G'day. Im gonna be running a 4 x 50w rms amp, but only using 2 of the channels (for now), so what size fuse should I use for the power line. The amp already has a 30amp fuse built in, but this is more to protect the wire. Im just afraid of connecting to wimpy a fuse and having it blow all the time

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Fuse at battery should match, the total of the amp fuse(s). So 30 amps.

If you need to go less, don't go higher.

I know what your saying is right in practice but theory kinda proves it to be wrong.

for example the amp which requires 30amp fuse is powered by 4 gauge wire 5.5 meters long. We know that power is lost the longer the wire is. So assuming the fuse on the amp is getting just enough power to put it on the edge of breakage, would it then not reqiuire more than 30amps of power from the battery terminal because of loss. And if in theory we put a 30amp fuse at the battery terminal would it then not guarentee the amp will never receive the power to fully put it on the edge.

Hmmm food for thought!

Not that anyone ever uses the amp to such extremities for longer than a sec or so cos who can stand the sound of distortion, seriously.

Go the 30 amp, better breaking a fuse than breaking an amp.

Dammit this distracted me looking up my ski trip... Tsk Tsk Tsk

Yeah, I was originaly thinking a 25amp fuse or something to blow b4 the amp's fuse does, but hey, the fuses are all almost the same price, so it doesnt matter

That's right, bigger fuse means more bang for your bucks