Blowin Fuses Yet Again!

[NucleaRR]

This is my first post in the forum so Hello to everyone. I know that you guys get these questions a lot but please help if you can.

I have a older system that has been in my truck since 2001. The amp is a MTX Thunder 8302, it's bridged to a 900w (peak power) sub, not sure what the RMS is on the sub. From what I can tell from the specs on the amp it is running 300 watts RMS x 1 in bridged mode. Each channel runs a 30amp blade fuse and there is a 30 amp AGU inline fuse. The power and ground wires are 8 gauge and I am running a 1 farad cap. Oh and the power wire goes through a rubber grommet in the fire wall, by itself with nothing around it. I use the RCA out on the head unit to a old inline channel fade knob to adjust the bass level manually.

I am blowing the AGU inline fuse. This started all the sudden out of nowhere. First I thought that maybe the fact that the wires under the hood have been exposed for so long that maybe the corrosion on the wire could be causing the problem. Crimps were used during the original install but there was no shrink wrap on the terminations. I reworked all the connections, the one at the battery, front side of the inline fuse and on the back. I used shrink wrap and made sure to cut back to fresh copper in the wire. I replaced the fuse and all was good for a few days.

I got in the truck and started it up and heard a low intermittent rumble lasting about 2 seconds and then nothing. When the head unit was powered up there was no more bass. I replaced the fuse which worked for a few days then the same thing happened.

I began lurking on here to see what the problem could be and tried a few things that I read. I check all the ground wire connections to make sure the grounds were good. I checked the power wire to make sure that the wire was not cut or grounding anywhere. When the original install was done a wiring kit was used so all the connections on the amp are covered at the ends so there is no frayed or wire strand touching the ground.

Today I decided to make sure that all the connections on the amp were clean and free from debris. At this time I noticed that the remote wire was a little loose. I wanted to know if the wire being loose could cause a fluctuation making the fuse blow. I figured that if the wire lost connection the amp simply would shut off. I am not sure if this could be the culprit.

So all that leads me to this. The amp is older, could it just be done? Something internal maybe? If it is, why does it work for a few days then shut down? Should I try not driving it as hard? I don't really push to much through it though, I mean the gain is barely past halfway. I am not really a bass head I just like to have the full range.

It is frustrating me to have to keep buying fuses to have bass for only a few days. I don't want to do further damage by putting in the new fuses. Plus I don't want to keep treating the symptom and not the cause.

I hope I provided enough info. Please help if you can. Thanks in advance.

Click to read more...

 

[KyleBechtold 5,000+ posts]

inline fuse is too small

 

[KyleBechtold 5,000+ posts]

well.. how many fuses are on the amp?

it may not make sense they are blowing now but had a buddy with a measly little 30a and needed 60a it lasted for a year or two and then blew.. replaced it with appropriate fusing and it works fine

 

[dasinde91 10+ year member]

Dont run any fuse's...........

 

[NoPh33rRaCiNg 10+ year member]

You said each channel is running a 30 amp fuse, there are (2) 30 amp fuses showing on the amp, so 30x2 = 60. Run an 80 or something for the inline between your battery and amp

 

[kr15 5,000+ posts]

your inline should match your amp, it doesnt so your amp is attempting to draw more current that the inline can handle

 

[bugflipper 10+ year member]

20 over as gent above stated is a very good idea. Even in 4 wire there is resistance. Plus under hood temp. The older the wire, the more resistance. The amp may be drawing 50 amps. but engine heat and resistance may still overpower the 60 amp.

 

[Louisiana_CRX 5,000+ posts]

some people just keep replacing fuses by stepping up in fuse ratings till they don't blow no more to solve that problem //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[NucleaRR]

Thanks, everyone for the replies. I had a friend who knew about car audio help me years ago. He said because I was only using one channel from each side of the amp to bridge it that I only needed a 30 amp inline. I didn't know any better. I do now. I already bought some 60 amp fuses thinking that the inline was not enough. This same thing happened back when I got the amp but I adjusted the crossover on the amp and it fixed the issue. I'll pop the 60 amp in and let you guys know how it goes. Thanks again.

 

[The HACKER 10+ year member]

Yes sir sounds like you got it, but a good thing to know, is fuse to the wire size not the equipment. As the fuse is meant to protect the wire not the equipment. Thats why your amps has its own fuses. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[mazdakid 5,000+ posts]

Yes sir sounds like you got it, but a good thing to know, is fuse to the wire size not the equipment. As the fuse is meant to protect the wire not the equipment. Thats why your amps has its own fuses. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

mine doesnt

 

[The HACKER 10+ year member]

Well then pat yourself on the back, because you just won a million dollars. //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

Nah but thats odd, u sure they arent on the inside, what amp?

 

[bugflipper 10+ year member]

Well then pat yourself on the back, because you just won a million dollars. //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif
Nah but thats odd, u sure they arent on the inside, what amp?

A lot of older amps didn't have any fusing. A few had a pencil fuse on the power wire. We used to just do what the gent with the jeep above stated. Better to blow a bunch of fuses than an amp.

 

[Snow90 10+ year member]

your inline should match your amp, it doesnt so your amp is attempting to draw more current that the inline can handle

Wrong.

The inline should match the max current handling of the wire.

 

[QuikSilverRS91 10+ year member]

Wrong.
The inline should match the max current handling of the wire.

+1

If your amp draws 100 amps and the wire can only handle 50, you could quickly find yourself aflame.