KEF 104.2 Overhaul Parts

[vic2020]

I'm finally getting around to overhauling my 32 Year old KEF 104.2 reference speakers. I have had these since new and have been unable to find a good replacement for them that does not cost silly money!


Anyway I need to have the woofer surrounds and donuts replaced. I could do this myself or I could get a company to do it. If I do this myself where is the best place in the UK to buy the correct parts? If I get someone else to do it - who should I use? Only looking for companies based in the UK. Thanks

 

[GD70]

Falcon in the UK for the crossover caps. The center doughnuts off epay. I just restored a set for a client a couple months ago, and the woofers have rubber surrounds, not foam. Are you sure they are not rubber?
Can you post pics if possible? Very cool you’re the original owner. Really excellent sounding speakers.

Another known issue is the Ferrofluid drying up in the tweeter VCs, which reduces their output. There some excellent video showing the process. The set I worked on ended up needing the tweeters replaced. The Ferrofluid was so sticky and hard I was unable to lift the dome and coil in one piece, so be very careful if you decide to remove and replace the fluid.

Link to resto thread.
https://audiokarma.org/forums/index.php?threads/kef-104-2-restoration-and-pics.955030/

Cheers, Glenn

 

[vic2020]

Falcon in the UK for the crossover caps. The center doughnuts off epay. I just restored a set for a client a couple months ago, and the woofers have rubber surrounds, not foam. Are you sure they are not rubber?
Can you post pics if possible? Very cool you’re the original owner. Really excellent sounding speakers.

Another known issue is the Ferrofluid drying up in the tweeter VCs, which reduces their output. There some excellent video showing the process. The set I worked on ended up needing the tweeters replaced. The Ferrofluid was so sticky and hard I was unable to lift the dome and coil in one piece, so be very careful if you decide to remove and replace the fluid.

Link to resto thread.
https://audiokarma.org/forums/index.php?threads/kef-104-2-restoration-and-pics.955030/

Cheers, Glenn

I haven't got the woofers out yet, but yes definitely it looks like foam surround - I think later units had rubber surrounds. I do have a brand new pair of tweeters that I bought from KEF in 2004 but have never fitted - however these may also have dried up now but will investigate all. KEF are only 20 minutes down the road from where I live but unfortunately they do not offer any service or parts for the 104/2 anymore. I had been toying with replaing them with a set of KEF R3 as I dont really need such a large speaker as the 104/2 anymore (I now have neighbours) but the R3 on a stand is not really taking up any less space, and I think I would need to go a lot further than an R3 to better the 104/2. All of that said any thoughts on how I can make the exterior look 'as good as new' there are a few minor scuffs and scrapes - I was thinking a very light sand down with 200 / 300 grit paper - taking care not to go through the veneer, clean up, followed by a few coats of some kind of matt finish spray on laquer - lightly sanding in between.

What's special about the falcon caps? I work in electronic design so can readily source pretty much any component. How would there caps differ from any other high quality cap of the same value?

 

[Lou G]

The earlier 104/2s have rubber surrounds. The later bi-wire models have foam surrounds.

The newer KEF speakers with their aluminum dome tweeters and aluminum drivers have a very different sonic signature compared to the 104/2. If you are considering them, make sure you can audition them before making a purchase.

 

[rickb119]

any thoughts on how I can make the exterior look 'as good as new' there are a few minor scuffs and scrapes

This works great, and can be found on Amazon. https://www.howardproducts.com/product/restor-a-finish/ I used it on a couple of receivers and was amazed with the results. It's often recommended here (on AK). I would NOT use lacquer on these.

What's special about the falcon caps? I work in electronic design so can readily source pretty much any component. How would there caps differ from any other high quality cap of the same value?

As long as you stick with NPE's, you should be fine. Replacing the existing NPE's with film will alter the sound.

 

[vic2020]

Mine are definetly not bi-wire but they do have foam surrounds... Do people generaly prefer the newer sound or the older sound - When audioning the 104/2 i was totally blown away by them - I was working as a sound engineer back them and using some very high end stuff in the studio and the KEFs were easily as good as the big PMCs (al

This works great, and can be found on Amazon. https://www.howardproducts.com/product/restor-a-finish/ I used it on a couple of receivers and was amazed with the results. It's often recommended here (on AK). I would NOT use lacquer on these.

As long as you stick with NPE's, you should be fine. Replacing the existing NPE's with film will alter the sound.

When I spoke with KEF back in the early 2000s they said all of their finishes would have been sprayed with a clear coat polyureathane laquer - similar to car a paint. Restor a finsish says it will have little effect on hard polyureathane finishes. What I am looking for is to get it back to exactly the finish it left the factory with.

 

[rickb119]

When I spoke with KEF back in the early 2000s they said all of their finishes would have been sprayed with a clear coat polyureathane laquer - similar to car a paint. Restor a finsish says it will have little effect on hard polyureathane finishes. What I am looking for is to get it back to exactly the finish it left the factory with.

Good to know, in case I ever decide to refinish mine.

