hermanv said:
Good observation Herman,
A circular magnetic field flows around the outside of the conductor regardless of the material. If the excitation current is alternating the the crowding of the current to the surface is more pronounced if the material is iron instead of copper, and it of course increases with frequency due to the skin effect.
Many metal film resistor leads are now magnetic. As you pointed out, the steel increases tensile strength. 1960's Mepco/Electra metal films were excellent, the later ones (after Centralab acquired Mepco) all had plated steel leads and end caps. The Mouser Xicon and the Digi-key Yageo parts leap out of the bag when a magnet comes near!
Roederstein and Holco resistors are no longer available. Many of the Vishay/Dale RN60 types I have are non-ferrous, but all the RN55s are iron. The Vishay/Dale data sheet says that the end caps are either copper or iron. The Roedersteins RN55 had steel leads. I don't know anything about the leads on Precision Resistive Products resistors.
Steel leadout wires that are sharply bent for mounting on PCBs is bound to put the component under stress and damage the crystal structure of the leadouts as well.
It's no better with surface mount resistors. They use 100% tinned (RoHS) nickel barriers. Gary Galo thinks the Ni may be a better match to the NiCr resistive element.
Best, Chuck Hansen
Chuck, one symptom of audiophilia nervosa is an aversion to any materials in component terminations that are magnetic. Is there any data you're aware of showing a justification for that? It always makes me wonder when another tube guy tells me about changing some resistors because the end caps are magnetic, but he's still got a chassis-full of tubes with magnetic innards AND a couple of huge hunks of highly magnetic iron that the signal passes through.
Sy,
I for one and numerous others discovered long ago why Cardas copper binding posts are far superior to steel bolts used in standard terminal posts.
As to passives (and active gain devices) I guess the guy who can design a circuit that works with the absolute minimum of parts is going to be a winner.
Here is an extract from a Pass labs owners manual that I would like to use for educational purposes as it that sums up a few of the points made in this thread (courtesy of Passlabs).
I am not hear to preach to the choir or push the Pass barrow but his whole approach makes one hell of a lot of sense and it seems to work.
"For a long time there has been faith in the technical community that eventually some objective
analysis would reconcile critical listener's subjective experience with laboratory measurement.
Perhaps this will occur, but in the meantime, audiophiles largely reject bench specifications as
an indicator of audio quality. This is appropriate. Appreciation of audio is a subjective human
experience. We should no more let numbers define audio quality than we would let chemical
analysis be the arbiter of fine wines. Measurements can provide a measure of insight, but
are no substitute for human judgment.
As in art, classic audio components are the results of individual efforts and reflect a coherent
underlying philosophy. They make a subjective and an objective statement of quality which is
meant to be appreciated. "
I for one and numerous others discovered long ago why Cardas copper binding posts are far superior to steel bolts used in standard terminal posts.
As to passives (and active gain devices) I guess the guy who can design a circuit that works with the absolute minimum of parts is going to be a winner.
Here is an extract from a Pass labs owners manual that I would like to use for educational purposes as it that sums up a few of the points made in this thread (courtesy of Passlabs).
I am not hear to preach to the choir or push the Pass barrow but his whole approach makes one hell of a lot of sense and it seems to work.
"For a long time there has been faith in the technical community that eventually some objective
analysis would reconcile critical listener's subjective experience with laboratory measurement.
Perhaps this will occur, but in the meantime, audiophiles largely reject bench specifications as
an indicator of audio quality. This is appropriate. Appreciation of audio is a subjective human
experience. We should no more let numbers define audio quality than we would let chemical
analysis be the arbiter of fine wines. Measurements can provide a measure of insight, but
are no substitute for human judgment.
As in art, classic audio components are the results of individual efforts and reflect a coherent
underlying philosophy. They make a subjective and an objective statement of quality which is
meant to be appreciated. "
SY said:
Hello SY,
No, I don't have any objective evidence, but just in case the experience of the high-end designers is true, I see no harm in using parts with non-magnetic leads, and silver-plated-copper teflon-insulated wire, for instance.
