Synergistic Red Fuse ...

One thing I wonder is how many people actually take the time to a/b the sound with 2 fuses repeatedly. That is what I tasked myself to do. Gotta admit I feel pretty silly now having spent time doing it and not hearing much of consequence. If I had bought the fuse instead of just testing a loaner for free, I would probably pop it in and just leave it there no matter what since I made the investment and the thing seems to sound fine. Once I did that, as time passed, it would become even harder to clearly associate any changes I hear to just the fuse. Heck I change nothing for months sometimes and things never sound exactly the same to me. Is it me? the system? The fuse? The humidity and barometric pressure? Who knows. As long as it sounds good in general day in and day out, and it makes me want to listen more, I am happy and will not sweat those details.

Al, I have a question, if I may---you recently suggested a fuse experiment whereby a garden-variety fuse could be temporarily replaced with the same fuse, but with a much higher amperage value so as to reduce resistance as the variable in sound quality.  Can you explain just what is used in fuses to create the different amperage ratings that then influence failure at the indicated rating?  From pictures, I have always thought that the filament sizes/widths are increased to achieve the higher ratings in otherwise same-type fuses, and this would to my thinking also indicate a reduction in resistance or, as you stated, more of a straight wire approach.  I ask because I have pushed all of the amperage ratings in my boutique fuses, especially in my Maggie 3.6Rs, in an attempt to move toward a straight wire without having to tear the fuse bank out as some Maggie users do, i.e. the stock ratings for the Maggie tweeter and midrange are 2.5A and 5A, whereas I am using 8A and 16A fuses. This nullifies any protective function of the fuses, but I have not had any problems so far because I am careful with volumes and believe I have a stable power supply. Am I reducing resistance in the final signal path by inserting higher ratings/larger filaments? Thanks for your evaluation, and are you thinking of accepting the SR fuse challenge in one of your own components?     

One rather mundane thing I just thought off with the red fuse.   Every fuse I have ever used is glass.  When the fuse is suspected of blowing, you easily examine the filament inside through the glass  for a gap to confirm the fuse is gone and replace.   

Can't see inside the red fuse.   If no sound in device, you either have to take a meter to the fuse and measure resistance or just have a known  good backup available to swap in and try.  But you can't tell if the red fuse is good or not  by just examining it. 

I know that's not very exciting compared to sound of fuses but still worth noting.    Always a good idea to keep a spare good fuse or two around.  You might suffer with a normal fuse for a short time for that then order and replace that with a new red or black fuse eventually.

Can you explain just what is used in fuses to create the different amperage ratings that then influence failure at the indicated rating? From pictures, I have always thought that the filament sizes/widths are increased to achieve the higher ratings in otherwise same-type fuses, and this would to my thinking also indicate a reduction in resistance or, as you stated, more of a straight wire approach.

That sounds exactly right to me, JA. And that is borne out by examination of the detailed technical datasheets that are provided by the leading manufacturers of non-audiophile fuses. Within a given series of fuses, that are similar in most respects other than their current ratings and "melting points," resistances become progressively lower as current ratings increase.

I’ll add that I would expect in general that the characteristics and behavior of fuses in speaker applications figure, IMO, to be much more critical than in the case of many and probably most electronic component applications. First, it doesn’t seem highly unreasonable to expect the small fraction of an ohm resistance of these fuses to constitute an audibly significant fraction of the impedance of many speakers. And of course fuses in passive speakers (and some fuses in active speakers) directly conduct the audio signal, or at least some of its frequency components, as opposed to a mains fuse or a DC rail fuse in a component. Also, since the resistance of a fuse varies somewhat as a function of the amount of current it is conducting, the fluctuations of that resistance as a function of the dynamics of the music will be greater in a speaker application than in the case of most electronic component applications. With the fluctuations in themselves perhaps having audible consequences. Finally, in the case of mains fuses in electronic components, if the AC line voltage at a particular location happens to be significantly greater than whatever voltage the component was designed to sound best at (presumably 120 volts in most cases, for equipment sold in the USA), it seems conceivable that more fuse resistance could actually sound better than less, since it would result in slightly less voltage being applied to the component. But that possibility would not be applicable in the case of a fuse in the audio signal path of a speaker.

... are you thinking of accepting the SR fuse challenge in one of your own components?

As I mentioned earlier in the thread, I suspect I’ll give one of the SR black fuses a try at some point, probably initially in my CDP. But right now and in the coming weeks I’m focusing on other priorities in my system, including a repair the CDP is undergoing, a repair I’ll be attempting to do myself on my vintage tuner, and break-in of my AT-ART9 cartridge and subsequent finalization of the related tonearm adjustments.

Best regards,
-- Al

P.S: Thanks very much to Charles for the kind words he posted yesterday.