Car amp or battery?
08-25-2010, 01:06 PM
#1
0 Watt CAFz'r
Thread Starter
Join Date: Aug 2010
Posts: 3
Car amp or battery?
okay i have a MTX 3002 car amplifier, i have had it for a week and its been working pretty good until now, when i turn on my car the amp does not turn on. the red light on the amp would on but its very dim, and sometimes it flashes. sometimes when i leave my car off and try to listen to music the amp will randomly turn on and start playing music. then i would start the engine and the amp wont turn on again.... i then took my amp home and connected it to a computer PSU and it turns on fine and plays music well....is it my amp? or car battery? i dont know what to replace or get repaired
08-25-2010, 03:27 PM
#3
500 Watt CAFz'r
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I will agree that there is most likely a wiring problem. Could be a compromised power cable, could be a $#!tty ground, could be the speaker wires touching either on the amp side or the speaker side, could be a compromised/shorted speaker wire. Nonetheless, Step 1=check all wiring
08-25-2010, 05:04 PM
#4
Yankee
Join Date: Oct 2003
Posts: 3,599
As the folks above said it is an installation issue. If it works fine during your 'bench test' then what is inferior in your cars set up? This is, as stated, probably a wiring issue. Verify positive power + from the battery goes to the + and the - from the amp connects to a paint free ground point. All connections should be socket wrench tight not finger tight.
Also don't forget the speaker wire needs to be neatly connected (no frayed copper) and tightly connected. The other little detail with speakers is the impedance load the amp sees, amps have a minimum impedance they can drive and if you go below it the amp will give you the big red light too.
An amp overheating will give you a red light (protection) but your symptoms don't indicate that is your problem
Also don't forget the speaker wire needs to be neatly connected (no frayed copper) and tightly connected. The other little detail with speakers is the impedance load the amp sees, amps have a minimum impedance they can drive and if you go below it the amp will give you the big red light too.
An amp overheating will give you a red light (protection) but your symptoms don't indicate that is your problem
08-25-2010, 11:23 PM
#5
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i dont think its my wiring to be honest because when i connect my older amp, it works perfectly without any problems, so im guessing it must be the amp, but i wanna know whats wrong with it exactly hopefully so i can get it repaired
08-26-2010, 05:51 AM
#6
Yankee
Join Date: Oct 2003
Posts: 3,599
... this is trouble shooting you must eliminate all issues till your left with only one (and the last one being the LEAST probable and most expensive which is the amp is bad).
so now you said you have just placed an older amp (same power rating) in your car and today it works fine...
so what is the voltage to the amp using a digital or analog multimeter?
... BTW the amp were talking about is new correct?
so now you said you have just placed an older amp (same power rating) in your car and today it works fine...
so what is the voltage to the amp using a digital or analog multimeter?
... BTW the amp were talking about is new correct?
08-26-2010, 12:46 PM
#7
500 Watt CAFz'r
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I'm gonna blame midget fairies.... We have contradicting issues here... First the amp doesn't work in the car, then it works out of the car, then another amp works in the car... First thing's first, check all wiring. Don't rely on what you think you know, verify the wiring is all good. Meter the power at the amp and see what the voltage drop is. If you put a lower powered amp in place of the "broken" one it won't draw as much and can fool you into thinking the wiring/power supply is ok. I suspect either poor ground, loose connection(s), improper wiring, or (I doubt this considering the power level, but) a lacking power supply
08-26-2010, 06:23 PM
#9
Yankee
Join Date: Oct 2003
Posts: 3,599
... you can think it is the amp... you would be wrong though (pretty sure for what little info I have)
As long as your power wire (+ and - lines) are 8 gauge or larger you should be able to power the new amp. Just because the old amp works doesn't guarantee the new amp isn't a little more picky on the quality of the power you are serving it.
If the new amp makes 800 watt MAX power then the car needs to provide 880 MAX watts to power the amp and the speakers, the voltage needs to be > 12v so if the battery/ alternator is weak OR the wiring is sub-par then that could cause issues and if it was a non-tight connection it would seem very random when it works and when it doesn't. Now put in a smaller amp and there is 440 max watts available so it is much easier to drive.
Now if the amplifier was ca-put it would be ca-put in the car and on the bench (95% of the time)... are you feeding the amp some kind of weird speaker load?
As long as your power wire (+ and - lines) are 8 gauge or larger you should be able to power the new amp. Just because the old amp works doesn't guarantee the new amp isn't a little more picky on the quality of the power you are serving it.
If the new amp makes 800 watt MAX power then the car needs to provide 880 MAX watts to power the amp and the speakers, the voltage needs to be > 12v so if the battery/ alternator is weak OR the wiring is sub-par then that could cause issues and if it was a non-tight connection it would seem very random when it works and when it doesn't. Now put in a smaller amp and there is 440 max watts available so it is much easier to drive.
Now if the amplifier was ca-put it would be ca-put in the car and on the bench (95% of the time)... are you feeding the amp some kind of weird speaker load?
08-27-2010, 12:59 PM
#10
500 Watt CAFz'r
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If the "broken" amp tested fine on a bench, the vehicle's wiring/other components are suspect. I have leaned heavily on the wiring side from the get-go, and as JohnVroom mentioned, even the impedances the amp is seeing can cause problems like this, but that is STILL a wiring issue LOL If the car battery was pooched, the whole car would be dead. If the alternator wasn't working, the battery would eventually drain, the whole car would be dead. A computer's power supply doesn't provide the same amount of current the car's battery can, so if the amp is powering up off of that, the amp is fine. Did you meter the power wires @ the amp? What voltages are you seeing? Have you metered the speaker wires @ the amp to see what impedance it's seeing?
