Common Car Amplifier Problems and Solutions

Many car amplifiers are incorrectly diagnosed and sent in for repair/returned because of incorrect hookup. Sometimes the amp itself really is at fault. Here are a few common problems and what can be done to troubleshoot, as well as fix them (my fixes are the most common. They are not definitive in any way. Your amplifier could have a completley different problem, though it is unlikely):

Problem: Amplifier does not turn on.

Solution: Rule number one in amplifier hook up is to make sure the amplfier has a good ground. This means that it is secured to bare metal that is clean, rust-free, and tight.

Is the remote wire hooked up? Be sure it is, and that it is hooked up to the blue wire w/white stripe coming from the head unit, NOT the solid blue wire.

After that point, if the problem still exists, you're probably looking at bad parts in the PSU (power supply unit). The majority of the time, it's because mosfets are blown. It is never a bad idea to try hooking up the amplifier in a different car or taking it in to be tested just to be sure. Sometimes you can open the amp up and find physically fried components. For space constraints, I'll leave it at that.

Problem: Amplifier goes into protect.

Solution: This can be caused by too low of an impedance from the way the speakers are wired, and sometimes a poor charging system (if the amp goes into protect when the volume is turned up).

Otherwise, it's likely that the output transistors failed. That's the most common cause for an amplifier to go into protection.
With
no power applied to the amp, grab a multimeter, set it to ohms, and measure the
resistance between the output transistors terminals. You should
find none that have anything close to zero ohms between any of the
terminals. If you find one or more that read ~0 ohms between
therminals, they need to be removed from the circuit and checked. If
you have several in parallel, it may seem as though the entire group shorted, but generally one fails and the others are OK. Of course, when
you have one defective transistor in a group of parallel transistors,
you must replace all of the transistors in that group.
Open or
broken emitter resistors can cause an amp to go into protect. If you
don't find any shorted outputs, make sure there are no broken terminals
on the emitter resistors

Problem: Amplifier is getting very hot/shutting down.

Solution: This is normally a result of the gains/input sensitivity being set too high. In addition, a lower impedance than the amp is rated for can cause this problem (and in the case of a lower impedance, it can cause permanent damage). Make sure your gain isn't turned up all the way, and that there is at least a bit of dial space between the max and where it is currently set. Be sure the speakers are wired to an impedance the amplifier can handle, and that the speakers are in good working order.

If the above have been met and the amplifier is still overheating, the best thing to do is add external cooling fans. PC fans work great, and I suggest getting the 3-5" models. They can be hard wired to the car's electrical system and a simple switch can be wired inline to turn them on and off.

Problem: Amplifier's volume turns down.

Solution: Many new amplifiers have protection circuitry that will limit the volume if they begin to get too hot. In this case, you would want to refer to the above problem for the solution.

Problem: Amplifier keeps blowing fuses.

Solution: This is usually caused by shorted output devices or power supply
rectifiers. I'll refer you to the solution for the amplifier going into protect as it is basically the same thing, and is usually the root of the problem 95% of the time. Beyond that, it could be a shorted
filter cap, some sort of short across the power rails, some short across the output, or shorts across the primary,. And, let's not forget
loose hardware (any missing screws or nuts? A loose one under a pc
board can short out most anything.)

Problem: Amplifier has intermittent or no sound.

Solution: This basically comes down to two troubleshooting steps:

  1. Try connecting a portable CD player to the RCA inputs (via headphone to RCA cable) and see if you get sound. If you do get sound, then the RCA cable from the head unit could be bad, or the head unit's RCA outputs could be fried or not turned on.
  2. Try hooking up a known-working speaker. If the speaker works, then
    chances are the ones you have are blown. Press down on the
    speaker cone of the likely blown speaker, and if it scratches, it's definitely bad.

Again, if that doesn't solve the problem, there is definitely a problem with the amplifier itself. Usually one of the output devices is to blame (seeing a consistency here? ;) ).

Problem: There is alternator whine or noise through the speakers.

Solution: This is another classic example of a bad ground. You must have a good ground connection. If the ground has been checked and is not the problem, a noise suppresor might be necessary. You can find one here.

Admittedly, some of my solutions are not for the novice, but I thought it would be good if they had an idea of what is actually wrong with their amplifier. If the problem you are having is not listed here, email me or engage me in the TechLore Forums.

