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Class D (Switching) Amps

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  • #61
    Some interesting direct comparison although not comprehensive or deep, can be found in this review done by Dr. Michael Bump.

    http://www.enjoythemusic.com/superio...tas_Review.htm

    he does mention the various implementations of the Hypex NC1200 Ncore briefly. There is more of a direct comparision with the VERITAS Monoblocks (Hypex NC1200 Ncore) and the new Merrill Audio ELEMENT 116 Monoblocks.

    Merrill Audio.

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    • #62
      I believe Myles is in hand with a pair of one of these. It would be nice to hear his feedback. That or an idea when the published date Maybe.
      PAP Trio 10/Voxativ & PAP Trio 15 Horn speakers, Ampsandsound Casablanca monoblocks, First Sound Audio Mark 3SI preamp,
      Mojo Audio Deja Vu server, Mojo Audio Mystique V3 DAC, The Linear Solution Ethernet Switch, Blue Jeans Ethernet cablling,
      Akiko Corelli, Custom power strip direct wired to panel with OFC copper wire. Inakustik Ref Air 2404 Speaker cable. Genesis and Inakustik NF2404 Air Interconnects.

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      • #63
        I heard the mola mola and the silver devalua too. Both seemed ok to me. Not crazy good but ok did not offend
        but some say if one puts in a good class a amp it's more obvious.
        speakers cust infinity IRS V , new caps and LPS , magnets etc.
        mark levivson pre no 26 amps no 33
        digital three cust servers , win ser 2016 , AO
        Dacs lampi various

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        • Kingrex
          Kingrex commented
          Editing a comment
          Yes, the article is 2 birds of a feather.

      • #64
        Another review of the Merrill Audio ELEMENT 118 Monoblocks.
        https://www.soundstageultra.com/inde...ipment-reviews


        Merrill Audio.

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        • #65
          Alan Sircom, Editor in Chief of Hifi Plus provides a comparison also done locally,
          "There are a handful of amplifiers that create a sound as fast and as precise as this, but one of the few that is still in production is DarTZeel. The two have a lot in common sonically, although the Element 118 is perhaps even more neutral-sounding than the Swiss triumph."

          Read the whole article here.
          http://www.hifiplus.com/articles/mer...er-amplifiers/
          Merrill Audio.

          Comment


          • #66
            Originally posted by EdAInWestOC View Post
            Maybe someone can chime in and help me with something.

            I don't understand the use of class D in an audiophile class amp. Everything about an amp is about modulating the power supply to produce a carbon copy of the input signal. Introducing switching into the power supply and the output devices sounds like an invitation to introduce non-linear content into the output.

            The very best traditional amps are all about their power supplies and the ability to supply instantaneous current into a difficult load (the speaker) during a very demanding program source. Adopting a switching approach into this arena certainly introduces efficiency but what are we doing to the output signal?

            Each time I read about a class D amp, I hear reports about different sounds that these devices introduce. This sounds like an approach that would be welcomed for other amplification purposes but for absolute fidelity it sounds like a wrong turn.

            I am sure some of these are much better than others but for absolute fidelity I find the approach absurd. When we want efficient amplification class D makes all the sense in the world. When we want absolute fidelity class A is the best approach and I have never heard anyone argue otherwise.

            The KISS principal still holds true no matter how much someone may argue for some other hi-tech approach. We wandered away from tubes in the 1960s when everybody saw the amazing efficient solid state devices.. Then someone compared a solid state amp to a tubed amp and listened.

            To be sure the tube amp sounded better than any early transistor amp and that still holds true today. The high end is not about efficiency or compactness, its about fidelity. The old vacuum tube makes music better than sand. The transistor can sound pretty dammed good, now that we have has decades to learn what was right and wrong, but for absolute sound quality the tube is still king.

            It isn't efficient and wastes lots of power and space but who cares? That isn't what this hobby is all about. And that really irritates a lot of people who do not understand why we all spend so much on such antiquated equipment. We could make music with a smart phone and some bluetooth earbuds. Why do we all insist on such old fashioned stuff?

