Depends on the PSU design.50AE said:
As I implied, grounding and induction need to be got right. Most people instinctively get these wrong at first; some later learn how to do it.
However, in most cases beliefs about mains cables are merely myths. An exception may be if certain 'high end' equipment is involved, as some 'high end' designers are better at writing stories than designing electronics. They flourish because some of their customers are better at reading than listening.
And I'm hearing all the same from you again and again. Right and wrong, wrong and right.
Do you mind giving specific example to the community, with objective data, what design do you consider right? Can you give more specific arguments?
Why are you so certain of your opinions? What would you do if someday science proves you wrong?
Do you mind giving specific example to the community, with objective data, what design do you consider right? Can you give more specific arguments?
Why are you so certain of your opinions? What would you do if someday science proves you wrong?
Driving isn't just about speed and differences that no one can tell without a chrono or other instruments. Driving is not just speed.
They already have a different metric about driving! That's why they keep driving a vintage car rather than a new one.
On top of that, it also applies to new car vs new car. I would buy a Porsche GT3 every time instead of C7 Z06 (the standard model not the faster GT3 RS that matches the C7 track performance), despite the fact it costs a bit more and is a bit less powerful and so slower....on track
I don't remember all the poor designs I have seen over the years - usually being discussed on this very forum. I just remember that I was surprised at first to see so many of them, and to discover that there is only a weak correlation between genuine quality and price - and that this correlation turns negative at the very top end.
I am certain of my "opinions" because they are based on science: boring things like circuit theory, which is merely the low frequency approximation of Maxwell's equation. If science proves me wrong then I will accept it; that is what scientists do. I do not expect to see Maxwell's equations overturned by an audio designer.
I am certain of my "opinions" because they are based on science: boring things like circuit theory, which is merely the low frequency approximation of Maxwell's equation. If science proves me wrong then I will accept it; that is what scientists do. I do not expect to see Maxwell's equations overturned by an audio designer.
Perhaps a small illustration of a small 'blind' test to prove something often overlooked?
Four friends and myself did such a test - particularls later. During a great many 'events', one person was correct as many as 6 out of 6 times consecutively, on two occasions. 5 out of 5 consecutively occurred a number of times. In the end some 150 tests were done. (How long did all this take?!)
Well, it was not an audio test, it was the tossing of a simple coin. As expected, the end result was within >74 - <76.
Point: If those intervals of 5 or 6 correct out of 5-6 were to have occurred right at the beginning and the experiment terminated after such, what could be more positive proof of dead certainty? Yet the truth was that the correct result was 50-50.
The moral is obvious. A single test or even several cannot render a result of any statistical value, only chance. Even after 150 events our results were not exactly 75-75. Statistics as I recall, and depending rather much on the nature of a test, is frowned on if not at least 10 tests are done, preferably quite more.
Four friends and myself did such a test - particularls later. During a great many 'events', one person was correct as many as 6 out of 6 times consecutively, on two occasions. 5 out of 5 consecutively occurred a number of times. In the end some 150 tests were done. (How long did all this take?!)
Well, it was not an audio test, it was the tossing of a simple coin. As expected, the end result was within >74 - <76.
Point: If those intervals of 5 or 6 correct out of 5-6 were to have occurred right at the beginning and the experiment terminated after such, what could be more positive proof of dead certainty? Yet the truth was that the correct result was 50-50.
The moral is obvious. A single test or even several cannot render a result of any statistical value, only chance. Even after 150 events our results were not exactly 75-75. Statistics as I recall, and depending rather much on the nature of a test, is frowned on if not at least 10 tests are done, preferably quite more.
At risk of making a 'random' post again, I have an anecdote.
A friend of mine at one point had a wonderful sounding 300B setup. He decided to try some mains conditioning cables.
The sound afterwards - to me - was horrible compared to what it was before. It was as if all the tube 'magic' had been stripped away.
I can't start to explain why - perhaps you guys can - but mains cables can certainly make a difference. And if anything, this goes to show that 'expectation bias' doesn't always work in the skeptics' favour!
One further matter: Damping Factor. (and I have not reread the entire thread right now. Apology if this is repetition.)
There is a persistant misunderstanding of the importance of this figure, viz. that the definition is in error. It does in fact tell us very little about a system's actual effect on a loudspeaker.
Not using formula style: It is popularly defined as the impedance of the load (loudspeaker), divided by: the total of amplifier output impedance plus cable resistance plus whatever else is in the feed line. As an illustration, a loudspeaker cable has a total resistance of 100 milli-ohm and the amplifier measures another 100 m.ohm; it shows a DF to a 8 ohm loudspeaker of 40.
This is in fact wrong. The damping ('shorting') of the loudspeaker voice coil to affect e.m. 'braking', is done by the whole resistance in the circuit. That includes the forementioned resistances plus the voice coil wire resistance.! That did not suddenly disappear from the equivalent circuit!
The truth is then that for practical components, the true 'braking factor' (DF) can never be higher than 1.4 (taking the v.c. resistance of an 8 ohm driver as 5,5 ohm, a practical digure). This state of affairs is illustrated by many articles om this subject, showing the diminishing effect of cable and amplifier output impedance on loudspeaker performance, as those go smaller than the v.c. resistance. (For simplicity I took resistance figures; in practice the mentioned values are impedances, also dependant on frequency. But one thing at a time.)
