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
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
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?
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?
More investigation: following link is of interest, although a lot is missing...
http://www.geocities.com/etude317/TLconstruction.html
http://www.geocities.com/etude317/TLconstruction.html
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.
Still, good luck with whatever route you take.
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.
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.
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.
My B110 must be around somewhere on some box.
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
http://www.hifiloudspeakers.info/
also the following link is better than the one I previously posted
http://www.geocities.com/etude317/TL.html
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.
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.
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.
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.
Try www.falconacoustics.com . They have the replacement crossovers as new or in kit form - just checked ; £22 each. The owner worked on a lot of the early KEF units and has a wealth of experience. Nice guy and sensible prices too. They sell Coles as well at £18 each.
pinkmouse said:
I have read somewhere recently about the 'quack' in the B110, and now it has been mentioned I can hear it clearly and I hate it! Or else my mid range box is not sufficiently damped (on reflexion - sic - and looking again at my reprint copy, I cut a lot of corners building these beasts - I certainly didn't put enough wadding at the lower back of the TL.).
I bought my wife for Christmas a Teac H350 (Cd, DAB, amplifier, I paid too much but wanted it in time) and TDL KV1 bookshelf speakers (only TDL because of the brand and history, yes I got dupped, I realised they are nothing to do with old company, but didn;t realise richer now own the brand) and it sounds very good for what it is (at least compared to her old ?ASDA AIWA system which was driving me mad), and made me realise the limitations of my high end system.
Good news - Concerto xover has clearly marked specs (caps all say ecap, so i assume they are electrolytics and need replacing, which is simple), and I have full specs of the R50/HiFiAnswers.
I'll keep y'all informed if and when I progress.
I'm just starting renovating a pair of R50's and can endorse what ericallen says - the best place for the crossover and the Coles 4001G's is Falcon Acoustics who have been extremely helpful.
Replacement KEF drive units are generally pretty easily found on eBay, although it's usually cheaper to buy an old pair of Concerto's and keep the units for spares rather than buy the units individually.
Being TL, they may not be the most efficent speaker around but when you hear the overall soundstage they produce with effortless deep bass in a decent sized room the design is still outstanding even after 30 years in my opinion.
There's also a vast amount of information on the KEF units etc. on hifiloudspeakers.info
Hope this helps, I'll be very interested to hear how you get on!
Replacement KEF drive units are generally pretty easily found on eBay, although it's usually cheaper to buy an old pair of Concerto's and keep the units for spares rather than buy the units individually.
Being TL, they may not be the most efficent speaker around but when you hear the overall soundstage they produce with effortless deep bass in a decent sized room the design is still outstanding even after 30 years in my opinion.
There's also a vast amount of information on the KEF units etc. on hifiloudspeakers.info
Hope this helps, I'll be very interested to hear how you get on!
4-way using Kef B139
I am looking at doing the 4-way using the old Kef B139, Vifa C13, Kef T15 and Foster ribbon. I got the Kef's for nothing, the Vifa at a sellout and the Foster ribbon was acquired cheaply because I felt the Kef T15 didn't have much top end. (is actually a 35mm dome with Fs=500, which explains the problem)
Note the shape of the Vifa C13 is very similar to the old Kef B110
I've attached plans. The reason for the height of the tweeter is that these are aimed as being my main HT speakers, and 1050cm is the mid height of my screen.
(the second hand nature of the drivers will make them near impossible to sell, so I may as well design them for a specific duty for myself.)
This is a prelim sketch only, so if there are any comments that might help,... thanks
I have also linked to a speculative 4-way series x-o layout which might interest some of you.
http://users.tpg.com.au/users/gradds/Revised 4-way.jpg
http://users.tpg.com.au/users/gradds/3+1 series x-o.jpg
I am looking at doing the 4-way using the old Kef B139, Vifa C13, Kef T15 and Foster ribbon. I got the Kef's for nothing, the Vifa at a sellout and the Foster ribbon was acquired cheaply because I felt the Kef T15 didn't have much top end. (is actually a 35mm dome with Fs=500, which explains the problem)
Note the shape of the Vifa C13 is very similar to the old Kef B110
I've attached plans. The reason for the height of the tweeter is that these are aimed as being my main HT speakers, and 1050cm is the mid height of my screen.
(the second hand nature of the drivers will make them near impossible to sell, so I may as well design them for a specific duty for myself.)
This is a prelim sketch only, so if there are any comments that might help,... thanks
I have also linked to a speculative 4-way series x-o layout which might interest some of you.
http://users.tpg.com.au/users/gradds/Revised 4-way.jpg
http://users.tpg.com.au/users/gradds/3+1 series x-o.jpg
Transmissionline with B139...
Hi,
your 4way speaker arrangement was also used in the first IMF speakers. Later they were replaced by speakers of the "same" specifications, but done with modern materials by TDL (Transducer Developements Limited).
I have a complete kit of this speakers, that means:
oval bass speaker: TDL 128
midrange: B110 lookalike
treble: 25mm aluminium dome tweeter with ferrofluid damping
supertweeter: 19mm softdome.
These are speakers originally used in the TDL Monitor TL
I've also got a fitting crossover, which is done by Falcon Acoustics.
Shame on me, I've never built up this kit (didn't have any time) , but I think, these speakers should perfectly fit into your cabinet. So..., if I can give you any further help, please send me an email.
Thank's and have a nice time
Wolfgang
Hi,
your 4way speaker arrangement was also used in the first IMF speakers. Later they were replaced by speakers of the "same" specifications, but done with modern materials by TDL (Transducer Developements Limited).