Tubes are an interesting example. The pins are kovar to match the tempco of the glass. The lead wires (at least in the Bendix Red Bank tubes) are tungsten or platinum, the support rods are nickel , the cathodes are coated with barium oxide, the grip supports are nickel-plated copper, the grid wires could be gold, the plates are nickel with a black oxide finish. All kinds of different metal-to-metal junctions. Then there is the metal used in the tube sockets, the copper interconnection wiring, solder, etc.
You point is well taken, which is why the subjective evidence of the successful high-end designers seems to be as important as the objective evidence.
Best, Chuck Hansen
One of the MAIN factors between the Parasound JC series products and the cheaper products, is that we INSIST on non-magnetic connectors, wire, terminals, etc. IF we find them we reject them! However, I can't prove it to SY. I have a powerful magnet near my workbench and I use it to test for magnetic properties in components, when I am suspicious. I have found that a 'little' magnetic pull MAY not be too bad, but if the component runs to the magnet as if it were in love, then I will try to find a replacement.
I have thousands of connectors, resistors, caps, etc with steel leads. IF SY (or anyone else) would take them off my hands at a wholesale price, I would be happy.
I have thousands of connectors, resistors, caps, etc with steel leads. IF SY (or anyone else) would take them off my hands at a wholesale price, I would be happy.
Thanks, guys.
Macka, the case of binding posts is somewhat different. There, the issue is a reliable, gas-tight mechanical connection. I certainly haven't done any rigorous investigation (other than tracing things I'm not liking to poor mechanical connections), but I do wonder if what you're observing is not the magnetism of the steel but rather its hardness.
FWIW, I use Tiffany binding posts for my speaker connections.
Macka, the case of binding posts is somewhat different. There, the issue is a reliable, gas-tight mechanical connection. I certainly haven't done any rigorous investigation (other than tracing things I'm not liking to poor mechanical connections), but I do wonder if what you're observing is not the magnetism of the steel but rather its hardness.
FWIW, I use Tiffany binding posts for my speaker connections.
SY said:
While thought experiments are interesting (and in the case of some situation that have nothing to do with audio, perhaps the only viable alternative), they are no substitute for the real thing.
Why in the world would you sit around and try and *guess* how something might sound based on your limited (mis?)understanding of the situation, when you could easily just sit down and perform a listening test?
What's even more baffling to me is that you (and others) persist in arguing with people who have done the work...
Another recent example in this thread of this ridiculous attitude was during the discussion on cryogenics. Scott Wurcer put out the fact that his listening panel was able to identify cryo'ed DAC chips with 100% accuracy. And most of the posters on this board simply ignored this factual evidence (which, by the way, should even satisfy the "double-blind" crowd) and continued to argue based on their limited and incomplete understanding of the physical world.
When the discussion turned to reality versus models of reality (eg, Planck's constant), one poster arrogantly used the fact that we can send space probes to Pluto, implying that we actually understand gravity.
This is about as ridiculous as it gets.
If anyone can explain to me the *mechanism* whereby gravity produces action at a distance, please let us know. I'm sure you will be up for the Nobel prize.
This is *exactly* the same situation as what is happening with audio. We have boatloads of empirical evidence (eg, audible changes in cryo'ed IC's), without an exact detailed mechanism. Many the intellectual flea-weights who hang out here have no problem accepting gravity (despite not having any reasonable explanation for its mechanism), yet foam at the mouth and fling spittle when something like cryogenic treatment or magnetic parts are mentioned.
No wonder John is having a hard time teaching you people anything. Most of the thread is wasted by trivial arguments like these, coming from people who are either too lazy to do the work or too hard of hearing to tell the difference.
chascode said:
Hi Chuck,
Thanks for these insights. The whole thing about the use of magnetic materials is fascinating. There is certainly a theoretical cause-effect regarding excitation of the magnetic domains, but it is unclear if anyone has ever been able to measure its effect on a signal under short-distance situations like component leads and end-caps. I agree with the conservative approach of assuming that there may be something audible here, and perhaps lumping it into the pile of things we just perhaps don't understand. At the same time, it would be fascinating to come up with some kind of a measurement that produced different results for magnetic and non-magnetic versions of the same component that could have some relevance to sonics.
