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Help! How to add BSC components (RC parallel to L) in PCD ?

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  • Help! How to add BSC components (RC parallel to L) in PCD ?


    I have been trying out Jeff Bagby's Passive Crossover Designer. Its an awesome program but I am not sure how to add BSC components ( RC parallel to L).
    It might be possible to design a crossover with such an RC network, but I believe it needs a much bigger inductor coil. And it limits the flexibility of the simulation.

    I have added a link to an image ( from Troel Gravesen) to illustrate what I am talking about. ( not sure why I can't attach, says image corrupted!)

    Someone kindly let me know if such a simulation is possible in PCD?

    If not, please suggest alternate ( free) simulators.


    Image BSC-RC hosted in

  • #2
    Yeah, PCD can't do that. XSim can. Not sure why you would want that circuit. Without seeing the values the resistor is probably just adjusting the impedance of a notch/ tank filter. if that's the case you can use PCD without the resistor in a Parallel RCL Notch filter
    John H

    Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower


    • #3
      If you like PCD you could try WinPCD by David Ralph. WinPCD started out as a functional copy of PCD that didn't require Excel. Since then David added features that allow you to sim the resistances in both the L and C braches in Troel's circuit. Both PCD and WinPCD require a "trick" that might not be apparent: select the "Parallel RLC Notch Filter" in the "Before Crossover" block and set the R value to a very large value. This effectively removes the R value from the circuit, leaving only the L and C braches. The attachment shows one way to sim the circuit in WinPCD.

      You could also try XSim which allows any crossover topology. It's a great tool too, but I miss the built-in design to target curves. That wouldn't matter in this case since you have an existing design.


      Click image for larger version

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      Attached Files
      Last edited by ernperkins; 11-06-2019, 06:03 PM.
      "Everything is nothing without a high sound quality." (Sure Electronics)


      • #4
        Thanks for your replies. I tried Xsim and checked out what RC parallel to L actually does. And it wasn't what I imagined in my head.

        But such an option in PCD would have been nice anyway, just for the sake of flexibility. But whatever options we already have might be more than sufficient, I guess.
        I tried the trick in PCD as well, though unable to add DCR and series R to the capacitor


        • #5
          FYI, "RC parallel to L" isn't a normal BSC circuit.
          A normal BSC circuit is just "R parallel to L". (Maybe you've figured this out now.)