Somewhat OT here, but as much of the discussion referred to DF ..... (The originator of this term, Fritz Langford-Smith of RDH IV fame, corrected this in a then copy of the Australian monthly "Radiotron", but the term was ingrained by that time.)
[P.S.: This excludes negative amplifier output impedances achieved by positive feedback and other such active circuitry.]
There is a persistant misunderstanding of the importance of this figure, viz. that the definition is in error. It does in fact tell us very little about a system's actual effect on a loudspeaker.
Not using formula style: It is popularly defined as the impedance of the load (loudspeaker), divided by: the total of amplifier output impedance plus cable resistance plus whatever else is in the feed line. As an illustration, a loudspeaker cable has a total resistance of 100 milli-ohm and the amplifier measures another 100 m.ohm; it shows a DF to a 8 ohm loudspeaker of 40.
This is in fact wrong. The damping ('shorting') of the loudspeaker voice coil to affect e.m. 'braking', is done by the whole resistance in the circuit. That includes the forementioned resistances plus the voice coil wire resistance.! That did not suddenly disappear from the equivalent circuit!
The truth is then that for practical components, the true 'braking factor' (DF) can never be higher than 1.4 (taking the v.c. resistance of an 8 ohm driver as 5,5 ohm, a practical digure). This state of affairs is illustrated by many articles om this subject, showing the diminishing effect of cable and amplifier output impedance on loudspeaker performance, as those go smaller than the v.c. resistance. (For simplicity I took resistance figures; in practice the mentioned values are impedances, also dependant on frequency. But one thing at a time.)
Somewhat OT here, but as much of the discussion referred to DF ..... (The originator of this term, Fritz Langford-Smith of RDH IV fame, corrected this in a then copy of the Australian monthly "Radiotron", but the term was ingrained by that time.)
[P.S.: This excludes negative amplifier output impedances achieved by positive feedback and other such active circuitry.]
An excellent point!
It reminds me of someone a while ago on one of these forums who was proposing to make high-impedance OTL-friendly loudspeakers by winding the voice coils with resistance wire rather than copper wire. It took a lot of arguing for him eventually to be convinced that he might just as well make the equivalent circuit, using a normal voice coil and an external series resistance (thus demonstrating that the idea was really a non-starter since the fraction of the output power from the amplifier that ended up reaching the speaker would be tiny!).
Chris
As I have said several times, low Zout or high Zout (or high/low damping factor into a nominal load) are quantities that don't mean anything without specifying the actual driver and loudspeaker design that will be used. Generalizations simply do not work for optimal results! Forget marketing non-sense.....
Okay, but you always seem to be repeating the same cardinal things all over again - "Poor designs, bad designs, flawed designs".
Do you have an article written by yourself or if you don't, would you like to write one where you're thoroughly explaining what are the criteria towards good (power supply, amplifier) designs and why.
If I was a thirsty for knowledge beginner in this domain, I'd seek arguments of your conclusions and I'd always ask the "Why?" question. Are you willing to do that?
I cannot disagree with you that the probability of pure chance exist, but my goal was not trying to prove anything, but to give an example how I believe such experiments should be represented.
I'm also not a total believer that random DBB test are always significant, but it's another topic for a discussion.
I've a acquired a lot of unbiased experience were changes to the wiring seemed to make the resulting sound subjectively worse, so it's not a surprise. Advice - wait for burn in before the final conclusion
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My only published article on audio was about the complementary pair. It explained some results found by Douglas Self.50AE said:
I don't see the need to publish yet another article on PSU design, as the facts are available already. I would simply be repeating the basic stuff I have read in texbooks and the more advanced stuff I have gleaned from the wise people on this forum. The article I mentioned above was presenting new information, which made it worth writing.
So does everyone.
What is conditioning cable?
"this" as in your anecdote from subjective none double blind test? In that case, it doesn't equal to objective blind test.
How long does it take and for what reason should he wait for it?Advice - wait for burn in before the final conclusion
I've read text books about PSU designs and I still do. I even re-read the already checked ones. Can you give me a hint about information I've probably missed?
Are you assuming an information to be considered as a truth just for the reason being written in a textbook? Afterwards, aren't the practical results that confirm the theoretical knowledge. Do you mind sharing some practical results of yours in the audio domain?
I'd recommend him 24h hours at least. Then listen to the same piece of equipment again. Compare it to a fresh one. Check if he can hear a difference.
Why 24 hours? Why not 24 minutes or 24 seconds?
What kind of listening test setup did you use?
My crystal ball is away for repair at the moment so I can't look inside your head and determine what you don't know about PSU design.50AE said:
No. Textbooks should always be read critically, aiming for understanding rather than mere reproduction. However, most textbooks are correct in most of what they say. Textbooks cannot, of course, correct all possible misunderstandings; I have sometimes come across people who say 'textbooks do not say X is false; therefore X must be true'. Textbooks try to teach some appropriate subset of the truth; they do not usually attempt to unteach all possible untruths relevant to a topic.
Experiments give raw data. To convert that data into useful information you need to apply correct theory. Get that wrong and you will deduce a false idea from the raw data. People 'measure' all sorts of things and 'prove' all sorts of ideas.
There is nothing so practical as a good theory, someone one said. I published my analysis of the complementary pair. This correctly explained the results for quiescent current found by Self.
Would you like to share some of your theoretical analysis in the audio domain?
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