Cheers,
Bob
Charles, one point: Scott did not say that the sorting was done as a result of a listening panel. I doubt that it was, and in my first conversation about it some years ago, he expressed doubt that it was.
To be honest, doing a proper listening test of more, uhhh, outre speculations requires a LOT of time and effort. Which is, of course, why no-one does it, including the fans of such, uhhh, technologies. I do a lot of listening tests, but they focus more on topologies, speakers, and room acoustics, where I think the payoff is a lot more tangible.
To be honest, doing a proper listening test of more, uhhh, outre speculations requires a LOT of time and effort. Which is, of course, why no-one does it, including the fans of such, uhhh, technologies. I do a lot of listening tests, but they focus more on topologies, speakers, and room acoustics, where I think the payoff is a lot more tangible.
Charles Hansen said:
You know Charles, this is a difficult long-distance communication. We all have a kind of listening experience, and a lot of us worked hard to collect it. According to my listening experience, preamps sound best in case they have strong, low distortion, class A low output impedance output stage. Low impedance I mean something like 5 ohm. Must be able to feed any capacitive load and must be unaffected by cables and inputs of amps. Now John has 1 kohm output at BT and would certainly not agree with me. Shall I say the same you said?
scott wurcer said:
Stormtrooper: Let me see your identification.
Obi-Wan: [with a small wave of his hand] You don't need to see his identification.
Stormtrooper: We don't need to see his identification.
Obi-Wan: These aren't the droids you're looking for.
Stormtrooper: These aren't the droids we're looking for.
Obi-Wan: He can go about his business.
Stormtrooper: You can go about your business.
Obi-Wan: Move along.
Stormtrooper: Move along... move along.
Since I've been an audiophile, many tweaks and "improvements" have come and gone. The ones that are gone are mostly rejected by the marketplace as either not functional or for improvement not proportional to their cost.
Specialty wires and cables have not only survived these market tests, the number of variants and manufacturers have exploded. I'm going to guess that here are at least 100 companies. To make a living these companies must sell hundreds of cables each, spread out over the last ten years probably over a million specialty cables have been sold.
While none of this explains why or even if every variant genuinely works, it certainly supports the notion that something repeatable is going on.
Probably the single most common attribute of all these vendors is conductor purity, whether silver or copper, 4 nines or better seems to be the rule. I just can't buy the mass delusion argument, true I use my ears rather than some instrument, but the improvement I hear has led me to spend a significant sum on wire alone.
Maybe it has nothing to do with magnetics, some vendors argue it's grain boundaries. In any event, I see little reason to dismiss the phenomena as a form of mass delusion.
Why can't I measure it? Well maybe we can, but admittedly we're not too sure what it is we should measure. Let me digress briefly. Most audiophiles hear an improvement between Redboook and DVD-A or SACD. In both cases the amount of digital data has increased. Given that Redbook is one part in 65,536 (216), that's a least significant bit resolution of .0015%. Many pieces of test equipment peter out long before that level of resolution. Yet we still hear an improvement. We can make a piece of equipment that resolves any cable attribute to that level, but we are still unsure what parameter(s) to measure. Certainly traditional test equipment (resistance, capacitance and inductance) can't resolve value changes to .0015% or below.
Given the vitriol and passions for either side of the "cables have sound" arguments, no scientist worth his grant money will touch the subject for fear of being called a quack. The few that have superficially looked have concluded that there are no first order explanations for the effect and then entered the Olympic conclusion jump that second or third order effects therefore couldn't exist either.
As an EE I was certainly trained that this can't be. As an audiophile I not only hear an effect, but when describing it to others in the room they say they hear the same thing in the same way on the same passages of a given recording.
Specialty wires and cables have not only survived these market tests, the number of variants and manufacturers have exploded. I'm going to guess that here are at least 100 companies. To make a living these companies must sell hundreds of cables each, spread out over the last ten years probably over a million specialty cables have been sold.
While none of this explains why or even if every variant genuinely works, it certainly supports the notion that something repeatable is going on.
