KEF Concerto - Baileys Transmission lines crossover upgrade

Discussion in 'Speakers' started by chevelosm, Apr 11, 2016.

  1. chevelosm

    chevelosm Khosaku Kikuchi's Grandson

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    Hi guys,

    I have a early pair of the bailey's transmission line speakers that use the B139, B110 & T27. I have finally listened to them but the T27 seem to roll off too early which you miss all the fine detail at the top end. They have the original untouched DN12 crossover. I want these to sound their best in changing or upgrading the crossovers.

    Do I just do a recap of the DN12 crossover?
    Do I upgrade to the falcon accousics crossover, maybe add a coles tweeter
    or
    Make the Radford crossover?

    Your opinions please......

    20150819_183157.jpg
     
    abennett101 likes this.
  2. sqlsavior

    sqlsavior AK Subscriber Subscriber

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    I'd start with the first option.
     
  3. thilaseen

    thilaseen Super Member

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    I think recapping will solve your problem. In fact I,m pretty sure of it going by my experiences with the old KEF caps.
     
  4. 2ndtimelucky

    2ndtimelucky Active Member

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    Definitely re-cap first. The original Kef caps are cheapo Elcap brand IIRC :)
     
  5. canuckaudiog

    canuckaudiog On a quest for high fidelity

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    Yep, recap them first. Then evaluate. Highs are usually the first thing to go with old caps.
     
  6. chevelosm

    chevelosm Khosaku Kikuchi's Grandson

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    Thanks guys

    Any particular brands?
    Alcap sold by Falcan Accoutics no.5?
     
  7. canuckaudiog

    canuckaudiog On a quest for high fidelity

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    Go with what makes sense to you from an economic standpoint. I'm a fan of Alcaps, as you likely know, but I also like the Mundorf M-Lytics which are a good price and have similar ESR characteristics to the Alcaps. My only advice is do not "upgrade" the capacitors to mylar or polypropylene, stick with electrolytics in place of electrolytics.
     
  8. Donkey Karma

    Donkey Karma Super Member

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    No disagreement here, at all. Just wondering your reasoning, sonics, price... fitment?
     
  9. canuckaudiog

    canuckaudiog On a quest for high fidelity

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    There's a few reasons, but the main one is because of the properties of capacitors. Specifically, ESR (equivalent series resistance). On average, electrolytics exhibit around 2-3 ohms of ESR, less if they are of the low loss variety. Mylar film or polypropylene capacitors, on the other hand, have almost no ESR at all. This resistance affects the balance of the speaker, and when designers create crossovers for two, three, four or more way speakers, this comes into account.

    Essentially if you take an electrolytic and swap in a polypropylene (for example, those inexpensive Dayton audio polypropylene capacitors) it is like removing a 2 ohm resistor out of the circuit. I'm sure as you can guess, this negatively affects the balance between the drivers at that handoff point. To further complicate this, ESR is like the impedance of a speaker in that the resistance varies over the frequency range. This is why I mentioned the fact that Mundorf M-lytic capacitors have similar ESR properties to Alcaps - if you choose an electrolytic that has somewhat different ESR properties, again it could change the balance of the speaker. This is why people comment that polypropylene capacitors sound "bright". In fact, they probably don't, it's the relative difference in the change of balance to the speaker that makes people perceive them as bright.

    Now of course, you can go ahead and swap it with something different, but in high quality designs (like the one that is the subject of this thread), generally there is a lot of thought and time that goes into the crossovers, so you will more likely achieve the best results by simply replacing the parts with parts that have similar properties. This is why I stress to replace Elcaps, which are popularly used by British speaker manufacturers in the 70s and 80s, with Alcaps, because they are very similar and will retain the original balance of the crossover. Andrew Jones, whom we are all very familiar with, in fact said the very same thing, that when recapping you need to be aware of the ESR properties of the original capacitors because designers factor that into the crossover.

    Anyway, I'm not sitting here saying it is wrong to tinker or tweak. That's part of the fun. But my philosophy is that before you do that, at least have a chance to hear the original design in a restored state so that one, you can appreciate the original design, two, so you have a baseline and three, it may end up sounding so damn good that you won't bother going any further and save yourself the money and hassle. I went through a bout of modifying a pair of Celestion 66s where I used polypropylene capacitors, and I eventually went back to electrolytics because with the polypropylene capacitors the speakers sounded unbalanced and wrong. They were in fact unlistenable it was so bad. I even added resistors in series with the capacitors to compensate for the change in ESR, but what I learned when I measured them is that all it did was lower the SPL at the crossover point and didn't really solve the problem. I've since attempted to do the same thing again, and the same thing happened - the original design using like for like parts sounded best. Since then (and even before then) I have always replaced like for like, and the results have always been very rewarding.

    That's why I suggest to replace electrolytics with electrolytics.

    If something I said doesn't make sense or you would like me to elaborate more let me know.
     
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  10. Donkey Karma

    Donkey Karma Super Member

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    I think you have the "elaboration"handled. :)

    All opinions very well made and no points of contention. Very well put stated sir.

