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View Full Version : museum worthy KEF speakers?



frank23
07-07-2006, 11:55 AM
These are no Lansing speakers, but look what I found in the garbage today.

A 38 year old pair of small KEF cresta speakers in almost perfect condition.

I was taking left over paint to the chemical depot and someone left these small speakers there. I immediately recognised the KEF B110 bas/mid so I knew these were more than mere old boxes, and I took them home.

I haven't hooked them up, but they look to be in almost perfect condition. Allmost 40 years of age. And the nice thing is, they come with the manufacturing date, the assemblers signature, the testers signature, the resonance frequency of the tweeter [the other is slighty higher]. Both were manufactured on november 28th 1968 by the same assembler.

They can be used horizontally and vertically and are a mirrored pair.

KEF can't have been a large company back then. At least not one were the employees were anonymous to the customers! What a find it would have been if these had been JBL's...

Frank

edgewound
07-07-2006, 11:59 AM
Frank,

Those are very retro cool...let us know how they sound.

Steve Gonzales
07-07-2006, 12:53 PM
I didn't know that KEF had been around for that long. Very cool style. It's nice to know that there are still some cool finds out there, as my particular area seems to have dried up. Congrats, Steve G.

JohanR
07-08-2006, 01:51 AM
I think the bextrene coned B110/B210 series came out in around 1967, so I would say, yes, they are collectibles.

JohanR (who had many Brittish speakers and recently converted to 1970's JBL's)

edgewound
07-08-2006, 12:27 PM
I think the bextrene coned B110/B210 series came out in around 1967, so I would say, yes, they are collectibles.

JohanR (who had many Brittish speakers and recently converted to 1970's JBL's)

Those look to be PVA coated paper cones.

frank23
07-08-2006, 12:33 PM
Those look to be PVA coated paper cones.

I think they are indeed coated paper. They must be a forerunner of the bextrene conusses as they are the same size and have the same chassis shape [as far as I remember].

I have some pics of scanned documents that are for sale on ebay. They are hard to read but it seems the bass conus was made of a material that was called something like "akoustikers" or whatever with a neoprene surround and the back side coated in nylon. Maybe I should buy the documents. The resale value of these Cresta's will probably make up for it. Oops, just bought them.

By the way, I realised just now that it is a closed system, no bass-reflex.

Frank

Hoerninger
07-08-2006, 03:06 PM
The B110 was made of Bextrene from the beginning, look here
http://www.kef.com/history/Hist1960.asp
I'm owning two of them since the late sixties. They are still wonderful middletone speakers. They are not so good for bass because of their relativ low Q.
___________
Regards
Peter

Chas
07-08-2006, 06:17 PM
Those are really cool. Keep them and enjoy. Want more bass? Try a pair of KEF 104 Reference's from the early seventies. They were/are remarkable for their size. Similar two way design with a T27 tweeter and B200 woofer. But these little guys have a B139 style oval passive radiator.

A real tribute to the designer, Raymond Cooke. Very listenable, even today. Gotta a pair in the basement over here and I wouldn't part with them. There was a later mod called 104aB, that had an improved crossover slope.

frank23
07-09-2006, 04:48 AM
not to go too far in this matter, as I am not too interested in KEF myself, being a JBL fan, but I found this info and so it seems that what looks like a coated paper cone seems to be a 1st generation B110 with a bextrene cone with added damping material on the front of the cone

btw the drivers pictured below come from the internet and are not the ones in my cresta's we're talking about here. They seem to be 2nd generation B110. I just placed these here to show that the cones look the same, so my Cresta's seem to be bextrene coned also.

Frank

http://www.review33.com/avforum/forum_message.php?topic=63030607080912&page=28

KEF B110 :

Quote from LS3/5a e-group :

there should be 4 versions of B110

B110 A6362 4-8 ohm 1967-early 70's
original unpainted frame, damping on front of Bextrene cone Neoprene rubber surround

KEF Cresta, early Concerto, original LS3/5 1970-74


B110(A)SP1003 8 ohm early 70's-early 90's

some unpainted, mostly black chassis, damped front Bextrene cone Neoprene rubber surround
called B110 or B110A (constructor series)
LS3/5a 15 ohm versions, IMF midranges, many British / DIY speakers

B110B SP1057 8 ohm Mid 70's-early 90's
Black chassis, higher power voice coil materials, Bextrene cone damped on back, PVC surround

KEF Cantata, R101, R105 series/107 series midrange, DIY designs


B110C SP1228 6 ohm 1987-late 90's
Black chassis, higher power voice coil materials, Bextrene cone damped on back, PVC surround, production restarted 2002 in China

KEF and others' LS3/5a 11 ohm versions, Rogers AB1 woofer Variant B110 SP1380 is a SP1228 out of spec above about 250 hz. - can be used for AB1


There are other B110 SPxxxx drivers, notably the SP1190 mid drivers built into the baffles of the KEF 104/2 speaker.

