fuses - the $39 ones or the 85 cent ones

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.

I was curious about the theory that vibration applied to wires and/or electronics would generate some kind of signal.

Try this. Get a male XLR connector, and solder a 50-100 ohm resistor between pins 2 and 3, and connect pin 1 to the XLR shell - this emulates the source impedance of a microphone. Connect this through a typical cheap guitar-store microphone cable to any reasonably low-noise, high-gain mic preamp, and crank it up to full gain and listen.

Now slap the microphone cable around, and you will hear the effects of cable microphonics - they're obvious. Substitute a typical pro-grade cable (i.e. Belden 8412), and you will hear a significant difference. You might actually be able to repeat this with your phono-cable leads - it's just that the cartridge itself is microphonic as well, so it's less definitive.

But that's of course NOT the reason that some fuses have sand in them. The sand keeps the fuse filament from failing for mechanical reasons (i.e. shock, mounting position) when the fuse is operated continuously near its rated current, and the filament softens.