    I have come to your side on this subject when recapping some 2nd, 3rd order xxovers. Things can get sloppy fast.

    First order single cap xxovers (only that I have done) seem to have execpted the poly with grace.

    Thank you sir!
     
  11. canuckaudiog

    canuckaudiog On a quest for high fidelity

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    No problem, thanks for asking!

    Yes it's a little more complicated and not as simple as buying a capacitor with the same microfarad rating and calling it a day. Every crossover is different as well, and there may be cases where a polypropylene will in fact work fine. As you mentioned, single order crossovers are generally a good candidate for it. More complicated crossovers, however, it can, as you say, get messy fast.

    Plus, when you factor in the cost of some boutique caps, you may as well spend your money right and put them where they will actually do good.
     
  12. Yvan_donald

    Yvan_donald Well-Known Member

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    hi Canuck everything fine and still love your new acquisition. Listen I'm no expert on ESR but when you tell people film capacitors change the voicing of the original, to me it's a big statement specially when I have upgrade mine with very good caps, by that upgrade I have raise the quality of the music rendering of my IMF +giving me the best tonal and natural sound without changing the original voicing. I think not all of us have the same earing experience. I have been gone to many classical concerts and I know my speaker are well balance and sound accurate,just to say an many peoples have said IMF deserve much better quality capacitors than the original to sound at their best.Even Falcon say their best cap are the Claricap. Best regards,Yvan.
     
  13. Yvan_donald

    Yvan_donald Well-Known Member

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    Hi,I did one to be like in intruder but because my IMF have KEF components for mid and bass it is very similar for the X-over (Elcaps).
     
  14. baco99

    baco99 AK Subscriber Subscriber

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    The Alcap brand used by Falcon are of very good quality and made to very tight tolerances. Falcon will also hand match so you have exact values for each speaker with a percent or 2. If you want to maintain the original design intent, that's what I would do. If you want to experiment, then you can choose any cap you want. But for a rare British speaker like that, I'd go the Falcon route.
     
  15. Yvan_donald

    Yvan_donald Well-Known Member

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    Hi,yes but Falcon said theirs best quality caps is Claricap, And for me capacitors made a big step in research,but price said everithing and many peoples don't want to invest the money and still believed it's not worth. But please don't tell me Alcaps are the best for my speaker, original intend? In the day it was the only option but it's not true anymore.
     
  16. Yvan_donald

    Yvan_donald Well-Known Member

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    Hi,and I will add today is easier to know when a recording is well done to a one where the engineer just muff it.Before it was less obvious.
     
  17. J1mbo

    J1mbo Active Member

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    An excellent post by any standard.
     
  18. J1mbo

    J1mbo Active Member

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    454
    I do like the elliptical drivers and radiators KEF used to do; they should bring those back really.
     
  19. chevelosm

    chevelosm Khosaku Kikuchi's Grandson

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    Location:
    Melbourne, Australia
    Just ordered Alcaps 2% torr for both my bailey's and IMF compacts using np electrolytics. Will fit them, see how they sound and get back to you all. In the future i do plan to make the radford xover and see how they sound.

    I want to be able to achieve the midrange and top end sound from the 104abs and the lower freq of the IMF's incorporate into the bailey's then i will be very happy.

    I'm planing to do the other 3 sets, IMF,TLS50'S, IMF Studios and the Kef 104ab's when i get some time.



    Thank you to all of you for your interesting posts.
     
    Last edited: Apr 14, 2016
  20. canuckaudiog

    canuckaudiog On a quest for high fidelity

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    Location:
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    Hey Yvan,

    It may sound like a big statement, but I stand by it. It is possible to prefer the way a speaker sounds with boutique caps, I'm not discounting that. There are many people out there who have rebuilt crossovers with entirely different parts and experienced improved results. However, I would never suggest to do that first when recapping - as I said in my previous post, it would be worthwhile to first restore the speaker using like for like parts so that you can at least experience what it sounded like originally (or at least very close to it). From there, go hog wild - you will have a better reference point and will at least be able to appreciate the upgrade and see if it indeed made a difference or not. Plus, the cost of electrolytics is fairly inexpensive so it isn't a costly venture.

    Keep in mind that this is very general and each speaker is a different case. In my opinion and based on what I have seen and experienced, this more applies to higher end speakers than it does to middle of the road or low end. The thinking there is that the higher end the speaker, the more engineering, time, and development was put into it, therefore there would be more reason to go with the original design than attempt to improve on it. I do realize that generally speaking the reason to bother with upgrading the capacitors is because of the fact that with mass production, corners would be cut and the parts used were picked as a cost-saving measure or what was available at the time. However, my point is that, although this may be the case, the designer worked with the parts they chose and designed the speakers around them. So, to simply change them, even though there are technically better parts, would (potentially) change the balance of the speaker to something other than the original designer intended.

    Anyhow, I digress - we are rambling off topic here now as this thread is about the speakers chevelosm is asking about. My apologies if I took this a bit off topic. If anyone cares to continue the discussion on this, please feel free to start a conversation with me and I would be happy to continue this conversation there.
     
    Last edited: Apr 14, 2016
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