The other day I blew the 25 fuse on my amp, threw in a 40 and it was working fine, this morning on the way to work, halfway through godsmack, the sub just stopped working....i wasn't blasting it either, just moderate loudness, the fuse on the power line and on the amp look fine. I had the sub setting to a 6 out of 15, could that 40 be too big of a fuse? any ideas of whats going on? thanks guys and gals

If your amp was manufactured with the 25 and you put a 40 in there...1.) you masked the problem 2.) The circuitry in the amp may have only been able to carry 25 amps or less...you may have melted some internals or burned something up.

Did the amp just go into protection mode? If you blew the 25 amp fuse, you really should have replaced it with a 25...and if it happened again, you should have then had it looked at to determine what's shorting out. Putting in a higher fuse is a bad idea and can often times lead to stuff burning up/fires.

Also, are there any fuses inside the amp that could have blown? Or maybe fuses on or near the headunit? Good luck...hopefully the amp isn't toast.

mmm... well the 40 has only been in there for a day, i planned to stop at the hardware store after work to pick up a 25. i doubt its busted up, well i have my fingers crossed anyways. :/

its in protection mode...

check your ground,I had the same prob,went twice as heavy with ground wire than power and that fixed it.

went twice the size for ground

mmm my ground is pretty snug and my ground wire is 8 guage i think? pretty beefy definitely the same size as yours baja. i just put in a 25 fuse and it still won't work. The led's will light up but thats it. since it was working earlier this afternoon i'm gonna say that something inside is melted.... for $12 the dealer will fix it and send it back to me within 2 weeks. i guess i'll be off to the post office in the morning.

going into protect mode usually indicates one or more mosfet output transistors has shorted.Thats out of the manual for my amp.

mm i'm hoping they can just fix it up real quick and get it back to me. the music sounds okay right now, but i really need those low and deep wavelengths back.

like was posted above only put same fuse in never use larger thats asking for issues. there can be several issues goin on. and would need more information.

1) what's the RMS power of the amp?
2) what Ohm load is amp stable to?
3) what is the RMS of the Speaker(s)?
4) what Ohm load is speaker(s)? and how many voice coils?
5) are the sub(s) still good? take a ohm meter to them and see what they read.
6) make sure ground is to a clean, un painted metal surface and bolted solid (i prefer to use a factory bolt, or i drill a hole and use nut & bolt so i know it's solid) don't do the 2-3 screw in ground they suck.
7) do you have a fuse under hood by battery?

just bc a shop if fixin the amp doesn't mean that the problem your having will be fixed, could be something else going on here.

ok i've found this so far
NITRO BMW-481 (BMWX-481) <br>2-...800W AMPLIFIER for the amp
Sony XS-L1237 12" 4-ohm subwoofe...rutchfield.com for the sub

i do have a fuse under the hood, but its fine and the ground is clean. i'm not too sure what all thus RMS stuff means... i have a meter and can make measurements soon. with the amp... when i first blew the fuse the two blue led's would still light up when the reciever was turned on, just no music came out. once i realized it was the fuse i made the mistake of replacing the 25 with a 40. after a day when i was driving home the sub just stopped working. replaced the fuse and still nothing. when i turn on the reciever the led's still light up. just no sound. when i turn on the reciever the amp is in protection mode. where should i go from here?

RMS is the true power a amp puts out or a speaker can handle.. Max/Peak is a useless rating thats there for people who like to see big numbers.

looks like that amp does 200w rms @ 4ohm bridged. and the sub is rated @ 75-300 rms (which is a strange listing) but either way should be ok w/ it. just make sure sub isn't distorting. even though your w/in specs you can still blow a sub/amp.. distortion is the bigest killer of stereo equipment.

what i was making sure of was that you were not overpowering the sub. also that the load on the amp was correct. i have seen too many people just hook up any sub to any amp and not make sure they will work together.

**edit**
the reason i was goin to have you measure the ohm load of the sub was to make sure it's still correct @ 4ohm (or very close to that) bc if the sub is blown then you will blow up amp again when you hook it up.

aah, i thought the set up was within each components range when i bought them. its been running fine all summer since i put it in there. its just this week that i blew the fuse for the first time. right now the amp is out of the vehicle. i gotta wait till tuesday to get back at it. so i'll measure the ohm load, and if its around 4 then that's good, but where would i go next?

measure load of the speakers....bc if amp is getting fixed should be good..but if ohm load is like 2 or 0 on speaker and you hook it up again it will blow amp again. just things i do @ shop when checking ppl's systems out.

so check the speakers or sub? the amp just runs the sub, the speakers run off of the alpine reciever.

