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  1. Old Comment

    Wharfedale Dovedale cone rubber repair

    No luck with this technique...so no pics worthy of posting.

    The treated surround has shrunk alright but is now smaller than when I started AND its not retained any of its improved compliance. A total bust.

    Next:- to experiment with the technique described here:-
    http://boomboxery.com/forum/index.php/topic/10126-make-your-own-speaker-surroundbetter-than-foam/[/URL]

    Or use the now slightly under-sized, over-hard original surround as a mould and apply many coats of spray PlastiDip or the cheaper (in Australia) Amor All Custom Shieldhttps://www.youtube.com/watch?v=Ne3edUf_xXI
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    Posted 26th June 2017 at 11:11 AM by Roj Roj is offline
  2. Old Comment

    Wharfedale Dovedale cone rubber repair

    Thought of a more thorough way to recon the outer surround so I removed it completely. That was a bit of a task as the glue was rather hard. Achieved removal with minor damage which will not matter after reinstalling.
    Used
    1. 2 large ziplock bags. Big enough to allow the surround to sit flat and stay that way during the heating phase. New bags are best as there will be few pin holes or compromised welds
    2. ~20mL Oil of Wintergreen (OoW)
    3. ~250mL water
    4. Paper towels
    5. Rubber gloves
    6. Large microwave oven

    Placed surround, concave up, into first bag.
    Taped the bag's corners inwards to prevent fluid from residing there.
    Add the OoW and water and seal.
    Placed that into second bag as first was leaking a little. Seal it.
    Covered the glass turntable with paper towels.
    Placed into large microwave oven but on top of a small plastic lid to raise the centre of the bags and force the fluid to the perimeter.
    Set 1min High, 3 min Low and 20 min V.Low and Start.
    Checked fluid temp a few times by hand. Always hot but did nor appear to boil.
    Removed and allowed to cool.
    Removed paper towels containing leaked fluid and thoroughly cleaned oven. A little pong from there.

    Preliminary result was that the surround is very compliant but a little expanded such that the flats at inner and outer are not flat. The roll was a little distorted.
    Cleaned off the softened glue from both flats. Behaved like it was contact adhesive which, if so, might be ok in a factory with jigs but which I will not repeat given the forgiving nature of the adhesives currently available.
    Laid out as flat as possible on clean paper.

    Now for a long wait to see if enough shrinkage occurs and the flats resume being flat and the hard won compliance remains.

    Results with some pics then.

    Roj
    permalink
    Posted 18th June 2017 at 01:34 AM by Roj Roj is offline
  3. Old Comment

    Wharfedale Dovedale cone rubber repair

    Thought of a more thorough way to recon the outer surround so I removed it completely. That was a bit of a task as the glue was rather hard. Achieved removal with minor damage which will not matter after reinstalling.
    Used
    1. 2 large ziplock bags. Big enough to allow the surround to sit flat and stay that way during the heating phase. New bags are best as there will be few pin holes or compromised welds
    2. ~20mL Oil of Wintergreen (OoW)
    3. ~250mL water
    4. Paper towels
    5. Rubber gloves
    6. Large microwave oven

    Placed surround, concave up, into first bag.
    Taped the bag's corners inwards to prevent fluid from residing there.
    Add the OoW and water and seal.
    Placed that into second bag as first was leaking a little. Seal it.
    Covered the glass turntable with paper towels.
    Placed into large microwave oven but on top of a small plastic lid to raise the centre of the bags and force the fluid to the perimeter.
    Set 1min High, 3 min Low and 20 min V.Low and Start.
    Checked fluid temp a few times by hand. Always hot but did nor appear to boil.
    Removed and allowed to cool.
    Removed paper towels containing leaked fluid and thoroughly cleaned oven. A little pong from there.

    Preliminary result was that the surround is very compliant but a little expanded such that the flats at inner and outer are not flat. The roll was a little distorted.
    Cleaned off the softened glue from both flats. Behaved like it was contact adhesive which, if so, might be ok in a factory with jigs but which I will not repeat given the forgiving nature of the adhesives currently available.

    Now for a long wait to see if enough shrinkage occurs and the flats resume being flat and the hard won compliance remains.

    Results with some pics then.

    Roj
    permalink
    Posted 18th June 2017 at 01:30 AM by Roj Roj is offline
  4. Old Comment

    Discrete Op Amp measurements

    Well done indeed !
    permalink
    Posted 13th June 2017 at 02:22 PM by kasey197 kasey197 is offline

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