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Thread: Linear vs Switched mode PSU

  1. #251
    Join Date: Mar 2017

    Location: Seaford UK

    Posts: 1,861
    I'm Dennis.

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    I concur with Jez's metaphorical explanation, and was going to post it myself a while ago.

    It can be taken further.
    The outlet of the water tank can be seen to have a large diameter pipe and the water under the enormous pressure from the tall tank, this being parallel to the O?P of a PS being capable of delivering high current quickly, which will respond to large signals and big transients. (It's O/P impedance is low).

    Although mains can be supplied at very high power, the I/P to the tank is in small pulses, those necessary to restore the tank to its 'full' point.

    Expectation bias must apply to everyone and in all we do.
    We bring to any situation a personal database of our experience which is a 'map' and a survival tool which prepares us.
    But it has limits intellectually which in the case of our pursuit, made much worse by the pressure of advertising, which become apparent under scrutiny. Scrutiny also upsets us, often ruining our performance, at least I found this to be very true of me in examinations, the atmosphere of which increased my anxiety greatly.

    A man on a gold course who has lost his ball sees a white piece of paper in the distance as his ball, expectation.

    Yes we do hear a change most initially, and then we acclimatise, that is also in our biology.
    If you put a clamp on your finger and wait, after a few minutes the feeling of it goes, or place your hand in some cold water, the same happens, but on returning to the normal temperature it will now feel hotter.

  2. #252
    Join Date: Feb 2011

    Location: Red Rose Country

    Posts: 153
    I'm Colin.

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    Quote Originally Posted by Marco View Post
    Entirely plausible...

    One has to recognise that expectation bias works BOTH ways, so one can 'expect NOT' to hear a difference, and don't (due to being adversely influenced by one's objective belief system), even if perhaps one exists, just the same as one can 'expect TO' hear a difference (due to being adversely influenced by one's subjective belief system), even if perhaps one doesn't.

    Therefore, objectivists don't get the sole right to play the expectation bias card, as ANY human being, no matter their belief system, can be fooled!

    Marco.
    Nick Gorham over on AT posted this link a few days ago http://www.audio-talk.co.uk/phpBB3/v...t=6989#p148640 that would appear to back up Arkless own views and a perfect example of why any AB comparison will normally "show" there is no difference between two bits of kit, and so (for example) why all amplifiers sound the same.

    Try and see. You'll be quite surprised of the results you get.

  3. #253
    Join Date: Feb 2008

    Location: South Wales

    Posts: 9,151
    I'm NotTakingLifeTooSeriouslyTheseDays.

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    Ahh good old NASA!
    Quote Originally Posted by struth View Post
    actually they have, and it wasn't easy



    story here
    "Today scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality"
    Nikola Tesla



    Its now a conspiracy theory to believe that the Immune system is capable of doing the job it was designed to do.
    A fish is only as healthy as the water its swimming in ! [Dr Robert Young]


    www.tubedistinctions.co.uk

    Matthew 5:10

  4. #254
    Join Date: Jul 2017

    Location: Crook, County Durham, UK

    Posts: 48
    I'm Christopher.

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    Quote Originally Posted by Toppsy View Post
    Nick Gorham over on AT posted this link a few days ago http://www.audio-talk.co.uk/phpBB3/v...t=6989#p148640 that would appear to back up Arkless own views and a perfect example of why any AB comparison will normally "show" there is no difference between two bits of kit, and so (for example) why all amplifiers sound the same.

    Try and see. You'll be quite surprised of the results you get.
    And Nick goes on to say:

    But once you have "seen" it, its very much harder to not see it.

    But the meaning (IMHO) of the video is that

    Hearing a difference means there is a difference

    Not hearing a difference is not proof of the absence of a difference.

  5. #255
    Join Date: Nov 2010

    Location: Sheffield/Peak District. UK

    Posts: 574
    I'm Richard.

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    I think most of us have been here before... and probably we all have entrenched views. It's illuminating that this thread is also running parallel with the 'myth busters' one.

    A blind or double-blind A/B test is still subjective in the cases we are discussing as no test meters etc are involved - just one's ears.
    I would suggest it is the only way to discern whether two or more pieces of equipment are different from each other in terms of SQ.

