@M- I AM!
I think it interesting, that various fuses measure differently, when their direction is reversed: ( http://www.partsconnexion.com/prod_pdf/hft_facts.pdf ) No- I have not personally experimented with reversing my HI-FI Tuning fuses; being quite satisfied with the improvements in presentation, with them inserted arrow pointing toward load.
Hi Al- Sorry I missed your comments. I've found this thread WAY too tedious, to try to follow. Unless I've missed something, since my time at Case Institute; no one has yet actually observed electrons on the quantum level. That leaves Electrical Theory, still theory. No one has yet seen electrons tranverse the chevron shaped crystal barriers in drawn metals, or- if there is a noticeable/quantifiable effect, with regards to their direction. No one yet knows how/what to measure, with regards to the very complex musical signals our equipment is manipulating, and obtaining the best reproduction of ambient info, sound stage(depth/width/height), image specificity, etc. Of course, we do know; the cleaner(blacker) the background- the better the resolution. Nothing I've found has resulted in greater returns, in this regard, than tweaking power supplies(over 30yrs now). It's been my experience, that the better everything before and after these fuses(ie: fast/soft recovery rectifiers/high filter capacity/dedicated 4AWG circuits/carefully selected PCs/decent power purifier for lower current draw components): the more obvious the benefits of these special fuses. BTW: I'm of the camp that holds the power supply as being directly in the signal path. To me; any gain device(transistor or tube, that is) is a switch(or valve), turned on/off(controlled) by the incoming signal and modulating the voltage/current from the power supply, to the following gain stage or speakers. Just my way of thinking($0.02) Best regards- Al
Ah yes, "Conventional Wisdom." About the time of the steam locomotive's invention; scientists determined that the human body could only withstand about a 35MPH maximum speed. It's only been lately, that scientists understood how Bumblebees could generate enough lift to fly:(http://www.news.cornell.edu/releases/March00/APS_Wang.hrs.html) Imagine how bland a world, without these on pizza or pasta: (http://www.tomatogardeningguru.com/history.html)
"No doubt some boutique fuse manufacturers are just supplying the same product for both fast and slow, but that's another story." On what are you basing that assumption? One might replace a fast blow fuse, with a time delay type, BUT- it would be VERY foolish, to do the opposite. ie: Generally; time delay is necessary, to allow a power supply's caps to charge. Rail or B+ fuses need to respond immediately, should a downstream device short/draw high current, or serious damage can occur elsewhere in the unit's circuitry.
Mr B- I wonder what the odds are of one of these fuses getting off the line completely filled. It would then take very little expansion, to result in leakage. Hydraulic pressure HAS to go somewhere. Perhaps combined with a loose cap/poor seal? Manufacturing anything, without some kind of failure rate(however slight), is next to impossible. I just don't believe that it's leaking when it blew, was simply coincidental.
Hello Mr. A- There are fast and slo-blo fuses manufactured in both 6.3 X 30mm and 5 X 20mm sizes. It's the internal conductor/construction that determines the lag time. Generally speaking; a single thin wire would indicate a fast-blo type, but it would be much better to check your owner manual, or with the manufacturer, for the recommended fuse.
Mr A- If you intend to reverse your internal fuses anyway: do your measurements while they are removed from the amp, to eliminate any possible issues. Place them on something non-conductive and be certain not to touch your fuses or probes during the procedure, so as not to affect the results(the variations of which will be minuscule anyway).
The molecular structure of all metals is crystalline. The grain boundaries of the crystals, and oxides between, can act as mini diodes. That's why oxygen-free(7N) and Ohno Constant Crystal wire is so popular, in higher-end cabling. When drawn into wire; the crystals form themselves into a consistent chevron pattern(ie: <<<<<<<). That wire can be found directional when passing electricity, should not be a surprise(even in a fuse).
There's nothing, "theoretic," about the molecular structure and grain boundaries of metals, and the effect on electrical conductivity. Just in case you're actually interested in facts: (http://scholar.google.com/scholar?q=metal+grain+boundaries+and+conductivity&hl=en&as_sdt=0&as_vis=1&oi=scholart&sa=X&ei=Yy9dVMjWKsKcygTgwILYCg&ved=0CBsQgQMwAA)