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Old 27th December 2005, 03:47 PM   #1
essence is offline essence  United Kingdom
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Default Upgrading R50 KEF TL

Like I assume many, I built a HiFi Answers TL speaker back in ? 1972 or so. This uses KEF B139, B110, T27 and Coles. It is basically the same as the Cambridge R50.

I have always liked it, but it is getting a bit old. The B139's are failing, the crossover must need caps replacing, the T27's and Coles' are dead, etc. etc.

I understand I could do a lot better nowadays with efficiency and quality.

I have a choice to start again (maybe Ariel's) or do an upgrade job.

My main problem is time and money! I don't have 3 weeks of time to build something new (I am being harrassed right now by my children as I write), although I would find it enjoyable, and there are many other demands on my money.

What I wondered is - is there a suitable driver replacement which would only need a cabinet front panel change and cross over change, or is the basic cabinet not worth keeping and I should start from scratch?

It would of course be quite simple to find an assortment of quality drivers which would fit (maybe replace the 139 with two 5" (eg vifa), replace the 110 with similar, etc.), but of course the cross over needs replacement - I have the ability to do this with some learning, but not the time.

Has anybody else done a serious refurbishment/driver replacement of these enclosures, and what was the experience? I know enough, as an ex physicist, to know what I don't know, and only want to follow a design which has had experienced and educated consideration.

Thanks
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Old 27th December 2005, 04:52 PM   #2
essence is offline essence  United Kingdom
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I already have found myself that at www.theloudspeakerkit.com they have a TL6 which uses a TL design with dual Vifa p17wj-00-08.

As far as I can see these two would just fit into cabinet, and are not too expensive.

So there may be some scope for what I am trying:

B139 -> 2 x p17wj-00-08
B110 -> 1 x p13wh-00-08
T27/Coles -> ?

Now all I have to worry about is the cross over. Maybe the ariel cross over design (and Ariel tweeter), but split the mid/base into separate mid and bass with simple design?
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Old 27th December 2005, 11:19 PM   #3
essence is offline essence  United Kingdom
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More investigation: following link is of interest, although a lot is missing...

http://www.geocities.com/etude317/TLconstruction.html
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Old 27th December 2005, 11:43 PM   #4
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This may be a bit obvious, but all these drivers turn up regularly on eBay, why not just replace them, rather than shoehorn different drivers into a box that is not optimal for them? By all means rebuild the crossovers with new components, that will make a real difference and should be pretty straightforward, but these are classic speakers, and if refurbished could give you another 20 or so years of enjoyment.


Still, good luck with whatever route you take.
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Old 28th December 2005, 03:37 PM   #5
essence is offline essence  United Kingdom
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Yes, i realise that, I even picked up a pair of Concertos at a school fete for about 70 a year ago so I can have the units for spares, but I am now reluctant to ruin the concertos as they go well in the bedroom (very different sound to the R50, much more boxy, but smooth for bedroom music...). I may replace the concerto crossover as well (that 'may' should probably be a 'must').

I guess my rationale was to increase sensitivity and replace drivers with better quality ones, obviously driver quality has improved since 1972, and I see the B110 has differing views. I may also be getting a little tired of the very laid back sound of my current setup, and want something a bit more forward, although the bass is better than most I have heard. Wilmslow Audio suggest a couple of alternatives to the B110 and T27.

I do tend to play the speakers quite loud, and a few hours of reggae or R&B at full volume does make me worry about the drivers (I also listen to a lot of classical etc., and full volume Bruckner also makes me look warily at the flapping B139's, eg. in the 9th Symphony climaxes).

I've no idea how many R50's were bought or built, but there must be quite a few who have upgraded somehow rather than throw them out after all that woodwork.
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Old 28th December 2005, 05:43 PM   #6
soongsc is offline soongsc  Taiwan
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I have a pair of B139 that I never got around using. Whenever I look at the box and open them up once in a while, I think I'm going to get to them some day, but that day had never come. If someone is convincing enough, I might be pursuaded to let them go to a better home.

My B110 must be around somewhere on some box.
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Old 29th December 2005, 07:25 AM   #7
essence is offline essence  United Kingdom
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this is useful

http://www.hifiloudspeakers.info/

also the following link is better than the one I previously posted

http://www.geocities.com/etude317/TL.html
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Old 30th December 2005, 10:35 AM   #8
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Richard Allan's do a new version of the B110 for about 140. KEF say that they are a replacement for the older B110s and are reckoned to be the best yet, though not heard them. I got a pair of B110s of Ebay for 60 incl postage recently and B139s arent too expensive.
I might have a pair of Coles hanging around, reply if you want me to have a look. I also have a pair of Wilmslow crossovers for B139, B110 and T27's.
I'd replace with KEF units throughout, if you are after a different design, start from scratch. The older KEF units had distinctive characteristics that the crossover was designed to even out.
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Old 30th December 2005, 04:47 PM   #9
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My current leaning is towards trying to refurbish as much as I have - nobody has said so explicitly, but reading between the lines it seems the R50's are still competitive if as-new, and it would be too big a project to try to redesign and it might end in tears.

Can anybody confirm that - strange but true - that the R50's as new are still competitive with current speakers, unless you pay ridiculous amounts?

I think my first step will be to replace the capacitors on both my Concerto and R50 xovers - I assume after 30 years that will do no harm! Cheap and should be immediate benefit.

Next, maybe buy a pair of new Coles which are still available and not too expensive (about 23 from Wilsmlow Audio).

Then look for some T27's, maybe the problem is the xover all along and the units are fine, maybe replace via ebay or whatever, maybe look at Wilmslow audio's suggested replacement (a Seas H831 or H457, about 20 and 25 each respectively).

B110's may be OK, if not ebay again or Wilsmslow audio's suggestion of close alternative Monacor SPH135/AD (about 30 each). From what i understand, the B110 causes the most problems wrt xover, and if I replace with the Monacor I either have to confirm the 'faults' are similar in both, or else modifiy the xover to remove the compensation for b110 faults.

B139, they seem to rattle on accasion, maybe best if problem continues to send to Richard Allan for repair.

Next stages, maybe update xovers for both concerto and r50 with Wilmslow Audio update, but they are not cheap (over 100 per pair).

Of course I can just hand over the whole question to Wilmslow audio, but the experiences of others are always valuable.
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Old 30th December 2005, 05:07 PM   #10
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For me, the B110 has always been the weak link in those big old TLs and Kefs. If you can get to hear the new Richard Allen versions to see if they are worth the money, then that may well be the way to go. Get that midrange sorted and you will have very nice speakers indeed.
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