Hi, i walked past a charity shop a few weeks ago and notice two pairs of interesting speakers. Small bookshelf with rather a datedd look. On closer inspection they were Kef Crestas and came from the late 60's, rather than the new speaker with this name. On a Whim i bought both pairs , they were £5 a pair !
Turns out they both have the classic compliment of a T27 tweeter and a B110 mid range unit. Cabinets are chipboard but with some extra internal bracing. Simple 4 part crossover. One pair sounded fine, the other pair both had blown tweeters. Assume they both came from the same owner, maybe second pair were replacemnts or he/she was playing with quadrophonic ?
I carefully removed the busted tweeters and desoldered them from the internal wiring. Tested across the terminals and they are open circuit, so assume the coils have failed. I started to carefully dismantle one, am at the large central bolt on the back point.
These vintage cresta speakers appear sometimes on ebay and go for a large amount, presumably from people looking for donor T27 b110 drivers ?
I got them as both sons are going away to college and need a simple room hifi. These might sound good while looking distinctly average and hence less likely to get pinched.
So :
1) can a t27 be repaired ?
2) is there a cheap drop in tweeter that has the same hole arrangement. There is no way i can contemplate paying £100 on a pair of t27s but also don't want to sell the B110s and end up with a carcas cabinet. Best idea night be to fit a different tweeter, a pair < £30
Thanks
Turns out they both have the classic compliment of a T27 tweeter and a B110 mid range unit. Cabinets are chipboard but with some extra internal bracing. Simple 4 part crossover. One pair sounded fine, the other pair both had blown tweeters. Assume they both came from the same owner, maybe second pair were replacemnts or he/she was playing with quadrophonic ?
I carefully removed the busted tweeters and desoldered them from the internal wiring. Tested across the terminals and they are open circuit, so assume the coils have failed. I started to carefully dismantle one, am at the large central bolt on the back point.
These vintage cresta speakers appear sometimes on ebay and go for a large amount, presumably from people looking for donor T27 b110 drivers ?
I got them as both sons are going away to college and need a simple room hifi. These might sound good while looking distinctly average and hence less likely to get pinched.
So :
1) can a t27 be repaired ?
2) is there a cheap drop in tweeter that has the same hole arrangement. There is no way i can contemplate paying £100 on a pair of t27s but also don't want to sell the B110s and end up with a carcas cabinet. Best idea night be to fit a different tweeter, a pair < £30
Thanks
Hi guys
I'm in almost the same predicament. I am buying a pair of Kef Concertos from a friend of mine, and the one T27 tweeter is also blown. He is giving me a pair of Seas tweeters with them for free, but I don't think that they are drop-in replacements. So I also need advice on a T27 replacement.
Enjoy,
Deon
PS. I am getting the Kefs in a package deal. The second half of the package is a Lenco turntable, and they are the real reason for me forking over the money. But I want to get the Kefs going as I want to give them to a friend. His musical diet consists mostly of soft rock and vocals, so they'll suit him well.
I'm in almost the same predicament. I am buying a pair of Kef Concertos from a friend of mine, and the one T27 tweeter is also blown. He is giving me a pair of Seas tweeters with them for free, but I don't think that they are drop-in replacements. So I also need advice on a T27 replacement.
Enjoy,
Deon
PS. I am getting the Kefs in a package deal. The second half of the package is a Lenco turntable, and they are the real reason for me forking over the money. But I want to get the Kefs going as I want to give them to a friend. His musical diet consists mostly of soft rock and vocals, so they'll suit him well.
I have a pair of brand new, unused, old stock, T27, model sp1032.
How much are you prepared to pay?
How much are you prepared to pay?
I think you should try the SEAS units, Deon. The 91dB SEAS 27 TFF and TFFC are generally considered a suitable replacement, perhaps needing a 2 ohm series (3W wirewound) and 10 ohm shunt (10W wirewound) 3dB L pad attenuator.
Seas Prestige 27TFFC H881
The 89dB Morel CAT298 is considered a drop in replacement.
Morel Classic CAT298
Both tweeters have 104mm faceplate, just like the KEF T27 originals. Probably anything that fits will work after a fashion or can be adapted. I would look for an efficiency of 89dB and a minimum DC resistance of 5 ohms and soft domes if I was guessing.
