since 'R' does not need to be a constant, but just the result of U/I, I wonder how a violation could happen?
I think Scott is referring to the more generalized law, J = σE, which one can also think of as a variant of Kirchoff. It's required by continuity.
Yes, I guess you can't violate something which is not a law. What I was trying to say that there is no problem with conductors which do not follow Ohm's law, because there are no conservation laws which insist that they should follow it. You can derive Ohm's law from assumptions about electron scattering in solids, but that makes it the result of an approximate theory not a law of nature.
It's sort of semantic, if you suppose R is some property that has to be constant for conveinience then things don't fit. Remember including even the simplest non-linearity in general will yield intractable solutions.
Relating J and E is just a more generalised expression of Ohm's law. It is not required by anything fundamental.
Yes and the common usage is when the VI curve is non linear it is called non-ohmic. The design assumption is that a 100 ohm resistor is a 100 ohm resistor until the smoke leaks out. It is a new plain of design to allow for passive components to show their non linear behavior.
A while back we discussed Vbe. I found a thread where "real" engineers were berating a newbie who was looking for a bipolar transistor with a Vbe lower than .6 volts or so. They all knew you had to have that .6 volt diode drop or you could not have a transistor! Their world model only had fixed points of reference.
That approach will usually get your designs up and running. Improving them requires understanding the lower level effects. The only absolute to me is that I am never krong!
Yes I stand corrected. I was referring to EW&WW which I believe it is called now. I tend to forget the less important things and remember things that matter.
jan, why the sarcasm?
It would be better to stick to the subject matter without getting personal.
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Yep - downloaded a few. Read a few, digested a few. Spat a few out.
False premise. Now back to the original question which was about your claim. Do you have any support for it or is it just posturing?
The statement in your first sentence is actually flawed and incorrect by logical reasoning.
However, in your second sentence you contradict your first.
The correct wording to make it fact would be "I am not aware of it being demonstrated". And that of course would be conditional that a person is telling the truth or recollecting it if it were demonstrated.
Yes, Craig, I will grant the possibility that perhaps someone has done a remarkable thing and is hiding it. It is possible.
It is not likely.
It is not likely.
I ama bit late here, but I should have clarified mt statement: Indeed I was reffering to the noise floor which you see in the harmonic distortion spectra plots.
"There are some here saying that in "properly designed" IC op-amp circuits (hope that quote is correct - just shoot me if it aint) you cannot hear the difference in sound quality to a good discrete design."
If someone tells me they can hear a difference between two op-amps in a circuit I can accept that within reason - maybe they are hearing things that are not there, but I will accept that that is their reality.
If some tells me all opamp circuuits sound 'harsh, gritty' or 'not good' because they are IC based . . . well that's absolute nonsense and I believe this is actually what this thread morphed into (I guess robmill must be scratching his head now wondering where his innocent question has lead to).
If someone tells me they can hear a difference between two op-amps in a circuit I can accept that within reason - maybe they are hearing things that are not there, but I will accept that that is their reality.
If some tells me all opamp circuuits sound 'harsh, gritty' or 'not good' because they are IC based . . . well that's absolute nonsense and I believe this is actually what this thread morphed into (I guess robmill must be scratching his head now wondering where his innocent question has lead to).
The reason cables MAY sound different is because they have different R, L and C characteristics (length, disctance between conductors, maybe insulator dielectric etc). Nothing to do with the linearity of copper, directionality, 6 9's etc.
That said, I just like nice thick cables - I bought some great stuff in Akihibara and rolled my own about 3 years ago. Cost me 50 bucks with connectors. Cable problem solved.
That said, I just like nice thick cables - I bought some great stuff in Akihibara and rolled my own about 3 years ago. Cost me 50 bucks with connectors. Cable problem solved.
Yes, the key point is that 'properly' is a series of details to pay attention to, not everyone's list is the same and some people's lists are far longer than others'.
Indeed take no non-falsifiable claims seriously until people put up support for them and make them able to be falsified. That includes meaningful explanations for what 'gritty' and 'not good' are and what 'IC based' means in practice.
BTW, I was looking on another thread, and wonder of wonders, Charles Hansen is using/has used AD844's (CFA opamps) - albeit it with no global feedback - in one of his CD players.
So, have we or have we not converted the man who wrote that 'dirty bit of sand' letter to Stereophile to the wonders of IC opamps?
So, have we or have we not converted the man who wrote that 'dirty bit of sand' letter to Stereophile to the wonders of IC opamps?
I would like to hear from the proponents of the properly designed and implemented IC op-amp circuits as to:
Is there a difference in the sound qualities between different IC op-amps?
Given what has been said by the proponents over the last 16 odd pages regarding the lack of difference between them and a good discrete design, surely IC op-amps, being so similar to each other relative to a discrete design, must all sound the same.
Is there a difference in the sound qualities between different IC op-amps?
Given what has been said by the proponents over the last 16 odd pages regarding the lack of difference between them and a good discrete design, surely IC op-amps, being so similar to each other relative to a discrete design, must all sound the same.
Craig, I don't think most people here will 'go to war' over a statements like 'opamp x sounds different to opamp y' or 'op-amp x sounds better than opamp z'. There may be a lot of reasons for percieved differences, since specs from one op-amp to another do vary, there could be circuiy/layout execution differences and so on. I think on well specified (i.e. devices selected for their great audio performance credentials), you are not going to hear huge differences.
The beef here is about the sweeping generalizations concerning opamps (and IC's) having a bad sound. And as someone pointed out elsewhere, these statements are always made with such certaintly and authority when in fact they are in almost every case based on pure conjecture or opinion and not any scientific or engineering facts. And the myth is then simply perpetuated ad infinitum. For anyone new entering the field, it takes the first 5 years to wade through the bs. Ditto the debate on feedback and DB testing as well.
If you personally believe discrete designs are better - great. But don't then make generalizations about IC opoamps that are simply not true, and don't stand up to scrutiny.
The beef here is about the sweeping generalizations concerning opamps (and IC's) having a bad sound. And as someone pointed out elsewhere, these statements are always made with such certaintly and authority when in fact they are in almost every case based on pure conjecture or opinion and not any scientific or engineering facts. And the myth is then simply perpetuated ad infinitum. For anyone new entering the field, it takes the first 5 years to wade through the bs. Ditto the debate on feedback and DB testing as well.
If you personally believe discrete designs are better - great. But don't then make generalizations about IC opoamps that are simply not true, and don't stand up to scrutiny.
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