            All of the above comes to mind when the subject of class D amps come up. It seems to be another modern device that has great potential. What does it sound like compared to an old-fashioned all class A amp?

            And that is why we do what we do.

            Ed
            Sorry to quote this so late in the game, but a few points about class D;

            1) a basic class D circuit is quite simple. Class D was originally proposed when tubes were King.
            2) the distortion of a class D amp is mostly governed by its encoding scheme. In a traditional solid state or tube amp, most of the distortion is the result of the operation of the output section. So from this it can be seen that if the encoding scheme is done in a precision manner, distortion will be low.
            3) its a simple fact that class D is still a developing technology. When a smaller player like my company can develop patents in the field of expertise, and as fast as we've seen the technology emerge, its pretty obvious that we are still at or near the steep part of the innovation curve. So its realistic to expect that it will improve over time. As far as tubes and solid state goes otherwise, both being a mature technology its likely that the differences will be very similar in two generations as they are today.
            4) introductions of new semiconductor technologies is likely to continue. A few years ago Gallium Nitride (GaN) devices were rare and expensive- now they are cheap and everywhere. Being ten times faster than the prior art, they collectively brought class D amps forward, as they allow higher switching speeds and that in turn allows for wider bandwidth and less residual (the remaining sine wave after the switching frequency is filtered out of the output).
            5) the semiconductor industry really isn't liking to build linear style power devices like output transistors the way they did 20 years ago. They are steadily moving over to devices designed for switching applications. So while this really isn't a direct reason to consider class D, it is a reason why designers might see it as more attractive since its easier to get the parts needed to make an amplifier.

            FWIW I've head class D amps that sound like a very good tube amp- transparent, wide, deep soundstage, detailed yet relaxed- all the things you would associate with good tubes.

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            • #67
              Originally posted by atmasphere View Post
              FWIW I've head class D amps that sound like a very good tube amp- transparent, wide, deep soundstage, detailed yet relaxed- all the things you would associate with good tubes.
              Yet pretty much like digital I can’t get past their unnatural synthetic qualities...
              david

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              • #68
                Originally posted by david k View Post

                Yet pretty much like digital I can’t get past their unnatural synthetic qualities...
                david
                It really depends on the amplifier!

                Just a FWIW: class D amps are analog, not digital (I know you weren't suggesting that but I felt the need to clarify). Older amps I would describe as having different artifacts from traditional solid state (or tube amps). I didn't like their lack of authority in the bass range. Perhaps 'synthetic' is a good way to describe the earlier ones.

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                • #69
                  Originally posted by david k View Post

                  Yet pretty much like digital I can’t get past their unnatural synthetic qualities...
                  david
                  You just can't help yourself david lol. Millions love and we are all wrong 👌
                  speakers cust infinity IRS V , new caps and LPS , magnets etc.
                  mark levivson pre no 26 amps no 33
                  digital three cust servers , win ser 2016 , AO
                  Dacs lampi various

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                  • #70
                    A bud gave me a few thoughts I found to be true in part
                    one is low imp as it's switching it has little to no reserve so gets unstable.
                    Next is jump at high rate output it's flat at lower volumes it's better.
                    Last I don't get but here goes many use them in the low freq and it's exactly where they are worse
                    better on upper Mids and above.
                    Atmaphere please help me understand and I'm not pushing back you are way more knowledgeable then I am
                    and always love your replies unlike David's one trick pony comments lol.
                    speakers cust infinity IRS V , new caps and LPS , magnets etc.
                    mark levivson pre no 26 amps no 33
                    digital three cust servers , win ser 2016 , AO
                    Dacs lampi various

                    Comment


                    • Rob
                      Rob commented
                      Editing a comment
                      I've found the bass on every class D amp I've tried to be excellent, they have a damping factor that far exceeds linear SS amps.

                  • #71
                    Originally posted by Alrainbow View Post
                    A bud gave me a few thoughts I found to be true in part
                    one is low imp as it's switching it has little to no reserve so gets unstable.
                    You really don't want to overdrive a class d amp. I regard the major disadvantage of class D to be the output impedance- 'tight bass' does not exist in real life and IMO/IME is a coloration. To improve class D performance you have to go to faster output devices; it works out that the faster the device, the lower ON resistance it will have so the lower the output impedance. I'm thinking current feedback might solve this.

