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ARCHIVED FORUM -- April 2007 to March 2012
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This is the first Archived Forum which was active between 17th April 2007 and 1st March February 2012

 

Latest post 04-11-2008 10:12 AM by riis. 25 replies.
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  • 03-03-2008 3:06 PM

    • riis
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    Refoaming Beovox M75

    I've bought a pair of Beovox M75 at a flea market. They look awful but they are going to be my next restoring project. All units are working but the woofers have of course got foam rot and need refoaming and also the mid-range units seem to be bad though they are still without holes.

    Where do I find the materials for refoaming? I've seen a couple of American sites but I'd prefer to order from an European site in order to avoid customs duty and V.A.T.

  • 03-03-2008 3:10 PM In reply to

    Re: Refoaming Beovox M75

    I sent you a PM

    Eugenio Colazzo

  • 03-03-2008 3:36 PM In reply to

    Re: Refoaming Beovox M75

    The bass units on the M100s are rubber so I am surprised the M75s need reconing. The phaselink unit seems to be the fragile one.  I love these speakers - I think they are my all time favourites - great sound and the veneers used are the best B&O ever did IMHO.
  • 03-03-2008 3:55 PM In reply to

    • riis
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    Re: Refoaming Beovox M75

    Nevertheless the woofers are totally rotten. I'd like to show some pictures, but how do I attach pictures in this forum?

    I agree with you on the quality of the veneer. The cabinets were really awful, but after polishing and oiling they are (almost) like new. I have some before and after pictures.

  • 03-03-2008 5:33 PM In reply to

    Re: Refoaming Beovox M75

    To post a picture, click on the Options tab above and there is a browse window that will open where you can choose your photo.
  • 03-04-2008 12:30 AM In reply to

    • riis
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    Re: Refoaming Beovox M75

    Here is a photo taken before I started the retoring project. As you see the woofers er rotten, but the mid-range units are also in a bad condition.

    Can they be refoamed? Or do I need new ones. If so are they still available?

     


  • 03-04-2008 1:42 AM In reply to

    Re: Refoaming Beovox M75

    I am sure those can be fixed.
  • 03-04-2008 2:05 AM In reply to

    • riis
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    Re: Refoaming Beovox M75

    Here are a couple of "before and after" photos of the cabinet.

    Before

     


  • 03-04-2008 2:10 AM In reply to

    • riis
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    Re: Refoaming Beovox M75

    and after.

    Hard to see it is the same speaker, but it is.........


  • 03-04-2008 8:09 AM In reply to

    Re: Refoaming Beovox M75

    riis:

    Here is a photo taken before I started the retoring project. As you see the woofers er rotten, but the mid-range units are also in a bad condition.

    Can they be refoamed? Or do I need new ones. If so are they still available?

     

    Heve you checked at the address I sent as PM? 

    Eugenio Colazzo

  • 03-04-2008 8:47 AM In reply to

    • riis
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    Re: Refoaming Beovox M75

    Yes I have. Thanks for the link. I can find foam rings for the woofers, but what about the other unit, which needs refoaming. It's the unit just above the woofer. I thought it was the mid-range but is it really the phase-link instead? The specifications on the M75 says:

    Woofer: 25cm
    Phase link unit: 12,5 cm
    Mid-range unit: 6cm
    Tweeter: 2,5cm

    When I measure the units none of them is 12,5 cm. The closest is 11,5 cm, which is the unit just above the woofer...

  • 03-04-2008 10:35 AM In reply to

    • Ben
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    Re: Refoaming Beovox M75

    I think there must either be a discrepancy in the specification, or there were different versions of the M75 with a 12.5cm unit.

    Mine also measure smaller. I refoamed mine with a 4.5" foam surround modified to fit. I cant remember where I got the surrounds for the M75, but i've used www.speakerbits.com and www.newfoam.com in the past on other speakers with good results.

     Your cabinets look great BTW!

  • 03-04-2008 11:40 AM In reply to

    • riis
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    Re: Refoaming Beovox M75

    ben12345:

    I think there must either be a discrepancy in the specification, or there were different versions of the M75 with a 12.5cm unit.

    Mine also measure smaller. I refoamed mine with a 4.5" foam surround modified to fit. I cant remember where I got the surrounds for the M75, but i've used www.speakerbits.com and www.newfoam.com in the past on other speakers with good results.

     Your cabinets look great BTW!

    What did you have to do with the 4.5" to make it fit? How did you solve the problem with centering the cone? Did you use shims?

  • 03-04-2008 1:48 PM In reply to

    • magnushj
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    Re: Refoaming Beovox M75

    www.goodhifi.com is also a good source of foam surrounds. I have used them a couple of times. The website looks a bit dodgy, but they are very helpful with finding the correct size for your unit and they ship fast. 

