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How'd I mess up this X-over?

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  • How'd I mess up this X-over?

    This is my first DIY crossover, dont' really have a lot of knowledge about electrical components.

    This is the crossover for the Overnight Sensations. I tested these with both drivers before putting them in the cabinet and everything "worked". They still work in the cabinet but when the volume gets turned up (Lepai 2020A amp) the amp makes a metallic click and shuts off, it continues to cycle off. On my bigger amp the things shut down at about mid volume. Tested each speaker independently and they each do the same thing when running by themselves. When they're running the speakers sound OK, a little tinny and not much low end even on heavy bass tracks. I attached a photo of my X-over build. I appreciate anyone who's willing to work with a newb to Dx what I did wrong. I'd like to understand my mistake here so I can do better on future projects.

    Thanks much in advance.

    Click image for larger version

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  • #2
    Re: How'd I mess up this X-over?

    Just to clarify, is it just the crossover you posted a pic of doing it, or is it both crossovers? If it is just this one, check your solder joints, you may have a bad one around the woofer coil (Guessing).
    HAGD,
    Marc

    Even though I try to tell everyone upfront, understand that I am still a Newb. I wish the status of Seasoned Veteran/Senior Member, etc. was earned with time not posts...

    TMWW thread

    Maurbacs DCR Tower

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    • #3
      Re: How'd I mess up this X-over?

      Both speakers behave the same way, I tested each separately and they both cut out as volume increases.

      Thx

      Comment


      • #4
        Re: How'd I mess up this X-over?

        One thing you might try temporarily to see if it's causing an issue is: disconnect the 0.22uf capacitor around the woofer coil, and then see if your amps still shut down.

        Comment


        • #5
          Re: How'd I mess up this X-over?

          I'm no authority, but it appears to me your crossover in the photo does not match the schematic at all. The woofer and tweeter leads appear to be labeled opposite to what they should be, for starters. I'm getting a headache before getting anything sorted out, but I think you probably have an impedance issue or something because the parts are not connected correctly.

          Comment


          • #6
            Re: How'd I mess up this X-over?

            I think I see the problem, but it will be about an hour or so before I can do the detailed analysis and get back to you.
            don't feel bad, I've messed up plenty of crossovers......

            I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
            "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

            High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
            SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
            My Voxel min sub Yet-another-Voxel-build

            Tangband W6-sub

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            • #7
              Re: How'd I mess up this X-over?

              Good question WernerM. My thoughts exactly.

              As for this picture... I traced through and visually it looks ok. (The polarity isn't obvious but that wouldn't cause any electrical issues, only acoustical phase weirdness. The design is for reversed-phase tweeter.)

              So does this exact crossover work but it's "MATE" is giving you trouble??? It sounds like the Lepai is reaching thermal limiting and shutting itself off to protect against damage. The fact that your other amp is also experiencing problems with this speaker is curious.

              Some brainstorming:
              - Verify the wires that are soldered to the woofer are not accidentally shorted against the metal body of the woofer frame.
              - Verify that the 10 ohm resistor is not a 1 ohm. (can't read it from the picture.)
              - Verify that the 0.22uFcap is actually a 0.22uf cap.
              - Verify your solder connections are all solid.
              - VERY gently, press on the woofer's cone to make sure it moves freely and without any rubbing noises.
              - If nothing else works, try disconnecting the small 0.22uF cap and see if the problem persists. The filter should still work without the 0.22uF cap. Temporarily disconnecting it will be ok. (I believe it's a tank-trap to address cone ringing at higher frequencies.)

              I'm out of ideas dude. Good luck diagnosing the issue. Maybe someone else can offer some further insight and troubleshooting ideas.
              ~Marty

              Baby Eidolons
              Sapphos
              Cables (Post #54)
              Other speakers (Post #21)
              Design Thoughts (Posts: 6,10,13,33,35)
              Boundary Augmentation
              Dispersion/Interference

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              • #8
                Re: How'd I mess up this X-over?

                Originally posted by R=Futile View Post
                I'm no authority, but it appears to me your crossover in the photo does not match the schematic at all. The woofer and tweeter leads appear to be labeled opposite to what they should be, for starters.
                Huh? You must not be tracing through correctly. I don't see them reversed.
                ~Marty

                Baby Eidolons
                Sapphos
                Cables (Post #54)
                Other speakers (Post #21)
                Design Thoughts (Posts: 6,10,13,33,35)
                Boundary Augmentation
                Dispersion/Interference

                Comment


                • #9
                  Re: How'd I mess up this X-over?