Nice find on the Lenco. Built like a tank, eh? 🙂
Seas Prestige 27TFFC H881
The 89dB Morel CAT298 is considered a drop in replacement.
Morel Classic CAT298
Both tweeters have 104mm faceplate, just like the KEF T27 originals. Probably anything that fits will work after a fashion or can be adapted. I would look for an efficiency of 89dB and a minimum DC resistance of 5 ohms and soft domes if I was guessing.
Nice find on the Lenco. Built like a tank, eh? 🙂
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Hi Steve
Thanks for the info. It will be great if the Seas can be drop-in.
As for the Lenco, this will be my second one. I want to rebuild them both ala Jean Nantais. I'm trying to lay my hands on as many as I can get at reasonable prices. I have other TTs (a Technics SP10, a Technics SP15 and an old Linn LP12), but I have the most hope for the Lencos. 🙂
Enjoy,
Deon
Thanks for the info. It will be great if the Seas can be drop-in.
As for the Lenco, this will be my second one. I want to rebuild them both ala Jean Nantais. I'm trying to lay my hands on as many as I can get at reasonable prices. I have other TTs (a Technics SP10, a Technics SP15 and an old Linn LP12), but I have the most hope for the Lencos. 🙂
Enjoy,
Deon
Just give it a go on the tweeters. Not rocket science.
The Concerto probably got upgraded to acoustic butterworth filter later, which was more complex, but here's the early schematic along with a Cresta picture. Those non-polar capacitors do dry out and degrade with age.
What sort of cartidges do you use on your vinyl? Grado was the one I liked the most in moving magnet, but needed a heavy tonearm.
The Concerto probably got upgraded to acoustic butterworth filter later, which was more complex, but here's the early schematic along with a Cresta picture. Those non-polar capacitors do dry out and degrade with age.
What sort of cartidges do you use on your vinyl? Grado was the one I liked the most in moving magnet, but needed a heavy tonearm.
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Hi Steven
I will definitely give it a try. They will them become my main speakers while I repair my other units. I have a pair of Tannoy 15'' dual-concentrics (which need a foam surround replacement) as well as a pair of Goodmans Axiom 201 drivers (one has a loose voice-coil). These all have to wait, as I am spending the money I have to repair them on the Kef-Lenco combo. 🙂 The Tannoys will be next thing to be done, as they are a complete speaker. The Goodmans will need additional units on the top and the bottom to be a complete unit. That is a future project.
As for the other TTs (and tonearms)- they are all in need of attention. This is partly due to me having to move house six times in two years (mainly due to financial reasons). The SP10 has developed a stutter, the SP15 has a problem locking onto it's speed and just spins at the full speed the motor will allow, and the Linn needs a PSU (I have the parts for one, but the armboard also needs to be drilled, and I am not sure it's worth it, considering the other units available). The Lenco that I already have needs an arm as well as a good plinth. The new one needs an arm. Unfortunately I have had a number of very lean years, so I could not afford to do any work on them. :-( As for tone-arms, I have two. A Linn Basik+ as well as an Ortofon ATP-12. My cartridges are the Grado Prestige Gold and a Ortofon MM with a 78RPM stylus.
As for amps, my main units have all been affirmatively redistributed (i.e. stolen- just some South-African humour there 🙂) ). I have a Naim NAC-42.5, but as you probably guessed, it needs attention. It needs a new selector switch as well as a psu. Other than that I have an old JVC Nivico reciever that is currently under repair. It's a beast of an old thing, and it will be my main amp for the time being. I am slowly repairing and rebuilding my system, but it will still take a bit of time.
Enjoy,
Deon
I will definitely give it a try. They will them become my main speakers while I repair my other units. I have a pair of Tannoy 15'' dual-concentrics (which need a foam surround replacement) as well as a pair of Goodmans Axiom 201 drivers (one has a loose voice-coil). These all have to wait, as I am spending the money I have to repair them on the Kef-Lenco combo. 🙂 The Tannoys will be next thing to be done, as they are a complete speaker. The Goodmans will need additional units on the top and the bottom to be a complete unit. That is a future project.
