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KEF 101

 
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mr quackers
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Joined: 20 Jun 2013
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PostPosted: Thu Jun 20, 2013 8:33 pm    Post subject: KEF 101 Reply with quote

I have KEF 101 = I think the date is 198? - I unscrewed the bottom plate revealing the crossover and date stamp is smudged - it is 198?
Do I need to change the components due to age and who can do this for me - I cannot solder as my hands shake.
I understand components degrade over time.
Thank you for any help.
I am a novice and new member to the site.
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Jay_Plesset
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Joined: 12 Feb 2013
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Location: oregon city, oregon

PostPosted: Fri Jun 21, 2013 3:45 am    Post subject: Not sure you need to replace crossover parts Reply with quote

I have three sets of 101s, and yes they are from the early 1980s. I've been toying with replacing the capacitors myself, but they sound so good, I've not bothered.

Unless you're hearing some problems, I'd suggest simply enjoying them.
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3 pair ref 101
103.2
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speakerguru
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Joined: 18 Nov 2005
Posts: 959
Location: Green Hut, Tovil

PostPosted: Fri Jun 21, 2013 8:50 am    Post subject: Reply with quote

Welcome mr quackers and congratulations on owning a fine pair of speakers, the KEF 101s.

I still have a black pair from when I worked at KEF. I am ashamed to admit I have not done anything to them, apart from grille repairs, since I got them. The T27s have no ferrofluid to degrade and I have not heard any drastic changes (although I'm sure my ears have degraded ) in their sound, so I am leaving the XO well alone. Maybe one day I'll get out the LCR meter and check the capacitor values....
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proffski
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Joined: 22 Aug 2003
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Location: Tewkesbury UK

PostPosted: Fri Jun 21, 2013 11:49 am    Post subject: Reply with quote

Spot on chaps, if it aint broke... Smile
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mr quackers
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Joined: 20 Jun 2013
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PostPosted: Fri Jun 21, 2013 5:45 pm    Post subject: KEF 101 Reply with quote

Thank you all for the advice.
As I understand it, the components in crossovers can gradually deteriorate over long time which means the sound quality/balance can change over a period of time and humans tend to simply not notice a gradual deterioration/change in sound quality/balance over a long period of time - so there could be lots of old speakers with crossovers which have changed values over the years and people have not noticed it because the sound change has been over a long period of time.
I think caps and resistors can change values according to some things I have read elsewhere.
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proffski
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PostPosted: Fri Jun 21, 2013 6:27 pm    Post subject: Re: KEF 101 Reply with quote

Capacitoirs may well age, and as Speakerguru has already pointed out their performance can be easily checked.
Wire wound resistors will not change value, I have not often come acceross carbon film or metal oxide resistors in crossover networks.

Good luck with your quest! Wink
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Thierry
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Joined: 02 Sep 2010
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Location: France - Outskirts of Paris

PostPosted: Mon Jun 24, 2013 8:44 am    Post subject: Reply with quote

The only time I had to replace a capacitor in a passive crossover was when it blew into pieces because of a massive power surge. Speakers were B&W D5s (wonderful little speakers) connected to a 200W amp and I was fiddling with the preamp and a function generator. Because of my own stupidity a high pitched tone at full throttle was sent to the power amp. Woofers remained intact but the tweeters and their capacitors litterally exploded, filling the cabinet with tiny bits of melted plastic. An horrifying sight, belive me.

About components supposedly aging, last year I ordered a capacitors set for my KEF 105.2s from Falcon Acoustic (Jerry is a very nice chap and I highly recommend his business). After thorough measurement of the original capacitors I installed the new ones on one speaker only, keeping the untouched 105.2 as a reference. I must admit I couldn't hear any difference between the rejuvenated 105.2 and the one that stayed original.

Of course this is valid only when you stick to the original crossover design and capacitors technology, keeping unmodified ESR.

Thierry
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speakerguru
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Joined: 18 Nov 2005
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Location: Green Hut, Tovil

PostPosted: Mon Jun 24, 2013 9:24 am    Post subject: Reply with quote

I have experienced a capacitor going virtually open circuit resulting in no midrange on one side. Even a deaf man could hear that Laughing.

The speakers were Model 103.4 which I had donated to my village hall, so they have long periods of not being used. Maybe that contributes to the electrolyte deterioration.
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proffski
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PostPosted: Mon Jun 24, 2013 11:25 am    Post subject: Reply with quote

Many years ago I donated my first Concerto type kits (with the old style B139 Chassis) to my local youth club. These proved very popular as within a fortnight they had cabinets with holes and no drivers... but they left the crossovers! Evil or Very Mad
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