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Re: [regsaudioforum] amplifier errors

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  • Fred
    Would I be correct in remembering that you regard amplifiers as being a done deal in that competent designs sound much like each other? (Yet) To read what
    Message 1 of 7 , Mar 1, 2011
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      Would I be correct in remembering that you regard amplifiers as being a "done deal" in that competent designs sound much like each other?

      (Yet) To read what reviewers describe of "serious" amplifiers, you'd think differences so great that lesser than exotic (and extremely expensive) is quite unacceptable. To be blessed by the best thou must PAY! (Phrrrph!;-)

      A link to an interesting vendor appeared in another forum http://www.higherfi.com/amplist/amplist.htm

      Ah well, if my QUAD system's still bettering your figures (as is likely) there's much to be said for good vintage gear but I can't help but wonder what a double blind test against an exotic might reveal?

      :-)

      Fred.


      --- On Tue, 1/3/11, Robert <regonaudio@...> wrote:

      From: Robert <regonaudio@...>
      Subject: [regsaudioforum] amplifier errors
      To: regsaudioforum@yahoogroups.com
      Date: Tuesday, 1 March, 2011, 2:16


      Amp errors from exact voltage amplification in

      good amps are about 70 or more dB down from signal.

      Now 60 dB down from signal means

      error of size 0.1 %

      So the freequency response shift in dB corresponding would be

      20 log (1.001)< .01 dB

      This is too small to be heard as a response change, and it

      is surely far below the errors of speakers, even the best speakers.

      It is indeed far below their PAIR MATCHING--far far below.



      Even 1% error, 40 dB down, would be a response shift

      of

      20 log(1.01)=about 0.08 dB.

      THis might be marginally audible as a response shift--but this would involve the amp error being ALL about response shift in some broad

      band, a type of error that is rather unusual except into extreme

      loads in the top end. (Amps do sometimes sound slightly different in top end balance, especially into oddball loads because the top end impedance involves an output network in most of them so it is not so low, the output impedance, as it could be).



      In short, amplifiers (solid state low output impedance onces)

      differ much less from each other in frequency response even into real loads than do speakers with the only real possibilities for audible differences being in the top, on account of output network and of

      course the bottom if the amp is rolled off subsonically, not flat to DC.



      REG
    • Robert
      A vexed issue with a long answer if I covered every aspect. But let me hit the high spots 1Amplifiers do not sound exactly alike, if only perhaps because their
      Message 2 of 7 , Mar 1, 2011
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        A vexed issue with a long answer if I covered every aspect.
        But let me hit the high spots

        1Amplifiers do not sound exactly alike, if only perhaps
        because their top and bottom end frequency responses are different.

        2 To my mind, the differences among correctly designed low output impedance amplifiers are so much smaller than the differences among speakers as to be not worth worrying about very much--except in extreme instances of odd loads like electrostatic top ends.
        A good speaker that you like and that is well set up will sound really good with almost any amplifier with enough power. A bad speaker that you do not like set up badly will not sound good with amplification by divine power.

        3 As long as there is ANY difference(and one is tempted to say even if there were no differences!), people are going to get off on
        making choices and expressing preferences. One of the deepest impulses
        of the human being is the desire to think that mine is better than yours.

        I would not say I am immune to these impulses. But I tend to take them out in other directions than audio electronics.

        4 If you like what you have, stick with it. This seems like good advice altogether(also about,e.g., human relationships, human/canone relationships . etc)

        5 For what it is worth, the current dumping Quad models of old
        (I do not recall what you have) actually had very large errors in the differential input/output tests because the low end rolloff
        caused quite a lot of phase shift in the bottom end and ditto to some extent in the top(though the effect there is less), even though
        this rolloff was largely out of band. Welcome to minimum phase systems, where your phase response can be bad eeven at frequencies
        where the freqwuency response is good!
        Does this matter? Not much, since speakers almost all have much much more severe rolloffs (and consequent phase shifts) and of course as UB has so clearly show, phase is knocked all over the place by the room anyway. But can one hear the difference? Absolutely: if you switch to a flat to DC amp, the sound will without question change.
        Whether the change is signicant--your call.


        There will never be any logical approach to these issues until audio reviewing starts to do double blind testing. And even then, if people
        know it is electronics being tested, then those who want to believe electronics matter a lot will believe the differences they hear(and there likely will be some) are very important. In fact, the harder the difference is to hear the more it matters to some audiophiles.

