PS Audio PWD MKII HiFi Tuning fuse direction

Geoff, the poster specifcally asked about application of a (directional??) fuse in an AC circuit.

If something can be categorically ruled out on undisputable theoretical basis, I personally would not advocating trying it anyway because "stranger things have happened" and it is better to be "safe than sorry".

If you take this philosophy to its logical consequences, all bets are off. For example, you could consider moving your DAC to other side off your audio rack and hear if it makes a difference. You should also try the black and silver version of any given component before deciding what to buy...

The fuse sits in the AC circuit .... I go along with the alleged efficacy of a lot of hard to rationalize tweaks, if someone says they hear a difference. But directionality of a fuse in an AC circuit goes too far even for me.

Because interconnects sit in a DC circuit, where current flows in one direction. The fuse on the PWD sits in an AC circuit meaning the polarity switches 60x per second. How can directionality of a fuse make a difference when the direction of the current flowing through that fuse changes direction 60x per second?

I have hard time rationalizing directionality of cables and fuses, but in a DC circuit we can at least entertain the idea it makes a difference. In an AC circuit in my view it is categorically impossible there is a difference.

I'm afraid of wasting my time. To me the notion of sound quality difference through directionality of fuses in an AC circuit is as absurd as the notion as the black chassis sounding different than the silver.

....I would, however, discount any reports of perceived differences in which the person did not go back and forth between the two orientations at least several times....

I personally would discount any reports that are not confirmed in double blind test, where the observer repeatedly picks the optimal orientation.

The differences in directionality are only reported in a DC circuit. The AC measurement do not have a direction 1 and direction 2 measurement, because in an AC circuit there is no directionality. The flow of current changes direction 60 times per second.

Even the difference in directionality in the DC circuit are methodologically suspect.

First, the report does not say if the best measurement for the allegedly directional fuses correspond with the recommended direction. If you do two measurements there will always be a random difference between two measurements. To proof directionality, you need a batch of allgedly directional fuses, measure each one multiple time and show that the recommended direction measures better within statistical margins of error. There is no indication at all this is what they did. The report does not even say what the standard diviation is for the measurements, and therefore you cannot tell whether or not the differences are statisically significant or random.

Second, the difference between direction 1 and direction 2 measurement is higher in the non directional cheap fuses, than in the allegedly directional high end fuses. If the expensive fuses were explicitly designed to be directional, you would expect the exact opposite.

In conclusion, directionality of fuses in AC circuit is bogus, and in DC circuit highly suspect.

Obviously you have not heard the PWD mkii black version yet. It sounds best on the top shelf on the left. I had it on the right for a while. Big mistake.

Geoff, again, the difference are measured in a DC circuit. AC current switches direction 60 times per second. Even if the fuse is directional, you would not hear it in an AC circuit. The paper does not even suggest you would. So lots of reasons to be skeptikal about claims of hearing directionality differences in an AC circuit.

I am not disputing you may hear a difference in a DC circuit.

In response to your question, I am just poining out that based on the laws of physics it is categorically impossible that in an AC circuit there is a difference depending on what you direction you put in your fuse, because the direction of the current itself changes direction 60 times per second.

This is true even it the fuse itself is "directional". Paul McGowan of PS audio has made the exact same argument on the PS audio forum. So far, no one has disputed this, but the argument is made "why not try anyway". To me this defies all logic, but that's just me.