As for the other TTs (and tonearms)- they are all in need of attention. This is partly due to me having to move house six times in two years (mainly due to financial reasons). The SP10 has developed a stutter, the SP15 has a problem locking onto it's speed and just spins at the full speed the motor will allow, and the Linn needs a PSU (I have the parts for one, but the armboard also needs to be drilled, and I am not sure it's worth it, considering the other units available). The Lenco that I already have needs an arm as well as a good plinth. The new one needs an arm. Unfortunately I have had a number of very lean years, so I could not afford to do any work on them. :-( As for tone-arms, I have two. A Linn Basik+ as well as an Ortofon ATP-12. My cartridges are the Grado Prestige Gold and a Ortofon MM with a 78RPM stylus.
As for amps, my main units have all been affirmatively redistributed (i.e. stolen- just some South-African humour there 🙂) ). I have a Naim NAC-42.5, but as you probably guessed, it needs attention. It needs a new selector switch as well as a psu. Other than that I have an old JVC Nivico reciever that is currently under repair. It's a beast of an old thing, and it will be my main amp for the time being. I am slowly repairing and rebuilding my system, but it will still take a bit of time.
Enjoy,
Deon
Aw, you're breaking my heart Deon! This sounds all quite run down. 🙂
We've got a nice second hand shop in Portsmouth, run by an Iranian TV repair guy. He's always very honest about what he's selling. I've had a nice Rotel RA-931 amp and some quality Monitor Audio 2-way speakers from him. Like yours, the SEAS metal tweeters were pretty far gone. Ferrofluid dried up. I first came here in search of a fix. Nowadays I am totally into the DIY bit. Love it.
All my vinyl is long gone, so I'm not doing that any more. Much as I like Vinyl. The T27 is 6.25 ohms and 0.05mH, efficiency is hard to guage from KEF's specified 80dB for 1W of pink noise. But in practise you will attenuate any modern replacement tweeter which are more efficient, I'd reckon.
We've got a nice second hand shop in Portsmouth, run by an Iranian TV repair guy. He's always very honest about what he's selling. I've had a nice Rotel RA-931 amp and some quality Monitor Audio 2-way speakers from him. Like yours, the SEAS metal tweeters were pretty far gone. Ferrofluid dried up. I first came here in search of a fix. Nowadays I am totally into the DIY bit. Love it.
An externally hosted image should be here but it was not working when we last tested it.
All my vinyl is long gone, so I'm not doing that any more. Much as I like Vinyl. The T27 is 6.25 ohms and 0.05mH, efficiency is hard to guage from KEF's specified 80dB for 1W of pink noise. But in practise you will attenuate any modern replacement tweeter which are more efficient, I'd reckon.
Hi,
Falcon Acoustics | The Leading DIY Speaker Parts and Kit Supplier since 1972
have more reasonable prices than Wilmslow Audio.
consider this :
http://www.falconacoustics.co.uk/dr...seas-22tff-h1280-tweeter-prestige-series.html
http://seas.no/images/stories/prestige/pdfdatasheet/h1280_22tff_datasheet.pdf
FWIW IMO it would be better to sell them to someone who will look after them
because of the sought after drivers rather than them being somewhat inevitably
being partied to death at some point, those old drivers can't take much abuse.
rgds, sreten.
http://www.inner-magazines.com/news/280/72/KEF-Cresta---the-original/
according to http://www.g4dcv.co.uk/ls35a/repair.html
"There were several versions of the B110 made by KEF:
B110 A6362 4-8 ohm 1967-early 70's. Unpainted frame, doping on front of Bextrene cone.
Neoprene rubber surround. The A6362 was used in the original LS3/5, KEF Cresta ......."
That makes the B110 versions you have highly collectable.
Falcon Acoustics | The Leading DIY Speaker Parts and Kit Supplier since 1972
have more reasonable prices than Wilmslow Audio.
consider this :
http://www.falconacoustics.co.uk/dr...seas-22tff-h1280-tweeter-prestige-series.html
http://seas.no/images/stories/prestige/pdfdatasheet/h1280_22tff_datasheet.pdf
FWIW IMO it would be better to sell them to someone who will look after them
because of the sought after drivers rather than them being somewhat inevitably
being partied to death at some point, those old drivers can't take much abuse.
rgds, sreten.
http://www.inner-magazines.com/news/280/72/KEF-Cresta---the-original/
according to http://www.g4dcv.co.uk/ls35a/repair.html
"There were several versions of the B110 made by KEF:
B110 A6362 4-8 ohm 1967-early 70's. Unpainted frame, doping on front of Bextrene cone.