    In terms of 'expectation bias' one must realise that scientists in the 'normal Baconian' methods don't show any at the start of the experiment -as they set up what is known as the 'null hypothesis', i.e. that there is NO difference between the two (or more bits of kit/processes etc). This is done as much to help in the inevitable stats test as not wanting to show bias; (yes, I'm aware that the mischievous will say that showing no bias at the start is in it's way a bias of sorts). Science, like democracy, is not perfect, but is the best (many would say only) method we have.
    Although I have been 'a scientist' (and yes, research into the efficacy of antibiotics) I, when it comes to hi-fi, am much more of a subjectivist. How many of you have experimented with idiotic notions as: painting a green ring on the inside of CDs (to absorb stray red laser light) and sticking triangular black magnetic paper on two opposite corners of mains plugs (I can't recall the rationale for that)?

    I do, however, despite what I have just written, prefer that any perceived, subjective, differences in SQ have some possible scientific explanations. Hardly a crime!

    I seem to recall that this original thread was about power supplies and noise injected into the mains...Have we got any further on with that discussion? Are there any firm conclusions/ways forward?

    BW

    Richard
    Last edited by Bonky; 26-07-2017 at 10:41.

  6. #256
    Join Date: Feb 2011

    Location: Red Rose Country

    Posts: 153
    I'm Colin.

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    Quote Originally Posted by PalsHuffMor View Post
    And Nick goes on to say:

    But once you have "seen" it, its very much harder to not see it.

    But the meaning (IMHO) of the video is that

    Hearing a difference means there is a difference

    Not hearing a difference is not proof of the absence of a difference.
    Yes agreed but Nick goes on to further say:

    Lets say B is actually a better less distorted (or in some way better sounding thing), if we hear A first, and then B, we think we have heard a improvement, so we say, ahh, that sounded better, lets go back to A again. But now we can't unhear the improvement, so now going back to A we still hear what we thought was a improvement going from A to B, and we begin to doubt or first thought. Now we go from A to B again, and still hear no improvement, the more we do it the more it becomes clear that we can't hear any difference, and our first thought of a improvement was false.

  7. #257
    Join Date: Nov 2010

    Location: Sheffield/Peak District. UK

    Posts: 574
    I'm Richard.

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    Quote Originally Posted by Toppsy View Post
    Nick Gorham over on AT posted this link a few days ago http://www.audio-talk.co.uk/phpBB3/v...t=6989#p148640 that would appear to back up Arkless own views and a perfect example of why any AB comparison will normally "show" there is no difference between two bits of kit, and so (for example) why all amplifiers sound the same.

    Try and see. You'll be quite surprised of the results you get.
    I laughed at this:
    Eg,
    I listen to amplifier A and it sounds good
    I listen to amplifier B and it sounds more detailed "ooh, I haven't heard that triangle before"
    I listen to amplifier A and now the triangle I hadn't heard on that amp is there, large as life.
    I listen to amplifier B again and now it sounds the same as amplifier A - Bugger!

    R

  8. #258
    Join Date: Jul 2017

    Location: Crook, County Durham, UK

    Posts: 48
    I'm Christopher.

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    We all hear the difference between A & B in the video on first play.

    On subsequent plays, our brains trick us to believe that the difference is no longer there. But, of course, the difference is still there.

    It doesn't mean that A/B testing is fundamentally flawed, just that we need to understand how our brains operate.

  9. #259
    Join Date: Feb 2008

    Location: South Wales

    Posts: 9,151
    I'm NotTakingLifeTooSeriouslyTheseDays.

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    Quote Originally Posted by PalsHuffMor View Post
    We all hear the difference between A & B in the video on first play.

    On subsequent plays, our brains trick us to believe that the difference is no longer there. But, of course, the difference is still there.

    It doesn't mean that A/B testing is fundamentally flawed, just that we need to understand how our brains operate.
    "Today scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality"
    Nikola Tesla



    Its now a conspiracy theory to believe that the Immune system is capable of doing the job it was designed to do.
    A fish is only as healthy as the water its swimming in ! [Dr Robert Young]


    www.tubedistinctions.co.uk

    Matthew 5:10

  10. #260
    RothwellAudio Guest

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    Here's the link to the video mentioned above, just in case anyone doesn't want to follow a link to a link.
    https://www.theatlantic.com/technolo...unhear/373036/

    Yes, I had a demonstration of this exact phenomenon about 35 years ago and I've never forgotten it. It shows very clearly that judging things by simply listening isn't a simple matter.

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