        That being said, I would like to point this out:
        A well known speaker manufacturer(perhaps I should not say who)
        used to demo his speakers at shows with NAD electronics. But he would
        exhibit visually some ultra pricey stuff(different kinds at different shows). Everyone would love the sound. A great many people would praise the electronics. He could not reveal the truth for fear of
        seeming guilty of gratuitous humiliation. But some of us were on the inside and we knew. It was hard to keep a straight face listening to the ravings about the wonderful electronics. Well, except that they were wonderful--just not expensive.

        To each his own, but it is a true story. NO ONE who did not know
        what was going on EVER said, "wonderful speakers, but why are you using such lousy electronics". NO ONE. EVER. NEVER HAPPENED.
        NOT ONE PERSON. Think about it....would be my suggestion.

        REG

        --- In regsaudioforum@yahoogroups.com, Fred <glenndriech@...> wrote:
        >
        >
        > Would I be correct in remembering that you regard amplifiers as being a "done deal" in that competent designs sound much like each other?
        >
        > (Yet) To read what reviewers describe of "serious" amplifiers, you'd think differences so great that lesser than exotic (and extremely expensive) is quite unacceptable. To be blessed by the best thou must PAY! (Phrrrph!;-)
        >
        > A link to an interesting vendor appeared in another forum http://www.higherfi.com/amplist/amplist.htm
        >
        > Ah well, if my QUAD system's still bettering your figures (as is likely) there's much to be said for good vintage gear but I can't help but wonder what a double blind test against an exotic might reveal?
        >
        > :-)
        >
        > Fred.
        >
        >
        > --- On Tue, 1/3/11, Robert <regonaudio@...> wrote:
        >
        > From: Robert <regonaudio@...>
        > Subject: [regsaudioforum] amplifier errors
        > To: regsaudioforum@yahoogroups.com
        > Date: Tuesday, 1 March, 2011, 2:16
        >
        >
        > Amp errors from exact voltage amplification in
        >
        > good amps are about 70 or more dB down from signal.
        >
        > Now 60 dB down from signal means
        >
        > error of size 0.1 %
        >
        > So the freequency response shift in dB corresponding would be
        >
        > 20 log (1.001)< .01 dB
        >
        > This is too small to be heard as a response change, and it
        >
        > is surely far below the errors of speakers, even the best speakers.
        >
        > It is indeed far below their PAIR MATCHING--far far below.
        >
        >
        >
        > Even 1% error, 40 dB down, would be a response shift
        >
        > of
        >
        > 20 log(1.01)=about 0.08 dB.
        >
        > THis might be marginally audible as a response shift--but this would involve the amp error being ALL about response shift in some broad
        >
        > band, a type of error that is rather unusual except into extreme
        >
        > loads in the top end. (Amps do sometimes sound slightly different in top end balance, especially into oddball loads because the top end impedance involves an output network in most of them so it is not so low, the output impedance, as it could be).
        >
        >
        >
        > In short, amplifiers (solid state low output impedance onces)
        >
        > differ much less from each other in frequency response even into real loads than do speakers with the only real possibilities for audible differences being in the top, on account of output network and of
        >
        > course the bottom if the amp is rolled off subsonically, not flat to DC.
        >
        >
        >
        > REG
        >
      • Charles Daniell
        ************ That being said, I would like to point this out: A well known speaker manufacturer(perhaps I should not say who) used to demo his speakers at
        Message 3 of 7 , Mar 1, 2011
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          ************
          That being said, I would like to point this out:
          A well known speaker manufacturer(perhaps I should not say who)
          used to demo his speakers at shows with NAD electronics. But he would
          exhibit visually some ultra pricey stuff(different kinds at different shows). Everyone would love the sound. A great many people would praise the electronics. He could not reveal the truth for fear of
          seeming guilty of gratuitous humiliation. But some of us were on the inside and we knew. It was hard to keep a straight face listening to the ravings about the wonderful electronics. Well, except that they were wonderful--just not expensive.

          To each his own, but it is a true story. NO ONE who did not know
          what was going on EVER said, "wonderful speakers, but why are you using such lousy electronics". NO ONE. EVER. NEVER HAPPENED.
          NOT ONE PERSON. Think about it....would be my suggestion.
          *************

          One of the great stories of audio!
           
          Wonderful, just not expensive!
           
