Popped some fuses in my amp today.

Poseur

Member
Contributor
:
03.5 Lsr Blue P5
Alright, so I'm generally fairly on top of things concerning my stereo, always overly safeguard, etc. So it kind of caught me off guard today when I was re-adjusting my gains on my amp, after slightly turning things up, I hopped in and drove around a bit and was enjoying my newfound extra kick, then on a long extended drop popped the three 30a fuses in my 1100w monoblock. I've got them fused on my dist block as well with a single 80a that didn't pop. SO my question for the gurus is is this normal? I was a bit over-extended on my gain adjustment, I know, but I've been running perfectly fine for 3months of daily use with it set a bit lower. The first thing I did was check my ground, and it's still very good, Is there something strange going on here? I turned it back down and put in new fuses and it works just fine, but in the meantime, I've pulled my other fuse from my dist block because I'm worried something might not be right, and when you've got enough juice flowing to pop 90a worth of fuse, I'd consider it grounds to be a bit concerned. Makes me quite nervous. Perhaps this sort of thing isn't un-common, and I've just never come across it before, and I'm hoping that's the case, but like I said, with thismuch power flowing I'm a bit nervous. I'd die if I managed to burn down my baby.
 
well your fuses in your fuse block are there to protect the wire not the amp. it might have just been a spike the coincided with turning up the gain. remember a gain is not a volume control.
 
maybe try reseting your gains. I wish I knew what the problem was.. but hard to say on this one. the only thing you changed was the gain.. and now you are having problems.. try reseting them.. like you did when you set up your system.. the whole 75% of the volume little under distortion thing. u know what I mean..
 
See the thing is when I initially set everything up, I set my amp for my fronts, that way, but when setting up my sub, I was scared of the amp's power and my sub's relative freshness, so I just kind of left it down a bit. I just remembered this the otherday, so I went to re-adjust everything. Again, a bit timid of my amp's 1100w and my speaker's claimed 1000w handling. So I didn't even turn it up far enough to get distortion, Relative to my front amp (same chassis, same maker, 75x4 class a/b) which I figure from the dial to be set somewhere at about 2-2.5v, the sub amp's set to about 3v. They're both similar amps and I'm unsure if this is a fair comparison or not, but either way, I'm pretty sure I'm not up to full potential. I'm beginning to think that I may just need to run a different ground because it would appear to be a problem with power flow. Annoying thing is that I KNOW my ground's very solid. I'm currently grounded from underneath where the rear Center console bracket mounts to the car. Paint scraped, ring solidly crimped and soldered, etc. Perhaps I'll just bump that up to 2g for my ground. Right now, I've got 2g going to my dist blocks, then 4 running for a short stretch from there. with both my power and ground.

I'd set everythign up and it sounded good, no distrtion even starting, but ultimately I didn't want to be sitting anywhere toolong with my stereo up that loud advertizing to all of the wanna-be-thugs around here. When the fuses blew, I was driving at a constant speed, and Heared absolutely no distortion, or anything out of the ordinary, just all of the sudden "well I know y'all wanted that 808..." and then I had no more bump.

My only other theory is that I'm pretty sure the life of my battery's coming to an end. Running over 1kw through an otherwise FULLY stock electrical system for 4 months now, and I can tell it's getting weak, might that be a possibility of a strange power fluctuation? Wake? of anyone in here, if it's likely to happen, I know you must've run across this before. Anyone else running 2hp or so of sound have any issues with this?
 
Last edited:
Okay, so I got fuses back in, and went out to see if I could dupluicate this situation and I can't! even got my gains up to where they should be right at distortion and backed off a notch. DAMN, and I thought that 12a was hard-hitting before...

Noone has any kind of clue what this could've been? I'm kinda driving timid, but hey the fuses are still there to keep tabs on things. I'm positive everything is hooked up alright, so i'm just gonna go with it, and hope it doesn't happen again at this point.
 
Poseur said:
Okay, so I got fuses back in, and went out to see if I could dupluicate this situation and I can't! even got my gains up to where they should be right at distortion and backed off a notch. DAMN, and I thought that 12a was hard-hitting before...

Noone has any kind of clue what this could've been? I'm kinda driving timid, but hey the fuses are still there to keep tabs on things. I'm positive everything is hooked up alright, so i'm just gonna go with it, and hope it doesn't happen again at this point.
could have just been a spike or something. that stuff happens. cause you are sure you have everything hooked up right. and you know there was no short or anything. so I would say go with it?? glad it sounds better now..
 
It could be that the fuses were weak to begin with, and pushing them that much harder sent them over the edge. The new fuses you installed are just that, new. They will weaken over time as well if you're running close to the rated current through them.

Because audio is not a static load (like a light bulb), it could be that you are drawing upto (and maybe slightly over) the fuse rating...but because it happens on very short peaks only, the fuse may not pop. BUT, on a period of extended low frequency content, this could cause the average current draw to exceed the fuse rating and pop. It's only a theory in this case, but I've seen it happen before.

If your amps are not clipping, I wouldn't worry about it. If you're really curious, get a high current clip-on DC amprobe and measure how much your system is drawing.
 
couple things, i think john has hit on it above, chances are you just had a spike, u can get them that will exceed your fuse rating by more then double the rating, but because its so quick the fuse doesnt blow.

another thing, have u ever looked at the ground wire from your battery to the frame of the car? not sure how mazda's are but on chevy's and pontiac, they usually come with a very small gauge ground wire, and most people overlook upgrading this wire when they upgrade the power wire for their new amp.
 
Thanks guys, thisis makeing me rest a bit easier. Especially before a short roadtrip this weekend. I prettymuch never listen to things that loud anyway, but who knows. Atleast this time I've got an extra bunch of fuses in the glovebox so that jsut about assures they'll never blow, right? ;) As far as grounding, I've been intending to do a multi-point grounding setup, but for the time being have only piggybacked the stock negative batt to the car with a 2g. But I'm about to get real serious with the rest of that soon here.
 
Poseur said:
Thanks guys, thisis makeing me rest a bit easier. Especially before a short roadtrip this weekend. I prettymuch never listen to things that loud anyway, but who knows. Atleast this time I've got an extra bunch of fuses in the glovebox so that jsut about assures they'll never blow, right? ;) As far as grounding, I've been intending to do a multi-point grounding setup, but for the time being have only piggybacked the stock negative batt to the car with a 2g. But I'm about to get real serious with the rest of that soon here.
I made my own ground kit. I used the lenghts from 1sty's kit. I have the measurments if you need um.. let me know.
 
I think I've got a thread about it bookmarked somewhere, but yea, Definately I'd really like the lengths, I've got lots of time on my hands lately. Initially I was gonna just buy one from 1st, but now that I'm broke, I think scrounging for spare lengths of wire I've got sitting aorund sounds much more doable.
 
I wanted to support 1st, but I had a 15ft piece of 4Ga from an old system. So I just got soem terminals and went at it. plus I had to use differetn terminals than what he has. and I used a 2Ga wire to the fuse box. So I just did it my self. I have have the lenghts in a PM I will forward it to you when you rae ready.. lata
 
Fuses on an amp protect the amp from issues with the speaker wires. I would recheck your connections at the subwoofer. It sounds like something may be loose and cause a quick short.
 
Back