Post by: Sahib on December 06, 2007, 05:11:05 PM
Mr Borwick holds BSc in Physics. He taught at the BBC Engineer Training School, He is a fellow of the AES and served as the Vice President Europe Region. He helped set up Bachelor of Music degree course at the University of Surrey in 1971 and was a seniorlecturer. He has been Audio Editor of Gramaphone magazine for more than 20 years. Obviously all of this information about him relates back to 1988 when the book was published.
Below is an extract about speaker cables. The writer of the section is Martin Colloms, whom also has a published book about speakers and seems a credible writer too.
I have been researching this audio cable issue for some time and I am armed with really in depth reference books on conductors and semiconductors and I won't take no mambo jambo. So, it seems a credible book is in my hand, or is that the case?
Bruno and the rest of the gang I would most welcome your views.
| Quote: |
.... Microscopy at a moderate x200 magnification reveals the structure of the conductor. Bar-refined copper shows a highly crystalline makeup, of some 150 000 crystalls per metre. An analysis of the structure indicates that the crystals have a pure interior, while the impurities congregate at the crystal boundaries. The oxygen content is present in the reduced form of Cu2O, a semiconductor. Considering te conductive path between crystals, the boundary has the properties of a junction diode, a capacitor and a low shunt resistance, the latter being the dominant feature. |
Cemal
Post by: dcollins on December 06, 2007, 07:14:27 PM
| Sahib wrote on Thu, 06 December 2007 14:11 |
.... Microscopy at a moderate x200 magnification reveals the structure of the conductor. Bar-refined copper shows a highly crystalline makeup, of some 150 000 crystalls per metre. An analysis of the structure indicates that the crystals have a pure interior, while the impurities congregate at the crystal boundaries. The oxygen content is present in the reduced form of Cu2O, a semiconductor. Considering te conductive path between crystals, the boundary has the properties of a junction diode, a capacitor and a low shunt resistance, the latter being the dominant feature. |
Shouldn't this be trivial to measure electrically?
Is any other industry aware of this?
DC
Post by: bruno putzeys on December 07, 2007, 03:48:37 AM
| dcollins wrote on Fri, 07 December 2007 01:14 |
Shouldn't this be trivial to measure electrically? |
Spot on.
Talk of microdiodes and other esoteric stuff is a classical attempt to explain a phenomenon (audibility of differences in conductor material) which has not even been proven to exist yet. The reasoning goes that if one can offer some plausibloid sciency sounding explanation (sufficiently convoluted to buy into oneself) this excuses one from doing the groundwork. The #1 hallmark of pseudoscientific "explanations" is that proving the truth of the explanation is invariably harder than proving the truth of the original claim.
The person proffering such an explanation will then go on to say that they themselves don't have the equipment to prove this, or worse that such equipment doesn't yet exist, but that once the equipment and/or exorbitant funding become available their hypothesis will certainly be confirmed. We're lulled into believing that it's all but ready to be written in schoolbooks and that proof is nothing but an expensive formality which it is more economical to forgo.
You can scare these people witless by showing that their explanation makes predictions that are easily testable with the current state of technology. The microdiode hypothesis predicts that the resistance of a piece of copper wire is non-linear. Needless to say, no nonlinearity has been shown so far. That should not be a surprise. For starts I didn't know you could make a diode using intrinsic semiconductor material. Secondly, what current density do we need to get enough voltage across these "microdiodes" for them to start affecting conductivity? Enough to liquefy the copper or will we need do vaporise it? So far for "microdiodes" and their psychological resonance with "microdetail". Maybe the genius who knows something that only the inhabitants of Betelgeuse might have managed to prove might first see if his suggestions are at least consistent with the stuff we know already.
Still, the most important thing is that explanations are only called for inasmuch as the claimed phenomenon is first shown to exist. This is not a principle, it's a matter of economy. Sometimes it makes sense to skip a controlled trial if the explanation is easier to prove than the original observation (e.g. astrophysical phenomena that are observed only once). Even then, the explanation itself should be proven in full.
In this case the claimed phenomenon is:
"Conductor composition in loudspeaker cables makes an audible difference."
Next, it is attempted to prove the truth of this statement by this explanation:
"Copper has a non-linear resistance
AND
non-linearities of this order of magnitude are audible."
Whoa. We've just replaced ONE hard-to-prove claim by TWO hard-to-prove claims. Worse still, the second is of the same nature as the original claim itself. Proving the existence of a non-linearity at -180dB still means nothing if the audibility of this isn't also demonstrated. I can't see how we're making headway like this.
Take by contrast the casual observation that a Cary 300B amplifier sounds different from a Halcro DM58. You can skip the listening test here. Just measure distortion of either. The Cary amp measures THD in whole percents, the Halcro amp does not distort measurably at all. The audibility of 2% of distortion has already been rigorously proven so here a measurement is more economical than a rigourous listening test.
