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Old 21st November 2008, 09:33 PM   #1
drkool is offline drkool  United States
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Cool KEF 105.2 crossover networks

Howdy, I have a pair of KEF 105.2 speakers with bad crossovers, I know how to solder well enough to replace the capacitors and have ordered a complete set to replace them all. But I don't know enough about electronics to dissconnect the overload circuit. Would it be to my advantage to dissconnect it? Does anybody know the crossover points of these speakers? And would I be better off just buying a pair of generic crossovers from Parts Express, and bypassing the rotary switch circuit in the speaker head? I know there has to be some signal loss in the 20 or 22 gauge wire ehich connects the midrange, and tweeters in the speaker heads.
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Old 21st November 2008, 10:15 PM   #2
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Location: Santa Cruz, California
I don't know these speakers personally, but I do know that the crossover in the KEF's will be well designed. A generic XO from PE will almost certainly sound worse.

You can take the protection off - you'll be flying without a net! Don't push them.

I'd also expect the gauge of wire to be factored into the crossover, as well as the parasitic resistances of the inductors and capacitors. This is one situation where changing a component can make a big difference in sound.

Go ahead and experiment, keep the old parts in case and never make an irreversible change (unless you're really ballsy )
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Old 25th November 2008, 10:24 PM   #3
qguy is offline qguy  Canada
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You might find this KEF Forum helpful...
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Old 9th January 2009, 09:30 PM   #4
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I agree with the previous posts. The Kef crossovers were selected to 1% tolerance and computer matched to the drive units to get the flat response within the spec limits. Any other generic crossover will sound different but almost certainly worse compared to a good original. The best would be to replace the elcaps which may have degraded over this time, but ideally each would need to be measured to match up a replacement of the same value. The tweeter caps if replaced with polyester or ploprop can need a very small resistor in series to simulate the ESR of the elcaps, otherwise it can end up too bright.
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Old 2nd January 2011, 08:26 PM   #5
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Hi , Im new and was attracted to the site because I have the kit version of KEF 105 2 (cs9) purchased from Falcon Accoustics in 1985. I am looking for the schematic for the crossover as my dog got in back up of the speakers and chewed off some of the wires.

I noticed a post from David who was an engineeer at Kef related to the crossover componets being matched to the drivers. Since mine came off the shelf in kit form they are not matched is the wiring schematic the same as the retail units.

Is there a way to contact David?

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Old 2nd January 2011, 08:58 PM   #6
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The entire consrutction leaflet, including XO, archived on Falcon V2

community sites,, ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
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Old 2nd January 2011, 10:16 PM   #7
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Wirring For 105.2
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File Type: jpg 105_2Crossover.jpg (31.7 KB, 237 views)
File Type: gif 105-20804a.gif (14.4 KB, 206 views)
File Type: gif 105-20804b.gif (17.8 KB, 203 views)
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