Measuring caps with WT3?

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  • LING GOWA
    Senior Member
    • Dec 2007
    • 165

    Measuring caps with WT3?

    How does one measure caps with WT3?
    Website
  • JonMarsh
    Mad Max Moderator
    • Aug 2000
    • 15213

    #2
    One doesn't. WT3 is unreliable and flaky in my experience- as an owner. Ended up getting the real deal from Smith and Larson.

    Not to be harsh- YMMV - just look at all the posts with people getting weird results with WT3 on Tech Talk.
    the AudioWorx
    Natalie P
    M8ta
    Modula Neo DCC
    Modula MT XE
    Modula Xtreme
    Isiris
    Wavecor Ardent

    SMJ
    Minerva Monitor
    Calliope
    Ardent D

    In Development...
    Isiris Mk II updates- in final test stage!
    Obi-Wan
    Saint-Saëns Symphonique/AKA SMJ-40
    Modula PWB
    Calliope CC Supreme
    Natalie P Ultra
    Natalie P Supreme
    Janus BP1 Sub


    Resistance is not futile, it is Volts divided by Amperes...
    Just ask Mr. Ohm....

    Comment

    • fjhuerta
      Super Senior Member
      • Jun 2006
      • 1140

      #3
      You mean, the WT2, Jon?
      Javier Huerta

      Comment

      • JonMarsh
        Mad Max Moderator
        • Aug 2000
        • 15213

        #4
        Yeah, that's what I have- from Smith and Larson. WT2. Was trying not to directly send people away from our sponsor. But maybe I can get away with it, considering all the cabinets and crossover parts I've bought from PE in the last two weeks!




        Like these! Destined for the ultra secret Modula Xtreme system!!



        Attached Files
        the AudioWorx
        Natalie P
        M8ta
        Modula Neo DCC
        Modula MT XE
        Modula Xtreme
        Isiris
        Wavecor Ardent

        SMJ
        Minerva Monitor
        Calliope
        Ardent D

        In Development...
        Isiris Mk II updates- in final test stage!
        Obi-Wan
        Saint-Saëns Symphonique/AKA SMJ-40
        Modula PWB
        Calliope CC Supreme
        Natalie P Ultra
        Natalie P Supreme
        Janus BP1 Sub


        Resistance is not futile, it is Volts divided by Amperes...
        Just ask Mr. Ohm....

        Comment

        • LING GOWA
          Senior Member
          • Dec 2007
          • 165

          #5
          Ultra secret.... you can tell me....I won't tell anyone.....trust me.
          Website

          Comment

          • ---k---
            Ultra Senior Member
            • Nov 2005
            • 5202

            #6
            I'm not arguing with Jon. He is typically right. But for us those with the WT3 already or what have you, here is a post by Curt Campbell that discusses how to do it.
            Want a second or third opinion about your speaker cabinet design or other audio related problem? Post your question or comment on the Technical Discussion Board. Hundreds of technicians, engineers, and hobbyists, nationwide read and discuss electronics related questions each week. We welcome your participation

            To determine capacitance from the impedance sweep, a simple calculation must be accomplished.

            The formula for determining capacitance is:

            C = 1 / (2pi f Xc) –where C is in Farads and Xc is the impedance of the capacitance in ohms at a specific frequency.

            We can make this formula easier to remember by assuming a measurement frequency of 159 Hz:

            C (in microfarads) = 1000 / Xc)

            Or for 1590 Hz:

            C (in microfarads) = 100 / Xc)

            Example: An unknown value cap shows an impedance of 500 ohms at 159 Hz when an impedance sweep is done. Substituting that value for Xc in the formula we have:

            C = 1000 / 500 = 2 uF

            OK. While the above calculation can be easily done in one’s head, the more astute of you will have by now noticed that there is no vertical index line on WT3 at 159 Hz or 1590 Hz. -While you could eyeball it, as I do, or save the impedance file and then open it up in notepad to find the value, it perhaps would be easier to choose a demarcated frequency close to a normal crossover frequency, like 200 Hz or 2 kHz. A close approximation for those frequencies is:

            C = 80 / Xc for 2000 Hz

            C = 800 / Xc for 200 Hz

            -And maybe an easy one to remember for Xc measured at 1000 Hz:

            C = 159 / Xc

            For best accuracy, I’d make my measurement at a frequency where the impedance is changing value rapidly. The impedance and frequency scales of WT3 can be expanded to make the capacitance measurements quite easy and accurate.