Ah nothing starts the day like trashing some pseudoscience good
Post by: Kees de Visser on December 07, 2007, 05:36:02 AM
| Bruno Putzeys wrote on Fri, 07 December 2007 09:48 |
Take by contrast the casual observation that a Cary 300B amplifier sounds different from a Halcro DM58. You can skip the listening test here. Just measure distortion of either. The Cary amp measures THD in whole percents, the Halcro amp does not distort measurably at all. The audibility of 2% of distortion has already been rigorously proven so here a measurement is more economical than a rigourous listening test. |
- the 2% distortion is in the audible band
- the distortion doesn't create audible artifacts further in the signal chain
- the distortion is insufficiently (psychoacoustically) masked by the source signal.
I've read enough about audibility to know that it's very hard to make predictions about it
Post by: Sahib on December 07, 2007, 07:56:44 AM
May amazement is not on the idea that a diode action will exist between copper cyrstals, it is in a book which is edited by a person in that calibre.
I would like to find out if any of AES members picked up on this and whispered into the vice president's ear when the book came out.
Post by: Larrchild on December 07, 2007, 05:26:41 PM
Yet, in RF equipment everywhere, I see mere copper wire and copper coaxial cable and copper traces carrying RF with no adverse effect. Conversely, bad RF in audio gear seldom, if ever, gets rectified by wire, but instead, by transistor junctions and the like.
Here's a copper conductor with about 100,000 watts of RF on it.
That should get those diodes a hopping making some DC on there eh?
Nawwww.
Post by: dcollins on December 07, 2007, 08:38:38 PM
| Bruno Putzeys wrote on Fri, 07 December 2007 00:48 | ||
Spot on. Ah nothing starts the day like trashing some pseudoscience good |
Because cables need to break-in.
Just like film/foil capacitors.
"My speaker cables have an impedance of 8 Ohms"
"Silver cables have more harmonics than Copper"
And for my money, the winner:
http://www.machinadynamica.com/machina41.htm
That should keep us busy for a while.
DC
Post by: Bruce on December 08, 2007, 02:59:19 PM
| Larrchild wrote on Fri, 07 December 2007 17:26 |
An outward indication of this diodic activity would probably manifest itself as demodulation of radio frequencies within the wire itself at some frequency range.(as per the claimed non-linear junctions) Yet, in RF equipment everywhere, I see mere copper wire and copper coaxial cable and copper traces carrying RF with no adverse effect. Conversely, bad RF in audio gear seldom, if ever, gets rectified by wire, but instead, by transistor junctions and the like. Here's a copper conductor with about 100,000 watts of RF on it. That should get those diodes a hopping making some DC on there eh? Nawwww. |
Indeed. I work with rf as my profession. Commercial repeaters are allowed up to 350 watts output in the US, which is about +56dBm. At the same time, the receiver is listening for signals as low as -120dBm. If there is any diode action happening (broadband noise) in the feedline, it is more than 176dB down from the transmitter's carrier, which should suffice for audio.
-Bruce
(PS - Amateurs are allowed up to 1500 watts out or +62dBm, which would push the ratio to 182dB, although I don't know of any repeaters actually operating at that power.)
Post by: Larrchild on December 08, 2007, 04:18:55 PM
You need to have a noise floor, as you say, near -180dBc for it to work. Cell sites would hear their own transmitters, instead of you.
Now there is "skin effect" at rf, where the center of the conductor is not passing current. But still, with 100,000 watts at 100Mhz on the copper FM antenna, I'd expect some residual DC to be created from this effect. Even with poor conversion-efficiency.
Post by: Sahib on December 08, 2007, 05:47:59 PM
| dcollins wrote on Sat, 08 December 2007 01:38 |
the winner: http://www.machinadynamica.com/machina41.htm |
Hey DC,
That was only the second. I was the winner. That was my entry for Dan Lavry's competition.
| Quote: |
In the jungle of audio world how can you hack the best speaker wire? You can’t right? Wrong. Now you can and we bring it right to your door. Free delivery included over purchases of 2 x 6’ at only $2,759.99 per foot. Many long hours, sleepless nights and years of hard work were poured in our R&D department for the discovery of a perfect a speaker cable with a pyramid crystalline structure producing warm lows at which frequencies when your amplifier is sweating most of its power. And our speaker cable takes all that pressure not only from your amplifier but also all the way from your pre-amplifier combating nasty influences of capacitance, inductance and skin effect, while maintaining super-clean upper bandwidth in spite of high frequency transients. Its normalised copper content means that it can handle impulse audio responses at the tiniest signal level to largest with bigger and wider control over audio band and beyond. Built in dual kinematic twisted structure means the directionality of the signal is preserved at the highest with providing equal delay in signals on both channels. Temperature compensated barometric stabilization means that our cable can reduce the jitter level by a factor 1.60773299432111 over 50 bits data. Considering that the most data rate used in digital electronics is 32 bits, a generous head-room of 18 bits is maintained. In the case of non-digital audio applications the logarithmic control is better than the industry standard very analogue to extremely analogue. Finally its superior performance and fast response is sworn by the industry authorities . Just ask Dan Lavry of Lavry Engineering. You will agree that our state of the art speaker wire is the innovation of the millennium. |
Cemal
Post by: johnR on December 09, 2007, 07:48:15 AM
Post by: Sam Lord on December 09, 2007, 04:43:11 PM
| Bruce wrote on Sat, 08 December 2007 14:59 |
Indeed. I work with rf as my profession. Commercial repeaters are allowed up to 350 watts output in the US, which is about +56dBm. At the same time, the receiver is listening for signals as low as -120dBm. If there is any diode action happening (broadband noise) in the feedline, it is more than 176dB down from the transmitter's carrier, which should suffice for audio. -Bruce... |
My point is more general. Why swat flys with a hammer? If both common and esoteric interconnect cables null below, say, 120dB in easy line level-level work (e.g. short length, low-z out, high-z in), and they shield and balance well, what more is there to say?
