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Since its inception ten years ago, the Harbeth User Group's ambition has been to create a lasting knowledge archive. Knowledge is based on facts and observations. Knowledge is timeless. Knowledge is human independent and replicatable. However, we live in new world where thanks to social media, 'facts' have become flexible and personal. HUG operates in that real world.

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Analysis of speaker cables

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  • #31
    Originally posted by STHLS5 View Post
    How do you think a 10 feet cable going to improve this? Wouldn't it be the best to connect these wires directly to the speakers' terminals?
    If the amplifier has no zobel networks on its outputs (thinking of classic Naim gear here), that would be a bad idea! Most amplifier designs need some inductance on their outputs to damp HF oscillations (Naim specified a minimum length of a particular type of cable).

    If you amp does have Zobel networks - which is very probable! - then the less cable the better... and the smaller the effect that the cable will have.

    Now looking at the transistor complement of that amp (and those power resistors), it probably has a nice high damping factor. Going back to the first study, the frequency response of their test system when using such an amplifier was not significantly affected by the cable used in the test.

    However if you were to use a high-capacitance cable (litz or similar) it might affect the performance of the amplifier as described in Nelson Pass' study.

    Comment


    • #32
      A sense of proportion?

      I illustrated the semiconductor junction and its tiny lead-out wires previously. If we now take a razor blade to the PCB track of the crossover (which is much thicker and broader than the PCB track on the amplifier) you can see just how thin it is. Thin, but entirely adequate for the current that it will carry.

      So does the speaker cable need to be much thicker i.e. have more copper per metre than this? Well yes, thicker would be good considering the length the current must travel from the amp to speaker (and hence to minimise loss as heat) but as thick as a hose? No.

      Note the fat wires from the adjacent coil, itself much thicker than the track foil but flattened out, probably about the same number of copper atoms per unit volume. Do bear in mind that this crossover track is likely to be several times thicker than the track inside the amplifier. Anyone have a close-up of an amplifier PCB tracking adjacent to a ruler for scale?
      Attached Files
      Alan A. Shaw
      Designer, owner
      Harbeth Audio UK

      Comment


      • #33
        Originally posted by hifi_dave View Post
        Over the years we have carried out countless 'blind' listening of cables and other items in the hi-fi chain and customers can always hear differences.
        Simple logic tells us there are two and only two possibilities here: either (a) by "blind listening" you mean what I do, a rigorous and careful AB or ABX comparison, where the volume remains constant and you and the customer do not know which cable is being used at any given time, the kind of test described by Alan in various posts, or (b) you mean something different by "blind listening." In case (a), you and your customers should immediately contact James Randi, who, as ST pointed out, will hand you 1 million dollars. But I suspect that (b) is the case. And that being the case, it would be more accurate for you to say, not "customers can always hear differences," but rather "customers always _believe_ they hear differences."

        But "belief" doesn't prove anything; evidence does. To restate a simple point: if "golden ear" folks or just regular folks could indeed reliably detect (in a careful ABX test) sonic differences between pairs of cables, wouldn't some such tests have confirmed this? Again, think about how much money Monster, Pear Anjou, or Opus cable companies would make if they could prove that their cables "sound better" with such rigorous testing. Yet no one has published such test results. That's a proof by contradiction: if folks really could detect sonic differences, then some rigorous tests would have confirmed this. But no such test has been published. Q.E.D.

        Why would anyone believe that they can't hear the difference between cables?
        Well, for example, an engineer who understands the physics of current, wires, etc, someone like Alan, say, might well have solid, scientific reasons for expecting that any differences would not be detectable by the human ear. In my case, not being an engineer, I have no expectations one way or the other, so I depend on evidence. And in the absence of any convincing evidence that differences can be detected, but in the presence of scads of cases where tests have failed to demonstrate that such differences can be detected, I remain a skeptic.

        Bruce

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        • #34
          HackerNAP board pic

          Here a photo of both sides of an amplifier board. The board is about 90mm wide, and the output-stage current path is highlighted. When the components are fitted the path length is 35mm from the decoupling capacitor to the output terminal - the current goes through one transistor, one 0.22 ohm resistor, and a 0.5uH inductor.

          Other than that there are wires from the +ve power supply to the board, from board to +ve binding post, and from -ve binding post back to the transformer centre tap.

          Tracks are 4mm wide, BTW.
          Attached Files

          Comment


          • #35
            Uncertain mind

            Originally posted by honmanm View Post
            If the amplifier has no zobel networks on its outputs (thinking of classic Naim gear here), that would be a bad idea! Most amplifier designs need some inductance on their outputs to damp HF oscillations (Naim specified a minimum length of a particular type of cable).

            If you amp does have Zobel networks - which is very probable! - then the less cable the better... and the smaller the effect that the cable will have.

            Now looking at the transistor complement of that amp (and those power resistors), it probably has a nice high damping factor. Going back to the first study, the frequency response of their test system when using such an amplifier was not significantly affected by the cable used in the test.

            However if you were to use a high-capacitance cable (litz or similar) it might affect the performance of the amplifier as described in Nelson Pass' study.
            The picture wasn't mine. I got it off the net. But you have raised an interesting observation regarding high-capacitance cables. I will try similar cables. I am still keeping my mind open, as the debate was going on I was changing my players power cord. Alternating between a reference, solid core Belden and the original cable that came with player. Yes, I detected some difference. I have done this comparison many times before and it is always the same when we first change the cable. We detect some difference.

            As days go by, you will be asking again what happened to the highs or deep bass that you first heard with the cable change. And we start all over again with different cables and tweaks.

            ST

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            • #36
              Audio - where science and ego mix

              Cables. Where to begin? You have Science and perceived real world results. I think the truth lies somewhere in between. I think it's most important to first set your ego and bias' aside for a moment, and research both arguments in a honest effort to get at the truth. That is what we are after, right?

              Then we must factor in the variables; listener preference, the physical shape of ones ears, the equipment, the setup. Ear shape is interesting topic that often goes without mention. Next time your listening to music, take your index fingers and push the center of your outer ears forward about 1/16"...notice something? Pretty darn significant huh? How might this single variable effect ones choice of speaker? How might it effect the sensitivity to subtle change? Sometimes people phrase arguments in such a way, that it seems they think the human ear is a device, without error and/or variation. I'd submit that people with "wide" ears are especially sensitive to treble energy.

              While I think it's silly to be deeply entrenched in either camp (believer/non-believer) I personally exercise some common sense with my choices. I have experienced differences in some cables. I've often found that multi-strand cables tend to sound out of focus/hashy when compared to solid copper conductor type cables. I also on occasion chose the "cheaper" cable over the more expensive one because it simply sounded better. Audioquest Diamondback vs Copperhead is an example. I have always preferred the cheaper Copperhead.

              Personally, I'd never spend more than I have already on cables. My speaker cables (Kimber 8TC v.2) were $456 for an 8ft/pr; and the Kimber Hero IC's at about $285 for 1 mtr set. Having said that, the much cheaper Kimber PBJ is excellent as well; and with hindsight I would have kept it. Digital cable is different, in my opinion. I think a digital cables ability to be as close to the 75ohm spec as possible, far out-weighs any material/topology considerations that you have with analog cables. I love the Belden 1694A, and have had digital cables 6x the price that didn't perform as well, and neutral as the Belden.

              Comment


              • #37
                Balanced approach to cables

                Thanks for the nice, sane post Steve. People get too excited about cables.

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