Neoprene rubber surround. The A6362 was used in the original LS3/5, KEF Cresta ......."
That makes the B110 versions you have highly collectable.
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We're digressing now aren't we....😎
The KEF Cresta looks a pretty good unit. It has the magic LC notch on the bass filter to get the B110 smooth. Similar to the B200 Chorale essentially.
Crossover is the DN13 SP1017 for the B110 SP1003 and T27 SP1032 AFAIK.
Here's a picture for the record...there isn't an exact schematic available, so you could do a service to the community by posting one, jives.
Oh, sreten, that cheapie SEAS 22TFF tweeter you posted. It's a 98mm unit. That would be a bad thing, wouldn't it? 😉
The KEF Cresta looks a pretty good unit. It has the magic LC notch on the bass filter to get the B110 smooth. Similar to the B200 Chorale essentially.
Crossover is the DN13 SP1017 for the B110 SP1003 and T27 SP1032 AFAIK.
Here's a picture for the record...there isn't an exact schematic available, so you could do a service to the community by posting one, jives.
Oh, sreten, that cheapie SEAS 22TFF tweeter you posted. It's a 98mm unit. That would be a bad thing, wouldn't it? 😉
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Hi Steve and Sreten
Steve, don't feel sorry for me. I am where I am mainly because of my own bad decisions and laziness. Luckily it is not too late to change, and I've been making quite a few of those lately.
Sreten, thanks for the suggestions, but it would be almost pointless to try and sell them. I live in South-Africa, and by the time transport and freight costs and C&E is added in, I don't think people would be prepared to pay very much. As for them being partied to death, have very little fear of that. My buddy John is not the partying kind at all! His previous system, one he had for many years, was an old plastic all-in-one with tiny 4-inch drivers in chipboard boxes. It was terrible. He now has an el-cheapo HT speaker system (think less than 50 US dollars for the entire set). He is not one to try and play at concert levels. However if I do get an offer for the Kefs that will allow me to get him a good pair of speaks, I might just do it. Thanks for the suggestion on the tweeters. I want to see which ones I get with the speakers before I make my next move. If I can repair the Kefs for free, so much the better.
Enjoy,
Deon
PS. Steve, didn't you used to make your own brand of speakers? 7th Dimension or something like that. Slim,good looking floorstanders with a line-array of about four full-range drivers. Are you still making those? They were quite interesting speaks as I recall. 🙂
Steve, don't feel sorry for me. I am where I am mainly because of my own bad decisions and laziness. Luckily it is not too late to change, and I've been making quite a few of those lately.
Sreten, thanks for the suggestions, but it would be almost pointless to try and sell them. I live in South-Africa, and by the time transport and freight costs and C&E is added in, I don't think people would be prepared to pay very much. As for them being partied to death, have very little fear of that. My buddy John is not the partying kind at all! His previous system, one he had for many years, was an old plastic all-in-one with tiny 4-inch drivers in chipboard boxes. It was terrible. He now has an el-cheapo HT speaker system (think less than 50 US dollars for the entire set). He is not one to try and play at concert levels. However if I do get an offer for the Kefs that will allow me to get him a good pair of speaks, I might just do it. Thanks for the suggestion on the tweeters. I want to see which ones I get with the speakers before I make my next move. If I can repair the Kefs for free, so much the better.
Enjoy,
Deon
PS. Steve, didn't you used to make your own brand of speakers? 7th Dimension or something like that. Slim,good looking floorstanders with a line-array of about four full-range drivers. Are you still making those? They were quite interesting speaks as I recall. 🙂
I rather think that sreten was referring to me. I doubt my sons would use these speakers to party, but surely speaker Valhalla is only reached when over driven ?