Once a cable maker (still going strong!) brought to our main room interconnects and speaker cables with all pure gold conductors. They didn't sound good.
Post by: Larrchild on December 09, 2007, 04:52:18 PM
Some guy does have a patent for Gucci wire using unipolar crystals.
Post by: johnR on December 10, 2007, 03:47:01 PM
| Larrchild wrote on Sun, 09 December 2007 21:52 |
You are right as I thought about it, yesterday. Not DC because they are not oriented in series, but some evidence of detection, nonetheless. |
Random orientation would imply random phase of the detected signals. If they all picked up the same signal, and I'm not sure if that would be the case, I suspect they would sum to zero or close to it.
Post by: Larrchild on December 10, 2007, 03:58:33 PM
I'm just looking for a way to verify the phenomenon.
Who knows? If you could excite individual crystals by using voltage nodes of rf on the wire, you might have the computer of the future!
Just not better speaker wire, lol.
Post by: Sahib on December 13, 2007, 10:01:03 AM
I have just got an interesting conversation with an expert from the Copper Development Association in the UK.
Gentleman's comment was that, the idea of oxygen content around a copper crystal forming a diode action is a complete nonsense. In fact he also used the phrase "mambo-jambo". He also commented that the oxygen content in an ordinary copper conductor has barely effect on conductivity.
I realise that we all knew that but I just wanted to bring some credible comment on the issue. My next move will be to drop a note to mr. ex vice president.
Post by: John Roberts {JR} on December 13, 2007, 10:42:39 AM
JR
Post by: Barish on December 14, 2007, 05:11:20 AM
M.
Post by: Larrchild on December 14, 2007, 03:14:25 PM
So, if few elsewhere are convinced, patent-examiners must have really killer systems at home, eh?
Post by: John Roberts {JR} on December 14, 2007, 10:04:11 PM
| Larrchild wrote on Fri, 14 December 2007 14:14 |
There are actually a bunch of patents for fancy crystal copper wire for use in audio/video transmission. So, if few elsewhere are convinced, patent-examiners must have really killer systems at home, eh? |
Or perhaps patent examiners are not required to spend their own money to buy every invention they deem novel enough to award a patent.
The inspection of novelty is far more rigorous than any test for utility.
JR
Post by: johnR on December 15, 2007, 07:27:47 AM
| Larrchild wrote on Fri, 14 December 2007 20:14 |
So, if few elsewhere are convinced, patent-examiners must have really killer systems at home, eh? |
Looking at some of the dubious patents that are granted, I think it is safe to assume that patent examiners do not always have sufficient expertise in the particular field covered by a patent. The fact that the patent office makes money from awarding patents doesn't seem to encourage impartial investigation either.
Post by: John Roberts {JR} on December 15, 2007, 10:29:49 AM
| johnR wrote on Sat, 15 December 2007 06:27 |
Looking at some of the dubious patents that are granted, I think it is safe to assume that patent examiners do not always have sufficient expertise in the particular field covered by a patent. The fact that the patent office makes money from awarding patents doesn't seem to encourage impartial investigation either. |
I agree mostly. While I doubt the examiners get compensated for how many they award, it is not likely that they will be skilled in the art for any of the categories they are responsible for. They are more likely to be just out of school and working to get experience so they can move across the street and make the big bucks as a patent lawyer.
I suspect a lot of the silly patents could be easily shot down if the patent office opened up a public review period and investigated criticism from the general public. But somebody would have to vet these critiques and that would cost money, plus there would be some aggressive disputes raised against strategic patents that are probably better reviewed in court.
It's an imperfect system but better than no system.
JR
Post by: bruno putzeys on December 15, 2007, 12:57:14 PM
Post by: John Roberts {JR} on December 15, 2007, 01:33:55 PM
I have seen patents that IMO game potential prior art interference by using obscure terminology to describe common parameters or mechanisms. While different engineering disciplines may use slightly different terminology the example I have in mind seemed intentional to hide citations from a literal search.
I believe, once upon a time patent applicants also submitted working models in proof of concept. I suspect this was dropped due to logistical burden. I'd like to see the models for sundry perpetual motion machine applications, which by definition should still be running.