Probably the single most common attribute of all these vendors is conductor purity, whether silver or copper, 4 nines or better seems to be the rule. I just can't buy the mass delusion argument, true I use my ears rather than some instrument, but the improvement I hear has led me to spend a significant sum on wire alone.
Maybe it has nothing to do with magnetics, some vendors argue it's grain boundaries. In any event, I see little reason to dismiss the phenomena as a form of mass delusion.
Why can't I measure it? Well maybe we can, but admittedly we're not too sure what it is we should measure. Let me digress briefly. Most audiophiles hear an improvement between Redboook and DVD-A or SACD. In both cases the amount of digital data has increased. Given that Redbook is one part in 65,536 (216), that's a least significant bit resolution of .0015%. Many pieces of test equipment peter out long before that level of resolution. Yet we still hear an improvement. We can make a piece of equipment that resolves any cable attribute to that level, but we are still unsure what parameter(s) to measure. Certainly traditional test equipment (resistance, capacitance and inductance) can't resolve value changes to .0015% or below.
Given the vitriol and passions for either side of the "cables have sound" arguments, no scientist worth his grant money will touch the subject for fear of being called a quack. The few that have superficially looked have concluded that there are no first order explanations for the effect and then entered the Olympic conclusion jump that second or third order effects therefore couldn't exist either.
As an EE I was certainly trained that this can't be. As an audiophile I not only hear an effect, but when describing it to others in the room they say they hear the same thing in the same way on the same passages of a given recording.
PMA said:
Pavel, there is no reason to include yourself among the people that don't bother to listen. It is clear that you listen to your designs. The fact that you have reached different conclusions than John or me can only be resolved if we do our listening tests together, in the same room with the same system. Then we can point out to each other exactly which part of the sound quality we are focused on, and how it affects the musical presentation.
As far as driving cables, I am somewhere between you and John. In my experience it is preferable to have the output impedance of the driving stage be somewhat higher than the characteristic impedance of the cable. Unless one uses very strange cables, a balanced twisted pair is usually pretty close to 110 ohms. So these days I try to shoot for an output impedance between 150 and 300 ohms.
As the output impedance is reduced, it becomes more and more difficult to drive capacitive loads without overshoot. I have found that overshoot is audible as a sense of added detail. And in my experience, this added detail is fatiguing and artificial over the long run.
I am very interested in John's approach to use a transconductance output stage and let the output impedance be determined by a load resistor (in his case 1 kohm per phase). There are two obvious advantages:
a) The signal path is shortened as a the buffer stage is completely eliminated.
b) There is never any possibility of overshoot and/or ringing and/or oscillation due to a capacitive load. (And all loads are capacitive to some degree or another.)
Now in my case I am personally rather reluctant to let the output impedance rise as high as John does. There is no real good reason for this other than my own personal biases (meaning that I have not done any listening tests on this!). However, it might be interesting to make a transconductance output stage with enough current drive capability to use a 100 or 200 ohm output loading resistor and see how it sounds.
In the end, the only way to know how it will sound is to build it and listen to it.
And the only way for people to agree is to spend time together in the same room with the same system. In the case of you and me, I suspect the main difference is simply due to different listening experiences and different sonic priorities.
hermanv said:
Herman, clearly you are simply a victim of mass delusion. Are you sure that Obi-wan wasn't in the room with you?
~~~~~~~~~~
Stormtrooper: Let me see your identification.
Obi-Wan: [with a small wave of his hand] You don't need to see his identification.
Stormtrooper: We don't need to see his identification.
Obi-Wan: These aren't the droids you're looking for.
Stormtrooper: These aren't the droids we're looking for.
Obi-Wan: He can go about his business.
Stormtrooper: You can go about your business.
Obi-Wan: Move along.
Stormtrooper: Move along... move along.
jacco vermeulen said:
No, that's not the implication. Give me some x-ray and SEM/Auger/EDAX and I could probably sort them without any kind of electrical measurement. I have no idea of how they did it (Scott didn't either when he told me about this), but if I were to make a bet, that is where I'd put my money.
BTW, I'm Mr. South today; in New Mexico for a little vacation.
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