Comments

MY 200W AMP POWER LIGHTS LED COMES ON BUT NO SOUND THROUGH MY TWO TWELVES.

my amp seems to be working fine [only the green power light is on/not the red protect light] but NO sound comes through my sub.. but my back two interior speakers still play music/whereas my front speakers don't

*and the music gets all scratchy unless i change settings to play through rear speakers only

Hello, pls I built an 8 watt multimedia amplifier using this TDA2030 but the outputs distortion is really loud. you can hear a songg playing but the sound is not clear enough. What do u think is the cause and solution? tanxxxxxxx

what could cause an car amp to turn on and off at the same time?? it won't stay on constantly, any one at there with a solution

hi my green light comes on then changes to red straight away any ideas

I have a 2000w crunch amp 2 15' cvr kickers n an soundstream epicenter
I get sound n everything from my subs but I get some really nasty bass like if the subs were to burn out.....my cuzin has the same sound as me n his sh+t sounds awesome any idea wat it can be?

i have a sound magus x1502 the amp worked fine until last night, the amp makes a clicking noise and the red alarm light is on, everytime the amp makes a clicking sound the power cable vibrates to every click, i have checked over the wires and fuse a number of times with no luck, i have not opened the amp yet to look inside but if anyone has any ideas that would be great. cheers

I just set up my new 1200 watt amp&sub it works fine but when it is on my front window wipers dont work and when it is off they work! im puzzeld can anyone help???

Hey I have a 2,000 watt amp and i have been useing it before for my subs and recently i put it back into my truck and it works good with a low volume but once i turn it up the woofer starts going crazy and i know its not the woofer becuase i put the woofers conected to another amp and it works perfct. So what can be wrong with my amp?

i have an american pro amp its like 800 watts and it goes into protection mode when turned on..i get a second of bass or sound but thats it...if i turn the switch on and off a few times i may get 3 to 4 seconds of sound but it goes right back to protection mode,, anybody know whats wrong??

I'm using my factory head so I had to use a Adjustable Line Output Converter. I have that wired directly to my back speakers (one left, one right) then to the RCAs then to the inputs on my amp....

Problem is when I have both RCAs (right and left) hooked into my amp...sound is very faint with little or no bass. When I have just one(doesn't seem to matter which one left or right)of the RCA hooked into the amp. it seems to work fine.

I'm very confused. Why does this happen and how do I fix it....besides only using one input, that doesn't seem correct.

And yes my wiring is perfectly fine. I have good connections everywhere. Using 4 gauge wire. I've tested and retested all my connections.

I would appreciate some ideas. Thank You.

my 50watt walmart amp does not pound or even power my three 15inch subs. and i cant figure out why :(

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I don't have a problem with my amp turning on I have a problem with my amp turning off when I turn my car off, what did I do wrong?

I have a Sony xplode 222 running my mids and highs and a boss audio 2.500 running my subs, it's s cheap setup but sounds suprisingly good , my problem is that my amps lose powr for no reason . Then out of nowhere they'll come back on. I've ran a 4awg power wire to a distribution block and good ground , I'm stumped any advise would be greatly appreciated

Just bought a new amplifier, everything is wired up correctly but I'm still having problems, as soon as I tick the car over the red light flicks on and off and nothing happens? When I Turn the car back off, the green light comes on then off. Red light comes on and off and then both come on and fade? All this happens with in 2 seconds? Does anyone have any ideas? Really need to sort this out its driving me nuts! Thanks

I have a JL Audio amplifier 300/2 that I had on my truck , it turns on but gets hot and it barely moves my subs I don't know what's wrong with it.

I just traded some stuff for a 1800 Watt Fahrenheit. Power acoustik and I'm pretty sure left channel is blown but when I hook it up to the right out the sub bounces in it sounds all distorted and choppy.any suggestions (sub is good)

Can someone help me out? I have 12v from my battery but when I check it at the amp it only reads around 9v, which is not enough to push the amp. Does anyone know what would be the problem for this, or what I could do to fix this? It was working before it just stopped working while I was driving. The green light is on and the red light is flickering but no sound from the subs, it is a kicker cx 1200 if that helps at all.

Ok hooked up a 600w amp today and I have checked EVERYTHING. The radio will randomly just shut all sound off. When this happens I can not control the radio at all. No volume or changing song/ station, so when this happens there is no sound for a few seconds or minutes and it is random we can go 30 minutes without a problem or it can happen every 5 seconds. Please help.

