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The fuse in my d block for my sub amp was hot as hell, I am using 4 gauge power and ground. Can anyone tell me why it would get so hot? I am using a alphasonik pma4150 on 2 jl 10w7s. I did bridge them on the channels so maybe that was it. I have since wired them back 2 stereo but didn't run it for a long period of time so I don't know if it got hot.
 

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Sounds like you're pulling too much current for the fuse size; what size and type fuse are you using in the block? What are the onboard fuses in the amp rated at?

Keep in mind that fuses aren't on/off switches that blow instantly when the rated current is exceeded.

From the great website Basic Car Audio Electronics

Fuse Opening Time:
A fuse does not blow when the current reaches its rated current. It is designed to pass its rated current without opening. A fuse will take varying times to blow under different conditions. A fuse will pass significantly more than its rated current for a very short time. It may take 10 minutes or more to blow a fuse at 25% over its rated current. The table below is an example of the specifications for a slow blow fuse. You can see that a 20 amp fuse may pass 40 amps of current for as long as 5 minutes before blowing although it probably wouldn't take a full 5 minutes to blow. The times for other fuses will be slightly different.
 

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Discussion Starter #3
its a glass fuse dont know what size cuz it doesnt say it on the fuse. the amp doesnt have an onboard fuse. But i have since switched the fuse for an 80 amp so i will see how that goes. on a side note another question, would/could it be safe to bridge the 4 channels at 3 ohms? i know its a lil low for whats recommended(4ohm) but could it be done and last? I did it for a few minutes just 2 hear what is would sound like and it was great, very clean, but i was afraid 2 leave it that way so i put it back.
 

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its a glass fuse dont know what size cuz it doesnt say it on the fuse. the amp doesnt have an onboard fuse. But i have since switched the fuse for an 80 amp so i will see how that goes. on a side note another question, would/could it be safe to bridge the 4 channels at 3 ohms? i know its a lil low for whats recommended(4ohm) but could it be done and last? I did it for a few minutes just 2 hear what is would sound like and it was great, very clean, but i was afraid 2 leave it that way so i put it back.
just becarefull putting in fuses that are higher than recommended. those fuses are there to protect you amps. you do have a fuse up by the battery as well correct?

most "good" amplifiers will not have a problem with 3ohms. it is a little overdriven that way, just watch your gains. if the amplifier gets overly hot or goes into protect, then undo it.
 

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I respectfully caution against a bridged amp running below 4ohm- but then I do the same for a mono amp running less than 2ohm even if stated stable to 1ohm. It's simply hard on equipment and generates a lot of heat that can be hazardous on its own if not managed properly. No disrespect intended as asking the question shows that you are doing well by expanding your knowledge with regards to this hobby, but it also implies a lack of experience that should be coupled with an extra level of caution and respect while you continue to learn.
 
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