                    Next is jump at high rate output it's flat at lower volumes it's better.
                    Not sure what you mean here.

                    Last I don't get but here goes many use them in the low freq and it's exactly where they are worse
                    better on upper Mids and above. [/QUOTE]

                    Until recently, I've not liked class D bass either. Designing the power supply for a class D is a bit trickier, as the at idle the amp uses little power; in transients quite a lot. So a power supply for a class D amp has to have proper bypass and reserve to play bass right. It really seems to me that's been a while in coming.

                    Comment


                    • jonathanhorwich
                      jonathanhorwich commented
                      Editing a comment
                      So far in all the sessions I have recorded I have never heard tight acoustic bass before doing the recording even though it is considered something to shoot for in playback. What the acoustic bass sounds like at the mic with the musician playing is often not thought of as good sound by some on their playback system.

                    • david k
                      david k commented
                      Editing a comment
                      @ jonathanhorwich, I never heard tight, room shaking or subterranean audiophile bass from an acoustic instrument, even the Japanese taiko drums don't sound anything like the audiophile adjectives one hears.

                      david

                  • #72
                    Sorry for confusing you.
                    but you seems you get it all.
                    Jump is slew rate in dynamics so it's the speed of the change
                    jump is when you hit a rim shot that makes you jump lol
                    If not it's hey that was nice but does not knock the ash off your cigar
                    At higher volumes it seems to run out of gas so little jump
                    speakers cust infinity IRS V , new caps and LPS , magnets etc.
                    mark levivson pre no 26 amps no 33
                    digital three cust servers , win ser 2016 , AO
                    Dacs lampi various

                    Comment


                    • #73
                      Originally posted by atmasphere View Post

                      It really depends on the amplifier!

                      Just a FWIW: class D amps are analog, not digital (I know you weren't suggesting that but I felt the need to clarify). Older amps I would describe as having different artifacts from traditional solid state (or tube amps). I didn't like their lack of authority in the bass range. Perhaps 'synthetic' is a good way to describe the earlier ones.
                      You found any that you'd recommend over your own amplifiers? There's more to sound than just smoothness and stage size I still find bass of class D amps totally lacking any texture or tonal depth just flat.

                      david
                      Manufacturer: American Sound Turntables and The Nothing Rack
                      Distribution: NEODIO

                      Special Sales: van den Hul
                      Industry Representation: Lamm, Kharma OLS Speakers, Ortofon, ZYX, Keith Monks, Audio Desk, Jensen Transformer, Venta Airwasher

                      Unique Items: Vintage Horn Speakers
                      http://www.audionirvana.org/forum/ti...stening-room-1
                      http://www.audionirvana.org/forum/ti...earfield-setup

                      Comment


                      • #74
                        Originally posted by Alrainbow View Post
                        Sorry for confusing you.
                        but you seems you get it all.
                        Jump is slew rate in dynamics so it's the speed of the change
                        jump is when you hit a rim shot that makes you jump lol
                        If not it's hey that was nice but does not knock the ash off your cigar
                        At higher volumes it seems to run out of gas so little jump
                        IME, if the amp is working right dynamic character is a function of the recording, not the equipment. And this extends to class D as it does any other amplifier. But you don't want to run a class D out of gas- you can get away with it with some tube amps but in class D its a different ballgame- you really do need to have more power than you will ever need.

                        Comment


                        • #75
                          Originally posted by david k View Post

                          You found any that you'd recommend over your own amplifiers? There's more to sound than just smoothness and stage size I still find bass of class D amps totally lacking any texture or tonal depth just flat.

                          david
                          We've been working on our own class D for about 2 1/2 years. We have a patent pending. I've yet to hear a production class D amp that I would recommend over our own amps (although if the customer has a speaker incompatible with our amps I would make a recommendation for that or other solid state amp). But I'm hearing amps that do have texture and tonal depth- they are anything but flat.

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