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W4-1757SB disassemble and suspension noise fix

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  • W4-1757SB disassemble and suspension noise fix

    Yesterday I was checking my collected drivers and found one of my W4-1757sb has made some pretty ugly noise. It sounds like hitting a metal particle with every visible excursion cycle, no matter 30hz or 200hz. These driver are not cheap so instead of throwing them away I decided to try fixing them. I found no information on the internet, so I post mine here, hopefully some one will find it useful. Other disassembly of TangBand driver can be found here: http://attlid.eu/p_swift.html

    At the beginning it look fairly straightforward. There're screws so it must be pretty modular. But I was wrong. There's glue everywhere, even soldering lead-wire was lots of pain because they are clamped before soldering in the factory.

    Finally here it is.

    Motor. Pretty powerful motor with double Neo Magnets from both side of Pole iron, and copper cap. I will guess this is the one of the most highend traditional 4-inch driver motor out there. Actually the structure is the same as my Morel SCM634. Just smaller.

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    Voice coil assembly. Voice coil adaptor to connect voice coil and the sandwich "cone". Winding height about 5.5mm. Pretty thin wire, looks like not a high-power design. But the decent sized aluminum former here should help greatly.

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    Some glue for the spider/former joint is missing on the right side of the coil former. I filled the gap with some CA glue.
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    About the repair. I first thought there must be particles in the magnetic gap, but I was wrong. It's very clean, I used 3M double sided tape to wipe it through and found nothing. So the noise must be the suspension.

    I have to say TangBand seems never get the suspension right, whether design or build quality. I have enough Tangband drivers that are making all sorts of funny noises. I even have a W6-1139sif that the spider was teared away from the basket when it's brand new. What a shame Tangband. It's the biggest difference compared to European drivers. What's the point of making a "low distortion motor" when the spider is clicking like crazy?

    For this particular driver the culprit was mainly in the red circle of the seemingly well-designed spider. The glue was loose, so I have to peel the lead wire further away from the voice coil former, and that solved the issue.

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    Re-assembled driver. Soldering looks ugly, it's because I tried it about 3 times to try to reduce mechanical stress if the soldering area. It's also the 2nd source of mechanical noise. Despite the look, now it performers much better than the virgin driver especially in the bass part.

    I hope Tangband increase its build quality. I never had this many suspension noise issues from Euro or even Asia companies like SB Acoustics. The full day spent on repairing this driver was fun but not worth it.

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  • #2
    Thanks for documenting your driver repair journey.

    It looks like the design is right, but the implementation is inconsistent... glue here, but not there. People just don't pay attention to what they're doing it seems.

    I've used dozens of Tang Band drivers and I do remember having issues with the 1138W5's near when they first came out... a few of them were noisy. But the ones I've gotten in the past 4-5 years have all been okay.

    TomZ
    Zarbo Audio Projects Youtube Channel: https://www.youtube.com/channel/UCEZ...aFQSTl6NdOwgxQ * 320-641 Amp Review Youtube: https://youtu.be/ugjfcI5p6m0 *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
    *Part 2 *Gluing multiple curved laminations of HDF

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    • #3
      I had a w3-1364 shipped without a face cover once. The phase plug looked crooked, so I attempted to straighten it, and the whole motor and plug fell out the back side.
      it was under warranty, so PE replaced it.
      I bought an early 1139 after release, during the first couple hours of use the spider came loose at the perimeter. Darren replaced that one at Dayton DIY 2004, IIRC.

      Wolf
      "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
      "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
      "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
      "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

      *InDIYana event website*

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      My blog/writeups/thoughts here at PE:
      http://techtalk.parts-express.com/blog.php?u=4102

      Comment


      • #4
        Originally posted by tomzarbo View Post
        Thanks for documenting your driver repair journey.

        It looks like the design is right, but the implementation is inconsistent... glue here, but not there. People just don't pay attention to what they're doing it seems.

        I've used dozens of Tang Band drivers and I do remember having issues with the 1138W5's near when they first came out... a few of them were noisy. But the ones I've gotten in the past 4-5 years have all been okay.

        TomZ
        I found their bass drives are mostly good or only have minor issues(the w6-1139sif was not good but very easy to fix). But the full-range drivers are strange. My W5-1611, W5-2142 all have noises that I can't repair without destroy them. But many W3s or W4s are good, except W4-1757sb but I'm in better luck to be able to repair without re-cone.


        Originally posted by Wolf View Post
        I had a w3-1364 shipped without a face cover once. The phase plug looked crooked, so I attempted to straighten it, and the whole motor and plug fell out the back side.
        it was under warranty, so PE replaced it.
        I bought an early 1139 after release, during the first couple hours of use the spider came loose at the perimeter. Darren replaced that one at Dayton DIY 2004, IIRC.

        Wolf
        It's always great when it's covered in warranty.
        I remember mine is good when I first bought it, or not as bad. Maybe my memory is wrong, or the glue was teared a little bit after some use or age.

        BTW, I found their rubberized glue relatively easy to peel off, compared to like CA glue which is next to impossible.

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