worth changing inductors in a crossover?

Discussion in 'DIY Discussion' started by bottleneck, Jul 31, 2005.

  1. bottleneck

    bottleneck talks a load of rubbish

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    hiya

    Im soon to be upgrading the 25 yr old crossovers in my speakers.

    Why? well, because I've heard that it can make a decent difference and its not all that expensive really. Also, Im sure after 25 years the caps at least will have degraded.

    The crossover consists of 2 x caps, 2 x inductors and an L-pad (see pic).

    I'll be changing the caps and wire for sure.

    I could also change the inductors. Does anybody have experience of changing inductors? Do they degrade, and is it generally worth it?

    Cheers!
    Chris
     

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    bottleneck, Jul 31, 2005
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  2. bottleneck

    bottleneck talks a load of rubbish

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    nb -

    thats not 'my' crossover, its a library pic. Someone else has already changed their caps for Solens.
     
    bottleneck, Jul 31, 2005
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  3. bottleneck

    Anex Thermionic

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    Yeah its worth doing, check out the air core ones by Mundorf (as in the caps). I've used them, big mothers but sound excellent and not expensive really.
     
    Anex, Jul 31, 2005
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  4. bottleneck

    mosfet

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    The permeability of ferrite material does change with age although I doubt this is of any real consequence to the performance of your crossovers Chris. Air-core inductors saturate (a reduction of inductance) at higher current than ferrite core – this may have some subjective benefit.

    After 25 years the capacitors would certainly be worth replacing as you suggest especially if they are electrolytic types. Also experiment with removing the crossovers from the loudspeaker enclosures. This I find is where the best gains in performance are to be had.
     
    mosfet, Jul 31, 2005
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  5. bottleneck

    Graham C

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    No they don't degrade, unlike polarised caps. You could change them for different spec if you have a good reason?
    Air cored have a lower distortion [theoretically]. Unless you know the DC resistance of the existing ones and can substitute the same DCr in an air cored [hint: about 10 times the size of ferrite] then you have just made the bass 'woolier'...
     
    Graham C, Jul 31, 2005
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  6. bottleneck

    mosfet

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    FYI Graham look up disaccommodation factor as it relates to changes in permeability against time and temperature. I doubt this is of any real consequence to loudspeaker crossovers and of a similar magnitude to other ageing like the compliance of driver surround.

    I'd also caution against changing crossover inductors for the reasons you give.
     
    mosfet, Jul 31, 2005
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  7. bottleneck

    avanzato

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    avanzato, Aug 1, 2005
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  8. bottleneck

    Graham C

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    Graham C, Aug 1, 2005
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  9. bottleneck

    bottleneck talks a load of rubbish

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    I think if I can find what they are supposed to measure (and if they still do measure that amount) I'll leave well enough alone and just change the caps.

    Heres hoping I can find out the crossover specs on a 25 year old speaker :rolleyes:
     
    bottleneck, Aug 1, 2005
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  10. bottleneck

    Anex Thermionic

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    Despite what this thread sounds like your speakers won't blow up if your slightly out, if you don't like the result, put the old ones back in. When I changed from standard inductors to the mundorfs I found massive improvements everywhere.
    You may even find slight changes in inductor value improve the speaker- it may fit your room better or even just your tastes.
     
    Anex, Aug 2, 2005
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  11. bottleneck

    zanash

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    Yes big air cores....ferrites saturate to easily

    contact wilmslow audio ...

    Or roll your own....a number of web sites will give you all the info you need.
     
    zanash, Aug 2, 2005
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  12. bottleneck

    Graham C

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    Use Falcon [link above] if you need inductors, they make them. You don't need to use air core for bass drivers. There are infinite types of ferrite, and since Falcon make xovers for other companies, they can easily advise how to get a higher spec, or you can work it out from their choices listed [much wider than Wilmslow]. The point being that if you match the DC resistance then you have not changed a sensitive parameter [especially in a reflex box] in the xover. You may as Anex says, prefer a different xover. Just for comparison, going from a ferrite to an air cored is usually electrically equivalent to going from thick speaker cable to bell wire in a long run from amp to speakers. I would suggest go to a larger higher spec ferrite for lower distortion. Air core theoretically has lower distortion but is affected by outside magnetic fields, fixing screws, metal objects etc and will thow big magnetic fields outside its own volume
     
    Graham C, Aug 2, 2005
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  13. bottleneck

    Anex Thermionic

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    The mundorfs I suggested are the size of a house anyway, I've always found it easier to just mount them elsewhere. Possibly that may alter the performance characteristics (I've used short flying leads on them before) but they still seem to do the business. Be interesting to compare with some ferrite though.
     
    Anex, Aug 2, 2005
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  14. bottleneck

    zanash

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    I'd take the whole crossover out and place in a seperate large box, running an umbilical to the speakers using ...say speakon connectors. This makes a clean simple solution.
     
    zanash, Aug 3, 2005
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  15. bottleneck

    bottleneck talks a load of rubbish

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    putting the crossovers in another box isnt really an option.. there is an L-pad built into the back of the speaker (shown in pic), and it wouldnt be logical to have half the crossover in the box and half out..

    Im still trying to get the inductor values (haven't managed yet!)
     
    bottleneck, Aug 3, 2005
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