Celestion Ditton 25 help needed

Discussion in 'DIY Discussion' started by Dom, Jul 23, 2018.

  1. Dom

    Dom

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    Hi there .. I am trying to replace the caps on a pair of wonderful celestion Ditton 25's mark 2 circa 1980

    I am looking for any tips .. preferably from someone who has replace the caps in vintage speakers before
    .. I'm looking for the schematic of the cross over ... I've found only one online and would like to get the values confirmed before proceeding with the replacement 20180614_123609.jpg
    All help greatly appreciated .. Thanks Dom
     
    Dom, Jul 23, 2018
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  2. Dom

    Sergeauckland

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    Aren't the values written on the existing caps? That's the most reliable way, as circuit diagrams may reflect earlier or later releases.

    Whatever the values, don't be tempted into 'audiophile' components, loudspeakers of that vintage would most likely have used non-polar electrolytics, unless what you have is clearly different.

    S
     
    Sergeauckland, Jul 23, 2018
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  3. Dom

    Dom

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    Thanks S

    I'm hoping the values are on the caps .. But reading other threads they might not be ..
    So i was hoping to find plan B before it was needed .. just in case ... Plus I was hoping to learn what type of caps to get the original sound .. So far Alcaps have been mentioned but if any one could add to this. I would be grateful
    Here is a pic of the unremoved board ...
    .. thanks for your help ... its needed :) Dom
     

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    Dom, Jul 24, 2018
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  4. Dom

    Sergeauckland

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    Two of the capacitors are made up of three or four in parallel, so the value required will be the sum of those. That may or more likely not, be available in a single cap, so you'll again have to buy several caps to put in parallel. The good news is that those all look like non-polar electrolytics, and so quite cheap, a pound or two each. I'm surprised that they didn't use standard cap values then made the inductors to specific values. It must have been cheaper to use standard inductors, and trim the caps. Anyway, it doesn't look difficult or expensive to change all the caps.

    S
     
    Sergeauckland, Jul 24, 2018
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  5. Dom

    Dom

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    Thanks ... . S
    one person on another thread thought. that some of them might have been replaced with pp ones already (yellow and red )
    One of the HF2000 is deffo lacking in presence at the mo ... And the bass doesn't quite astound you In the way my other slightly older pair can
    .. I'll let you know How I get on ... Thanks again D
     

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    Dom, Jul 25, 2018
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  6. Dom

    Dom

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    Hi there ...
    So I've removed 1 board and the values are
    25 uF
    2.2 uF
    3.2 uF
    3.7 uF
    Red ones say Metallised on them ...
    After reading up what i can ... I'm thinking to get all Alcap low loss .From Falcon acoustics.. If any one thinks this is a bad idea .. Please let me know ASAP [​IMG]
    The Bass issue maybe caused by the failing of the internal brace glue joints
     

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    Dom, Jul 26, 2018
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  7. Dom

    Sergeauckland

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    Those look perfect to me. I'd go for the 100v ones over the 50v, although even the 50v ones are likely to be adequate (just) for up to a 150 watt amplifier. The ones you have are 100v or 150v.

    S.
     
    Sergeauckland, Jul 26, 2018
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  8. Dom

    Dom

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    So I'd just like to say a thanks to every one for all the help ...
    So it looks like I will use Solen 400v MKP ..
    But I'm still toying with the Idea of using ALCAP 100V low loss for the 24uF
    from Falcon ...

    I'd like to make the order Today Saturday 28/7/18 .. !! but might hold off till Monday ..
     
    Dom, Jul 28, 2018
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  9. Dom

    Dom

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    So I've just started on repairing the bracing
     

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    Dom, Jul 28, 2018
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  10. Dom

    Sergeauckland

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    Those Solen are polypropylene, not non-polar electrolytic. I would be surprised if it made any significant difference, but the Solens at least should last indefinitely, whereas with the electrolytics, you'll be replacing them again in 30 years.
    S.
     
    Sergeauckland, Jul 28, 2018
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  11. Dom

    Dom

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    This is the sales blurb from Falcon Acoustics about low loss Alcap ......
    "" A loudspeaker which has been voiced using Alcap Low Loss capacitors or where Alcap Low Loss capacitors are replacing original black ELCAP Low Loss capacitors (marked LL) will remain true to the designer's intended sound character""

    If this is true .. and Noticable .. its a no brainer ... the 30 year life span is not a deal breaker .. If its Noticable :)

    A different question is :::
    There is a difference between the newer pair and the Values from previous posts about 25's ..

    my newer pair values seen = 25 uF 2.2 uF 3.2 uF 3.7 uF

    and an old thread schematic = 24uF 2 uF 3uF 3.5 uF

    The caps in the older thread looked like they were the older Electrolytic type and probably the original spec

    Any Ideas which values I should go with ?
     