 

[GD70]

I haven't got the woofers out yet, but yes definitely it looks like foam surround - I think later units had rubber surrounds. I do have a brand new pair of tweeters that I bought from KEF in 2004 but have never fitted - however these may also have dried up now but will investigate all. KEF are only 20 minutes down the road from where I live but unfortunately they do not offer any service or parts for the 104/2 anymore. I had been toying with replaing them with a set of KEF R3 as I dont really need such a large speaker as the 104/2 anymore (I now have neighbours) but the R3 on a stand is not really taking up any less space, and I think I would need to go a lot further than an R3 to better the 104/2. All of that said any thoughts on how I can make the exterior look 'as good as new' there are a few minor scuffs and scrapes - I was thinking a very light sand down with 200 / 300 grit paper - taking care not to go through the veneer, clean up, followed by a few coats of some kind of matt finish spray on laquer - lightly sanding in between.

What's special about the falcon caps? I work in electronic design so can readily source pretty much any component. How would there caps differ from any other high quality cap of the same value?

The cap kit from Falcon matches pretty much exactly the original spec caps to not alter the original sound at all. if you need to replace the woofer surrounds, shim the VCs. Glue the surround to the cone first, let dry, then to the basket. Then replace the doughnut dust caps.

 

[leesonic]

I just worked on a pair of these for a fellow AKer.

https://audiokarma.org/forums/index.php?threads/kef-104-2-restoration-and-crossover-recap.613028/

You could use the kit from Falcon in the UK, or you could source caps here from someone like Erse Audio. The tweeters will probably need ferrofluid replaced, and if the surrounds and doughnuts need replacing, you can source parts here.

Lee.

 

[Lou G]

Mine are definetly not bi-wire but they do have foam surrounds... Do people generaly prefer the newer sound or the older sound - When audioning the 104/2 i was totally blown away by them - I was working as a sound engineer back them and using some very high end stuff in the studio and the KEFs were easily as good as the big PMCs (al.

Interesting, I have never seen a non bi-wire version with foam surrounds.

I prefer the old school (pre 2000) KEF sound. The latest KEF speakers do have better detail and clarity compared to my 104/2s but do not sound as smooth and rich as the 104/2s.

When I spoke with KEF back in the early 2000s they said all of their finishes would have been sprayed with a clear coat polyureathane laquer - similar to car a paint. Restor a finsish says it will have little effect on hard polyureathane finishes. What I am looking for is to get it back to exactly the finish it left the factory with.

Important to know if it was polyurethane or lacquer. Polyurethanes and lacquers are two very different coatings.

Clear Coat Polyurethanes are an actual polymer that undergo a chemical reaction (crosslinking) during curing. The crosslinking makes it a very durable finish.

Furniture Lacquers are resin based solutions that do not undergo any chemical reactions but form films by solvent evaporation. Nitrocellulose is a typical resin used in lacquers. Ketones or esters are typical active solvents for this resin. Alcohols are typical latent solvents.

Polyurethanes produce much thicker coatings compared to lacquers. Lacquers are thin and actually penetrate the wood surface.

Nitrocellulose is the most common lacquer resin, but newer lacquers have been developed over the years. Two of these newer lacquers are acrylic lacquers (typically made with cellulose acetate butyrate and acrylic resins) and catalyzed lacquers which are hybrid reactive finishes that cure chemically, not solely through solvent evaporation. The chemical cure is initiated with an acid catalyst. Catalyzed lacquers contain some nitrocellulose resins, and also urea resins which makes them more durable.

 

[vic2020]

Interesting, I have never seen a non bi-wire version with foam surrounds.

I prefer the old school (pre 2000) KEF sound. The latest KEF speakers do have better detail and clarity compared to my 104/2s but do not sound as smooth and rich as the 104/2s.



Important to know if it was polyurethane or lacquer. Polyurethanes and lacquers are two very different coatings.

Clear Coat Polyurethanes are an actual polymer that undergo a chemical reaction (crosslinking) during curing. The crosslinking makes it a very durable finish.

Furniture Lacquers are resin based solutions that do not undergo any chemical reactions but form films by solvent evaporation. Nitrocellulose is a typical resin used in lacquers. Ketones or esters are typical active solvents for this resin. Alcohols are typical latent solvents.

Polyurethanes produce much thicker coatings compared to lacquers. Lacquers are thin and actually penetrate the wood surface.

Nitrocellulose is the most common lacquer resin, but newer lacquers have been developed over the years. Two of these newer lacquers are acrylic lacquers (typically made with cellulose acetate butyrate and acrylic resins) and catalyzed lacquers which are hybrid reactive finishes that cure chemically, not solely through solvent evaporation. The chemical cure is initiated with an acid catalyst. Catalyzed lacquers contain some nitrocellulose resins, and also urea resins which makes them more durable.

Well it was a long time ago now so I could be remember it incorrectly howver they definetly compared it to car spraying, and I recall asking a guy I knew at the time who did car paint if he could do it.

 

[Lou G]

It is important to know what the original finish is if you don't completely remove it. If the original finish is lacquer and you apply a polyurethane spray over it, the adhesion will be poor and may result in peeling or flaking. If the original finish is polyurethane and you apply a lacquer spray, the solvents in the lacquer can attack the polyurethane and cause a blotchy finish.

You should be ok if you completely remove the original finish. If you go with a polyurethane spray, you want to lightly sand with 320 grit between coats. With a lacquer spray you do not need to sand between coats because the solvent in each successive coat dissolves the surface of the underlying layer and provides good intermixing.