SpeakerTalk Forum Index SpeakerTalk
This forum has been set up to facilitate discussion of 1970s KEF speakers and drive units. The owner of the Forum has no connection with KEF Audio.
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

A History of Kef Drive Units

 
Post new topic   Reply to topic    SpeakerTalk Forum Index -> DIY with KEF drive units
View previous topic :: View next topic  
Author Message
speakerguru
VIP Contributor 750+


Joined: 18 Nov 2005
Posts: 959
Location: Green Hut, Tovil

PostPosted: Tue Sep 15, 2009 11:31 am    Post subject: A History of Kef Drive Units Reply with quote

Andrew Watson has added a bit of history to the KEF website.

see http://www.kef.com/gb/about/kefunits

Check out this pdf: http://www.kef.com/Resources/KEFUnits/A%20History%20of%20Kef%20Drive%20Units.pdf
Back to top
View user's profile Send private message
ColinR
Über Contributor 1000+


Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Tue Sep 15, 2009 2:00 pm    Post subject: Reply with quote

Very good Very Happy .

Only one serious omission and three(?) errors.


Due to lack of production capacity at KEF some early B110 and B200 models were made by their sub-contractor; Goodmans, who used the SP prefix for different drive unit types.

Sources, Malcolm Jones KEF's first employee and a few ex-Goodmans/Dalesford employees I've met over the years who've told me about them.


I've never seen a SP1072 T52B in any production version of the Ref. 105.2, the "head mounting bushes" are aligned for SP1049 with decor plate, which is a tad smaller than the T52B faceplate.

The CS 9 uses the SP1071 B300B not the B330 SP1060.

The SP1063 was not used in the C40 (C10-C80 range http://www.hifiloudspeakers.info/Anatomy/KEFDocuments/KEFSpeakers61to86/Gallery/index.htm), but a square wide flanged unit (also found in the C45) was.

I thought the C65 was a C60 rework and the first incarnation of Uni-Q.


Will the 60's Cantata be removed from the 70's section and be replaced by the SP1056?

Also will the later relationship with Audax (paper coned P200 drivers and 100D25 tweeters) be acknowledged at some future date?


Equally interesting, KEFTOPICS are available here

http://www.kef.com/gb/about/keftopics


on a personal note having taken ages over scanning my copies of them and the corresponding AES papers for this site in order to upset ePrey pimps and the like who like loadsa money for such "free" items, all I can say at the moment is bugger Rolling Eyes .
_________________
This post or any other information supplied to this website or any other by myself is not available for any form of commercial purpose i.e. to hi-fi magazines or as sales and marketing material for sleezeBay or Audiodogging pimps and the like.
Back to top
View user's profile Send private message
terry
Senior Contributor 200+


Joined: 22 Apr 2003
Posts: 262
Location: UK

PostPosted: Tue Sep 15, 2009 10:14 pm    Post subject: Well done KEF Reply with quote

It is good to see that KEF is at last dealing with historical matters. We have successfully filled a void over the last few years. This forum, however, has a wealth of information and anecdotes which makes us unique - thanks to the members. The statistics show where the contributions have come from too. Thanks ColinR (818), Proffski (606), SpeakerGuru (273), Parts, Gary Centaurus et al.
Back to top
View user's profile Send private message Send e-mail
KEF_Support
Introductory Contributor


Joined: 04 Aug 2008
Posts: 3

PostPosted: Wed Sep 16, 2009 11:33 am    Post subject: Reply with quote

Thanks to Speakerguru for the link to the new pages on the KEF website. I hope these new additions will complement the excellent knowledge base that exists on this forum and the Hifiloudspeakers website as a whole. HiFiloudspeakers is a great resource for all of us who share an interest in the heritage of KEF.

Thanks to ColinR for comments on the driver article and picking up the error on the bass driver of the CS9.

Our records show that the SP1072 tweeter was used in the 105.2 from SN2966, although I don't have a physical sample to confirm this.

One of the interesting facets of delving into the history is that you come across a few anomolies, a case in point being the C40 and C65, of which there were two of each model name, completely different products:

C40 (SP1139) and C65 (SP1138) were both released in 1979 and both used B200(SP1063) and T27(SP1032). I assume these were mainly export models.

Then there was the better known C40(SP3054) from the 1985 C10 to C80 range, and the C65(SP3120) a conventional non-Uni-Q system from the C15 to C95 range.

Thanks for the other comments which are duly noted.

Regards to all,

AW.
Back to top
View user's profile Send private message
Gary
Senior Contributor 200+


Joined: 07 Nov 2004
Posts: 275
Location: Toronto, Canada

PostPosted: Wed Sep 16, 2009 11:27 pm    Post subject: Reply with quote

ColinR wrote:
Also will the later relationship with Audax (paper coned P200 drivers and 100D25 tweeters) be acknowledged at some future date?


Fascinating! So - perhaps, maybe - did the Tangent speaker company simply use the KEF/Audax relationship to build their own speakers using Tangent crossovers - and their own Tangent boxes?
_________________
Sometimes I lie awake at night, and I ask, "Where have I gone wrong?" Then a voice says to me, "This is going to take more than one night."
-- Charles M. Schulz (as Charlie Brown)
Back to top
View user's profile Send private message
speakerguru
VIP Contributor 750+


Joined: 18 Nov 2005
Posts: 959
Location: Green Hut, Tovil

PostPosted: Mon Sep 21, 2009 12:21 pm    Post subject: Reply with quote

Gary wrote:
... did the Tangent speaker company simply use the KEF/Audax relationship to ...

