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In Reply to: RE: How can an external mains filter-But-think? posted by fmak on September 21, 2014 at 12:03:45
I believe this is your question. I looked at the entire thread.
"How can an external mains filter address the internal issues of switching power supplies inside a computer?"
What are these "internal issues" and why are they important?
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Follow Ups:
It is widely known, among those who have experience building a system using cMP recipe, that disabling Spread Spectrum, if your BIOS allows that, audibly improves sound quality. Regardless of whether it outputs via USB or a sound card.
Why is it so, in your opinion, and do you see any connection between that, and your own question?
"It is widely known, among those who have experience building a system using cMP recipe, that disabling Spread Spectrum, if your BIOS allows that, audibly improves sound quality. Regardless of whether it outputs via USB or a sound card."
I simply dismiss these reports as useless to me if I try them and don't notice a significant difference. The people who report these differences stop at that point and they do not go on to understand how/why these audible differences arise. In other words, they have the tinkerer mentality, not the scientific mentality. If I make my system sound better, I am not happy at this point. I want to understand why it sounded better. (Long years of experience has shown me that if I don't understand correctly what is going on it won't be long before the system reverts back to poor performance.)
I heard differences when tweaking BIOS settings when I was using a juli@ sound card. These went away when replacing the computer with a newer one and replacing the juli@ with a USB DAC. If I still heard them, I would get another DAC or experiment with various forms of USB isolation. If the USB power wire is continuous from the computer to the DAC I would start there. Also, I suspect that some of those "asynchronous" USB DACs aren't really asynchronous. The problem with software tweaking inside a computer system is that there are so many things to tweak, they all interact, and many of them change out from underneath you without your knowledge if you change something else.
As to the specifics of the spread sprectrum. I know why it was implemented, being familiar with how EMI is measured according to government standards. I don't know why changing this might affect sound quality, as this will depend on a myriad of specific details. It's easiest to see why undervolting and underclocking might improve sound quality due to lower CPU power consumption where there are problems elsewhere in the system. By the same intuitive power consumption metric, it is easy to see why inefficient linear power supplies might make things worse than a well designed switcher.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
power supply pollution and propagation into audio circuitry; a topic that is much discussed here. This is not the same as mains feedback.
What audio circuitry? There is no audio circuitry in a computer unless there's a sound card in it.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
usb performance and signal integrity is part of audio performance.
No more trick responses please.
Are you suggesting that your computer and USB have signal integrity problems? What is your definition of USB "signal integrity"? How would you know if there are problems? Why do you believe that the 12 volt power supply to the computer affects these problems?
Note: these are not trick questions. They are something that you should be able to answer, given that you used the technical term "signal integrity".
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
usb audio transfers.
If you can't, then you should not be posting here.
I have better things to do than to go on and on answering questions that should be obvious to you.
Unlike you I don't have errors on my usb audio PC.
My questions were formulated to allow you to show the depth of your knowledge or the breadth of your ignorance. You have done an admirable job.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
it was trick question despite your denial and a complete waste of my time. (as I suspected)
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