Hmm, well fate stepped in on this. I was removing one of the woofers from the good pair to see if the crossover was the same, and the bolt holding one corner just turned and turned and turned ....... The metal spiked 'Nut' which was hammered into the back of the chip board baffle broke loose, taking a chuck of wood with it. This means that the woofer can only be fixed by 3 of the 4 bolts without substantial repair . One bolt has the 'spike nut jammed on it
I think I might remove the tweeters from this pair and put them in the tweeter-less pair as their cabinets are a bit better.
BTW both pairs have that 3 part cross over - two inductors and a plastic cap ELCAP of some type (poly carbonate - this is from 1968 ?). I couldn't see the values printed on any of them.
I think I might remove the tweeters from this pair and put them in the tweeter-less pair as their cabinets are a bit better.
BTW both pairs have that 3 part cross over - two inductors and a plastic cap ELCAP of some type (poly carbonate - this is from 1968 ?). I couldn't see the values printed on any of them.
A 3uF or 4uF non-polar capacitor I would think. A coil on the woofer, a cap and coil on the tweet no doubt. Can sound very good with a well behaved woofer.
Sorry to hear about the mishap. Very little you can't fix with a molewrench, some WD40 and a bottle of PVA wood glue IMO. 😀
@Deon, the system7 loudspeaker only exists in my dreams at this stage, though slim and good looking are phrases I often hear about myself actually. But I'm sure it will be 7th Heaven when it arrives. 😱
Sorry to hear about the mishap. Very little you can't fix with a molewrench, some WD40 and a bottle of PVA wood glue IMO. 😀
@Deon, the system7 loudspeaker only exists in my dreams at this stage, though slim and good looking are phrases I often hear about myself actually. But I'm sure it will be 7th Heaven when it arrives. 😱
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OK well a bit of an update.
the two pairs I have are dated 1968 and 1970 according to the Quality check labels on each speaker.
the 1968 pair have plain black grilles and a better quality of veneer. Cabinet is chip board. This was the pair where both tweeters had failed. The B110 units have no rear sticker apart from a270 painted on the back. This type look like the Type 6362 as described on the Kef site. One of the speaker frames is painted black, the other bare metal.
the 1970 pair have Hessian style grilles (very 70's) and more 70's style veneer also chip board. I would also say that they don't quite feel quite as solid. the cabinet raps at a deeper note, though the construction seems the same. This was the pair where one of the B110 bolt threaded holes failed. The B110 appear the same as the Type 6362 though the dust cap is slightly more prominent.
These mid units had gaskets, the 1968 pair did not.
So....
I decided to put the T27 from the 1970 pair into the 1968 pair. I know this might seem a bit odd, but I figured that a) these seemed slightly better made and b) I didn't want to risk messing up any more B110 wood fastenings
The Cap in the cross over is a 4mFD value BTW, as system7 predicted.
I tested the resistance on the 2 1970 T27's , both had continuity , one was 3.6, the other 3.9. I guess I perhaps should have matched them with the LF response as marked on the Quality Inspections, one has 980 for the HF and 26 for the LF for example. Not sure how to do that
So now I have the 1968 pair working fine using the 1970 T27s and the 1970 pair in bits, with one damaged bolt hole for the BF110. I have removed the B110's . The T27 screw holes won't take much more use and probably could use some PVA. The gasket has pulled some of the chipboard away too. I'll ponder what to do with these. The grilles are not quite interchangeable, as I'd thought the retro Hessian looked more interesting than boring black. However the grill won't quite squeeze in. Also the 1968 grille has a cross brace beneath the tweeter. It struck me that this might function like the felt surround on the LS3/5a (my real speakers ).
They sound very good. rigged them up in my kitchen driven from a simple T-amp and an ipad with LOD cable. I have the 96Khz lossless version of "All things must pass" which I used as a test. Vocals sound a bit thick at times, both otherwise not at all bad. the treble sounds very smooth and not spitty as I'd feared. Bass is pretty minimal, but it doesn't have the mid hump of the LS3/5a. I wondered if some additional cabinet damping panels might help, for example I have used roofing flashguard on a roll before as a cheaper form of bitumen.
the two pairs I have are dated 1968 and 1970 according to the Quality check labels on each speaker.
the 1968 pair have plain black grilles and a better quality of veneer. Cabinet is chip board. This was the pair where both tweeters had failed. The B110 units have no rear sticker apart from a270 painted on the back. This type look like the Type 6362 as described on the Kef site. One of the speaker frames is painted black, the other bare metal.
the 1970 pair have Hessian style grilles (very 70's) and more 70's style veneer also chip board. I would also say that they don't quite feel quite as solid. the cabinet raps at a deeper note, though the construction seems the same. This was the pair where one of the B110 bolt threaded holes failed. The B110 appear the same as the Type 6362 though the dust cap is slightly more prominent.
