At what level?
I have been a "diode guy" since 1981, all types of diodes..
I have performed every test possible on diodes with every mil spec, as well as doin the 4.5 Kelvin stuff now.
Were you in the industry? I worked for diode manu's for 12 years in many capacities.
Jn
The mechanism is very well understood.
A standard cable characteristic impedance given normal manufacturing tolerances, will not display a directional issue. Especially at audio frequencies.
Reflections can only occur when the discontinuity is of the same physical size as the leading edge slew rate.
Jn
I was talking about possible reasons for directionality of cables used in high speed signal transmission since USB was mentioned
I wouldn't go that far, I'm wrong sometimes, at least I can cope with being corrected. I also like learning, I've learned, for instance, it's a good idea to quote you before I reply so that you can't edit it since you like playing word games with people and attempt to change the meaning of what they say, call it survival if you will
Well, I'm inspired. I'm off to give my power supplies a good tuning up - they haven't had one for a while and certainly lots of things affect the tuning as I tap the case with a piano hammer... The case has to sound just right....
He's never going to admit to being that guy, I presume you've seen Mr W's products? Amps "capable of delivering speeds into the Gigahertz range" 😀
At Radio Frequencies, yes, the effect can be significant. At Audio Frequencies the effect is much less pronounced. Transmission line theory is a subject worthy, not of a few page articles, but rather heavy multi hundred page books!
All this talk puts me in mind of the reason that brits have self closing shields over their mains power sockets and why N. Americans recommend putting those plastic plugs into the outlet ... to stop the electrons falling out.
Next thing you know, people will be talking about the different sound produced by pvc vs nylon insulation on wires.
Next thing you know, people will be talking about the different sound produced by pvc vs nylon insulation on wires.
Personally I only ever use gold busbars with diamond insulation. Makes the 2N3055s in the PA sound great.
No. Oscillating electrons are an AC current.Galu said:
A "pulsating direct current" is exactly equivalent to a DC current (not pulsating) plus an AC current.sbrook said:
Do you mean when you drop them on the floor, or when you put enough current through them to make a big bang? What have diodes got to do with cables?Rick Miller said:
For an audio cable to be directional it would need something in its construction which couples electric and magnetic fields together in a way which is sensitive to power flow. The materials used for audio cables cannot do this. Hence audio cables cannot be directional. However, if there is something wrong with the connectors so swapping it round give better contact one way then the cable may appear to be directional.
And, just to be pedantic... "AC Current" is a needless duplication 🙂
Like pin number... or lcd display... Pet hates! 😀
Like pin number... or lcd display... Pet hates! 😀
Is this an outcome of your own observations?
Have you TDR tested cables in both directions and there was a difference in the instrument’s screen?
George
Only a fool would take the position that our present understanding of physics is the final word.
In general no, we have done TDR for 40G backplanes. The terminations are the problem and in audio the impedance mismatch of cable and typical connectors is large. It is worth noting that these are pico-second to nano-second type events. In a typical cable sudden impedance changes would be difficult to create they would spread slowly and be relatively small.
Interesting to note very high quality cable and connectors (gold plated SMA for instance) are far cheaper than many of these audiophile concoctions (sometimes FAR cheaper). Do they show up much, no story but real engineering I guess.
May I suggest a new tweak, c-clamps applied at carefully computed points along a cable to modify the impedance. Better yet Jorgensen clamps made of myrtle.
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Now, this is driving me nuts. Made up argumentation, without any experimental or theoretical support.
Do yourself a favor and check out the Lorentz reciprocity theorem. It will explain why cables are not directional, as much as why antennas will work identically good for transmission and reception.
Only a fool would take the position that our present understanding of physics isn't the final word on audio electronics and other fairly undemanding applications.jfetter said:
Let us be clear about this, when some of our current physics is replaced by something better then two things are overwhelmingly likely to be true:
1. the new theory will include the current theory as a limiting case (e.g. as special relativity includes Newtonian mechanics at low speeds)
2. it won't be audio cable vendors or their customers who make the discovery.
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