JR
Post by: johnR on December 15, 2007, 04:19:28 PM
| John Roberts {JR} wrote on Sat, 15 December 2007 18:33 |
I have seen patents that IMO game potential prior art interference by using obscure terminology to describe common parameters or mechanisms. While different engineering disciplines may use slightly different terminology the example I have in mind seemed intentional to hide citations from a literal search. |
This was actually one of the things I was referring to. I can think of several cases where patents were granted in spite of prior art existing, or where the subject of the patent was obvious to practitioners in the field. Unfortunately for small businesses or individuals who find that the technology they have been using for years has suddenly been patented by somebody else, the cost of proving the patent invalid is prohibitive.
Post by: Larrchild on December 15, 2007, 06:42:24 PM
Must be one fancy inductor!
Post by: John Roberts {JR} on December 15, 2007, 06:50:57 PM
If the prior art is strong and fairly clear cut the patent wouldn't likely end up in court. The holder of such a sham patent would be unwise to overplay his hand. I recall back in the '80s I published a phono preamp kit (In Popular Electronic magazine) that used a balanced input gain stage. I got confronted by some guy in Texas who had convinced the patent office to give him a patent on differential input phono pre's. Talk about obvious art...
I ordered a copy of the patent file wrapper and looked at his arguments with the examiner and it was clear the patent examiner was unfamiliar with the general concept of balanced or differential inputs and thought that was novel. I made a copy of phono preamp schematic using a transformer front end from an old tube manual (which was both balanced and differential). I sent it to the inventor. By law when any inventor becomes aware of conflicting art he is supposed to notify the patent office himself. I doubt he did but he stopped bothering me.
JR
Post by: Larrchild on December 15, 2007, 06:59:51 PM
Might as well just submit this.
Post by: Phillip Graham on December 15, 2007, 09:22:54 PM
| Sahib wrote on Thu, 06 December 2007 17:11 | ||
Cemal |
There will indeed be some oxide in copper, and on the copper surface. Copper readily oxidizes at normal pO2! Its also very easy to measure the relative crystallographic orientations of the rolled copper, by making something called a "pole figure" on an X-ray diffractometer. None of this is news.
To consider a smattering of anything in a matrix of conductive copper at audio frequencies is laughable. This is easily shown by doing impedance spectroscopy using a potientiostat, an extremely common and useful technique in the world of electroceramics. This is not tremendously different than the use of a network analyzer in the ee world.
In recent years people have attempted to extend impedance spectroscopy to the world of metal alloys, with very unimpressive results. One the professors trying to pioneer that technique is in my department here at Georgia Tech. Eventually, if you go high enough in frequency, you can measure effects that are not purely resistive, but linking them to characteristics of the microstructure is nearly impossible.
That is not to say that certain materials defects don't play a tremendous role in the electrical performance of certain systems...Just not at audio frequencies!
When I was fabbing microchips there were all kinds of materials limiting factors to electrical behavior. The speed of waves in the metal back end layers is tremendously influenced by the dielectric constant of the surround substrate. Notice I say "wave" because we are at transmission line frequencies here.
Another high frequency effect that is common in microchips is the residual parasitic capacitance in two specific places. The first is at the materials boundary between the gate oxide and the source drain channel. The apparent capacitance here is tremendously influenced by crystal defects that can trap electrons (or holes). The triumph of silicon as a materials system for CMOS is in large part a function of silicon's ability to grow a very thin, stable, epitaxial, oxide layer. Silicon is not a direct bandgap material, nor does its oxide have a particularly high dielectric constant. Regardless, it has dominated CMOS processing due to silicon dioxide's stable, low defect thermal growth.
The second parasitic capacitance of note is in material forming the gate conductor (above the gate oxide dielectric). The gate conductor is capacitively coupled to the source drain channel through the gate oxide. The gate conductor has historically been polycrystalline silicon (polysilicon), which is then heavily doped via ion implantation to make it more conductive. The material has substantial residual capacitances, in part due to trapping of implanted material at the grain boundaries between the crystals of silicon.
Intel just turned the CMOS world on its head very recently, by introducing the Penryn chip. Penryn returns to a (shock!
) metallic gate conductor a titanium/nitraded titanium combination. The gate dielectric is now halfnium oxide. This is a really big deal in the CMOS world, since even though the "M" in "CMOS" stands for "Metal," polysilicon has ruled the day/gate for many years.The gate oxides in the computer you are reading this post on are at most 4 atomic planes thick. This is the size/frequency scale of materials science where these sorts of behaviors matter, and are clearly observable!
Not in the audio band, period, regardless of some physicist's misinformation.
[/Materials Engineering Hat]
Post by: Larrchild on December 15, 2007, 10:01:34 PM
Glad you chimed in. Sounds like you know.
| Quote: |
Eventually, if you go high enough in frequency, you can measure effects that are not purely resistive |
What frequency? And did you mean the normal reactance a wire gets at rf? Or some "other" phenomenon?
