Interconnects, some have directional indicators, why?

It wouldn’t surprise me if under many circumstances a symmetrically designed cable (i.e., a cable having no shield or having a shield that is connected at both ends) were to exhibit directional properties that have nothing to do with the inherent directionality of wire that has been alleged.

A common example of a symmetrically designed cable is a 75 ohm coaxial S/PDIF cable. I would expect such a cable to have small but very possibly measurable differences in VSWR (Voltage Standing Wave Ratio) depending on which way it is connected, due to a combination of soldering differences, mechanical tolerances, small impedance discontinuities in the wire itself, etc. The direction in which it is connected could therefore affect signal reflections and ultimately jitter at the point of D/A conversion.

Similarly, the direction in which a supposedly symmetrically designed analog audio cable is connected could affect energy at RF frequencies that is coupled into or out of the components it is connecting. With the possibility of effects at audible frequencies arising in various ways, such as via intermodulation effects or parasitic diode effects occurring within the components. An extreme example of RF affecting audible frequencies being the many reports that have been seen here and elsewhere over the years of people hearing radio stations when listening to phono sources.

If one has found a symmetrically designed cable to exhibit directional properties, and has verified that the observed directionality is consistent and repeatable across multiple trials, and is not due to extraneous variables such as differences in the warmup state of the equipment, before attributing the difference to inherent directional properties of the wire it seems to me that one must first establish that the cable is in fact symmetrical. And I would feel safe in asserting that no cable is symmetrical to an infinite degree.

So would it be the deviations from perfect symmetry of the cable that are responsible for the perceived difference, or would it be the inherent directional properties of wire that have been alleged by some? As I said here in a recent fuse-related thread:

... it seems to me that audio is somewhat unique in that there are countless technical variables that can be cited for which it is not readily possible to define a quantitative threshold separating what may potentially be audible in some systems from what is unquestionably insignificant. In the absence of that kind of quantitative perspective there is essentially no limit to what a perceived or claimed sonic effect can be attributed to. Or misattributed to.

Regards,
-- Al

The audio signal goes in with positive wire and backs out with negative wire.

That is not correct. During one half-cycle of each of the frequencies that is present the current corresponding to that frequency flows in via the positive conductor and out via the negative conductor. During the next half cycle of each of the frequencies that is present the current corresponding to that frequency flows in via the negative conductor and out via the positive conductor. The directions of the current in each conductor continue to alternate during successive half-cycles. Meanwhile, energy is transferred in just one direction, from source to load (assuming the load is resistive), with the alternating flow of current through both conductors being essential to that process.

BTW, the "positive conductor" is often referred to as the "signal conductor," and the "negative conductor" is often referred to as the "return conductor" or "ground conductor," but the electrons and the energy that is being transferred don’t care about names.

Regards,
-- Al

Regarding my previous post, when I said:

During one half-cycle of each of the frequencies that is present the current corresponding to that frequency flows in via the positive conductor and out via the negative conductor. During the next half cycle of each of the frequencies that is present the current corresponding to that frequency flows in via the negative conductor and out via the positive conductor. The directions of the current in each conductor continue to alternate during successive half-cycles.

… it occurs to me that some may interpret this to mean that current flows in both directions at the same time, as a result of the multiple frequency components that will be simultaneously present in a music signal. To clarify, I did not mean that. At any instant of time current will flow in one direction, corresponding to the polarity (plus or minus) of the voltage that is being put out by the signal source at that instant. The contribution of each frequency component that is present to the total current may make that total either larger or smaller at a particular instant depending on which half-cycle of that frequency component is present at the particular instant.

Hopefully that clarifies more than it confuses :-)

Regards,
-- Al

Hi Jim (Jea48),

I recall the discussion in that 2010 thread, in which I participated. IMO the

long series of arguments between Herman and Simply_q was basically silly

and unnecessary, and to a large extent revolved around the meaning of the

word "flow."


