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Wharfedale Bass units

Discussion in 'classic' started by lexi, Dec 12, 2009.

  1. lexi

    lexi pfm Member

    Any ideas on these ? From what model ? How old? What magnet type?

    [​IMG]

    They are 12 inch. Don`t remember even the Dovedales from 70s having that green foam diffraction ring.

    [​IMG]
     
  2. ian r

    ian r 401's Nakman

    Pre Dovedale they were paper cones in the 70's
     
  3. eguth

    eguth pfm Member

    I had a Wharfedale 15" woofer (purchased new in the late 60's-early 70's) and used it for many years until the cone went. I remember that the green strip on the front (on mine) was not foam, but felt.

    The magnet on mine (from memory) had a very similar label to the one in your photo, but the housing was different: it was more substantial and had a heavy cast frame.

    In the end, I prised the large magnet off and stuck it on the back of one of my replacement 12" woofers (I now use 2 x 12" woofers instead of 1 x 15"). Neither of my woofers are now Wharfedale.

    I would say that the 12" Wharfedale unit is probably good quality. The magnet may have weakened over the years, but you could put one or two extra magnets on top of the existing one, and experiment.
     
  4. lexi

    lexi pfm Member

    Thanks Ian and Eguth. I suspect the magnets are ceramic and maybe from about 1970 give or take. The green diffraction ring is felt. The frame is cast metal. Very well made.
     
  5. ClaraBannister

    ClaraBannister pfm Member

    I've seen Wharfedale speakers designated W12 FRS with the same cast frame, but Alnico magnets, quite different in appearance from those above. I think the magnets were red, IIRC.
     
  6. lexi

    lexi pfm Member

    Yes that`s the big deep magnets Clara...... Maybe even better. Funny how Wharfedale stopped using Alnico so early? Cost cutting? Cobalt got rare about the start of 1980. I think it was running out. Kef used Alnico for a good bit longer in B139 etc.

    Wharfedale always seemed to be more concerned with VFM rather than aiming for the higher price bracket which was often no better really.
     
  7. eguth

    eguth pfm Member

    I have pulled my files out and found a contemporaneous note made in 1969. In case this is of any interest I post it below.

    “Wharfedale 15” speaker
    15ohm. Mounted from INSIDE as per manufacturer’s recommendation.
    Unit tested at factory 31/10/68 (13,500 lines)
    resonance 23 cycles
    impedance 10/15 ohms
    made by Rank Wharfedale Ltd.”
     
  8. lexi

    lexi pfm Member

    Thanks Eguth. I think it's the same series as mine. Surrounds are perfect. This would be after Gilbert Briggs SFB designs?
     
  9. PigletsDad

    PigletsDad pfm Member

    Yes, I think SFB is late 1950s.
     
  10. ian r

    ian r 401's Nakman

    Me too This is a well built item, the Big Dovedale 70's bass unit was a complete waste of time I should know as I had the biggest speakers on campus ie Dovedales and they were indeed Rank and J Arthurs gong sounded like a slow phluff! So bigger wasnt better. This item has some handmade quality about it as in GA Briggs

    I must be feeling cryptic today
     
  11. ClaraBannister

    ClaraBannister pfm Member

    I know a chap from London who uses the term "J. Arthur" as rhyming slang, for something I'm too ladylike to mention here.
     
  12. eguth

    eguth pfm Member

    I note that the label on your magnet says (14,000 lines) wheras mine either said '13,500 lines' or was tested as this. I don't recall ever returning mine to the factory for testing. That yours has a more powerful magnet seems to indicate that it was manufactured some time after mine. I imagine that Wharfedale came to the same conclusion that I did- namely that the unit could do with a more powerful magnet. That is why I piled the magnets on and judged the result by ear, instead of sticking to what the designer intended.

    I eventually abandoned my 15" because to my ears it was too slow, and even with the more powerful magnets it was too slow. That is why I think you are better off with a 12" unit, or even smaller provided you can get low enough with enough power to the sound.

    What is 'SFB'?
     
  13. ian r

    ian r 401's Nakman

    Clara I could perversely say I am not aware of any delighful references that arise from words rhyming with J Arthur!

    However as I am feeling Cryptic as I write I am rolling around in a Universe of prosodic possibilities with Gilbert Briggs

    lady like hmmm!

    Thanks for the laugh
     
  14. PigletsDad

    PigletsDad pfm Member

  15. lexi

    lexi pfm Member

    Funnily enough Troels gives a similar Wharfedale twin cone full range a proper slagging on his site. They could have been clapped out methinks after many years ? I had a copy of SFB in mind for these bass drivers.
     
  16. eguth

    eguth pfm Member

    Thanks.

    I haven't trotted out my copy of Gilbert Briggs 'Loudspeakers' recently but (from memory) he gives some designs/instructions on sand- filled enclosures. They, along with brick enclosures, have his approval.

    I haven't actually tried any of this but I have used a sand- filled shelf for decades, and also concrete-lined and concrete/sand stands for my loudspeakers, with an additional concrete block on top of the enclosure. All of this is home- made. Interestingly, Gilbert Briggs suggested putting a bag filled with sand on top of the loudspeaker.
     
  17. PigletsDad

    PigletsDad pfm Member

    SFB is also interesting as it is an open baffle ( dipole ) design.
     
  18. eguth

    eguth pfm Member

    Gilbert Briggs gives details of his Wharfedale SFB on p.85 of 'Loudspeakers' (4th ed., Leeds, 1955).

    Two panels made of plywood, 1" apart, space filled with dry sand. Dimensions, height 40" (no other dimensions given), capacity 9 cu. ft., weight about one hundredweight.

    He gives further details but I will not post these unless someone wants them.

    He says results of this structure are similar to brick enclosures.

    My own experience with filling panels with sand is that it is essential to oven dry the sand first.
     

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