I've got a friend who owns a shop that sells Audioquest, I heard no difference trying ANY of it with my kit (which is average) and with £350,000 worth of visiting Krell / Sonus Fabre down in their demo-room.
Even the friends partner - in audio for 100yrs - admitted he couldnt hear difference.
Backwards or forwards in it's directional-ness made no chuffing difference.
That it is written in this patent, doesn’t make it true.
All ferroelectric crystals are piezoelectric but not all piezoelectric crystals are ferroelectric.
Ferroelectric materials are a subset of piezoelectric materials.
I haven’t found anything in the literature implied or explicit that SiO2 is ferroelectric.
We need a Materials Scientist to inform us.
George
The ferroelectric AC cleaning patent shows a certain amount of confusion. The author goes on about 'contact area' as though it was really important. The size of the device (150mm long) means that it can only remove VHF and upwards - not the dominant interference on mains supplies? I suspect what is going on here is that a minor issue, in most cases unimportant, is being blown up into a major issue. The alleged major issue sells the device; the minor issue, being real (but tiny), fends off criticism from people like us.
According to Wikipedia, it isn't. More confusion in the patent. However, sand is a lot cheaper than most ferroelectrics.scott wurcer said:
It is a fairly rare property. I first heard of it 40 years ago, when very few people had heard of it. It just happned that someone in my undergrad physics department was researching it.Rick Miller said:
Clever, they had a hard time coming up with a product name.
Denial, hmmmmm, let's move the "i" a bit so it's not so blatantly obvious. Denali, there we go, much better.
It is well known that if you want to sell something at a high price to certain audiophiles it helps if you use a relatively unknown (to them) technology even if the conventional technology would do a better job at a cheaper price.
I can see no technical benefit in dissipating unwanted signals in ferroelectrics (assuming the device works as claimed) when you could use ferromagnetics instead and get a much wider bandwidth of attenuation.
I can see no technical benefit in dissipating unwanted signals in ferroelectrics (assuming the device works as claimed) when you could use ferromagnetics instead and get a much wider bandwidth of attenuation.
Usually there is a distinction made between the complex wave impedance and the so-called characteristic impedance, the latter given by SQR(L/C) and valid at high frequencies, denoted as rated line impedance or Ci and is by definition not frequency dependent.
The complex wave impedance includes more elements like the resistance and losses, inductance and capacitance per unit length as well. It is frequency dependent for most cables (rising with lower frequency), an exception are special constructions that keep the variation low even at low frequencies (often by introduction of more lossy elements).
As line cords don´t know that they are used as line cords they behave not differently as other cables in this regard.
Dependent on the actual contruction the complex impedance might be different when comparing "hot - neutral" and "hot - earth" or "neutral - earth" but that relates to the different noise mechanisms existent on the power lines.
The power line impedance is (according to the literature) varying with frequency, means quite low at power line frequencies and rising with frequency. Variation range is bigger in the USA compared to the EU, although the curvature is similar. Power line impedances measured for example in Turkey and Japan show other impedance numbers wrt frequency. The publication for Turkey was afair more detailed and delivered measured numbers for rural,urban and industrial power nets. All different to a certaind degree.
See the attached gif (J.R. Nickolson, J.A. Malack. RF Impedance of Power Lines and Line Impedance Stabilization Networks in Conducted Interference Measurements.’ IEEE Transactions on Electromagnetic Compatibility, May 1973, 84 - 86.)
Attachments
What you call the 'complex wave impedance' is actually the characteristic impedance. The problem is that many do not realise that at lower frequencies it is complex and frequency dependent. They see Z=sqrt(L/C) and think this is the definition of Z, when in reality it is just the HF approximation.
When designing powerline modems, etc. the telegraphers equation was of little use. Impairments like an indeterminate number of bridge taps/splices made it look like a mess. You will also notice the magnitude of the PL impedance does not go up at low frequencies.
No. You said:Jakob2 said:
My understanding is that the definition of characteristic impedance is either of the following:Jakob2 said:
1. the input impedance of an infinite line
2. that impedance which if placed at the far end of a finite line would result in no reflections and the same impedance seen at the input end.
Hence there is not usually a distinction made between complex wave impedance and characterisc impedance; they are the same thing.
Characteristic impedance is not an HF concept; it applies to any ideal TEM mode transmission line at any frequency. It is the usual formula which applies to HF only, which may be why some people seem to think that this simplified formula somehow defines characteristic impedance as an HF-only concept.
The wave impedance is ratio of the transverse components of the electric and magnetic field, and is in general a complex number, as much as the characteristic impedance is in general frequency dependent. Only for a pure TEM plane wave traveling through a homogeneous medium is the wave impedance equal to the characteristic impedance of the medium (e.g. 377ohm for vacuum). Since power lines are not even close to a TEM propagation mode, we cannot conflate the two concepts.
Seems to be a matter of the nomenclature. There are in the german literature some inconsistencies, where "wellenwiderstand" and "charakteristische impedanz" (i.e. characteristic impedance) were used as synonyms but additionally as distinction in the way i described in my post.
If that distinction is made, then the term characteristic impedance denotes for example the rated impedance of a given coaxial cable like RG 58, the rated impedance is 50 Ohms although the "complex wave impedance" isn´t, as it covers the variation in the lower frequency region.
As said before, if the distinction is not made, then there is no distinction.... I still think it is obvious from my post, but i should have checked if this distinction is common in the english/american literature. My bad .....
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