Student finds KEF drivers

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
edwardowen2... atribute

I won't argue the merits of selling the drivers , and buying something more modern. But perhaps a well built LS3/5 clone (which appears to be what the small "internal box" in bibster's link is) could be an appropriate tribute.


If you'd like to do something that has a proven track record with these drivers, then look at the
unofficial LS3/5a Support site. It could have been one of the speaker your dad had in mind.

Or sell the driver to buy some LS3/5as..., and build some sort of sub (isobaric "sounds" good to me).
 
The old Kefs sound so good you want to give them a good thrashing!
Unfortunately the T27 tweeter was only rated for 6watts and the high frequency content of contemporary music Led Zep Deep Purple etc used to fry the voice coils and that was before CD's. I think they strengthened the voice coils but I would use a PTC protection device if I were building a crossover.
However this is with louder levels than would be acceptable in a normal domestic environment, a normal user would be OK
 
I have recently completed a 4-way using the Kef B139 in a TL, a Vifa C13Wg instead of the B110, a T15 tweeter, and a small Foster ribbon to help the top end along.
The Kef drivers are out of an old pair of "Kef Cadence" loudspeakers I think.

The bass that they do is really nice, just for that it is worth using them. I can't comment on the other drivers you have though, but I bet you could make something pretty darn nice using them if you put your mind to it.

http://users.tpg.com.au/users/gradds/ARGOS/manhattan.html
 
Ex-Moderator
Joined 2003
I know I'm repeating myself, but the bass produced by the Hi-Fi Answers transmission lines really is very good. Very tight, low distortion, clean and extended. I've heard B139 in a number of other enclosures and none were as good. Once you've got the bass right, it's much easier to get everything else right...
 
Ex-Moderator
Joined 2002
I must admit, I'm not a great fan of the 110 either, but I would definitely go with the drivers you have rather than selling them and buying new. A project like that is a great way to remember someone, and with care and attention, you will get a really fulfilling result.

There have also been some suggestions here as to using the B139 in various different boxes, a search should show more.
 
consort_ee_um said:
The old Kefs sound so good you want to give them a good thrashing!
Unfortunately the T27 tweeter was only rated for 6watts and the high frequency content of contemporary music Led Zep Deep Purple etc used to fry the voice coils and that was before CD's. I think they strengthened the voice coils but I would use a PTC protection device if I were building a crossover.
However this is with louder levels than would be acceptable in a normal domestic environment, a normal user would be OK

I've seen four (4) pair of T27's die, due to underpowered amps driven to high levels at parties, among other things.
Someone out there needs your T27's edwardowen2.

Jeff
 
Ex-Moderator
Joined 2003
Sadly, the T27 is fragile and unlike later drivers, can't be taken apart and reassembled to put ferrofluid in the magnetic gap (which would increase the power handling). Professional active crossovers include compressor/limiters to protect the drivers...

Oh, and just a thought. Given that your dad had the imagination to buy the best drivers at a time when loudspeaker design was poorly understood, he would have leapt at a chance to use them properly.
 
I have played with these drivers for over twenty years, and still have a set in the original Bailey design.
Unless you go radically different, such as to metal drivers, I suggest you build with what you have. You can have a lot of fun with different designs of your own, or build an excellent speaker from pre-existing designs.
I have never rated the LS3/5 particularly highly, as I miss the low frequencies. So my preference is to go 3-way, and preferably active. If not use an amp with over 100watts. The crossover is then critical.
I have used a 25watter ss, but only on classical, and that was pushing it even at domestic levels.
The B139 will still give excellent results, but must be crossed over low. It has a bad resonance at just above 1KHz.
The B110 is perhaps not quite as crisp as modern midrangers, but still quite good. This really controls the "sound" of the speaker, and a little mild response shaping can work wonders.
The T27 is OK but is not as extended in the highs as some modern units. Frankly I cannot now hear these v.high frequencies anyway, but a supertweeter as in some IMF designs may help.
If you can afford the room, build a TL design already proved such as the pro9 or R50. Wimslow Audio have good xovers, if a bit pricy. The sound will tend to be on the warm side, (as were all British speakers of that era), and can be bass heavy in the wrong room.
The reflex designs are smaller, easier to build, with less bass, (less warm), and can sound better in some rooms. Unlike the TL's, they can be built to a desired smaller size, then use electronics to compensate for the rolled off frequencies.
 
Seems it would be nice to do something with the actual drivers that your dad purchased. I was inspired to study and build TLs after seeing reviews and hearing the big IMF TLS Monitors.
Here are a few links for LS3/5a info, but obviously you should use the B139s and you probably would not need as much LF boost in the 3/5a with a woofer, better to find the best crossover for the 3 drivers. The right crossover is what will get the most out of these drivers.

http://member.melbpc.org.au/~jkaso/KEF_CROSS.jpg

http://www.g4dcv.co.uk/lsinside.html
 
This is interesting about the T27 being so fragile - 6 watts?!! I have been using a pair of 70's vintage KEF Calinda's for parties (shame I know, but I really had no alternative and I got them quite cheap) and several 6+ hour sets of me DJing later they just seem to lap it up!

I suppose I'm reasonably careful to monitor the sound though. I hate nothing more than a thrashed PA sound.
 
Ex-Moderator
Joined 2003
Do remember that the 6W power rating is for a continuous signal to the T27. Unless you listen to techno with an underpowered amplifier, the actual power delivered by music will be much lower. That's why tweeters tended to give two ratings, one continuous and one for music with a specified crossover. Thus, 6W, 50W could have been perfectly possible.
 
Hi

I hope you find a suitable project that you enjoy.

The kef drivers T27 abd B110 ( various forms ) were used in the LS35a which was a studio monitor for many years. It was replaced eventually by ADC and then B&W speakers. However these replacements cost many thousacds of pounds.

I have a few sets of the Kef drivers you mention - some used and some unused. I have kept them because I think they sound very musical. My wife agrees - and she is very unbiased about audio.

I think that the LS35a sounds the most musical, especially in the midrange and on voices. I am planning to make the a modern version of the LS35a with an added subwoofer. You could use the B139 to make the subwoofer. The designs for the LS35a and the subwoofer are all on the attached page.

http://www.ls35a.com/

If in doubt I reccomend that you use a low order filter. I find this allows as much sensativity and detail in the sound to remain as possible. Some may not agree but I find that complex filters loose some detail in the sound.

I hope you find this useful.

Don
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.