KEF 105 Mk1

[Jac Hawk]

Hi, I've just bought a pair of KEF 105 Mk1's, what can i say other than an itch i've been wanting to scratch since my dad had a pair on demo in 1977, my mum was the over riding factor in the decision making process back then and the feeling was the 101's suited my dad a lot better. Anyway these ones i've bought are overall in great condition, the cabinets apart from the baffle are almost perfect with only the slightest marks to the bottom corners where they've been bumped by a hoover, unfortunately someone over the years has decided to port them so there's a 4cm hole in each of the baffles, luckily though on this model the baffle is screwed into position so i'll be able to remove it and use it as a template to create new ones.

More troubling though as i want to return them to as an original state as possible, is the fact that someone in the past has removed the peak cut off and LED light circuit, the rotary knobs are still there as is part of the rotary selector switch so unless like me you take the back off or turn the LED'S on you wouldn't know there was an issue, anyway getting replacement circuit boards will be all but impossible, i've spoken to KEF who would have loved to help but the designs for these speakers were lost when the factory was flooded in 2013, so i'm hoping that someone who reads this either has the board or at least a schematic of what i'm looking for.

Over to you....

[Barry]

Crossover network:

https://www.audiosciencereview.com/forum/index.php?attachments/105-crossover-jpg.142305/

Dividing Network: 4th order Linkwitz-Riley band pass -6 dB at crossover points
Dividing Frequencies: 400 & 2,500 Hz

This crossover circuit may have been later simplified, as shown below.

Some photos of the crossover neworks:

https://theartofsound.net/forum/attachment.php?attachmentid=22996&d=1521202329

https://theartofsound.net/forum/attachment.php?attachmentid=22997&d=1521202377

with crossover networks:

https://theartofsound.net/forum/attachment.php?attachmentid=23043&d=1521398713

https://theartofsound.net/forum/attachment.php?attachmentid=23044&d=1521398925


I have found yet a third crossover network, which is similar to the above but with small changes to the component values.

https://www.diyaudio.com/community/attachments/filterpl301-jpg.478537/


Sadly I can find no information about the protection circuit/LEDs/rotary switch.

Hope some of this helps.

[Jac Hawk]

Thanks for that Barry, the crossover network is still the original as in your photo, it’s the separate circuit above the crossover I’m interested in

[VanDerGraaf]

Hi Jac,

I can lend you a full led circuit board to copy, but I would need it back when you are finished.

I saw those 105s on ebay- i can't believe someone cut a home-made port.
It's not as kf bass is lacking with these!

[Jac Hawk]

Hi Jac,

I can lend you a full led circuit board to copy, but I would need it back when you are finished.

I saw those 105s on ebay- i can't believe someone cut a home-made port.
It's not as kf bass is lacking with these!

Hi Rohan, thank's for the offer, tbh Probably only need a good quality photo of the front and back, with component values and overall size of the board, from there i can get a board made.

Yeh the guy i got them off told me they really didn't need to be ported and blocked the holes up shortly after he got them, i'll be getting new baffles made, the cabinets themselves are in very good condition, so i'll probably just give them a good clean, maybe a very light sand and a coat of satin varnish and get a new piece of foam that sits on the top, i'm told the foam helped with the sound, personally i can't see it making a massive difference but I want to get them back to as original as possible.

The guy i got them off told me they have been in daily use for the last 20 - 30 years and they sound very nice indeed, i'll check the caps and if they've drifted out of range look to do a falcon recap.

[VanDerGraaf]

I did forget to say, the only issue will be that you'd have to wait until I find it before I can send it!

[Jac Hawk]

I did forget to say, the only issue will be that you'd have to wait until I find it before I can send it!

i think a lot of folks took em out

[VanDerGraaf]

Update on this, I still haven't located it. It's because we've just moved. I will let you know when it turns up!

[Qwin]

Some pictures here that might help Mike.
https://theartofsound.net/forum/showthread.php?67279-Kef-105-%28mk1%29-restore