Are all fuses created equal?

I'm not an electrical engineer, the are much smarter people on this forum than I, but it seems to me that replacing a slo-blow with a fast blo fuse presents less of a risk than vice versa. The fast blo fuse should fail faster than a slo-blo, which would mean less risk of voltage spikes throughout the remainder of the circuit.
I would definitely try to obtain fuses with identical markings tho. I just went to rat-shack and the guy there selected the slow-blows for me, i brought my blown fuse with me and told him I wanted a slow-blow version. I also scoured the internet and found a list of approved fuses deep in the innards of the Rotel site. it was a spreadsheet of fuse types per amp.

as long as it meets rating it's good. the longetivity or built quality may differ.

here is Wiki fuses.. everything you might want to know about fuses:
http://en.wikipedia.org/wiki/Fuse_(electrical)

If they're correct rating and UL listed, they should be.

Hi Nick,

I suspect that the original fuse was a Cooper Bussmann MDL-2-R, for which the manufacturer's datasheet is shown here. Does that appear to be correct?

And what is the manufacturer's part number of the replacement you ordered? That number should be indicated on the catalog page of the distributor you ordered it from. It should then be possible to find the manufacturer's datasheet for that part number, and compare the technical specifications of the two fuses.

Without comparing the specific technical data, I don't know what the differences are between the MDL and ADL series. Based on a quick search, I couldn't find any relevant information about ADL types.

To address the more general questions, the major manufacturers of standard fuses, such as Cooper Bussmann and Littlefuse, provide detailed technical info in the datasheets that are available at their websites. I haven't had occasion to make any comparisons between their specs for similar fuse types, but I would expect that for similar fuse types made by the major manufacturers some spec differences would exist, but they would be minor.

I would not expect the same to necessarily be true in other cases. I have seen a number of posts here in the past indicating that users have found some Radio Shack slow blows to act more like fast blows. And concerning audiophile-oriented fuses, I second Elizabeth's earlier comments.

Concerning substituting slow blows for fast blows and vice versa, obviously substitution of a slow blow for a fast blow will compromise protection to some degree, while substitution of a fast blow for a slow blow may result in frequent blows that are unnecessary.

Best regards,
-- Al