[Waker]

What determines the size of the fuse element--that wire conductor in the fuse that burns when overloaded?  Is it the fuse rating of fast or slow blow, as in, does the slow blow burn slower because the element is bigger/thicker?  Or is it the amperage rating, as in, a fuse that blows at a lower ampacity has a thinner element and vice versa? Is it both?  I've been running HiFi Tuning fuses in my 3.6Rs--nice improvement--quite obvious--easy tweak.  On the speakers, the fuse bank calls for a 5 amp for the mid, a 2.5 amp for the tweeter.  I am using these ratings, but if the mass of the element is larger depending on the above, couldn't these values be pushed a bit to achieve more conductivity? I am already using slow blow--I am not worried about clipping or overload--have plenty of pure and stable curent and lots of power. Thanks to all for your knowledge and experience.         
 

[SteveFord]

There is two basic types of fuses: fast acting and slow blow. The fast acting type will open very quickly when their particular current rating is exceeded. This is important for analog meter movements, which can quickly be destroyed when too much current flows through them, for even a very small amount of time. Slow blow fuse have a coiled construction inside. They are designed to open only on a continued overload, such as a short circuit. The purpose of coiled construction is to prevent the fuse from blowing on just a temporary current surge.
Here's from another online article (from England but useful everywhere)
http://highfields-arc.6te.net/constructors/info/fuses.htm

[BaMorin]

What determines the size of the fuse element--that wire conductor in the fuse that burns when overloaded?  Is it the fuse rating of fast or slow blow, as in, does the slow blow burn slower because the element is bigger/thicker?  Or is it the amperage rating, as in, a fuse that blows at a lower ampacity has a thinner element and vice versa? Is it both?  I've been running HiFi Tuning fuses in my 3.6Rs--nice improvement--quite obvious--easy tweak.  On the speakers, the fuse bank calls for a 5 amp for the mid, a 2.5 amp for the tweeter.  I am using these ratings, but if the mass of the element is larger depending on the above, couldn't these values be pushed a bit to achieve more conductivity? I am already using slow blow--I am not worried about clipping or overload--have plenty of pure and stable curent and lots of power. Thanks to all for your knowledge and experience.       

Slow blow fuses usually have some type of heat sinking material in them as well.
problem with slow blows....besides the chance of frying a tweeter before the fuse blows.......is they sound like crap....mostly due to partial degradation every time you push the volume a bit.  They sound fine for a short period, then start sounding like a dirty connection.  Just my 2¢ worth

[raindance]

I'm not one to place much stock in fuse bypassing or fancy fuses sounding better, but I will suggest that you lose the slow blows and go with regular or fast blow fuses. Or just bypass 'em altogether if you are not worried about frying the speakers.

Slow blow has a coil (inductor) that resists fast changes in current flow. Logic says this will have an effect on rising edges of audio signals. Just how much effect, I can't say.

Fuse wire is thinner for lower current blow. So, 5A fuses have thicker wire than 2A fuses.

I have had many pairs of Maggies and tried most of the tweaks. The fuse bypass made a slight difference. Upgrading the caps made a slight difference. The inductor upgrade makes a slight difference. Getting the speakers set to the exact same tilt made a huge difference as did better stands.

[Wayner]

Fused speakers gives one a false sense of security. They will not stop a fast transient at loud volumes. Let's say as an example, your child was playing while you were gone and set the volume at full blast. You come home from work and decide to have a beer or 2. Then you decide that some nice music, like some new vinyl should be played, so you fire up the system. Perhaps being distracted by the wife or the child, you put your new vinyl LP on, set the tone arm over the lead in and hit the cue. You usually have the volume off, and were unaware that your beloved child has set a trap for you. The stylus hits the vinyl and all of the possible power is unleashed to your wonderful Maggies.

Sadly, there can be but one outcome. The fuses did not save the poor maggies (or anyone else's speakers) and perhaps the amp is now in peril.

A short fairy tale by Wayner

 

Added later: BTW, fuses will not stop any DC components from a failed upstream amplifier, or an amplifier of lesser power in clipping mode. This is what frys speakers.
 

[weitrhino]

Added later: BTW, fuses will not stop any DC components from a failed upstream amplifier, or an amplifier of lesser power in clipping mode. This is what frys speakers.

Agreed.  I submit that underpowered amps are far more likely to clip frying parts and fuses.

[*Scotty*]

For what it's worth I had a pair of MG3s that were saved by the recommended sizes of standard fast blow fuses. I was playing the Telarc recording of Groff's Grand Canyon Suite with 400watts RMS into 4 ohms.I exceeded the recommended power apparently and popped both the midrange and tweeter fuses on the portion of the recording with uncompressed thunderclaps. I would say that it is better to have fuses than not. Also, I can see no reason that would prevent properly sized fast blow fuses from being just as effective when the DC amperage exceeds the fuses rating as when AC exceeds it.
Scotty

[raindance]

You know, as a pro audio guy myself, I am constantly amazed that an audiophile can destroy speakers at all. Clipping is the most violent and unacceptable form of distortion and you have to hit the "rails" repeatedly to generate enough heat to fry a voice coil.

Here is a conclusion:
- If you don't listen very loud (never over about 94dB in an average size space), your preamp never outputs a DC offset on power-up or down, and your amps cannot fail in a mode that puts DC on your speakers, then remove the fuses.
- If you are a metal-head, don't get Maggies.
- If you have wooden ears and can't hear clipping, get a pro-audio system with a limiter.

[Letitroll98]

I'm gonna go in and listen to some Metal at over 94db on my Maggies now.  Maybe I'll leave the fuses in, eh?

[SteveFord]

I've popped fuses on MMGs and Lynda's daughter managed to blow the fuse on both MG1s when I wasn't around to supervise the little darling.
Oddly enough, when a capacitor failed on a VTL the fuses on the 3.6s didn't blow.  Sure made one hell of a racket, though - it sounded like someone banged twice on the front door with a log.
Instead, the ceramic SloBlow on the VTL went.  Luckily, the speaker came through it okay.