These mid units had gaskets, the 1968 pair did not.
So....
I decided to put the T27 from the 1970 pair into the 1968 pair. I know this might seem a bit odd, but I figured that a) these seemed slightly better made and b) I didn't want to risk messing up any more B110 wood fastenings
The Cap in the cross over is a 4mFD value BTW, as system7 predicted.
I tested the resistance on the 2 1970 T27's , both had continuity , one was 3.6, the other 3.9. I guess I perhaps should have matched them with the LF response as marked on the Quality Inspections, one has 980 for the HF and 26 for the LF for example. Not sure how to do that
So now I have the 1968 pair working fine using the 1970 T27s and the 1970 pair in bits, with one damaged bolt hole for the BF110. I have removed the B110's . The T27 screw holes won't take much more use and probably could use some PVA. The gasket has pulled some of the chipboard away too. I'll ponder what to do with these. The grilles are not quite interchangeable, as I'd thought the retro Hessian looked more interesting than boring black. However the grill won't quite squeeze in. Also the 1968 grille has a cross brace beneath the tweeter. It struck me that this might function like the felt surround on the LS3/5a (my real speakers ).
They sound very good. rigged them up in my kitchen driven from a simple T-amp and an ipad with LOD cable. I have the 96Khz lossless version of "All things must pass" which I used as a test. Vocals sound a bit thick at times, both otherwise not at all bad. the treble sounds very smooth and not spitty as I'd feared. Bass is pretty minimal, but it doesn't have the mid hump of the LS3/5a. I wondered if some additional cabinet damping panels might help, for example I have used roofing flashguard on a roll before as a cheaper form of bitumen.
Not to go too off topic...
Any reason for the slightly "abstract" speaker placement?
I hope you have improved it since this picture was taken. If not I suggest the following.
Have a play, Try and get a intuative feel for what sounds right. Good speaker placement makes ALOT of differance. Also try to keep the space around the eminating sound clear, A chest of draws like that is sure to clutter the sound
Here is my current ,soon to be altered mini setup as a example. Took the pic just now, so excuse the mess... Note the T27 tweeters
An externally hosted image should be here but it was not working when we last tested it.
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You can fill in the holes. then invert the tweeter 180 degrees, and rescrew into fresh chipboard
Frankly, waveinform, I think you have little to enlighten me on AESTHETICS. I am a man who listens to Maria Callas after all. TBH I think your own setup is a little "In your face" but just my opinion. 😀
Naturally I was aware my speaker placement was less than optimal. It has moved on now. But remember it is aligned for bookshelf so relies on wall reinforcement.
Far more interesting to me, is my crossover upgrades which are Zobelling along nicely:
Still hate those zingy metal tweeters though. That's the next thing to fix. 😎
Oh, FWIW, I do wonder when sreten will come out of the closet in Brighton and tell us what speakers HE has. 😉
Naturally I was aware my speaker placement was less than optimal. It has moved on now. But remember it is aligned for bookshelf so relies on wall reinforcement.
An externally hosted image should be here but it was not working when we last tested it.
Far more interesting to me, is my crossover upgrades which are Zobelling along nicely:
An externally hosted image should be here but it was not working when we last tested it.
Still hate those zingy metal tweeters though. That's the next thing to fix. 😎
Oh, FWIW, I do wonder when sreten will come out of the closet in Brighton and tell us what speakers HE has. 😉
I think you have miss understood, what my fundemental point was.
Personal "AESTHETICS" is a seperate matter.
" Frankly" system 7. Your good with crossovers.
Personal "AESTHETICS" is a seperate matter.
" Frankly" system 7. Your good with crossovers.
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