fuses - the $39 ones or the 85 cent ones

Isanchez -- thanks for such a complete report - yes, you were using your own ears, but this was a comparative exercise to begin with. And thanks for comfirming (my for now mere speculation) that vibration might be the main problem (I hold nothing against gold or silver filaments ;-) BTW, were both of the ceramic fuses you tried sand-filled?

The reason for my interest in mechanically isolating conductors is I've have been working with Purist cables for some time now (including a pair of their new, solid core Provectus speaker cables, Albert Porter kindly lent me to audition.) And I am absolutely convinced that a properly chosen shock-absorbing material around the conductors is essential to achieving the "blackest" possible background in the final sonics.

So it comes as no surprise that something like a hair-thin fuse filament hard-mounted in a chassis (and usually not far from the power transformer!) would sing like a bird.
I wouldn't be at all surprised that the exotic filament metals in the expensive brands might vibrate less than nickle/steel, but for thirty-nine bucks, they could throw in a little silica sand too!
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Nsgarch

BTW, were both of the ceramic fuses you tried sand-filled?

I don't know if the HiFi-Tuning fuse is sand-filled. Perhaps others know the answer to that question.

The reason for my interest in mechanically isolating conductors is I've have been working with Purist cables for some time now (including a pair of their new, solid core Provectus speaker cables, Albert Porter kindly lent me to audition.) And I am absolutely convinced that a properly chosen shock-absorbing material around the conductors is essential to achieving the "blackest" possible background in the final sonics.

I have observed this as well when auditioning cables. For instance, I think one of the reasons that the Nordost flatline series of cables "lean" toward the upper registers is that they are more prone to vibrations than other cables where vibration control has been part of the design requirements.

In the case of my fuse comparisons, the difference between the glass and ceramic fuses was quite pronounced. I think that the ceramic body + sand-filling + the little "bubble", if you will, on the filament, help to explain why the sound is cleaner with the Buss fuse in particular.

I should also mention that on the Maggies 3.6R, the fuses are easily accessible and can be changed in seconds without powering off anything. Of course, I made sure there was nothing playing.

One factor to take into account when trying fuses on a power amp or preamp is that, for safety reasons, the unit has to be powered off. Depending on the design and topology, the unit may need some time to fully perform at its best again. IMO, this can be an obstacle when doing A/B comparisons because there is always going to be a longer time delay between tries. Therefore, one may be hearing the difference between a "warm" and "cold" unit, as well as the difference between fuses.

Isanchez, are your Bussman's MDAs? I got some, and they have no sand in them.

Just heard back from CryoParts, their ceramic tubes are not sand-filled.

I was curious about the theory that vibration applied to wires and/or electronics would generate some kind of signal. So...I put a high gain phono preamp into a closed box with a speaker system, and blasted it with very high volume sound... much higher than it would experience with a normal setup. What came out of the preamp was absolutely nothing. No measurable voltage and no audible signal.

Vibration is certainly bad news for turntables, for tube electronincs, and, at very high levels, for disc players and maybe tape decks. But otherwise I don't believe there is an effect.