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KEF LS5/1AC Reference series studio monitors
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proffski
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Joined: 22 Aug 2003
Posts: 1297
Location: Tewkesbury UK

PostPosted: Mon May 15, 2006 1:34 pm    Post subject: Reply with quote

Is this what we are looking for? I'd suggest that these are saved whilst still available on the internet. Classic stuff!

1. http://www.bbc.co.uk/rd/pubs/reports/1979-22.pdf
2. http://www.bbc.co.uk/rd/pubs/reports/1977-03.pdf
3. http://www.bbc.co.uk/rd/pubs/reports/1976-29.pdf

"Share And Enjoy"!
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henryc
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Joined: 01 May 2006
Posts: 39
Location: Gloucestershire

PostPosted: Mon May 15, 2006 4:37 pm    Post subject: Reply with quote

Hi Proffski
Thanks for the links to the docs Great stuff!

Have a look at this doc as well:
http://www.cicable.com/pdf/bbc_monitoring.pdf
Makes very interesting reading ,except for the typos!
( see section on the history page 7)
All the best
Henry
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proffski
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Location: Tewkesbury UK

PostPosted: Mon May 15, 2006 5:23 pm    Post subject: Reply with quote

Call me an anorak if you must, but this sort of stuff gives me goose bumps and a nice warm feeling like a large shot of Laphroaig...

Thank you for the link, SPLENDID!
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qguy
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Joined: 08 May 2003
Posts: 85

PostPosted: Tue May 16, 2006 6:36 am    Post subject: Reply with quote

how come this model is not on the official KEF site ?
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proffski
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Joined: 22 Aug 2003
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Location: Tewkesbury UK

PostPosted: Tue May 16, 2006 8:36 am    Post subject: Reply with quote

The "Official" KEF site has lots and lots missing...
Guess the model was never released for the average consumer.

I have always been amazed how little pride seems to go into their site, a bit of world-renowned audio history.

This site sets a good example of how to do I properly.
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henryc
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Joined: 01 May 2006
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Location: Gloucestershire

PostPosted: Tue May 16, 2006 9:37 am    Post subject: Reply with quote

Hi guys
I have emailed the pictures to KEF archivists for their info
They were helpful earlier this year and sent me the description
I pasted in an earlier reply.
They have however completely missed the early broadcast models such as the LS5/1AC and other earlier models and experimental ideas .I guess the site is concentrated on the comercial domestic models which one can understand however as Proffski said it's a great shame because their work was so formative and built a foundation for so many new companies.
Their collaboration with the BBC as well is scantily covered and I believe like many others on this forum that they should celebrate the fact as it
is a glorious history and would add value to their brand(Speaking as a brand design consultant!)
Come on KEF Pull yer socks up and we will I am sure all help in supplying the company with the information.
Tell you what I will ring them now and speak to them directly and get things moving (hopefully)
I will keep you all abreast of developments
Until then keep the music playing
Henry
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proffski
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Location: Tewkesbury UK

PostPosted: Tue May 16, 2006 11:26 am    Post subject: Reply with quote

Hmm, are there any true audiophiles left at KEF rather than accountants?
A long time ago just having left school I sent an enquiry to KEF asking for information regarding T27 variants. The hand written reply was from none other that Raymond Cooke himself.

Now some of my Physics students are doing investigations into transducers and materials science.
I wrote to 25 UK speaker manufacturers and had some amazing help from a few. Many did not reply and a handful wrote back apologising for not being able to help, KEF were the least interested. I guess when the effective base is now in China, at least they replied…
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henryc
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Joined: 01 May 2006
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Location: Gloucestershire

PostPosted: Tue May 16, 2006 12:23 pm    Post subject: Reply with quote

Info needed for friend at Falcon Accoustics!
His response to my enquiries
The spec below was for the LS5/1A as it was passive and was fed by a modified Radford MA25 fixed bias valve amp, fitted with a bridging input transformer. The units were selected to 1/4 dB and then matched, so for a bass unit of +1/4dB ref, the tweeters were matched to +1/4, +1 1/4, -3/4dB so the 1 dB taps gave a very accurate match, much closer than the BBC spec for matching. It took longer and we occasionally had some units in limbo. We also had a special HF1400 made using Nomex to give higher power handling.

