05-12-12: AlmargThanks, Al. That's more or less what I thought when I looked at it. I suppose that means that the differences heard among fuses are either...
The most notable differences occur for non-harmonic frequency components that are at levels of 60 or 65 db or so below the amplitude of the 60 Hz component. Those differences were generally in the direction of favoring the expensive fuses, but in some cases favored the stock fuses. But consider that 60 db corresponds to 0.1% in terms of voltage, and 0.0001% in terms of power. And along the lines of Roger's comment, those percentages will be GREATLY reduced by rectification, filtering, and in the case of many components voltage regulation, that occurs in the circuitry between the output side of the fuse and the signal path.
1. Misperception.
2. Misattribution.
3. Attributable to other variables.
I'm interested in knowing which of these it is, though evidently it's not an easy question to answer. Within a week I'll have fuses from Hifi Tuning, Isoclean, and Furutech, in addition to the stock fuses. I will do my best to A/B, A/C, A/D, B/C, B/D, C/D them. It's certainly not science, but it's something.
Bryon