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Fuses keep blowing out on amp

getrdone52

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I have a 500 watt JBL 10'' sub with a Jensen 400 watt max out put amp. I had it hooked up for about 2 days and the fuse on the amp blew out. I was just sitting in the parking lot when it happened and it wasn't loud when it blew. Before I put the back up fuse in I checked all the wiring (me and a friend hooked it up) and everything looked good so as soon as I turned the truck on my the other fuse blew out. So now I'm thinking we bridged it wrong or the ground is bad. Idk I'm not too good with electrical issues so any help would be appreciated!
 


DJ Skillz

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What is the impedance of the sub? For example if it's a dual 4-ohm voice coil wired in parallel to 2 ohms, and the amp can only handle down to a 4 ohm load, that could be causing it.
 

kcm1582

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Do you have the specific models of amp and sub? May be a ground issue, where did you ground to? On the other side it might be in the wiring for the sub, since you said the amp was bridged I assume it is a 2 channel, is the wiring in the correct terminals and is the sub wired to the right ohm load?
 

getrdone52

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What is the impedance of the sub? For example if it's a dual 4-ohm voice coil wired in parallel to 2 ohms, and the amp can only handle down to a 4 ohm load, that could be causing it.
It's 4 ohm.

Do you have the specific models of amp and sub? May be a ground issue, where did you ground to? On the other side it might be in the wiring for the sub, since you said the amp was bridged I assume it is a 2 channel, is the wiring in the correct terminals and is the sub wired to the right ohm load?
I have the links to them
AMP: http://www.sonicelectronix.com/item_37042_Jensen-Power-400.2.html
SUB: http://www.jbl.com/estore/jbl/us/product/productDetails.jsp?pid=CS1014

I stripped some paint under the floor and screwed it into the floor. Ya the amp is 2 channel but if I didn't wire the sub and amp correctly wouldn't it not work at all?
 

--weezl--

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i forget the wattage on my system, but the ground for my amp is between the bolt for my passenger seat, and the bracket for the seat... no scraped paint, and i've yet to have an issue...

just to be clear, it's the fuse on the amp it's self, not the wiring fuse, right?
 

getrdone52

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i forget the wattage on my system, but the ground for my amp is between the bolt for my passenger seat, and the bracket for the seat... no scraped paint, and i've yet to have an issue...

just to be clear, it's the fuse on the amp it's self, not the wiring fuse, right?
I'm gunna move it to the bolt in the seat like you said. And ya its the fuse on the amp not the wires. I need to go get more fuses this weekend and I'll try it out. I hope it works!
 

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Amp could have a fault in it too


Sent from somewhere naughty!
 

DJ Skillz

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Amp could have a fault in it too


Sent from somewhere naughty!
This could very well be. Jensen amps are not exactly known for being reliable. Try running the amp with no load for a while and see if it still pops fuses. If it does, then it's most likely the amp itself.
 

--weezl--

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Also what's the gain set at?

Trying not to get too technical, but there is 2 different ways to control volumes, amps, and pads, a pad control literally pads down a constant signal, as a result there is no issue with moving the control to anywhere in the range that it moves. The amp control on the other hand actually controls how much power goes to the amp, and how much sound is produced in the amp, this volume control should never be turned up past 3/4, or you risk blowing the amp...

90% of the time an amp's gain or volume control is a true amp control, and not a pad, the easiest way to know which is which, if it says something like -35db then -20db, -15db, -10db, -5db and 0db being full blast, that is a pad, those numbers is how much sound the pad is removing, amps are typically 0, 1, 2, 3, 4, 5 or something similar, the highest number being full blast...

You will sometimes see hybrid controls, as I call them, it's a combination of both, 0 is somewhere in the middle... 3/4 should be taken as 3/4 of the distance from 0 to the top of the chart...


If you have been running it at more than 75% (3/4) there's a good chance that is your problem


Sent from somewhere naughty!
 

kcm1582

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Amp could have a fault in it too


Sent from somewhere naughty!

That's true, Jensen isn't exactly the highest quality manufacturer when it comes to audio equipment, and I've never had luck with them.
 

509lifted

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ok here is ur problem cause mine is the same what u have wrong is a 500 watt sub bridged to a 400 watt max out put amp so in reality ur amp can only handle roughly 200 bridged u need a bigger amp
 

kcm1582

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ok here is ur problem cause mine is the same what u have wrong is a 500 watt sub bridged to a 400 watt max out put amp so in reality ur amp can only handle roughly 200 bridged u need a bigger amp

:icon_confused:

Not even close, the sub and amp aren't the best match but that is far from the case. RMS power rating is what really matters and the amp pushes 200w @ 4ohms, and the sub is only designed to handle 125w.
 
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--weezl--

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not quite there... if you under power a sub, it doesn't act like a short and burn the amp out... it's not like normal electronics, there is impedence there regardless... if you connect a 50w amp, turn it up to the top end of normal operating range, and hook it up to a 1000w sub, the amp will work just fine... the speaker won't do much though...

not to mention that i have no idea where you got 200w from... if it's 400w max output, it's 200w per channel (provided it's a 2 channel amp) bridged would be 400w if it says 200w per channel, but no total wattage, it would still be 400w bridged... your logic only works if he's NOT bridging it, which he is

the other question is if it's 400w peak, or 400w rms... big difference... my sub can handle 800w peak, but only 400 rms... it's recommended for a 200-400w amp, it's powered by a mono 500w amp, and i've had no issues... actually, that's not true, i blew a 300/600w shallow mount with that amp, though it didn't blow like normal, it just rattled it's self to pieces, the voice coil was fine, and no burning smell
 

kcm1582

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sub

  • 10" Single 4 Ohm CS Series Car Subwoofer
  • Power Handling:
    • Peak: 500 watts
    • RMS: 125 watts
amp
RMS Power Rating:

  • 4 ohms: 75 watts x 2 chan.
  • 2 ohms: 100 watts x 2 chan.
  • Bridged, 4 ohms: 200 watts x 1 chan.


All numbers came right off the sonicelectronix site. So like I said the sub is over powered, but that would blow the sub not the amp.
 

--weezl--

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not really overpowered... you can safely run a 50w sub on a 1000w amp, as long as you set the gain properly... but yes, you would blow the sub, not the amp
 

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