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In Reply to: RE: How can an external mains filter posted by fmak on September 20, 2014 at 22:12:05
Yes, I'm referring only to the noise put back into the AC main line.
Follow Ups:
the other guy is saying that a mains filter beats linear supplies???
In reality both should be used. I am now assembling an all linear supply powered thru an isolation transformer. The difficulty is to ensure neat cabling which I think I have solved.
"I am now assembling an all linear supply powered thru an isolation transformer"
Ooooo you're using linear rectifiers? Excellent!
Just something to keep in mind. Your isolation transformer may add enough HF impedance to slow things down a bit and that can help a lot.
Regards, Rick
I prefer an isolation transformer with measured and stated isolation spectrum than a $2000 filter full of MO components, capacitors and whatnots without any form of performance information.
"I prefer an isolation transformer with measured and stated isolation spectrum than a $2000 filter full of MO components, capacitors and whatnots without any form of performance information."
Agreed. My point, albeit perhaps a weak one, is that rectifiers are a decidedly non-linear element (unless blown...).
"Performance information" is exactly the very thing we need more of, much more. It is a travesty, but an understandable one that so many audiophiles have come to regard specifications as taradiddle. Rather than gripe about folks who DO measure things for us, like JA, we should encourage them to branch out and measure more parameters.
It really matters not that the "audio industry" eschews thinking out-of-band, nobody ELSE does so there is ample gear and expertise available to adequately quantify emissions and susceptibility. On a relative basis it's DIY-able and there are plenty of standards and Labs that can do it more methodically and quantitively for a price.
I know that this is less of a concern for you sophisticated old-Worlders since CE does a better job of controlling emissions than the the FCC. Here in the Wild-West it's mostly caveat emptor...
Rick
CE was originally meant to control emissions in safety critical environments.
"the other guy is saying that a mains filter beats linear supplies???"
I think he is referring to the quality-design of the linear power supply.
How good is the filtering in the design.
He needs to be much clearer in his posts; it's habitual.
Thorsten was completely clear in his posts. As he pointed out, it's a matter of containing switching noise, not eliminating it. Even if a linear power supply is used to provide DC to run the motherboard there will still be switchers powering the CPU and RAM because these chips require high current at sub 1 volt for reasons of device physics.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
This is your interpretation of what he said, which is obvious.
What he said was something else, ie that a mains filter is many times more effective than reducing smps noise within the computer.
FMAK was no less clear, and entirely correct, in his post - and I believe I was, too, from less technical and more empirical perspective.
"and totally wrong, in assumption that containing it is all that's needed."
Please explain why you believe that Thorsten was totally wrong.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Why was he wrong?I believe that his experience, that it's all that's needed, stems from insufficient resolution of the system, in particular the computer that is so far from being optimized for audio playback, that it masks all the differences introduced by improved power supply.
As I mentioned, my experience - and apparently FMAK's, too - is that both mains filter and quality power supply improve sound quality. Using them in conjunction with each other gives the best result.
Edits: 09/22/14
You said he was "totally wrong". That can't be, since he has already admitted that his system might lack resolution. Had you left out the word "totally" I would not have replied. :-)
There is a question, though and that concerns the meaning of "resolution". This is a very ambiguous audiophile term. I am immediately suspicious of people who use this term because for me, at least, the purpose of an audio system is to enjoy music or to review and critique recordings. It is easy to increase the ability of a system to "resolve" certain differences in recordings, such as to increase high frequency response making it easier to hear artifacts of poor digital recordings, etc., but such systems will not make music enjoyable. There is also a question of whether a device "resolves" differences in its input that it is supposed to resolve. So, for example, a balanced interconnect does a poor job of "resolving" ground loops. So if one is using such a system it will not be very "resolving" of certain types of power problems, yet it will almost certainly sound better than a similar single ended system. I used these two examples because they are both analog and easier for audiophiles to understand who don't understand digital electronics, computers and software.
So, if a DAC and downstream analog components "resolves" differences in a computer involving tweaking (not DSP) to me this is an indictment of the DAC and/or amplifiers, not an indictment of an untweaked computer. Sure, I tweak my computer software if it consistently makes a difference in what I hear, but if remaining differences were such as to be consistently and significantly audible then I would get another DAC.
In the "What's Best" and "AVS Forum" threads, amir was able to consistently hear differences between different digital formats. His "resolving" system was nothing but a stock laptop with built-in sound card and a pair of headphones. I don't buy the "resolving system" argument at all unless a system is seriously lacking in an essential musical aspect, e.g. audible noise, lack of or uneven bass, unnaturally truncated highs or audible distortion and commonly used playback levels. Such a system must be rejected for poor ability to play music, not for any lack of "resolution".
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
that go far beyond "tweaks"
Leaving that term, and those out: that is in no way what Carcass is talking about. It is also very easy to leave out all of computer audio when discussing things like resolution, system synergy, etc.
One just needs to get specific, comparative experiences yield differing results. Compare a NAD CD player to a Moon Eclipse, in the same system and one is going to sound different and way wrong, - (given that it's a decent set of amps & speakers or even headphone amp and cans). We know this by actually going out and having those experiences. Listening to either one of those CDPs, or even a computer audio system transport with DAC through a pair of Avalon speakers with a VAC integrated is going to sound radically different than through a Sharp boombox.
Experienced people, (listeners/analysts), like Kal Rubinson, T-Bone, etc., never, ever, say the kinds of things that "theorists" do. People who have heard 100s of systems, and individual components don't say such things. Most of these "resolving" components and systems rarely sound the same, (but they sometimes do), and differences between components are heard easily without tweaks.
