short circuit and how it works

[ironslave]

my amp keeps blowing fuses well.. every amp i hook up.. this is from a short circuit... how does a short circuit work... and how do isolate the problem?

[geolemon]

First, basics.

Ohms Law.
Voltage = Current times Resistance.

As resistance goes down, the current flowing goes up.

Electronic components can only handle so much current flowing through them.
Take a fuse, for example. Too much current flows through it... it melts.
Well, guess what? Every electrical component does the same thing. The fuse is simply there so that IT blows first.

Think of an amplifier as simply a voltage source... AC rather than DC electricity. And instead of 60hz AC like in your house, it's frequency fluctuates with the music.

Think of the subwoofers you hook up as the resistance (or impedance, in AC terms... don't worry about it, but technically they present a different resistance at different frequencies, blah, blah, don't give it another thought - they are the resistance).

The lower impedance load (subwoofer/subwoofers) you hook up to your amplifier, the more current you make flow through the amplifier and subwoofer.

Amplifiers are only stable "down to" a certain impedance, because below that impedance, the componentry inside the amp will melt, and the amp will simply die... because of all the current flowing through it.
Or - hopefully if you are lucky, the fuse will blow first. You won't always be lucky. ;)

If you hook up too low of an impedance - you will get the fuse blowing symptom you mention - if not permanent damage to the amp. :eek:

What is a short circuit? It's a zero-impedence (resistance) situation.
Go play with that formula... I don't care what voltage you use... if you have a zero resistance, technically an infinite amount of current will flow - and that'll cause more than fuse blowing. :eek:

What is the solution?

Make sure...
Make doubly sure...
Then make triply sure that your subwoofers are wired properly.

There is no way around it - your subwoofers HAVE to be matched properly to your amplifier. You need to select subwoofers that can be wired in such a way that presents your amplifier with the impedence that it needs - or else select an amplifier that's compatible with an impedance load that you can offer it given the subwoofers that you already own.

You cannot skip this very singularly most important, most fundamental, most basic issue - and being ignorant of it will potentially cost you a lot of money, frustration, and zero bass.

So if I asked you "what impedance are you presenting to your amplifier?" could you answer?

If not - tell me what kind of subs you have (model numbers if possible), and what impedance they are, and how you have them wired, and we can tell you what impedance you are placing on your amp.

Also, if you tell us what amp it is, we can tell you if that's OK or if the fuse blowing you are experiencing should be expected given that load. :cool: