I had the fuse in my Klipsch iFi subwoofer blow. It's a 2A 125V slow blow fuse. Went to a couple Radioshacks and they only carry a 2A 250V fuse. Is it okay use that as a replacement? At the first the lady said, "Probably, but I wouldn't bet my life on it." Second store guy said "You only have to worry about over-wattage."

My concern is that if something hits say... 200V and the fuse doesn't blow, will I end up damaging other components downstream?

It is my understanding that current blows a fuse, not voltage. So you can happily use higher voltage parts.

Yes, it is fine. It is the current rating that you need to pay attention to; that and whether it is fast blow or slow-blow. Most fuses seem to be 250V anyhow...

Thanks guys. What's the purpose of the voltage rating then?

the fuse may blow but still conduct (due to arcing) if the voltage is higher than rated

wikipedia

about 1/3 of the way down.

So now I have in my hands a fuse that says 125/250V...

Just means it can be used for either.

And now I stuck it in, turned it on, and instantly blew the fuse... I guess my problems are a little more complicated now.

No, they were a little more complicated before, you just know that now.

(I mean, seriously, how else do you blow a fuse on a speaker, unless you got amp problems?)

Did you put the fuse in the right way around?

Did you put the fuse in the right way around?

Got a multimeter?

Borrowing one tonight. Going to check the current across the holders later tonight.

Dont do that, measure DC voltage. Likely to blow your sub if you try and measure current by replacing the fuse with the dmm, since there is definitely something going on.

What value should I be looking/hoping for?