    Dom, Jul 28, 2018
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  12. Dom

    Dom

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    But unfortunately certain values in LL Alcap are only available in 50v
     
    Dom, Jul 28, 2018
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  13. Dom

    Sergeauckland

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    Capacitors tend to have fairly wide tolerances, and 24/25uF is within 5% so of no real consequence. 2 to 2.2 is a bit wider at 10%, as is the 3 to 3.2, but again, nothing excessive.

    As to which is right, the old schematic or the new pair you have, I don't know. Are you able to look inside your old pair and see what that one has?

    As to voltage, 50v will do, if that's all that's available at the value, but you'd do better with 100v, even if you have to work out a different parallel combination to get to the same overall capacitance.

    S.
     
    Sergeauckland, Jul 28, 2018
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  14. Dom

    Dom

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    The smallest value 100v is 2.2uF and the next is 4uF ... not good for the 3.5 and 3 values ... but I can get 2x 12uF 100v and the rest in 50v or MKP 400v for the smaller ones and still use the 2x 12 100v
    or maybe all in MKP ??? lol ... I still don't know... But if Falcon are selling Alcap as the ones I want .. at the sameish price .. ???
    I've had a few people say I should just go with the MKP and I wont notice the difference ....
     
    Dom, Jul 28, 2018
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  15. Dom

    Sergeauckland

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    I would get as close to the values you need as you can, and don't worry about the type, 100v or above ideally, but 50v will do if that's all you can get.

    You could of course not bother with a passive crossover at all, and go active.........

    S
     
    Sergeauckland, Jul 28, 2018
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  16. Dom

    Dom

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    "" You could of course not bother with a passive crossover at all, and go active......""
    that is well aboye my pay grade .I've no idea what that would involve ... lol ... I'm just up for swapping the caps :) ...
     
    Dom, Jul 29, 2018
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  17. Dom

    Dom

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    So after far to much soul searching , navel gazing, and hair pulling .. I have just put in an order. To the values found on the board, and not the schematics posted here ... For. Solen MKP 400v ... With the exception of a 600v 1uF to run in parallel with the 400v 2.2uF .. to get the 3.7 uF
    Falon acustics in there blurb seem to be recomending the Alcap .. but charging more for MKP ... !!! ???
    So now I have my usual buyers regret ... But that was always gonna happen [​IMG]
    Here is the list ... Probably arrive Thursday or Friday
    Item
    Sku Qty Subtotal Solen 1.00uF 630V DC Polypropylene Capacitor Capacitor Tolerance 5% PPE100-+5% 2 £3.16 Solen 1.50uF 400V DC Polypropylene Capacitor Capacitor Tolerance 5% PB150-+5% 2 £3.16 Solen 2.20uF 400V DC Polypropylene Capacitor Capacitor Tolerance 5% PB220-+5% 6 £10.98 Solen 25.00uF 400V DC Polypropylene Capacitor Capacitor Tolerance 5% PB2500-+5% 2 £13.84 Subtotal £31.14 Shipping & Handling £4.50 Vat £7.13 Grand Total £42.77

    Let me thank every one for getting me this far [​IMG]
     
    Dom, Jul 30, 2018
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  18. Dom

    Dom

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    Hi there ... Well .. I said it would take me a week to listen to them .... well life got in the way ,and 6 weeks later I have just swapped back to my old un touched pair ...
    I'm now gonna listen to them for a week or so ...
    The new caps and fixing the internal bracing of the cab, have really sweetened up the sound. .Pretty much across the whole spectrum ..tightening up the base and clearing the treble ... And I would recommend it to any one with speakers this old.
    After playing just 2 songs .. on the un mod 25's I can literaly see!!! and hear the response is lacking some definition in the bass that the recapped ones now have [​IMG] ..
    Thanks every one .. And sorry it took so long to give the revue
     
    Dom, Sep 17, 2018
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  19. Dom

    Dom

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    After listening to the old pair for a week .. the difference is really noticable
    I am in no doubt the recapped pair are far superior :)
    And I have changed back today .. And will deffo proceed with the recapping of the old pair .. I hope they come up as good coz I prefer the old cabinets :)
    And also I have a pair of 50+ year old 10 inch RED dual concentric Tannoy Cadets to work on ... these I have really high hopes for :)

    SUMMARY

    VERY VERY HAPPY WITH THE RESULTS :)
     
    Dom, Sep 24, 2018
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