I have a complete kit of this speakers, that means:
oval bass speaker: TDL 128
midrange: B110 lookalike
treble: 25mm aluminium dome tweeter with ferrofluid damping
supertweeter: 19mm softdome.
These are speakers originally used in the TDL Monitor TL
I've also got a fitting crossover, which is done by Falcon Acoustics.
Shame on me, I've never built up this kit (didn't have any time)
, but I think, these speakers should perfectly fit into your cabinet. So..., if I can give you any further help, please send me an email.Thank's and have a nice time
Wolfgang
It's been a long time, but I've been busy, now I'm thinking of a project over the Christmas break...
My big problem remains what to do with the B139. I don't really want to replace with second hand or anything - I don't quite see the point of using something which may have ended their shelf life - eg. how good is the rubber surround?
So, I have a choice of maybe dual Vifa P17WJ (or equivalent Peerless PL18), in some push push arrangement, or else..
I've noticed the Tang Band 8x12 which might be ideal, but have seen nothing about them here, I can buy them in US or distributors in Germany (no UK distributor).
B139 details
fs 25Hz
Effective area Sd 354 cm2
Effective moving mass 43.5 g, 1.53 oz
Damping:
mechanical 5.5
electrical 0.4
total 0.37
Vas 164 litres
sensitivity pink noise input for 96 dB SPL at 1 m on axis 11V RMS
force factor BL 12.3 N/A
W8Q details
fs 27Hz
effective piston area 460 cm2
moving mass 115 g
Qms 4.21
Qts 0.29
Qes 0.31
sensitivity 1W/1m 89db
Vas 89 litres
force factor BL 14.15 TM (what unit is that?)
Anybody know anything about them? Although I'm a physicist I don't know what these parameters are in detail, or which are important for speaker design. But at first glance there is a lot of similarity. I would use them only for low frequencies, crossing over to a mid range unit.
Remember, I want to keep the existing boxes, just replace units and front panel.
Let me measure if two PL1's can fit...probably not.
My big problem remains what to do with the B139. I don't really want to replace with second hand or anything - I don't quite see the point of using something which may have ended their shelf life - eg. how good is the rubber surround?
So, I have a choice of maybe dual Vifa P17WJ (or equivalent Peerless PL18), in some push push arrangement, or else..
I've noticed the Tang Band 8x12 which might be ideal, but have seen nothing about them here, I can buy them in US or distributors in Germany (no UK distributor).
B139 details
fs 25Hz
Effective area Sd 354 cm2
Effective moving mass 43.5 g, 1.53 oz
Damping:
mechanical 5.5
electrical 0.4
total 0.37
Vas 164 litres
sensitivity pink noise input for 96 dB SPL at 1 m on axis 11V RMS
force factor BL 12.3 N/A
W8Q details
fs 27Hz
effective piston area 460 cm2
moving mass 115 g
Qms 4.21
Qts 0.29
Qes 0.31
sensitivity 1W/1m 89db
Vas 89 litres
force factor BL 14.15 TM (what unit is that?)
Anybody know anything about them? Although I'm a physicist I don't know what these parameters are in detail, or which are important for speaker design. But at first glance there is a lot of similarity. I would use them only for low frequencies, crossing over to a mid range unit.
Remember, I want to keep the existing boxes, just replace units and front panel.
Let me measure if two PL1's can fit...probably not.
On further investigation, maybe the TB is not quality I am after, frequency response not exactly flat.
Looking at others with similar fs to B139, I find Peerless XXLS 830843
Parameters are:
fs 25 Hz
Sd 352 cm2
MM 79.9 g
Qms 9.03
Qe 0.47
Qt 0.44
sensitivy 87.2 dB
Vas 86.7 ltrs
fs and Sd are similar to B139, so at first glance my existing TL cabinet will do the job. How important are the other parameters, eg Vas, for a TL?
I looked at Peerless 830452 but it had a uch lower fs, which I am beginning to understand would mean a much longer line.
Looking at others with similar fs to B139, I find Peerless XXLS 830843
Parameters are:
fs 25 Hz
Sd 352 cm2
MM 79.9 g
Qms 9.03
Qe 0.47
Qt 0.44
sensitivy 87.2 dB
Vas 86.7 ltrs
fs and Sd are similar to B139, so at first glance my existing TL cabinet will do the job. How important are the other parameters, eg Vas, for a TL?
I looked at Peerless 830452 but it had a uch lower fs, which I am beginning to understand would mean a much longer line.
OK, doing a bit more investigation, looked at
http://www.t-linespeakers.org/design/MJK-for-dummies/index.html
and I'm comparing 830843 with B139.
Qts. 830843 is 0.44, B139 is 0.37. Not too different. Above the limit mentioned of 0.3 for TL's.
fs is 25 for both.
Vas is 86.7 and 164 ltrs respectively.
Sd is 352 and 354 respectively.
BL is 12.5 Tm and 12.3 N/a respectively. On http://www.thielesmall.com the B139 is give as BL of 10.6 Tm
So is this a close enough match to use the same TL box?
http://www.t-linespeakers.org/design/MJK-for-dummies/index.html
and I'm comparing 830843 with B139.
Qts. 830843 is 0.44, B139 is 0.37. Not too different. Above the limit mentioned of 0.3 for TL's.
fs is 25 for both.
Vas is 86.7 and 164 ltrs respectively.
Sd is 352 and 354 respectively.
BL is 12.5 Tm and 12.3 N/a respectively. On http://www.thielesmall.com the B139 is give as BL of 10.6 Tm
So is this a close enough match to use the same TL box?
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