Can some one answer my question. My amp and speakerr have been wrking fine but as of late. When music comes on I have a lot of feedback frm my amp and the bass sounds muddy and not clear. Is this a ground wiring issue

I HAVE AN OLD DUAL XPR-4640 600 WATT AMP. I HOOKED IT UP WHEN I TURN UP THE VOLUME IT CUT OFF AND ON. THE LOUDER THE WORSE THIS GETS. IF I TURN DOWN THE BASS AND TREB. I CAN PLAY THE RADIO ABOUT 1/3 MAX WITHOUT IT SHUTING OFF AND ON. IF IT NEEDS REPAIRING HOW DO I FIND THE BAD COMPONENT. I HAVE THE ABILITY TO REPAIR JUST NEED A FEW CLUES.

Check the ground, make sure you have bare metal connection. sand the paint off where you are grounding to and make sure all connections to amp are tight, it sounds like the vibration is causing the problem.

Thank u very much for your help JD but that's not the problem. you see my amplifier and my radio are sitting on the bench. I was bench checking before I installed. I bought the amp used at a pawn shop in Houston. I really believe there's component burned out inside amplifier. The more I push it the quicker it shuts off. Comes right back on for a split sec if volume is up and stays on longer if volume is low. Also found solder shaking around in the cabnet. I need to know what component would give those kind of symptoms, and will a multi meter work to test it?

I just hooked up a 1200 watt amp and when I turn it on I get a high pitched whine even when the car isn't running! And it's getting hot and going into protect when I turn it up! Please help me troubleshoot this!

Just installed my amp today but the lights work in the amp and music is playing with light bass with light vibration from the music but I have no bass. And when I remove my remote wire from the amp it turns off, I also was told the solid blue wire was the remote wire so I used it, would the remote wire be my problem?

Hi there I've got a vibe mono block amp 2800w Basically there's full power green light but there there a Random nosie coming from the amp and the speakers When the RCAs are pluged in and unplugged I've never seen This before the speakers anit blown and I've changed all the wires And the head unit any help please or no of anyone that repairs amps

All of these problems stem from the ground from the alternator to the body is too small... and guy with amp on bench your power source is too small..

All these problems stem from bad ground from the alternator to the body....needs to be 4 guage min.. also guy with amp on bench is running out of power from power supply to small or dead battery

Almost all amp problems are from the ground wire from the alternator to the body is to small. Use 4 guage.. also guy with amp on bench is using to small power supply needs to be 50 amp or his battery is dieing..

The flickering in your amp mean it needs. more powwer its not getting enoff

amp mode: GM-X972.... light indicating protect mode....it will no power n??? please help!!!!!

Check voltage with a meter and make sure u are getting close to 12v from the battery, on the other side of in-line fuse and at the amp, it could be something as simple as a fuse. You have to troubleshoot, check power, then make sure you have a solid ground, clean paint off down to bare metal and make sure it's tightened to the body, then after that make sure your remote wire is wired to the right wire on your head unit. Just a few ideas off the top of my head.

How do I check my 600watt amplifier with a multimeter to see why I have no bass coming from amp?

Your rcas are what sends the signal to your amp for bass lines and vocals, check them and make sure they are plugged in all the way and that they are plugged into the right socket

my amp is on. all wires are hooked up correctly to radio,amp,battery,and subs. But my subs dont have any bass. there is music coming thru it softly and its clear. not like a blown speaker.

I havw a boss 5500 watt onx amp and my fan runs but there is no power to amp no light on red or green does anyone no why the fan would run but the amp wont come on please help me i only had this amp for 3 days been working fine.

Is my amp going to get damaged if it is firmly positioned under a seat but the car is in the sun for relatively long periods at a time?
I turn the key and check the power light and it blinks once .I have a 2ch Sony 150 xm MOSFET
I'm using my factory head so I had to use a Adjustable Line Output Converter. I have that wired directly to my back speakers (one left, one right) then to the RCAs then to the inputs on my amp.... Problem is when I have both RCAs (right and left) hooked into my amp...sound is very faint with little or no bass. When I have just one(doesn't seem to matter which one left or right)of the RCA hooked into the amp. it seems to work fine. I'm very confused. Why does this happen and how do I fix it....besides only using one input, that doesn't seem correct. And yes my wiring is perfectly fine. I have good connections everywhere. Using 4 gauge wire. I've tested and retested all my connections. I would appreciate some ideas. Thank You.
 

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