IMO, for pretty much all practical purposes it is reasonable to speak of

current as "flowing," even if that is arguably not what physically

happens. The basic point, as you and I and most of those on both

sides of the issue agree, is that when a voltage is applied to a load via a

cable energy is transferred in just one direction. Assuming, that is, that the

load is resistive, and that reflection effects that can occur mainly at RF

frequencies due to impedance mismatches are negligible. (Which BTW,

as I indicated in my post dated 12-2-16 can under some circumstances

very conceivably cause a cable to exhibit directional characteristics

regardless of the existence or non-existence of wire directionality).


Unfortunately, though, it seems clear that agreement on one-way

transfer of energy (assuming a resistive load and negligible signal

reflections at frequencies that matter) will not lead to agreement on

whether or not wire directionality exists.


Best regards,
-- Al

The issues of fuse directionality and cable directionality involve numerous factors that are different, and discussions of the two issues should not be commingled IMO. Some of those differences are:

1)A fuse has just one conductor, while an audio cable has two or more.

2)The lengths that are involved are vastly different. Most cable parameters, and arguably most cable effects, are proportional to length.

3)An audio cable conducts an audio signal. In the majority of applications a fuse does not.

4)The nature of the contact surfaces that are involved in the two cases is very different.

5)If all wires are directional to a degree that is potentially audible it would seem expectable that the directional effects of a fuse wire would be swamped by the directional effects of the vastly longer associated wiring. In the case of a mains fuse that would include the wiring in the power transformer, the AC wiring within the component, the power cord, and arguably even the AC wiring inside and outside of the house.

6)Regarding empirical evidence that has been asked for in some of the posts above, in recent fuse-related threads Ralph (Atmasphere) has cited experiments he has performed which have determined that the same effects resulting from changing the direction of a fuse can be accomplished by rotating the fuse in its holder. And probably even more effectively. In both cases dimensional imperfections in the fuse and its holder result in differences in contact resistance, and consequently voltage drop is measurably and audibly affected.

FWIW my comments on fuse directionality have been provided in various recent fuse-related threads. See for example the first of my posts dated 10-28-2016 near the middle of this page.

Regards,
-- Al

Geoffkait 12-5-2016
Current traveling down the wire generates a *magnetic field" - that’s the *induced magnetic field* and has absolutely nothing to do with either an em field or the *electromagnetic wave* that is the audio signal. The induced magnetic field is stationary, obeys the right hand rule, whereas the electromagnetic wave (audio signal) travels at near light speed, as I’ve described.

Geoff, I believe this is not correct. It would be more correct for DC, but as you'll realize AC (including audio signals) is continuously changing in both amplitude and polarity. And the magnetic field described by the right hand rule will therefore be continuously changing in both magnitude and direction.

Also, in the context of a signal propagating along a cable I believe it is incorrect to distinguish between an "induced magnetic field" (stationary or otherwise) and the "electromagnetic wave that is the audio signal." There is simply a magnetic field and an electric field. These two fields are what propagate at near light speed.

That said, much of the discussion of these matters, while perhaps of academic interest to a few, IMO has little if any practical relevance.  

Regards,
-- Al

P.S:  My thanks are extended to Marqmike for his gracious if perhaps somewhat premature comment :-)

Kijanki, thanks for the good comments about the Poynting Vector etc.

Jim, wow, the Boulder 3060 is certainly quite a monster -- 441 pounds including its 86 pound granite base, a price well north of $100K, and 6000 watts max power draw. Given the latter, it is of course designed for use with 240VAC, not 120.

Regarding your question, I doubt that anyone could provide more than a wild guess. Partly because the effects on the AC waveform of the 8 foot run you described wouldn’t seem to have a great deal of predictability, partly because those effects would seem likely to be less significant than variations in AC waveform characteristics and voltages among different locations, and partly because we don’t have detailed knowledge of the internal design of the amp. And even if we did have detailed knowledge of the amp’s design it seems quite conceivable to me that extensive tests and measurements would have to be run to pin down the specific sonic character of whatever effects might result, if any.

Best regards,
-- Al