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why do hi-end fuses keep blowing, while std don't?

I've had my McIntosh MC275 for several years running flawlesly. Up until last Nov I was using stock KT88 and rolled small tubes and had a Hi-Fi Tunning fuse without issues.

In Nov-13 I upgraded the KT-88 to Psvane black bottles measuring 60mA plate current. A few power-ons after I rolled the tubes, I turned on the amp to let it warm up, but returned to a blown fuse. I thought a tube might be bad so used a std fuse, but never had a problem again.

Two months ago I bought a new high-end fuse, replaced it, and soon thereafter the same happened: blown fuse. I replaced it with a std fuse again, which is still running.

So I want to upgrade the fuse, but chances are if I use the 2A fuse it will happen again. Yet I don't want to use a higher value fuse. I'm thinking the Psvanes might be drawing significantly more current than the stock KT88 and the Hi-Fi Tunning fuse might have a tighter spec, driving said fuses to fail while the std ones survive. Would you agree?

Suggestions as to how to resolve this?

thanks much!
lewinskih01

Showing 8 responses by geoffkait

geoffkait's avatar
geoffkait
23,365 posts
 
Oh, yeah! Like I’m the one missing the point. Break me a give!
geoffkait's avatar
geoffkait
23,365 posts
 
What's the moral to the story? As my old boss at NASA used to tell me, never get behind anyone 100%.
geoffkait's avatar
geoffkait
23,365 posts
 

A.E.’s are more skeptical than E.E.’s. But more to the point A.E.’s investigate rather than proclaim some conclusion or another without a thorough and complete investigation. That is, after all, the scientific method. That’s how we progress. But RM is not alone, I know many high end amp designers who are cock sure they’re right about a lot of audiophile ideas that have been accepted over the past twenty years. Like fuses, directionality of fuses, directionality of wire, aftermarket power cords, directionality of power cords, stuff like that.


I repeat, of the approximately 90,000 aftermarket fuses sold there has not been a single component damaged by a fuse that has been documented and verified. So,I think it's safe to write off RM's "experience"  as a fluke and dismiss him as one would any outlier.

geoffkait's avatar
geoffkait
23,365 posts
 
“Yes, Modjeski is skeptical (to put it mildly) of the audible benefits of power cords, fuses, overly-expensive (define that as you wish) interconnects and speaker cables, etc. But one thing you can be sure of, even if you don’t consider him an audiophile: he is an expert at electronics, circuits, tubes, transformers (he winds his own), and, yes, fuses.”

>>>>So what? That is an exactly example of an Appeal to Authority. That’s why I oft opine high end amplifier designers need to stop being quite so hyper circuit-oriented and step outside their own little comfort zone. And stop insisting they’re some kind of Electronics Wizard.  It’s a big wide world out there. As for high end fuses, could 90,000 people be wrong? You know, there is such a thing as being too skeptical. On the whole, audiophiles would be much better off if they believed in too much instead of too little.
geoffkait's avatar
geoffkait
23,365 posts
 
I knew somebody would bring up Roger Modjeski, since that’s the only case anyone ever mentions. Thanks for accommodating me and reminding everybody! 🤗 The problem is that somebody who hates aftermarket fuses and audio tweaks is the one reporting it. I put very little credence in that report. Besides, geez, that incident was so long ago as to be absurd. I assume there hasn’t been a similar case before or since. How long ago was it, ten years? More than ten? Who cares? As I am find of saying, amp designers are always the last to get the memo on fuses, power cords, isolation, just about anything that isn’t a circuit. It’s called having blinders on. 😎 Audio Circle was the perfect audience for that kind of nonsense, I will grant you that.
geoffkait's avatar
geoffkait
23,365 posts
 
In the long history of audio there has never been a single documented and verified component damaged by a high end fuse. If anything, by blowing too quickly they prevent damage to equipment. What a load of horse hockey! 🏒 Are some audiophiles really that superstitious? First they complain audiophiles fuses blow too fast. They must have got bored with that approach and complain they don’t blow fast enough. 🎻
geoffkait's avatar
geoffkait
23,365 posts
 
Don’t be a hater, Georgie. Be a lover.
geoffkait's avatar
geoffkait
23,365 posts
 
Most likely std fuse blows go unreported, so it would probably be unfair and untrue to say only audiophile fuses blow. 
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