Subs are speakers too...check all speakers hooked up to the amp (ie the sub).

got the amp hooked back up and everything was a go. sounded mint. just went out to grab some drinks, its back in protection mode. i'll have to check it out tomorrow sometime.

What was done to the amp while it was out of the vehicle?

Just curious...do you have the gain cranked all the way up on it? That'll overwork an amp really quickly as well. Also did you ever ohm out your sub?

well they just sent the back to me with the same package i sent it in and without any receipts, or paper so i have no idea to tell the truth man. : / the gain wasn't cranked. i bought a multimeter but am trying to figure out how to get an ohm reading. the sub has to be hooked up the amp to get a reading correct? Sorry guys im totally amateur at this...i'm trying to get it!!

It could also mean that your amp is overheating. I don't know where yours is but mine is underneath my backseat and that little of space for breathing room can make it heat up pretty quickly, and make the sub stop working. This has happened to me before even when the sub is turned way down.

ya i have it in an area thats pretty open so i hope its not because of that.

Have you had a chance to try it again to see if it came back out of protect mode? If it comes back out...something is overheating. But it could be due to bad components overheating so you may still be SOL.

As far as checking the resistance of the speakers, you should disconnect them. It's been a while since I took my basic electricity class, but I think if you try to ohm something out while it's still a part of the circuit, you will get resistance from other components in the circuit as well. Just disconnect the + and - wires from the amp and then touch one lead of the multimeter to one wire and the other lead to the other wire and that reading you get is the total resistance. You should never check the resistance of a component while it's powered up either...you can blow your meter up that way.

ya i just tried it and it was still in protection mode, thanks of the instructions on checking the resistance, i found some instructional video about it late last night too. i'm gonna go give it a try.

just measured the speaker load ~3.6
also disconnected the power cord from the amp and checked that ~0.7 assuming that i had it on the correct setting.

^ 3.6 ohms

i tried to measure the voltage coming into the amp...i had my setting at 200m and i was getting a reading for the power and remote at about 3.7volts shouldn't it be reading around 12V when the amp is off and higher when its on?

correction on the 12V setting, i had a reading of 13.36 on the amp when the engine was off, then 14.16 when the engine was on.

That voltage is normal...I'm guessing you got components burned up somewhere. The sub resistance seems okay.

well i'm dumping this amp and buying a new one this week. since i know i have the correct power going in, the fuses are fine, and its still in protection mode, there's an internal problem. i could turn the meter to AC and read the speaker outputs to try and really narrow it down to the real issue, but either way its still busted. more than likely they just did a bad job fixing it, maybe bad soder job or didn't fix everything that was busted. so i think monday morning i'll be looking at the kenwood 600W mono, they had one at best buy that i checked out today, it's nice and compact and will fit in the back of the trunk perfectly and is also pretty sturdy. i was looking at an alpine, but there was too much plastic on it for my liking, plus its a little too big to fit in the trunk with the sub.thanks for the help guys! on the positive i learned how to use my meter and now have a definite better understanding of stereo equipment!

alrighty, back again! i've got the amp hooked up and its working! so now i want to make sure all the settings are correct. i bought the kenwood 600W mono amp which puts out 200Watts for the 4ohm speaker. there is an "input sensitivity control" on the amp, its suppose to to be set to the pre-output level of my alpine reciever. i'm looking at the specs to my receiver and there are two maximum subwoofer output voltage levels 4V/10k ohms and 2V/10k ohms. the settings on the input control ranges from .2 (max) to 4 (min) should i have it set at 2 or 4?

so now i'm feeling a little dumb with this: my reciever has settings for 80hz, 120hz and 160hz also has lpf and hpf crossover. when i'm setting my gain, i want everything on the receiver to be basically off right?

**hit the wrong buttons on the earlier post, my reciever has a max output of 5V /10k ohms... and my gain control on the amp runs from 5 to .2