I refurbished a Kef refenre speaker for a friend.
Sounds very good and a loudspeaker to live with. Must be recaped due to the age. The filter was made with great attention and precise values you don't want to change because coupled to the coils values.
Maybe a recap kit can be found at Falcon Acoustic shop GB. Anyway you will need to measure the caps and from there go for newer "blue cap" : LL where it's needed and so on. Precision was between 2% and 5% and 0.5% dB level whithin a pair.
The tweeter needs a new dose of FF (easy to find and to do) and if you buy one pair, be sure both tweeters are playing and have not the dust cap breaked. Eventually ask to see it if genuines and not new drivers.
You can easily find surrounding foam or butyl kit for the woof if needed.
According the price, a still great speaker as were the Kef 107 and 104/2. Made for music.
Another answer could be : if you want to improve the filter, better to start with a nowadays diy kit instead. The Kef should spend you less monney.
Sounds very good and a loudspeaker to live with. Must be recaped due to the age. The filter was made with great attention and precise values you don't want to change because coupled to the coils values.
Maybe a recap kit can be found at Falcon Acoustic shop GB. Anyway you will need to measure the caps and from there go for newer "blue cap" : LL where it's needed and so on. Precision was between 2% and 5% and 0.5% dB level whithin a pair.
The tweeter needs a new dose of FF (easy to find and to do) and if you buy one pair, be sure both tweeters are playing and have not the dust cap breaked. Eventually ask to see it if genuines and not new drivers.
You can easily find surrounding foam or butyl kit for the woof if needed.
According the price, a still great speaker as were the Kef 107 and 104/2. Made for music.
Another answer could be : if you want to improve the filter, better to start with a nowadays diy kit instead. The Kef should spend you less monney.
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Thanks for the info diyiggy. I did order a recap kit from Falcon. They only have 5% left but the owner Jerry mentioned that the drivers have drifted over time so he thinks it's not a problem. My tweeters are not fluid filled and the surrounds of the speakers are poly so no changing there. I did have to rotate the woofers because of voice coil rub; apparently a common problem with these.
I'm interested to know if the protection circuit can be bypassed in these for improved sound?
I'm interested to know if the protection circuit can be bypassed in these for improved sound?
A version of the crossover circuit, including protection circuit, is attached for ease of reference.
There has been a fair amount of discussion of the KEF 105/2 on this forum.
Best located by googling 'diyaudio kef 105/2'
Attachments
I do have a pair of those and I did bypass the protection. It's very easy by adding a jumper. Can't say I noticed any difference at all. Where I did notice was when I used banana plugs instead of the screw clamp when hooking them up. The intermeshing teeth of the clamp make it virtually impossible to achieve a tight connection. The difference in sq there is remarkable.
I'm not Discopete but have refurbished several filters of old britanics ladies of those days and I can putt myself in the camp of caps addicts with care of timbers and details, aka called last outrage to the drosophiles camp
In the Kef ref serie they took care of ESR with caps and often resistor in serie with the driver signal conector is avoided. You can see it in the filter where you see some LL low Loss and sometimes not... not made by chance.
as for the driver protection, the value is so low that you will not see huge diference and anyway can be avoided if not playing for a party.
It's not important at all and you can sleep perfectly fine without this question.
On some Kef 104/2 sometimes there were one (US market ?) and none (EU market?). and the T33 were FF, if the T27 is not here, don't fotgett ref serie is made to playing loud and abble of those level for transcient.
Better to Focus on a good cable and good source instead where you will find a lot of margin more to enhance the sound of the 105. of why not as said the little part of the internal cable till the filter and binding posts.
In the Kef ref serie they took care of ESR with caps and often resistor in serie with the driver signal conector is avoided. You can see it in the filter where you see some LL low Loss and sometimes not... not made by chance.
as for the driver protection, the value is so low that you will not see huge diference and anyway can be avoided if not playing for a party.
It's not important at all and you can sleep perfectly fine without this question.
On some Kef 104/2 sometimes there were one (US market ?) and none (EU market?). and the T33 were FF, if the T27 is not here, don't fotgett ref serie is made to playing loud and abble of those level for transcient.
Better to Focus on a good cable and good source instead where you will find a lot of margin more to enhance the sound of the 105. of why not as said the little part of the internal cable till the filter and binding posts.
I do have a recap kit coming from Falcon but I will be marking originals very carefully and will be curious how much the original caps have drifted; of course who knows what the original values were in the first place since all I've read is that Kef matched all of the caps with the drivers selected for the individual speakers. I may determine I should've left them alone??
I'm not sure they used asymetrical XO, so with some logic you can find the filter order of each way and with simulator on line find approximativly the text book cut-offs. Caps can be in 20% precision, so sure they sorted them out till 5% to 2% in some place of the filter where the precision is needed. Falcon do that vis a vis of the official of the marking which is not far really as Kef ordered smetimes special values like 16 uF, 7uF and so on. two main goals : the two ways should be 0.5% dB max drift from each other and it is to cope with the original patient zero which had the Go approval.
My little experience is the loudspeakers find again all its energy and snap. Night & Day. The hardest to find is the large values of impedance notch where 10% can be a lot of uF but this is maybe not as important if they are not narrrow frequencies notches. As far you have the original drivers whatever they drifted (not night and day if not foamed surroundings), Falcon acoustic kits are good enough and the blue Alcap caps Kef uses in the late ref series instead of the marked black or blue Kef at criticals areasv are far better sonically (and not only due to the ESR).
My little experience is the loudspeakers find again all its energy and snap. Night & Day. The hardest to find is the large values of impedance notch where 10% can be a lot of uF but this is maybe not as important if they are not narrrow frequencies notches. As far you have the original drivers whatever they drifted (not night and day if not foamed surroundings), Falcon acoustic kits are good enough and the blue Alcap caps Kef uses in the late ref series instead of the marked black or blue Kef at criticals areasv are far better sonically (and not only due to the ESR).
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I have not used them in a long time. What I did do was hard wire them so the only connection was to the amp. I also rewired them internally. I would say they became more dynamic with a greater sense of immediacy during a little experiment I conducted about 35 years ago. You can do a search of Kef 105 if you want to read about it. It was quite remarkable.
You will be counting the forum members with 105.2's on the fingers of one hand I guess. So asking for such experience... but the RR series were designed to work with any solid state amplifier capable of driving 4Ω nominal load. My humble opinion is that any amp that doesn't succeed in that is wrongly designed.