Geoffkait 3-18-2018Geoff, you've stated this explanation a number of times in various threads. However with all due respect **even if** fuses are somehow inherently directional in AC circuits to an audibly significant degree I would be surprised if there were a single competent and experienced electronics designer in the known universe who would agree with this explanation.
But when we talk about fuse directionality we’re referring to the idea that the fuse sounds better when the fuse is inserted in one direction rather than the other. A fuse in an AC circuit is directional because what you hear in terms of sound depends only on the signal during the alternating cycle when it is traveling toward the speakers from the amp or to the amp from the wall, whatever. You don’t care what the signal sounds like when it’s traveling back toward the wall outlet. That’s why fuses in AC circuits are directional.
In the case of a mains fuse, when AC current is moving toward the component in the "hot" conductor it is moving away from the component in the "neutral" conductor. And vice versa. So it is moving both toward and away from the component at all times. And a mains fuse is in series with the current in the neutral conductor as well as being in series with the current in the hot conductor, via the primary winding of the power transformer.
And simultaneously, as I'm sure you will agree, energy is being transferred unidirectionally, toward the component at all times, in the form of an electromagnetic wave comprised of photons that is distinct from although intimately related to the AC current.
Similar considerations apply in the case of a speaker fuse, the relevant difference simply involving terminology (the two conductors usually being referred to as positive and negative rather than as hot and neutral).
I will have no further comment on this matter.
Regards,
-- Al