Yes it is! The cap is linear at any combination of f and C. The freq dependent output of the filter is an effect of the total circuit. Measure over the cap and it will show absolutely linear behaviour.
I don't want to be disrespectfull, but this is basic stuff since at least a century.
jan didden
I'm going to retract this statement because it is with other components associated with the filter that determines the output levels.
Of course no one builds a circuit that is only a cap and so the practical matter of any signal level or ''Delay'' as this thread started with, is dependant on the all things considered.
The only non-linearity a cap might have is within its own manufacturing defects.
This electronics theory may be 100 years old but I'm only 54.
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All this is assuming you have the "perfect" capacitor. ESR and inductance and dielectric absorption at different frequencies introduce non-linearites to the behaviour of the capacitor.
Yes it is. It is perfectly linear relationship between cap voltage, cap current, cap value. Also, if you double the current into the cap, you double the voltage rise. Etc Etc.
Look, I'm perfectly willing to spend my time typing away here at my keyboard, if I get the impression that we're going somewhere. But you keep on throwing up things that have absolutely no basis in reality. You could have checked that yourself; you know Google? Wikipedia?
So I'll stop now.
Edit: Saw you post just now. I retract the above. BTW, you may be 54, but they have books older than you
. I also hope you don't imply I would be a century old jan didden
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Agreed. No component is perfectly linear. I believe we were looking at first order issues.
jan didden
Edit: Saw you post just now. I retract the above. BTW, you may be 54, but they have books older than you
jan didden
Books? Those things with all the crazy tick-tack-toes and lines and college boy words.... wiki waaaht?
Not a hundred yet? Couldafooledme.
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YES PLEASE!!! I didn't really want talk about anything else! Especially stuff I'm stupid about! Now where did I put my not stupid list?
Hi !
Another newbie question for for the specialists here ,wich you probably tell me to go to school again :
Really dont understand how FEEDBACK lowers the output impedance,i thought that was made by the OPT secundary windings! a 8 ohm output OPT is less with feedback?
thanks
Feedback lowers output impedance by sensing the output voltage, then adjusting the current to get the required voltage (some fixed multiple of the input voltage).
An 8ohm OPT secondary does not present an 8 ohm impedance to the outside world, but when loaded by an 8 ohm impedance presents the correct load to the valves. The impedance seen outside may be higher or lower than 8, depends on the output stage topology (triode, pentode, UL, cathode feedback etc.). Whatever bare impedance is presented, feedback can reduce it - which is usually what we want as most loudspeakers are designed to be fed from a low impedance source.
An 8ohm OPT secondary does not present an 8 ohm impedance to the outside world, but when loaded by an 8 ohm impedance presents the correct load to the valves. The impedance seen outside may be higher or lower than 8, depends on the output stage topology (triode, pentode, UL, cathode feedback etc.). Whatever bare impedance is presented, feedback can reduce it - which is usually what we want as most loudspeakers are designed to be fed from a low impedance source.
Yes, those things from which we learned the stuff you guys are trying to find out
[snip]Not a hundred yet? Couldafooledme.
jan didden
I suppose it is conceivable that someone could design an amplifier with such low THD yet it has other problems which do not show up: such as a time delay of 2secs on all sounds above 2kHz. It would be difficult to do this accidentally with analogue techniques, yet possible with careful digital design. So let us assume that this is not a pathological example intended to confuse audiophiles.
With THD that low I would assume that all distortions are low, as normal distortion mechanisms contribute to THD. Assuming reasonable frequency response, noise etc then it should only sound horrible to people who prefer some low-order distortion ("musicality") or frequency response shaping ("warmth"). Such people are quite common, but few of them will admit to it. You can tell who they are, as they would describe your ultra-low THD amplifier as boring or clinical.
It is an unrealistic example, as the real argument is around amps with fewer zeros in their THD figure. Is 0.01% better than 0.1% - it all depends on how that extra zero is achieved. Is 1% better than 10% - I would say yes, but SE fans might disagree.
With THD that low I would assume that all distortions are low, as normal distortion mechanisms contribute to THD. Assuming reasonable frequency response, noise etc then it should only sound horrible to people who prefer some low-order distortion ("musicality") or frequency response shaping ("warmth"). Such people are quite common, but few of them will admit to it. You can tell who they are, as they would describe your ultra-low THD amplifier as boring or clinical.