    Beocenter 9500+Beolab Penta mk2+Avant+MX7000+Beosound Ouverture+1xBeolab 6000 :)
  • 03-04-2008 2:31 PM In reply to

    • Dillen
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    Re: Refoaming Beovox M75

    The tweeter and midrange drivers are both dome's. The filler and woofer are cones. The same filler is used in Beovox M100 and M100-2.

    Martin

  • 03-04-2008 4:45 PM In reply to

    • Alex
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    Re: Refoaming Beovox M75

    Can't really say I know much at all about these speakers, but the midrange units look very similar to the classic PMC design (copied by ATC), often considered to be one of the best midrange units designed (they cost in the order of £300+ now I believe).

     Weekly top artists:                   

  • 03-04-2008 6:45 PM In reply to

    Re: Refoaming Beovox M75

    Nice job on the finish!  What did you use?
  • 03-05-2008 5:22 AM In reply to

    • h1npw
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    Re: Refoaming Beovox M75

    Bit of an understatement jgunzelman!!!!!!!  Absolutely amazing - I would never have thought it was possible.

    riis - Is it possible to give us a step by step description on how you did it and what materials you used ?

    Cheers

    Nigel

  • 03-05-2008 7:19 AM In reply to

    • riis
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    Re: Refoaming Beovox M75

    h1npw:

    Bit of an understatement jgunzelman!!!!!!!  Absolutely amazing - I would never have thought it was possible.

    riis - Is it possible to give us a step by step description on how you did it and what materials you used ?

    Cheers

    Nigel

    Thanks Nigel. Of course I'll give a step by step description. Isn't it what this forum is about? To share our knowledge Big Smile I'm a bit busy right now but I hope to be able to post a description later today

    riis/

  • 03-05-2008 9:00 AM In reply to

    • Ben
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    Re: Refoaming Beovox M75

    I modified the surround by slicing a section out of it, and glueing it back together, creating the correct diameter. This was about 10 years ago, and not many different sizes of surround were easily available back then. Maybe you can find one that fits perfectly these days.

     I shimmed the woofer and 'phase link' units, but if i was doing it again, I probably wouldnt bother shimming the smaller driver. I've refoamed several small speakers since without shims with no problems. The smaller drivers with a light cone seem to self centre quite well.

    I still shim large drivers though, they have a tendancy for the cone to rock when there is no surround to support them.

    Maybe the size of the phase link units are measured differently because of the shape of their chassis'. I remember the surround was just slightly over 4"

     

    Ben

  • 03-05-2008 9:07 AM In reply to

    Re: Refoaming Beovox M75

    I had my M100.2s done by Recone and they couldn't get the correct surround for the phase link unit. They too did a cut and shut and it seems to work very well.

    I second the thoughts above - beautiful job on the cabinets. Well worth it too! While you are there, replace the capacitors - there are a lot! Made a huge difference to mine.  

  • 03-05-2008 10:59 AM In reply to

    • riis
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    Re: Refoaming Beovox M75

    Here is what I have done to the cabinets. Even though they looked terrible they didn't have any deep scratches or torn off veneer. I think the damage is mostly discoloration due to water from pot plants and vases. I don't know why the rosewood has grown light so much that it almost looks like teak.

    1. I cleaned the cabinets with wood cleaner, the stuff you use on not painted wood before you paint or oil it.
    2. I cleaned the cabinets with clean water.
    3. When the cabinets were dry, I started sandpapering and polishing with waterproof sandpaper # 600 and teak oil.
    4. You'll have to repeat step 3 several times as the sandpaper very quickly fills with a mixture of oil and dust. I think I repeated the process 4 times. You have to be careful not to go through the veneer. The veneer on the M75 seem to be of a very high quality, so you can do a lot of sanding without "going through"
    5. When you can't see any discoloration you stop sandpapering and you polish the cabinet with a dry piece of cloth.
    6. You oil the cabinets once or twice depending of how much they absorb.

    Be careful with the cloth you have used for oiling. Burn them or you risk self-ignition!!!

    riis/

     

  • 03-06-2008 1:21 PM In reply to

    • riis
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    Re: Refoaming Beovox M75

    I saw at Good Hifi's website that I can get rubber surrounds and now I can't help thinking, "Why don't I order rubber surrounds instead of foam surrounds" I have the idea that the rubber surrounds will last much longer, but what difference will they make sound wise compared with the foam surrounds? 

  • 03-06-2008 2:05 PM In reply to

    Re: Refoaming Beovox M75

    Minimal difference - I had the surrounds on my MS150s replaced with rubber and then had them tested - frequency response as flat as a pancake!
  • 04-11-2008 10:09 AM In reply to

    • riis
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    Re: Refoaming Beovox M75

    My restoring project is completed. The woofer and the filler have been refoamed, never tried it before but it was a rather straight forward job.

    The hardest part was to sandpaper and polish the cabinets, but I'm rather pleased with the result.

    And the sound is awsome...............

     


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