Post by: Phillip Graham on December 15, 2007, 10:24:30 PM
| Larrchild wrote on Sat, 15 December 2007 22:01 |
A polysilicon gathers no MOS. Glad you chimed in. Sounds like you know. |
I don't know that i know so well
I learned the process from the bottom up to the point I needed to (ie how to form an inverter, and that relation to boolean logic). I was working at AMD at the time, on an extending internship in college (University of Florida), and had a fantastic internal class in semiconductor physics from Dr. Jack Lee at the University of Texas at Austin. He steamrolled through the material at a great rate, but I loved it. Tied the materials side that I knew to some device physics.AMD, and the rest of the industry, just had the hammer thrown down big time by this Intel chip. IBM used to be the one to do that all the time--if they didn't invent it, they did it best.
I still have no understanding of the internals of real opamps and the like...
| Quote: |
What frequency? And did you mean the normal reactance a wire gets at rf? Or some "other" phenomenon? |
The frequencies aren't that high (ie in the megahertz and up). And yes, what you observe, at least from what I have read, are merely reactances, not diode junction type behavior. I will find a link to a good review article.
BTW, I just went to your website, beautiful looking limiter! The faster release times is a really nice touch. I also like the look of your LabVIEW tube tester VI
Part of my research involves running a Flashcut 7300 CNC mill here at GT for machining ceramic preforms, so the little engraving mill is a nice touch. What do you use for CAD/CAM?
Post by: Larrchild on December 15, 2007, 10:38:23 PM
I'm having a grand old time taking all my 70's and 80's HP and Tek gear and building LabView interfaces.
Post-processing makes old dogs, smart old dogs.=)
"Keptin..These Crrystals..they are acting very peculiarr!"
But unless copper wire is doing something besides becoming a coil with some capacitance in the rf realm, I'll stick to the wire of the common man, for now.
Post by: John Roberts {JR} on December 16, 2007, 10:52:54 AM
| Larrchild wrote on Sat, 15 December 2007 17:42 |
A patent for a widely-revered discrete opamp, ignores the mid-60's prior art of an emitter inductor in the 1st stage by Dick Burwen. Must be one fancy inductor! |
Since most inventions are basically a novel combination or reordering of already existing means, it is not unusual to share a common element with some prior art. While it would be incorrect to claim that prior art alone, it is not that unusual to use prior art in combination with other means for a new or incremental benefit.
Note: this does not give the inventor sole use, or even joint use in that prior art, it only protects that specific combination. Neither the inventor nor holder of the prior art can use the new combination art without reaching some agreement wrt sharing the prior art. If the prior art is public domain than this is not an issue.
One needs to study the patent claims and all the art involved to determine right or wrong here. I haven't so I don't know. I respect the work of both Jensen and Burwen.
JR
Post by: John Roberts {JR} on December 16, 2007, 11:04:02 AM
Now you have me interested with Intel's return to metal gates... Is the primary benefit from lower capacitance; higher clock speed, lower heat, or both? These days they may be pursuing efficiency as much as speed.
JR
Post by: Larrchild on December 16, 2007, 11:31:35 AM
| Quote: |
Since most inventions are basically a novel combination or reordering of already existing means, it is not unusual to share a common element with some prior art. While it would be incorrect to claim that prior art alone, it is not that unusual to use prior art in combination with other means for a new or incremental benefit. |
Right, so if I say "This inductor must be wound as so, as to do this (or not do this)", that adds to the existing prior art.
Post by: John Roberts {JR} on December 16, 2007, 12:47:48 PM
| Larrchild wrote on Sun, 16 December 2007 10:31 | ||
John Roberts:
Right, so if I say "This inductor must be wound as so, as to do this (or not do this)", that adds to the existing prior art. |
I suspect any published discussion adds to the art. I'm not a patent lawyer but my understanding is for something to be protectable intellectual property, it needs to meet several criteria; novelty, utility, and un-obviousness.
Not being obvious is subject to some debate and some elegant inventions appear pretty obvious after we are taught by the invention. The fact that something wasn't used prior to the invention should be proof it wasn't obvious, but that seems obvious.
JR
Post by: Phillip Graham on December 16, 2007, 01:52:59 PM
| John Roberts {JR} wrote on Sun, 16 December 2007 11:04 |
Now you have me interested with Intel's return to metal gates... Is the primary benefit from lower capacitance; higher clock speed, lower heat, or both? These days they may be pursuing efficiency as much as speed. |
Hey John,
I finally did get the package if I ever forgot to tell you
My chip designer friends say that dominant Ghz speed limits are the capacitance of the gate metal (ie polysilicon) and the design of some of the back end metal layers. A metallic gate material would reduce substantially that capacitance, methinks.
Heat-wise, Hafnium oxide has a much higher dielectric constant, and therefore can be thicker, reducing electron tunneling through the gate dielectric, and that reduces heat. Also the source/drain leakage currents are pretty high in general, and they are using some new nickel silicide (I believe) to reduce leakage across the transistor channel.
Finally the leakage currents between adjacent transistors matter, and there are a couple ways of dealing with that. Some people like AMD use silicon on insulator (SOI), which is basically a wafer with an insulating oxide layer slightly under the surface. I think Intel instead uses a pit of something under the transistor to reduce leakage.
