarion head-units have issues with high power systems, and they will shut the amp turn-on lead output off when the voltage drops below a certain threshold.




Posted By: DYohn
Date Posted: September 16, 2008 at 10:50 AM
Assuming the amp is not defective, the most common causes for an amp to shut down (protection) are 1) too low an impedance load, 2) too high gain setting, or 3) power problems.  As has already been asked, how are your subs wired?  What is the voltage at the amp when it shuts down?  How did you set your gain?

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Posted By: snotdobbs
Date Posted: September 16, 2008 at 12:06 PM
  posted_imageoh dyohn did you just call it impedance load?  im sure noones gonna flame you but i could have sworn i just saw a post about that..........posted_image




Posted By: snowsoldier
Date Posted: September 16, 2008 at 1:17 PM

i have both of my subs wired in series at 2 ohms. i was gonna make my way to a shop tonight and pick up some bigger wire and do the big 3 on my truck this weekend. i was also going to look into buying a capacitor for my system. i dont understand why people are saying that they are useless.... if they were why would they be used for vfd's and capacitor start motors in the oilfield and gas industry?





Posted By: aznboi3644
Date Posted: September 16, 2008 at 1:25 PM
haemphyst wrote:

I see many people using the phrase "impedance load" here. This is NOT a correct phrase, it is either impedance OR load. They are the same and at the same time, VERY different. To use both is similar to saying "PIN Number". Personal Identification Number number... "ATM Machine". Automated Teller Machine machine... "The department of redundancy department".

Please stop doing it! posted_image

The phrase is impedance, referring to the electrical load PRESENTED BY the speaker to the amplifier or load (definition 12), the electrical load SEEN BY the amplifer and an indicator of how much work the amplifier is expected to do, but PLEASE not both!




Posted By: DYohn
Date Posted: September 16, 2008 at 4:03 PM
I got yer load right here, buddy.  posted_image

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Posted By: DYohn
Date Posted: September 16, 2008 at 4:08 PM
snowsoldier wrote:

i have both of my subs wired in series at 2 ohms. i was gonna make my way to a shop tonight and pick up some bigger wire and do the big 3 on my truck this weekend. i was also going to look into buying a capacitor for my system. i dont understand why people are saying that they are useless.... if they were why would they be used for vfd's and capacitor start motors in the oilfield and gas industry?


"Wired in series at 2-ohms."  How many voice coils and what impedance are they?  And how did you set your gain?  And like I asked before, what is the system voltage when your amp shuts down??

Caps are not "useless."  They work well for what they do, but what they do is different from what most people expect them to do.  In most cases they will not help with dimming lights and certainly not with main power issues.  If the alternator and the system wiring cannot keep up with the load, then a cap will only make matters worse, not better.



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Posted By: aznboi3644
Date Posted: September 16, 2008 at 4:52 PM
DYohn] wrote:

I got yer load right here, buddy. posted_image


lol just pushing yer buttons, boss.




Posted By: DYohn
Date Posted: September 16, 2008 at 8:33 PM

aznboi3644 wrote:

DYohn] wrote:

I got yer load right here, buddy. posted_image


lol just pushing yer buttons, boss.

He he, I know, just pushing 'em back!  posted_image



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Posted By: stevdart
Date Posted: September 16, 2008 at 9:00 PM

jmelton86 wrote:

Ooh, ooh! I found a way to use them both in a sentence!
'the impedance curve of the load.' -Does that work?

Here's my try at it: 

When wiring the subs, always ask yourself:  "Will the impedance load the amplifier beyond its capacity?"

posted_image



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Posted By: snotdobbs
Date Posted: September 17, 2008 at 7:40 AM
Ha, that works.




Posted By: snowsoldier
Date Posted: September 17, 2008 at 4:38 PM
well when my bass hits it drops down to like 11.14 V then it charges back up then hen the bass hits again it drops down to like 11.42V that is when it shuts down. my gain is set at 3/4 on the 0.1 V - 1.0 V. if that makes sence to you. Its a dual coil and 2 ohms.




Posted By: forbidden
Date Posted: September 17, 2008 at 7:28 PM

Tell me more about your ground and the return resistance please....... Bad ground = big problems that manifest itself as power is increased.....



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Posted By: i am an idiot
Date Posted: September 17, 2008 at 7:47 PM
How do you have the 2 woofers wired in series to achieve a 2 ohm load?    Are they 1 Ohm speakers?




Posted By: snowsoldier
Date Posted: September 18, 2008 at 12:11 AM
each sub is wired by its self in series with the amp at 2 ohms. and the grounds are in good shape, i made sure that i checked it. but i went to visions today and talked to a guy that i know and he gave me a four gauge wire kit. i think that it is going to help alot actually. i only have 8 in there right now because thats what the kid had in it before i bought it with two acoustic speakers hooked up. when i put my system in i didnt even think to change out the wiring.




Posted By: DYohn
Date Posted: September 18, 2008 at 8:13 AM

snowsoldier wrote:

each sub is wired by its self in series with the amp at 2 ohms. and the grounds are in good shape, i made sure that i checked it. but i went to visions today and talked to a guy that i know and he gave me a four gauge wire kit. i think that it is going to help alot actually. i only have 8 in there right now because thats what the kid had in it before i bought it with two acoustic speakers hooked up. when i put my system in i didnt even think to change out the wiring.

Ah, you have your system wired incorrectly.  If each sub is wired for 2-ohms and both are connected to the same amplifier, then you are placing a one-ohm load on the amp.  It can't handle that.  You need to re-wire the system and place both subs in series so the amp gets a 4-ohm load.

The wire gauge of your power system will not cause the problem you see.



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Posted By: i am an idiot
Date Posted: September 18, 2008 at 9:18 AM

Just curious here,  What is the impedance of each voice coil and how many voice coils are on each woofer?






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