                  I also do not see a problem with the wiring. Your description of them sounding tinny leads me to believe ther is a soldering issue. Did you make sure to clean the the coating off of the leads on the coils before soldering? This has happened many times before because people don't realize there is a thin coating of laquer like stuff on them.

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                  • #10
                    Re: How'd I mess up this X-over?

                    As long as you're tweeking things... can you rotate the small coil like this:

                    Click image for larger version

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                    Honestly, it's a very minor thing. Probably won't make much difference to your ears, but theoretically there will be some minor interaction between the two coils when they're not oriented the way I show.

                    OF COURSE... THIS WILL NOT SOLVE YOUR ORIGINAL POSTED PROBLEM. It's just an additional nice touch to minimize mutual inductance created by the physical layout of the coils. You still need to troubleshoot the original issue.
                    ~Marty

                    Baby Eidolons
                    Sapphos
                    Cables (Post #54)
                    Other speakers (Post #21)
                    Design Thoughts (Posts: 6,10,13,33,35)
                    Boundary Augmentation
                    Dispersion/Interference

                    Comment


                    • #11
                      Re: How'd I mess up this X-over?

                      D'oh!

                      Must have had my glasses on upside down or something. :rolleyes:

                      Comment


                      • #12
                        Re: How'd I mess up this X-over?

                        First of all, thanks to all who have taken the time to respond. I'll respond to ReissM here since you've provided the most detailed reply, but all the posts have been helpful for me.

                        Good to know I didn't misinterpret the diagram, I was afraid there was some sequence of components I wasn't understanding especially where the 10ohm resistor; .35 mH inductor; black input; 6.8 uf; neg tweeter; neg midrange were all basically combined at a single connection. I did reverse polarity on the tweeter, although that isn't apparent here, I saw the neg symbol on the diagram. All the components values are as labeled in the drawing, I reaffirmed this. I've taken the board apart now and intend to reassemble it in a different way, but the solder joints seemed pretty solid, I unsoldered them and they had all flowed as they should.

                        I think the problem must have been shorting against the midrange/woofer bell. May have been the upright joint on the end of the 10ohm, maybe it was intermittent due to vibration, I don't know. If the circuit was laid out right and there were no shorts apparent on the board itself, that must have been what had happened. The board was the full size of the speaker floor and a lot of it was crammed under the Midrng/woof. In fact I had to push the larger inductor over to the side to keep it out of contact with the Mid/woof frame, so I'm guessing that was it.

                        Thanks again to everyone for the help.

                        Originally posted by ReissM View Post
                        Good question WernerM. My thoughts exactly.

                        As for this picture... I traced through and visually it looks ok. (The polarity isn't obvious but that wouldn't cause any electrical issues, only acoustical phase weirdness. The design is for reversed-phase tweeter.)

                        So does this exact crossover work but it's "MATE" is giving you trouble??? It sounds like the Lepai is reaching thermal limiting and shutting itself off to protect against damage. The fact that your other amp is also experiencing problems with this speaker is curious.

                        Some brainstorming:
                        - Verify the wires that are soldered to the woofer are not accidentally shorted against the metal body of the woofer frame.
                        - Verify that the 10 ohm resistor is not a 1 ohm. (can't read it from the picture.)
                        - Verify that the 0.22uFcap is actually a 0.22uf cap.
                        - Verify your solder connections are all solid.
                        - VERY gently, press on the woofer's cone to make sure it moves freely and without any rubbing noises.
                        - If nothing else works, try disconnecting the small 0.22uF cap and see if the problem persists. The filter should still work without the 0.22uF cap. Temporarily disconnecting it will be ok. (I believe it's a tank-trap to address cone ringing at higher frequencies.)

                        I'm out of ideas dude. Good luck diagnosing the issue. Maybe someone else can offer some further insight and troubleshooting ideas.

                        Comment


                        • #13
                          Re: How'd I mess up this X-over?

                          After a closer look. I see you had everything connected correctly.
                          You might find this guide helpful for your next build:
                          http://speakerdesignworks.com/nodal_analysis.html

                          I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
                          "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

                          High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
                          SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
                          My Voxel min sub Yet-another-Voxel-build

                          Tangband W6-sub

                          Comment


                          • #14
                            Re: How'd I mess up this X-over?

                            I'd suggest slightly deviating from Paul's schematic by inserting a 4 ohm resistor in series with the 0.22 uF tank capacitor. Without it the amp is seeing a VERY low impedance at higher frequencies. This may be what is causing your amp to shut down.
                            Craig

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                            • #15
                              Re: How'd I mess up this X-over?

                              Thanks don, that looks like a good article, I"ll give it a read.

                              Comment

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