The leakage currents in these chips can be really high, equivalent to hundreds of amps/cm^2.
Intel should be able to make faster chips, and lower power ones, with this new materials system. Makes me glad I am not working at AMD right now.
Post by: Larrchild on December 16, 2007, 02:38:59 PM
We really hate our stray capacitance at 10 Ghz!
BTW, I had noticed "Moore's Law" had leveled off a tad as the theoretical speed limit of signals on substrate of given stray components, and of a given size were being skirted.
This should get Moore back in the equation.
Post by: John Roberts {JR} on December 16, 2007, 02:54:39 PM
JR
PS: regarding your personal project I saw a post in some other forum about a cheap behri....er box that could be made passable by swapping out the 4560 opamp. I don't recall model or details.
Post by: bruno putzeys on December 17, 2007, 02:44:31 AM
| John Roberts {JR} wrote on Sat, 15 December 2007 19:33 |
I believe, once upon a time patent applicants also submitted working models in proof of concept. I suspect this was dropped due to logistical burden. I'd like to see the models for sundry perpetual motion machine applications, which by definition should still be running. |
Perpetual motion machines are the only inventions where the "submit prototype" rule is still strictly enforced.
Post by: Sahib on December 17, 2007, 05:01:43 AM
| Quote: |
Hi Cemal, I'm no semiconductor expert but in principle the proposal sounds reasonable: Cu2O is indeed a semiconductor and semiconductor/conductor grain boundaries certainly will give rise to some kind of barrier potential. These then have associated the things he claims - capacitance & resistance. Whether or not this constitutes a diode junction I'm not sure - I think the I-V characteristics of such a grain boundary are not so easy to measure but my guess is that theoretically this is what would be expected from such a combination of these materials. I guess a lot depends also on the distribution of the impurities since to be a diode it's going to have to present a high resistance to flow in one direction but not in the other. Sorry I can't be more helpful - maybe I can ask around here - we've got some real physicists working in the institute! |
This obviously does not suggest that this property can demonstrate the diode junction cahacteristics or have effects in audio frequencies but I thought of posting it.
Regards,
Cemal
Post by: John Roberts {JR} on December 17, 2007, 11:38:09 AM
| Sahib wrote on Mon, 17 December 2007 04:01 | ||
Well, the story took a different turn. My wife's cousin is a scientist in Anka in Germany. Although his expertise is in particul chemistry (if I am remembering right) he is also a fine physicist,though he is always modest about it. He works on the synchrotron day in-day out. So these guys count the beans on a regular basis. I asked him what he thought and here is his reply (his name is excluded);
This obviously does not suggest that this property can demonstrate the diode junction cahacteristics or have effects in audio frequencies but I thought of posting it. Regards, Cemal |
I don't think anybody disputes that impurities can have capacitance or threshold effects, but these impurities are all shunted by low impedance conduction paths so the tiny capacitors or tiny diodes will never see any significant terminal voltage or current flow. Conductors are made up of a very large number of these paths in series-parallel. I don't care if the impurities are blue LEDs. With dead shorts across every one, it doesn't matter what their transfer function is.
So if any effect can be attributed to these impurities it would be a degradation in the bulk resistance of the total conductor which is well measured and understood.
True believers will always find reasons to believe, and apparently keep a whole sub industry well fed.
JR
Post by: Larrchild on December 17, 2007, 05:06:56 PM
But maybe there is a better way to observe.
Post by: bruno putzeys on December 18, 2007, 04:36:08 AM
Post by: Andy Peters on December 18, 2007, 01:12:39 PM
| Bruno Putzeys wrote on Tue, 18 December 2007 02:36 |
Just imagine the amount of current you need to pump through the admitted shunt conductance before any appreciable voltage appears across one of these "diode junctions". |
I suspect that the copper wire would turn into a fuse.
-a
Post by: Sahib on December 18, 2007, 07:21:24 PM
Very recently my 27 years of friendship has ended. Although it appeared to be for a different reason but I know it was because of this cable issue. Unfortunately he has been in snake oil cable business for sometime and had been feeling uncomfortable with my open critisism in our Turkish forum. It became obvious that he was distancing himself from me for sometime and eventually the rope broke. Good job that it wasn't my wife. Imagine the reason for a divorce being the microdiodes in copper.
Cemal
Post by: John Roberts {JR} on December 18, 2007, 08:31:33 PM
Snake oil vendors still sell this stuff because it's very profitable and there is an endless line of fools willing to be separated from their money.
It doesn't speak well for us as population to properly evaluate the important science issues we must deal with regarding climate and energy policy.
JR
Post by: Larrchild on December 20, 2007, 02:52:20 AM
So what's left?
Just use big wire for low-ohmic paths.
All the science you really need in the speaker wire business.
The grandest non-linearities occur in the transformation from electrical to acoustic, in the speaker.
Why don't these "scientists" solve some of those glaring problems first?!
Must be harder to fake.
