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KEF Reference 101

 
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HightechRedneck
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PostPosted: Thu Oct 21, 2010 6:02 am    Post subject: KEF Reference 101 Reply with quote

Hello,
I recently acquired a pair of KEF 101 speakers in nice cosmetic condition but it appears two small capacitors (10uf) have leaked the electrolyte onto the circuit board and corroded away the traces beneath the capacitors. I have not performed a detailed examination to determine their function but I assume the capacitors comprise a part of the S-Stop circuitry. Can anyone advise regarding these caps and should I replace all of the capacitors while I have the crossover boards out? Should the S-Stop circuit be disabled or kept intact? Is there any chance the semiconductors in the S-Stop circuit would still be functional?

Many thanks for any advice.
Charles Campbell
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proffski
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PostPosted: Tue Oct 26, 2010 4:52 pm    Post subject: Re: KEF Reference 101 Reply with quote

There is a link on this site which may help you, the capacitors will be ageing now and I would change them if I was the proud owner.
However bear in mind that the components may have been specially batch tested and chosen so replacing with like for like may not necessarily give the correct precise values.
There are people far better qualified here to give you a more precise answer, this is the best advice I can guess at.

Link: http://www.hifiloudspeakers.info/Anatomy/SpeakerSystems/101/Gallery/pages/09R101.htm
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proffski
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PostPosted: Tue Oct 26, 2010 4:53 pm    Post subject: Re: KEF Reference 101 Reply with quote


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Last edited by proffski on Thu Oct 28, 2010 8:40 pm; edited 1 time in total
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HightechRedneck
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PostPosted: Tue Oct 26, 2010 5:32 pm    Post subject: Thanks for Reply proffski Reply with quote

I know the 101 speakers used tight tolerance capacitors and I have found a supplier that will grade and tolerance their capacitors for a slight premium. The capacitors they sell also looked remarkably similar to the ones that are presently used on crossover network.

Thanks for the Info,
Charles
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speakerguru
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PostPosted: Sun Dec 05, 2010 10:06 am    Post subject: Re: KEF Reference 101 Reply with quote

HightechRedneck wrote:
Should the S-Stop circuit be disabled or kept intact? Is there any chance the semiconductors in the S-Stop circuit would still be functional?

I've had my 101s from new. I still use them for monitoring and on the rare occasions when my PC has spontaneously re-booted durung an Adobe Audition session, the protection cct has performed perfectly.
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HightechRedneck
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PostPosted: Sat Sep 03, 2011 5:08 am    Post subject: KEF Reference 101 Manufacturing Variations Reply with quote

I have a friend who recently acquired a pair of KEF Reference 101's. Upon receipt, we noticed that the dust cap on his B110 woofers was different from mine. There is a glossy coating over my dust caps but none over his. Only the coarse weave of a formed cloth cap was present on his. Mine are S/N 12037 while his are later production 12879. Was this an omission / error or a change in manufacture?
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ColinR
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PostPosted: Sat Sep 03, 2011 10:21 am    Post subject: Reply with quote

Quote:
but none over his
Quote:
only the coarse weave of a formed cloth cap


Sounds like a sly repair to badly behaved child damage.
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HightechRedneck
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PostPosted: Sat Sep 03, 2011 4:56 pm    Post subject: My thoughts too but... Reply with quote

ColinR wrote:
Quote:
but none over his
Quote:
only the coarse weave of a formed cloth cap


Sounds like a sly repair to badly behaved child damage.


Colin,
That was my first thought as well, but careful examination using a high intensity light to illuminate the surfaces under the cap (you can see right through the open cloth weave), shows no indication of a previous cap installation or adhesive bonding. There are no witness marks of having removed a previous installation. It appears OEM and looks far too professional to be a field repair. Wish you could see it.

Furthermore, a close examination of the material, indicates it is the same as that used in my caps. Until I did this, I thought the caps on the B110 were Bextrene. I can shine the high intensity light into my "Coated" caps and illuminate the underlying fabric. It is a rather coarse weave, which appears identical to his caps, which are not coated.
Charles
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speakerguru
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PostPosted: Mon Sep 05, 2011 8:32 am    Post subject: Reply with quote

All KEF B110s had coated dustcaps. It was the last thing done in the production process.

I would guess that your uncoated ones have been repaired in some way. The front coat of "plastiflex" can be peeled off the "bextrene" cone quite easily. (There was no primer as used on the rear of the cone.)

If this is done carefully and then a new dustcap placed onto a fresh coat of plastiflex then you would not see any witness marks of the previous assembly below the dustcap (as you describe).
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