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  • Dynaudio Xennon 3 Crossover

    A friend plans to build a set of cabinets for Dynaudio drivers he has, and plans to use the Dynaudio Xennon 3 crossover circuit. He asked about a note on the schematic that shows "8 x 4.7uF" and "5 x 4.7uF" I've tried to find a way to upload the schematic, or a link to it here unsuccessfully using my phone, but a search will bring it up.

    Would anyone know if the "5 x 4.7uF" and "8 x 4.7uF" designations indicate 5-4.7uF capacitors in parallel? Likewise for the 8 x 4.7uF.

    Thank you.

  • #2
    Perhaps a part list, it probably uses a delay circuit on the tweeter.
    Guess xmax's age.

    My guess: 15. His grammar is passable. His trolling is good.

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    • #3
      No idea, the midrange part of the Xennon3 circuit looks complicated. It's a 20 year old design, as far as I know, perhaps there are some improvements?

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      • #4
        Eight 4.7uF caps (37.6uF) for one part of the circuit and Five 4.7uF caps (23.4uF) in the other.

        That would be my guess.

        And ONLY if the drivers he has are the same employed in the Xennon, otherwise a new crossover is required. I found some of my old D21AF, put them on the bench for a measurement and they still look great. So I put them in a cabinet with some 6.5" woofers and they made a great Christmas gift and sound fantastic. Dynaudio made and makes some nice stuff, and they really deserve a proper crossover.
        R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio

        Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51


        95% of Climate Models Agree: The Observations Must be Wrong
        "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

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        • #5
          The drivers are all Dynaudio. There are 2 sets of 5x4.7uF, and one of 8x4.7uF in the midrange section. He intends to make the crossover circuits as close to the original design as possible.

          I'll try to find a way to post the schematic lster today.

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          • #6
            The drivers may all be Dynaudio, but are they the same models as what was in Xennon?
            R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio

            Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51


            95% of Climate Models Agree: The Observations Must be Wrong
            "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

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            • #7
              I think they are, but I'll check.

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              • #8
                I checked, he is using the 24W-100 Woofer, D-76AF Midrange and D21AF Tweeter, rather than the D24AF tweeter.
                He knows there are a few component changes recommended by Dynaudio in the tweeter circuit for the D-21AF tweeter.
                I've managed to upload a copy of the information sheet with the crossover circuit.

                Thanks for the help with this.

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                • #9
                  That is no delay circuit, they must be going after a low esr, they do mean parallel all those caps together as far as I can tell.
                  Guess xmax's age.

                  My guess: 15. His grammar is passable. His trolling is good.

                  Comment


                  • #10
                    Designating the multiple capacitors(5x4.7uF & 8x4.7uF) in the circuit seems unusal, that's why I asked if anyone is sufficiently familiar with the crossover design and Dynaudio technology.

                    Initially we thought there may be a response advantage to individual capacitors in parallel vs. single capacitors. An alternative thought, quickly discarded, was that it might be a way around the expense of single ~23-40 uF capacitors, but given these were expensive drivers in an expensive system emphasizing true high fidelity, concern for the additional capacitor expense makes little sense.

                    It is a curious design, no doubt well justified, and it would be good to know the reasoning behind it

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                    • #11
                      Originally posted by TN Allen View Post
                      Designating the multiple capacitors(5x4.7uF & 8x4.7uF) in the circuit seems unusal,
                      Those values must have been on sale at the time.
                      "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche

                      http://www.diy-ny.com/

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                      • #12
                        Parallel caps to lower ESR is very common practice everywhere else in electronics, I don't see why XO's would be any different.
                        That said, Dayton Audio MP caps sound great, are a great value and measure very well too.
                        Guess xmax's age.

                        My guess: 15. His grammar is passable. His trolling is good.

                        Comment


                        • #13
                          In the above example, parallel large value electrolytics for a power supply is more about spreading the self-heating of the capacitors, and reduced ripple current per cap. Also for board size constraints to keep the form factor you see there would not be possible with a pair of big caps.

                          In a crossover, the ESR of a polypropylene small value cap is already very low, like 1/100th or less than that of an Electrolytic. By using multiple in parallel, you are actually lowering the tolerance, getting as close to the intended value as possible with less variation from part to part since you are always ending up with the average of multiples. Or as stated above, it may be also some cost saving of making a bulk purchase of the same value.
                          "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
                          exactly a Fc 3K for both drivers, anybody can do it." -Xmax

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                          • #14
                            Originally posted by dcibel View Post
                            Or as stated above, it may be also some cost saving of making a bulk purchase of the same value.
                            Polk did it back in the day and I'm sure they weren't the only ones.

                            "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche

                            http://www.diy-ny.com/

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