We used to check the 1Ac's with ear defenders on! First generation Dolby A tapes of the Beetles Here 'Comes the Sun' and ' sounded amazing.

I went round nearly all the London recording studios + ITV, ITN and Capital Radio with them in the early 70's.

I am writing a book to be published by Audio Amateur about the early days of KEF 1961 - 1974.

I was interested in the 80's mods to the 1AC's
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henryc
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Location: Gloucestershire

PostPosted: Sun May 28, 2006 9:54 am    Post subject: Just finished internal rewiring the beasts... Reply with quote

My what a revelation ..
The speakers have just been rewired internally. I removed very carefully! the bell wire connections,I still can't believe they used such thin wire to wire up the units,any way I bought the best I could affored and used braided Oelhbach Rattle Snake 3 cables /half Silver half OFC .
Weblink: http://www.oehlbach.de/CMS/product-detail.php?sprache=en&artikelnummer=1086
I removed the junction sockets at the base of the cabinet and fed the wires through the resulting holes . I changed the plugs to the power amp and replaced with gold plated terminals .
Replaced the interconnects with new QED quinex cables and replaced the XLR's and Phonos and sat back and listened.
I was prepared to hear a change in the sound ,afteral they couldn't sound any worse having been wired with bell wire, but I confess I was blown away with the change.
The bass is much cleaner more deep and controlled and the T52's which were a tad bright were now sweet and smooth in fact so detailed I heard layers of detail I have not heard before ,(Honestly)
The bass I would say has improved most of all .
Much more controlled ,faster , tighter, deeper, detailed, richer and more extended than before which was already Deeeep.
So in conclusion ,after £100 worth of cable, 5 hrs of carefull reconstruction I think the rewiring was well worth the effort and expense.
Try it yourself I don't think you will be dissapointed and may well be rewarded wiith a much better sound.
Do tell us if you do!
All the best
Henry
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darkmatter
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Joined: 26 Aug 2010
Posts: 14
Location: Eastern England

PostPosted: Fri Nov 03, 2017 9:27 pm    Post subject: Re: Just finished internal rewiring the beasts... Reply with quote

henryc wrote:
My what a revelation ..
The speakers have just been rewired internally. I removed very carefully! the bell wire connections,I still can't believe they used such thin wire to wire up the units,any way I bought the best I could affored and used braided Oelhbach Rattle Snake 3 cables /half Silver half OFC .
Weblink: http://www.oehlbach.de/CMS/product-detail.php?sprache=en&artikelnummer=1086
I removed the junction sockets at the base of the cabinet and fed the wires through the resulting holes . I changed the plugs to the power amp and replaced with gold plated terminals .
Replaced the interconnects with new QED quinex cables and replaced the XLR's and Phonos and sat back and listened.
I was prepared to hear a change in the sound ,afteral they couldn't sound any worse having been wired with bell wire, but I confess I was blown away with the change.
The bass is much cleaner more deep and controlled and the T52's which were a tad bright were now sweet and smooth in fact so detailed I heard layers of detail I have not heard before ,(Honestly)
The bass I would say has improved most of all .
Much more controlled ,faster , tighter, deeper, detailed, richer and more extended than before which was already Deeeep.
So in conclusion ,after £100 worth of cable, 5 hrs of carefull reconstruction I think the rewiring was well worth the effort and expense.
Try it yourself I don't think you will be dissapointed and may well be rewarded wiith a much better sound.
Do tell us if you do!
All the best
Henry


Reviving an old thread but I have owned a pair of LS5/1AEs for about 18 months now.

Have considered rewiring the internals with a higher performance cable, but am very wary of upsetting the balance of my LS5/1AEs

Would value thoughts from others on this.

Thanks,

Simon
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