            C
            __________________
            Curt's Speaker Design Works
            - Ryan

            CJD Ochocinco! ND140/BC25SC06 MTM & TM
            CJD Khanspires - A Dayton RS28/RS150/RS225 WMTMW
            CJD Khancenter - A Dayton RS28/RS150/RS180 WTMW Center

            Comment

            • JonMarsh
              Mad Max Moderator
              • Aug 2000
              • 15213

              #7
              Good post Ryan!

              I just wasn't in a good mood about the WT3 due to having bought two of them and both going south after not very long.
              the AudioWorx
              Natalie P
              M8ta
              Modula Neo DCC
              Modula MT XE
              Modula Xtreme
              Isiris
              Wavecor Ardent

              SMJ
              Minerva Monitor
              Calliope
              Ardent D

              In Development...
              Isiris Mk II updates- in final test stage!
              Obi-Wan
              Saint-Saëns Symphonique/AKA SMJ-40
              Modula PWB
              Calliope CC Supreme
              Natalie P Ultra
              Natalie P Supreme
              Janus BP1 Sub


              Resistance is not futile, it is Volts divided by Amperes...
              Just ask Mr. Ohm....

              Comment

              • fjhuerta
                Super Senior Member
                • Jun 2006
                • 1140

                #8
                I have the WT2, too - it was the first measurement equipment I got. I have never regretted it - it's so simple to use, support by the S&L team is amazing (I got a special build of the software when I was beta testing Win 7), and it's completely dependable. Measuring the LRC parameters of just about anything is pretty simple and straightforward - plus it does so much more. Love it!
                Javier Huerta

                Comment

                • ---k---
                  Ultra Senior Member
                  • Nov 2005
                  • 5202

                  #9
                  Originally posted by JonMarsh
                  Good post Ryan!

                  I just wasn't in a good mood about the WT3 due to having bought two of them and both going south after not very long.
                  Well, the credit should got to Curt. He is the brains; I'm just the parrot.
                  - Ryan

                  CJD Ochocinco! ND140/BC25SC06 MTM & TM
                  CJD Khanspires - A Dayton RS28/RS150/RS225 WMTMW
                  CJD Khancenter - A Dayton RS28/RS150/RS180 WTMW Center

                  Comment

                  • Undefinition
                    Senior Member
                    • Dec 2006
                    • 577

                    #10
                    Am I the only one who uses the demo mode of Praxis? I'm sure there are more turnkey solutions, but I prefer the price of this (free). It does require making your own testing probes, but I just use the ones I made for LSPCad.

                    Isn't it about time we started answering rhetorical questions?
                    Paul Carmody's DIY Speaker Site

                    Comment

                    • JonMarsh
                      Mad Max Moderator
                      • Aug 2000
                      • 15213

                      #11
                      Well, I've used the paid mode of Praxis, too, but I still find CLIO to be simpler- but how many people do you know with an Athlon PC with ISA slot and a Version 6 CLIO setup?

                      Of course, I also have an HP LCR meter, but because of it's size, it's usually in my climate controlled storage! You can get some good deals on older equipment from Test Equity and other places, plus eBay, of course.
                      the AudioWorx
                      Natalie P
                      M8ta
                      Modula Neo DCC
                      Modula MT XE
                      Modula Xtreme
                      Isiris
                      Wavecor Ardent

                      SMJ
                      Minerva Monitor
                      Calliope
                      Ardent D

                      In Development...
                      Isiris Mk II updates- in final test stage!
                      Obi-Wan
                      Saint-Saëns Symphonique/AKA SMJ-40
                      Modula PWB
                      Calliope CC Supreme
                      Natalie P Ultra
                      Natalie P Supreme
                      Janus BP1 Sub


                      Resistance is not futile, it is Volts divided by Amperes...
                      Just ask Mr. Ohm....

                      Comment

                      • Face
                        Senior Member
                        • Mar 2007
                        • 995

                        #12
                        Even the Sears by me stocks somewhat decent LCR meters.
                        SEOS 12/AE TD10M Front Stage in Progress

                        Comment

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