The only B110 drivers AFAIK available from KEF as NOS are the B110C's. They will function fine for the 11 ohm versions of the LS3/5a. Will function in the 15 ohm version but the crossover's equalization will be incorrect for the B110C.

unquote

mech986
07-09-2006, 11:45 AM
Hi Frank,

The information you quoted from the LS3/5a group is a posting of mine detailing the B110 subtypes that KEF built over the years.

All of the Bextrene coned drivers that KEF built required a PVA damping coating (Edgewound was right on with his observation) called Plastiflex to dampen specific cone reasonances inherent with Bextrene. This actually worked pretty well but added considerable weight to the cones which reduced their efficiency.

Later production Bextrene cones had other problems with different reasonances due to fire retardant being added to the OEM Bextrene material in the 80's (bextrene was also used to make automotive plastics like dashboards.

Your Cresta's were the first small KEF speaker with early B110 Bextrene drivers, unpainted chassis and have leadwires on opposite sides of the cone. Later B110's lead wires did not go through the cone but enterned on one side of the voice coil. I think the rubber surrounds on these units sounded somewhat better than later units. The Cresta is sort of the spiritual predescessor of the LS3/5a although it is considerably larger. Hope this helps.

BTW, agree about the 104/104ab. Very nice design that was used in multiple generations of KEF speakers.

Regards,

Bart
Yahoo! LS3/5a Newsgroup Moderator

frank23
07-09-2006, 01:58 PM
The information you quoted from the LS3/5a group is a posting of mine detailing the B110 subtypes that KEF built over the years.

Ha, that's nice, the small LS3/5a meets the large JBL's right here.

I must say that although I got into JBL about 5 years ago, in the 80's I had [and still have] the KEF constructor brochures. I especially liked the B200. Only I didn't have the money then to pay for them. The brochure itself was an important source of information for me in those years, starting exploring building speakers myself.

When I had the money, my interest had shifted to other brands. I'll try the Cresta's out within a few weeks and see what I've missed...

Frank

Chas
07-09-2006, 04:17 PM
Frank, if my experience with 104's is anything to go on, you really ought to look at the crossover caps. I thought my tweeters were dead, until I changed the caps. The KEF choice of OEM parts were pretty awful!

Fangio
07-17-2006, 04:31 AM
Hey Frank, same here a while back :)
Interesting to see the B110 again, as obviously collectible. If I had known there are KEF afficionados around, I would have shown this pair here too.

Found these some month ago, and had no use for them. A gentleman from austria restoring a LS3/5a is very happy with them now.

Wayne
08-09-2006, 08:27 AM
I actualy still have a set of KEF Concertoes, these were my first DIY & had the 1964 manufacturers tag on the inside of the baffle, which I completely redid as the cross-over's were located externaly screaming at my duaghters to come & play. As it turned out the B139 Drivers, which are flat, ended up with some pretty pattens on them thanks to my youngest, oh well still sound good. Will have to move these on soon as the JBL bug keeps growing, wish there were some/any vintage components in my neck of the woods.:(
17305

Wayne
12-21-2006, 07:41 PM
Hi all.

I recently returned from a trip over East, Aust that is, only to find that my recent ex decided to drive my KEF Concertoes,
(shown in above post) untill something went pop!
Thankfully my JBL's weren't up & running, but the thing that went pop was the complete destruction of a 5u cap in the x-over to the tweeter of the left speaker & the protection fuse in the same channel of my proton amp.
I have repaired the amp, but find myself bewildered at the amount of caps that are available & have a couple of questions for the experienced.
Should all the caps in both x-overs be replaced due to there age?
The original caps are non-polarised electrolytics rated at 50v with varying values (pics from web below), is there any reason why these couldn't be replaced with say Solens 400v range of caps if installed correctly. Is this overkill & are there cheaper caps just as good tried by yourselves.
Finally one for fellow Aussie members, were inside Aust is a good place to order quality caps.


21520 21521

Cheers Wayne.
:cheers:

Chas
12-22-2006, 07:31 AM
Definitely replace all the capacitors with at the least, 400V Solens. I have a nice old pair of 104's (non aB version), some of the original capacitors actually went open circuit, I had never seen this happen before....

After replacing all the KEF OEM caps with Solens, there was a major improvement - and the tweeters started working again.:bouncy:

Wayne
12-22-2006, 01:31 PM
Hi Chas

Thanks for the advice, figured complete swapout was the way to go. The 5u cap sure made a mess of its self inside the box, but the tweeter thankfully meters fine.
She never has liked any of my vintage gear :screwy: but I honestly didn't think she would deliberately over-drive them to that point.
There ain't no speakers hooked up any-where now, makes me :barf:
Now I'll track down some Solens, hopefully locally, fit them & try them out at a mates place, will be looking forward to some better sounding Concertoes.

Cheers Wayne.
:cheers:

LowPhreak
12-22-2006, 08:57 PM
frank23 -

Congrats on finding the orphans. :cool:

I had a pair of KEF C80's back in the early 90'S. A very decent sounding 3-way I thought.

One step down from the 104's, but had the same components except with the sealed cab B139 woofer instead of 104's 2x8" semi-reflex cab.

Not the most efficient speakers, but they had a very even 4 ohm impedance right across the range, and got going nicely with a 125 wpc or so.