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Driver replacement help.

Discussion in 'audio' started by linnfomaniac83, Aug 4, 2022.

  1. a.palfreyman

    a.palfreyman pfm Member

    Presumably you mean the arbour (for want of a better word) to place the VC former over for winding? Are there for example minor variations of ID between say nominally 1" VC formers?
  2. sq225917

    sq225917 Bit of this, bit of that

    I'd assume they are measured based on id of magnet hole and thus the internal of the coil former will vary according to paper and coil. So an inch coil could require 'any' arbor thickness under that dimension.

    As opposed to all inch coils being wound on inch arbor and paper and coil being made to suit. Coil thickness is part of electrical parameters, so thats a fixed thickness, and number of turns to get the required length and total inductance.

    Also he's making a coil to fit and id of magnet, plus coil electrical parameters are the immutable values, so the variable is arbor diam.

    I guess?
  3. Beobloke

    Beobloke pfm Member

    Yes, the big problem is getting the mandrels the right size to create the coil on. My brother-in-law used to be a director for a mechanical engineering company, which would have been perfect as he could get anything like this made in any size I could have needed, but he took early retirement 18 months ago!
  4. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    It's amazing what monkeys can be trained to do!
  5. a.palfreyman

    a.palfreyman pfm Member

  6. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Not managed to get them to the level of coil winding yet but several in the gov
    sq225917 likes this.
  7. Sean K

    Sean K pfm Member

    I understood blown/fused/melted voice coils were more likely to arise from using an under powered amp clipping and putting out dc.

    Given he's running (or was) 300 wpc, is it not more likely the moving part of the motor (cone, coil, surround) has just been hyper extended, buggering the surrounds?

    Very happy to educated on all the above, and no offence will be taken.
  8. canonman

    canonman pfm Member

    There were a couple of dodgy bodgers but I am pretty certain that I know who you mean and he screwed me too but Wembley Loudspeakers (in Acton!) were still in business last time I checked and I would recommend them.
  9. a.palfreyman

    a.palfreyman pfm Member

    Using an underpowered amp and driving it into clipping will blow the tweeters. This is because you effectively produce a clipped or square (ish) wave output that has lots of HF that destroys them. If you blow an amp and the output goes DC then you damage the mid-woofers as they won't stand much dc current and will get fried. In his case he was as you say likely overdriving them. Typical listening levels are only about 1/4W to 1W nominal with peaks of 10-20W.
    Arkless Electronics likes this.
  10. Vinny

    Vinny pfm Member

    Unless they have recently taken-on coil winding, they do not do it. Been there as a first port of call a few years back.
    On a purely commercial basis, if they are available, replacing the whole driver or cone assembly would make far more sense than rewinding a voice coil.
    Good to hear that the business is still running - my enquiry coincided with one of the partners dying, which seemed to have really affected the remaining one (apologies, can't remeber names).
  11. canonman

    canonman pfm Member

    OK, thanks. I seem to recall them actually replacing a coil but presumably that was one from previous stock. They have re aligned a BC1 bass unit too.
  12. colasblue

    colasblue pfm Member

    Have you tried talking to Ruark?

    Although they don't make speakers any more and don't have a stack of NoS drivers they can be helpful in selecting an alternative and currently available drive unit.
  13. Yank

    Yank Bulbous Also Tapered

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