          Charlie
        • Will_H
          Gee, after reading REG s rave review of the Magtech amp, I was all ready to buy one but maybe I ll just keep my little NAD 326BEE instead! Seriously though
          Message 4 of 7 , Mar 1, 2011
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            Gee, after reading REG's rave review of the Magtech amp, I was all ready to buy one but maybe I'll just keep my little NAD 326BEE  instead!
             
            Seriously though (well, actually, I am serious about the Magtech too), Paul Seydor was right about the little Nad, it is stunningly good.... nevermind the price.
             
            or
             
            ----- Original Message -----
            Sent: Tuesday, March 01, 2011 5:40 PM
            Subject: Re: [regsaudioforum] Re: amplifier errors

            ************
            That being said, I would like to point this out:
            A well known speaker manufacturer(perhaps I should not say who)
            used to demo his speakers at shows with NAD electronics. But he would
            exhibit visually some ultra pricey stuff(different kinds at different shows). Everyone would love the sound. A great many people would praise the electronics. He could not reveal the truth for fear of
            seeming guilty of gratuitous humiliation. But some of us were on the inside and we knew. It was hard to keep a straight face listening to the ravings about the wonderful electronics. Well, except that they were wonderful--just not expensive.

            To each his own, but it is a true story. NO ONE who did not know
            what was going on EVER said, "wonderful speakers, but why are you using such lousy electronics". NO ONE. EVER. NEVER HAPPENED.
            NOT ONE PERSON. Think about it....would be my suggestion.
            *************

            One of the great stories of audio!
             
            Wonderful, just not expensive!
             
            Charlie
          • sunilm_k2
            I certainly have noticed differences between solid state amps in their bass response, keeping the rest of the system the same. I have also noticed apparent
            Message 5 of 7 , Mar 3, 2011
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              I certainly have noticed differences between solid state amps in their bass response, keeping the rest of the system the same. I have also noticed apparent differences in treble (perhaps upper midrange).

              REG qualified his statement with "well designed". It is hard to tell what is, but according to some criteria, very few appear to be. For example, I can detect easily noticeable differences in sound when the power fed to the amps goes through a good conditioner. I recently changed the power chord to my preamp, and that produced what sounded like better bass (among other changes). Some of these changes are not really frequency response improvements as such, but perhaps lowering of noise transmitted from (lowered) noisy power. But better bass? Or is that just better perception of bass because of lower noise?

              Anyway, it seems that most of the bass response differences in amps might be related to output impedance. But there might still be some "magic" left in this part of the audio system ... namely the power supply.

              -- Sunil
            • Robert
              The rolloff in the subsonic has effects further up. All amps that are flat to DC(and with low output impedance) will have essentially the same behavior in the
              Message 6 of 7 , Mar 3, 2011
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                The rolloff in the subsonic has effects further up.
                All amps that are flat to DC(and with low output impedance) will have essentially
                the same behavior in the lower frequencies unless they
                are driven so hard as to cause sagging of the power supply(this
                includes driving weird loads).

                But these effects are SMALL.

                My real point is as always not that all amplifiers are the same--
                they are not--but that the differences are SMALL.

                Ask UB if he sees big switches in Acourate measurements when
                people change from one solid state amplifier to another.
                I would be very surprised.

                In experience, one can hardly see any change at all. Peter Walker
                was right when he said that moving one's speakers a few inches would cauee a larger change in the sound than changing amplifiers.

                MUCH larger.

                Of course if you keep everything the same, then changing amps may be
                detectable. Does that mean it is important? Not really. If you move a penny on your bedisde table a quarter of an inch you can see the difference. But few of us adjust the position of the pennies within a small tolerance before going to sleep.

                REG

                --- In regsaudioforum@yahoogroups.com, "sunilm_k2" <sunilm_k2@...> wrote:
                >
                > I certainly have noticed differences between solid state amps in their bass response, keeping the rest of the system the same. I have also noticed apparent differences in treble (perhaps upper midrange).
                >
                > REG qualified his statement with "well designed". It is hard to tell what is, but according to some criteria, very few appear to be. For example, I can detect easily noticeable differences in sound when the power fed to the amps goes through a good conditioner. I recently changed the power chord to my preamp, and that produced what sounded like better bass (among other changes). Some of these changes are not really frequency response improvements as such, but perhaps lowering of noise transmitted from (lowered) noisy power. But better bass? Or is that just better perception of bass because of lower noise?
                >
                > Anyway, it seems that most of the bass response differences in amps might be related to output impedance. But there might still be some "magic" left in this part of the audio system ... namely the power supply.
                >
                > -- Sunil
                >
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