Post by: bruno putzeys on December 20, 2007, 04:03:27 AM
| Larrchild wrote on Thu, 20 December 2007 08:52 |
Must be harder to fake. |
Nails it exactly. I can fake being a "bleever" but they can't fake being a scientist.
Post by: Larrchild on December 20, 2007, 09:45:49 AM
And there is a seeker born, every minute.
Post by: John Roberts {JR} on December 20, 2007, 12:59:26 PM
| Larrchild wrote on Thu, 20 December 2007 01:52 |
The grandest non-linearities occur in the transformation from electrical to acoustic, in the speaker. Why don't these "scientists" solve some of those glaring problems first?! Must be harder to fake. |
I like to look at larger venue sound reinforcement as it's harder to fool thousands of people at the same time.
While that technology is pretty slow changing I've seen two recent advancements that look promising. One is the use of DSP to correct for some known problems in horn-manifold systems. Another is a clever configuration where multiple drivers feed into a single horn and play nice together.
Some folks in the know, understand the weak links and are working on it.
Perhaps a little off topic for this forum.
JR
Post by: bruno putzeys on December 20, 2007, 01:47:31 PM
| John Roberts {JR} wrote on Thu, 20 December 2007 18:59 |
Perhaps a little off topic for this forum. |
I daresay this whole thread...
Post by: Sahib on December 20, 2007, 03:58:49 PM
Say it Bruno, say it.
Post by: Larrchild on December 20, 2007, 06:52:46 PM
But he's right.
This was a total bait-job, Sahib!
Post by: Andrew H on January 09, 2008, 11:20:39 PM
Post by: johnR on January 10, 2008, 09:55:34 AM
| Andrew H wrote on Thu, 10 January 2008 04:20 |
At this point, does anyone have any comments about stranded vs solid core? |
If the stranded wire has individually insulated strands (Litz wire), it will have lower resistance at high frequencies due to reduced skin effect. If not, it won't, regardless of what marketing people would have you believe.
Post by: Larrchild on January 10, 2008, 10:39:54 AM
Clearly, it does at RF.
Where does the transition occur?
Post by: bruno putzeys on January 10, 2008, 10:50:39 AM
One thing is certain: in speaker cables and at audio frequencies the lumped inductance will outstrip the effect of any skin effect by orders of magnitude.
Post by: Larrchild on January 10, 2008, 11:05:31 AM
Solid, stranded, no matter. The current is going through the entire cross-section of the conductor.
Post by: Tomas Danko on January 10, 2008, 11:17:46 AM
| Larrchild wrote on Thu, 10 January 2008 16:05 |
Then it sounds like it's down to: Just use Big Wire. Solid, stranded, no matter. The current is going through the entire cross-section of the conductor. |
Although strands would be easier to twist and bend, should this be required, I'd wager.
Post by: bruno putzeys on January 10, 2008, 11:29:59 AM
Post by: studiojimi on January 10, 2008, 12:32:06 PM
| Larrchild wrote on Thu, 20 December 2007 15:52 |
I'm all for grilling-up sacred cows, and Bruno does them well-done. But he's right. This was a total bait-job, Sahib! |
who is baiting who?
got hot sauce?
Post by: Phillip Graham on January 10, 2008, 01:31:04 PM
| Larrchild wrote on Thu, 10 January 2008 10:39 |
The burning question is: "Does skin effect exist in the audio passband?" Clearly, it does at RF. Where does the transition occur? |
This is an easy derivation to calculate. There is always some skin effect, but until it is making a meaninful effect on trace resistance, it is not going to matter.
I would argue the the point it might matter is when it becomes more significant than the change in resistivity due to a reasonable temperature gradient (say 10deg C). Does that seem like an acceptable characterization point?
Post by: Larrchild on January 10, 2008, 08:31:16 PM
| Quote: |
I would argue the the point it might matter is when it becomes more significant than the change in resistivity due to a reasonable temperature gradient (say 10deg C). Does that seem like an acceptable characterization point? |
And still the lumped inductance will swamp it.
Unless you put the speaker cable under the rug and push the lumps down with your shoe.
Post by: John Roberts {JR} on January 11, 2008, 11:22:09 AM
| Phillip Graham wrote on Thu, 10 January 2008 12:31 | ||
This is an easy derivation to calculate. There is always some skin effect, but until it is making a meaninful effect on trace resistance, it is not going to matter. I would argue the the point it might matter is when it becomes more significant than the change in resistivity due to a reasonable temperature gradient (say 10deg C). Does that seem like an acceptable characterization point? |
Hi Phil: Not to be contrary but IMO a proper evaluation of skin effect, would hinge more on frequency response error due to resistance change between say 20 kHz and 1 kHz, and how that delta R interacts with typical termination R, than the simple amount of resistance change. Also as Bruno says for longer lines the lumped characteristics will be important.
When I looked into this a couple decades ago I personally judged it insignificant for audio passband. This is another poster boy for typical audiophoolery. Yes, there's some "there" there, but much too little to worry about.