KEF/Audax relationship? I'm not aware there was any, other than that KEF bought Audax tweeters for a while (all the cloth sock models). The tweeters were not particularly reliable so later models used Panasonic tweeters.

Later still KEF switched to Tonegen for tweeters. Tonegen were eventually assimilated into the mighty Foster and it was Foster that made all the later Uni-Q tweeters.
Back to top
View user's profile Send private message
audiolabtower
VIP Contributor 500+


Joined: 06 Jan 2009
Posts: 544

PostPosted: Tue Sep 22, 2009 10:52 am    Post subject: Reply with quote

very interesting link, thank you.

I'm surprised that the same B200 SP1039 was used in the 104 and the 103. I thought it was optimised for reflex loading where the very large excursions tailed off to be taken over by the passive/port etc. But if it is a short coil/long magnet design then it should be great for sealed box since the distortion should be lower than other B200s at high volume?
Back to top
View user's profile Send private message
speakerguru
VIP Contributor 750+


Joined: 18 Nov 2005
Posts: 959
Location: Green Hut, Tovil

PostPosted: Wed Sep 23, 2009 12:00 pm    Post subject: Reply with quote

audiolabtower wrote:
But if it is a short coil/long magnet design then it should be great for sealed box since the distortion should be lower than other B200s at high volume?

The short coil/long gap arrangements gives lower distortion until the coil goes out of the gap. Then the distortion increases rapidly with larger excursion. So the answer is that the SP1039 gives lower distortion than other B200s (in either closed box or reflex design) up to its design limit range of movement. Beyond that, the question is, what type of overload behaviour is subjectively the least objectionable and that is a whole other can of worms.
Back to top
View user's profile Send private message
audiolabtower
VIP Contributor 500+


Joined: 06 Jan 2009
Posts: 544

PostPosted: Wed Sep 23, 2009 9:30 pm    Post subject: Reply with quote

I see, thanks. I always thought it was the best B200 Kef ever made.

Interestingly, talking about SP1039, have a look at

http://cgi.ebay.co.uk/hi-fi-speaker-KEF-8-inch-drive-unit_W0QQitemZ170383603286QQcmdZViewItemQQptZUK_AudioVideoElectronics_HomeAudioHiFi_HiFiSpeakers?hash=item27aba77656&_trksid=p3286.c0.m14

eprey item 170383603286

click on the enlarge and have a look at the front photo surround Smile
Back to top
View user's profile Send private message
speakerguru
VIP Contributor 750+


Joined: 18 Nov 2005
Posts: 959
Location: Green Hut, Tovil

PostPosted: Thu Sep 24, 2009 11:25 am    Post subject: Reply with quote

audiolabtower wrote:
eprey item 170383603286

Oh dear, oh dear. Not only has the vacuum formed shape of the surround flattened out, but it also looks like the surround is coming unstuck from the cone as well Shocked The dust cap doesn't look right to me either. It looks like one of the small ones used on a 1" coil units rather than a 1.25" ...??
Back to top
View user's profile Send private message
audiolabtower
VIP Contributor 500+


Joined: 06 Jan 2009
Posts: 544

PostPosted: Thu Sep 24, 2009 12:15 pm    Post subject: Reply with quote

I wonder if it is the original surround.... and shudder to think what it would sound like in a 104aB with the other of the pair a good one Smile
Back to top
View user's profile Send private message
Lee in Montreal
Senior Contributor 200+


Joined: 22 Aug 2009
Posts: 203

PostPosted: Sun Oct 11, 2009 3:07 pm    Post subject: Reply with quote

I checked some spec sheets and there seems I may have found some inacurracy.

The B300B - Sp1071 is rated with a Vas of 250 litres on these "official" spec sheets, while it is rated at 130 litres on some others that I found. From 250 to 130 litres, the implication is huge in terms of required cabinet dimension.
Back to top
View user's profile Send private message
SaSi
Senior Contributor 200+


Joined: 24 Aug 2008
Posts: 223

PostPosted: Sun Oct 11, 2009 6:19 pm    Post subject: Reply with quote

I recently found out that the KEF website now hosts, apart from the Museum, scanned copies of KEF Topics and datasheets of most of the '70s drivers. Look at
http://www.kef.com/gb/about/kefunits

and

http://www.kef.com/gb/about/keftopics

PS. It also appears that this section is alive, as the T52 PS1072 wasn't there yesterday when I first saw them.
Back to top
View user's profile Send private message
SaSi
Senior Contributor 200+


Joined: 24 Aug 2008
Posts: 223

PostPosted: Sun Oct 11, 2009 10:25 pm    Post subject: Reply with quote

speakerguru wrote:
audiolabtower wrote:
eprey item 170383603286

Oh dear, oh dear. Not only has the vacuum formed shape of the surround flattened out, but it also looks like the surround is coming unstuck from the cone as well Shocked The dust cap doesn't look right to me either. It looks like one of the small ones used on a 1" coil units rather than a 1.25" ...??

The B200 on my pair of 104s had a deformed surround almost exactly like the one in that auction. I received it that way. Have no clue as to how it happend. I still keep the driver as it really sounded more than decent.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    SpeakerTalk Forum Index -> DIY with KEF drive units All times are GMT + 1 Hour
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group