Kef Reference two, crossover upgrade...possible?

[bramdo]

Dear all,

thank you for taking the time to read my first post.
I do own a kef reference system that I could purchase years ago at a bargain price. The front speakers do consist of the kef reference two from the 90's: Here you will find kef ref 2 specs .

Over the years the levels of detail are decreasing and due to budget limitations (two kids, that helps ) I would like to follow the advice of some people to upgrade the crossovers .
Some sources mention in particular that an upgrade to polyprop capacitors will do some good.

Now, I have quite some friends who can solder and know something of electronics but this is the crossover so where do we start

An externally hosted image should be here but it was not working when we last tested it.

thank to all of you with any advice
Bram

 

[richie00boy]

Basically aim to replace all the electrolytic capacitors (round tubular shaped ones) with non-electrolytic such as polypropylene. The downside to this is they will be many times bigger than the electrolytics if you can even get them in the right capacitance at all.

Are you sure the decrease in details is not your hearing getting old

 

[AMV8]

Hi

I own a number of Kef systems incling the ref 2.

I have contacted Kef in the past and have made a number of changes ( improvements ) to mine.

Cabinet. All the Kef later systems stregthen the cabinet to improve the mid range by removing movement - of the front and back panels particularly. Kef now bond the front and back rigidly together. I have achieved this by placing a LOT of struts within the enclosure.

Cabinet seams. I have reglued all the edge and corner seams and added filets inside to strengthen the seams.

Crossover. The crossovers are computer matched by Kef for the speakers in the cabinet so it is difficult to change the component types without making other changes. For example the crossover design takes account of the resistence of the biaxial electrolytic capacitor. Therefore if you change the capacitors from biaxial electrolytics to plastic you will need to add resistors in series with the plastic capacitors to retain the same resistence. I have changed all capacitors since the elecrolytics do not really last much over 10 years. However I have retained good quality electrolytics except in the treble series cinnections. Here I have added a series resistor of 1R for each 10uf oc capacitence. This ensures that the original resistence is retained and therefore retains the original crossover slopes.

I hope this helps
Don

 

[bramdo]

wow....thanks

First of all, thanks for the replies and don't worry for my poor hearing...I still hear all te details of the 'conversations' with my younger babygirl

Don, Great tips and i'm very curious if you noticed any differences in sound since the work and research you have invested must have been tremendous.

I will take your explanation to a friend of mine and i hope he can start with the work on the crossover soon. Because i'm real new in this diy hobby , but eager to learn, I 'm more than happy with all the help and guidelines I can get.

thanks from Belgium
Bram

 

[rchua77]

Hi guys,

Sorry to threadjack the thread. Does anyone know the surround material of the drives in the KEF reference 2 (1st series)?

I've got a chance to purchase a pair but I'd had some bad experiences with foam surrounds. I'd like to know what material the Uni-Q and woofer surrounds are made of.

Thanks!!