It is an unrealistic example, as the real argument is around amps with fewer zeros in their THD figure. Is 0.01% better than 0.1% - it all depends on how that extra zero is achieved. Is 1% better than 10% - I would say yes, but SE fans might disagree.
With all this book reading.
Perhaps instead of DIY Audio this thread should be called University Challenge.
On a different note. I think the cosine information explains a lot of things. Most electrical people link a phase shift to time. However dare I say without getting flamed you say there is no phase shift only the cosine of the sine which appears to be a phase shift.
This makes sense.
This is an interesting thread, all I ask is that you remember DIY audio can be anyone brick layers, carpenters, as well as electronic engineers and people will ask questions of comments made. It is not fair to refer people to books in a DIY forum unless for interest or clarity. Feel free to delete my comment.
I promise I will not continue commenting just an observation!
Reading the Beano!
M. Gregg
Perhaps instead of DIY Audio this thread should be called University Challenge.
On a different note. I think the cosine information explains a lot of things. Most electrical people link a phase shift to time. However dare I say without getting flamed you say there is no phase shift only the cosine of the sine which appears to be a phase shift.
This makes sense.
This is an interesting thread, all I ask is that you remember DIY audio can be anyone brick layers, carpenters, as well as electronic engineers and people will ask questions of comments made. It is not fair to refer people to books in a DIY forum unless for interest or clarity. Feel free to delete my comment.
I promise I will not continue commenting just an observation!
Reading the Beano!
M. Gregg
Linking a phase shift directly with time is a mistake, even if electrical people do it. Time is just one possible cause of a phase difference.
Most people on here are happy to explain things to people who don't understand them. We accept that not all people have access to lots of good textbooks, although much of the information is now available free on websites. However, it is perfectly reasonable to expect people pursuing a scientific hobby to acquire the foundation knowledge of their chosen pastime. Alternatively, they should simply accept what they are told by people who do read books. The problems come when someone who has not done the necessary reading feels free to propagate false information or contradict those who do understand the basics. I do mean basics: there is nothing complicated in this thread.
The alternative would be to separate into two groups: those who understand the basics can have their arguments about details in one place, others can share their confusion with each other in another place. This would be counter-productive, although there is one audio website where one sub-forum insists on science only - all statements must, in principle, be backed by hard evidence or sound argument.
I would not wish to insult a bricklayer or carpenter by assuming that scientific knowledge is beyond them. The assumption that this might be so is a peculiarly British error. I remember a Russian maths professor once told me that when she lived in Germany she found that car mechanics there were quite likely to read Proust and visit the opera.
Most people on here are happy to explain things to people who don't understand them. We accept that not all people have access to lots of good textbooks, although much of the information is now available free on websites. However, it is perfectly reasonable to expect people pursuing a scientific hobby to acquire the foundation knowledge of their chosen pastime. Alternatively, they should simply accept what they are told by people who do read books. The problems come when someone who has not done the necessary reading feels free to propagate false information or contradict those who do understand the basics. I do mean basics: there is nothing complicated in this thread.
The alternative would be to separate into two groups: those who understand the basics can have their arguments about details in one place, others can share their confusion with each other in another place. This would be counter-productive, although there is one audio website where one sub-forum insists on science only - all statements must, in principle, be backed by hard evidence or sound argument.
I would not wish to insult a bricklayer or carpenter by assuming that scientific knowledge is beyond them. The assumption that this might be so is a peculiarly British error. I remember a Russian maths professor once told me that when she lived in Germany she found that car mechanics there were quite likely to read Proust and visit the opera.
Yikes,...! Gonna have to chew on that one a while. Like a bad bag of Jack Links.
One of the FB design issues I haven't got a good handle on yet is what value to choose for the resistor in GNF line. Since the size of the signal coming off the OPT is going to be huge at high volumes, if the signal isn't attenuated enough, then a negative signal larger than the drive signal may be reinjected. 6.8K seems to be a common ballpark value when combined with the cathode R. Also, what's the reason why FB is never returned to the grid?
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