People who attend shows also know these things to be true.
What people prefer in a playback system has nothing to do with the subject at hand.
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
My experience is with live acoustic music and the recording and playback of that. It does not extent to the never ending panoply of products being marketed to audiophiles, especially audiophiles who have lots of money and little ability to understand what they hear. My standard is live music. That is the only "state of the art" that is relevant to me. It is not necessary to go to audio shows and listen to dozens of flawed components and poorly set up systems to evaluate what one hears if one has this kind of absolute standard.
I suspect that most case of system synergy are just the fortuitous compensation of errors. If one is working in the dark out of ignorance this may seem to be "magic" but it is probably real. Unfortunately this is not something that the majority of audio salesmen or ex audio salesmen are likely to understand. (The best ones will have an intuitive understanding of the situation and wisely guide their customers.)
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
That none of your described stereotypes actually exist
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
I fail to see how subjectivism, as you're willing to accept it, is different from what I'm advocating. If I listen to option A and option B, and option B results in sound that is, at the same time, more detailed ("resolving") and less strident (or harsch), expanded in all dimensions - i.e. more enjoyable - what conclusion am I supposed to come to?I freely admit not being an EE, not having an education in that field, and not being able to have in-depth discussion in technical terms . However, why does that matter - in the sense why would that impact my ability to perceive audible differences?
How about this - what follows is to me pretty much what EE is to you or Thorsten:
Let's say you are a user of some financial analytical software. You're presented with 2 prototypes - and after 15 minutes of playing with each, you are certain that option #2 is more responsive, when running a particular type of analysis. As a user - is THAT all you need to know? Or you absolutely have to be aware of the fact that option #1 is implemented using SQL Server 2012 utilizing Columnstore indexes, and #2 - Netezza with highly optimized data distributions, resulting in maximized co-location?
Edits: 09/22/14
The basic issue is that "more details" may be wrong. It may not correspond to what is actually on the recording. This may be hard to appreciate, but less so if one has experience making recordings and playing them back. I do not question that people perceive differences. What I question is when they apply pseudo-technical reasoning to translate these perceptions back to specific causes. (Not generally a problem with you, BTW.)
When I evaluate a piece of software, I try to get a feel for what it is supposed to do, by experimentation or by RTFM. Then, at least in my better moments, I try it out with a few test cases. In many cases, if the software was ill conceived I succeed in crashing it on the spot. However, if it's just a matter of speed (a.k.a. performance) then I know there are may ways to expose or cover up performance difficulties. Decades ago I used to run competitive performance benchmarks, and was familiar with a variety of ways to present one's product "in the most favorable light". Later, I debunked various "scientific" performance analysis that showed that certain technologies (e.g. Ethernet) were inferior to others (e.g. Token ring). In most case, the manipulative techniques were obvious and covered in books such as How to Lie with Statistics.
My concern with databases and database theory was mostly around getting correct results, rather than optimizing performance. Back in those days, computer crashes were the rule rather than the exception, so data integrity was paramont. Hopefully, today the questions have advanced to matters of privacy and security.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Hi,
> I believe that his experience, that it's all that's needed, stems
> from insufficient resolution of the system, in particular the
> computer that is so far from being optimized for audio playback,
> that it masks all the differences introduced by improved power supply.
Well, first, I believe Tony was asking for the physical/electrical process involved.
Second, before you diss someone's system, should you not at LEAST hear it?
Third, I suspect that your experience and Fred's stem from ignoring EE101 and basic physics and thus not fixing glaring, totally brutal "you are f..ked" level problems and trying to put sticky tape over the stable doors after not only the hoses have bolted but after the stable boys burned them down plus the barn and the Masters house and joined the revolution!
A little sticky tape will fix it. No need to actually understand what is going on.
And as a result finding that that any change (including a fly farting at 20' outside your window) changes the sound of the system, which is of course precisely what I would predict.
Fourth, have fun and ignore the man behind the curtain. It does not actually matter.
Ciao T
At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to untolerable pain. Really, what more could we need?
As I said, my experience is diametrically opposite - and so is the experience of many people, who built systems using cMP recipe and its varieties.Going strictly by what you described as your Audio PC, I would not expect the system downstream from it to be truly resolving, because of that bottleneck - that's the extent of my comment about resolution.
Edits: 09/22/14 09/22/14
He said it himself! What I find unacceptable is someone admitting to this, and then boasting that he knew it all on the basis of science.
Signal conditioning and integrity are very basic concepts in electronic measurement and control, and yet some self proclaimed bods steadfastly refuse to accept these are important within a computer.
No point arguing with them as you will see in some of my replies.
Not worth arguing with you when you read what you want to in a post.
Assumptions here are what leads to unnecessary arguments.
2 evils are better than 10!
Thorsten's posts and reasoning were completely clear to those who have some understanding of electronics, power supplies, inner workings of computers, and radiated and conducted emissions.
He is also correct in stating...
"...it is important to fully understand the system if we wish to optimise it. Otherwise all is old wife's tales."
Random haphazard tweaks w/o understanding the system may be fun for those who enjoy blindly chasing their tails. Others recognize the limitations of such amateur approaches.
Answer my question logically and systematically; otherwise you are defaulting to your Apple fan type of postings.All you seem capable of doing is butting into posts that inmates are unable to respond to.
Edits: 09/21/14
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
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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