JR
Post by: Tomas Danko on January 11, 2008, 12:14:59 PM
Post by: Phillip Graham on January 13, 2008, 07:48:59 PM
| John Roberts {JR} wrote on Fri, 11 January 2008 11:22 |
Hi Phil: Not to be contrary but IMO a proper evaluation of skin effect, would hinge more on frequency response error due to resistance change between say 20 kHz and 1 kHz, and how that delta R interacts with typical termination R, than the simple amount of resistance change. Also as Bruno says for longer lines the lumped characteristics will be important. When I looked into this a couple decades ago I personally judged it insignificant for audio passband. This is another poster boy for typical audiophoolery. Yes, there's some "there" there, but much too little to worry about. |
Hey JR,
I, of course, don't think skin factor is an issue at audio frequencies, though it has cool applications (much) higher up. I do see your point, though.
Any change in resistance, due to temperature effects, would influence all frequencies equally (unless that resistance was in conjugate with a substantial real and/or lumped reactance). So, as I think about the purely resistive case, the skin effect would show a frequency dependence, but the temperature effect would not.
Is that what you were pointing out?
Post by: John Roberts {JR} on January 13, 2008, 11:01:42 PM
| Phillip Graham wrote on Sun, 13 January 2008 18:48 | ||
Hey JR, I, of course, don't think skin factor is an issue at audio frequencies, though it has cool applications (much) higher up. I do see your point, though. Any change in resistance, due to temperature effects, would influence all frequencies equally (unless that resistance was in conjugate with a substantial real and/or lumped reactance). So, as I think about the purely resistive case, the skin effect would show a frequency dependence, but the temperature effect would not. Is that what you were pointing out? |
Yes, frequency response changes are quite audible, while wide band resistance changes less so (IMO).
JR
Post by: Sahib on January 15, 2008, 06:35:43 PM
By the way, I am about to order a microscope to look into copper wires to see these microdiodes. Who knows, I may even discover few gold teeth.
Post by: Quince on January 15, 2008, 07:17:33 PM
Post by: Larrchild on January 15, 2008, 08:33:20 PM
| Quince wrote on Tue, 15 January 2008 19:17 |
Skin effect can only affect the frequency response, and cannot produce nonlinear distortion, right? |
No, that's the microdiode's job.
Post by: dcollins on January 15, 2008, 08:40:49 PM
| Quince wrote on Tue, 15 January 2008 16:17 |
Skin effect can only affect the frequency response, and cannot produce nonlinear distortion, right? |
Correct.
DC
Post by: John Roberts {JR} on January 15, 2008, 08:40:59 PM
| Quince wrote on Tue, 15 January 2008 18:17 |
Skin effect can only affect the frequency response, and cannot produce nonlinear distortion, right? |
Pretty much... Power feeds for some RF signals use hollow tubes to save copper. If the electricity isn't using it why pay for it?
If it was nonlinear it would rectify radio and such so no AFAIK not a source of distortion, and surely not at audio frequency.
JR
Post by: Larrchild on January 15, 2008, 10:04:23 PM
Post by: dcollins on January 16, 2008, 12:15:32 AM
| Larrchild wrote on Tue, 15 January 2008 19:04 |
It's just a distortion of great frequency on the internet. |
Just like Silver-plated Litz wire for audio.....
DC
Post by: Quince on January 19, 2008, 10:18:48 PM
I was looking at a white paper from Vishay about their bulk metal foils and their claim of significant reduction of current bunching noise over that of metal films. But can this even possibly be an issue within the limited dynamic range of hearing?
Post by: Larrchild on January 19, 2008, 10:31:25 PM
The thread is 'Lytics, but it morphs to resistors down the page.
Post by: johnR on January 20, 2008, 05:28:03 AM
| Quote: |
A bit off-topic, yet in the same general line, what do you people think of the possibility of resistors affecting sound? |
One of the main ways in which resistors can affect sound is due to their mechanical construction. Most axial film resistors have a spiral track of metal or carbon film, which means they are inductive. If good HF performance is critical, it's often better to use SMD resistors (despite what the "SMD is cheap crap" brigade would have us believe).
Post by: bruno putzeys on January 20, 2008, 05:34:29 AM
Post by: johnR on January 20, 2008, 05:42:41 AM
Post by: bruno putzeys on January 20, 2008, 01:06:16 PM
| johnR wrote on Sun, 20 January 2008 11:42 |
How are MELFs for inductance? Aren't they just a leadless version of a standard axial resistor? |
Yes, they're identical in construction. At first sight one would think that any spiral cut would increase inductance, but look at it like this: the inductance only becomes significant at frequencies above R/(2*pi*L). Suppose R=10 ohms, the inductance would need to be 16nH to be significant at 100MHz. That's unlikely. At higher resistances we'd need even more inductance before it matters. So unless we're doing RF circuits with low impedances, any purported inductance is not going to show up.
Post by: John Roberts {JR} on January 20, 2008, 04:04:18 PM
Can't say that I've ever heard problems from excess noise, even when there's a DC bias, but that doesn't mean it wasn't there, hiding behind the signal.
JR