KEF 103.2 rebuild

[Eppie]

First cab done. I bleached out the water stains back to bare wood colour but any oil or finish went dark all over again, so best I can do without replacing the veneer. Little more teak oil and then several coats of paste wax to bring out a little more shine. With the grills on and lights turned lower the staining is actually not that noticeable. Pretty satisfied with the result.

 

[Mark E. Long]

First cab done. I bleached out the water stains back to bare wood colour but any oil or finish went dark all over again, so best I can do without replacing the veneer. Little more teak oil and then several coats of paste wax to bring out a little more shine. With the grills on and lights turned lower the staining is actually not that noticeable. Pretty satisfied with the result.
View attachment 49632

I like it it looks really good !

 

[Eppie]

I like it it looks really good !

Thanks. The staining looks so much worse in that photo. I should have used more subdued lighting. Hopefully I'll be able to manage a picture of the pair on stands when done.

 

[Eppie]

Second cab went much faster. Repaired 6 out of 8 corners, a couple needing veneer patches. Dents were removed by laying a damp cloth over the dent and applying steam with a clothes iron. Then sanding smooth and restaining.

Patches applied, stained and oiled. Both speakers have gaskets for an air tight seal.

And a fresh coat of paint on the bottoms.

These should be ready for testing in a couple days when the paint has fully cured.

 

[Eppie]

Paint was dry enough after 2 days. Coat of wax on the bottom for protection and all set for testing. Hope to drive these out east for my daughter in a couple of weeks. One thing about these Kefs. Worst binding posts ever. Took 10 minutes to keep the wires from sliding off. Need to make her some cables with banana plugs. At least they look pretty now.

 

[Mark E. Long]

Paint was dry enough after 2 days. Coat of wax on the bottom for protection and all set for testing. Hope to drive these out east for my daughter in a couple of weeks. One thing about these Kefs. Worst binding posts ever. Took 10 minutes to keep the wires from sliding off. Need to make her some cables with banana plugs. At least they look pretty now.
View attachment 49703

Sweet how they sound ?

 

[Eppie]

Sweet how they sound ?

For speakers that are about 38 years old they sound pretty damn good. I did not recalibrate with Audyssey so tried Stereo mode which used the room correction for my Paradigms with subwoofer and then Pure Direct mode to bypass all processing which sounded a lot better of course. With a full range signal (no sub) these speakers have a lot of punch. They are bigger than my Paradigms and the extra cabinet volume and larger woofer produce satisfying bass.

I would describe them as being on the warm side with a rich bottom end. The soft dome tweeter compared to my Paradigms lacks brightness, so at first listen they sounded lacking in the higher frequencies. This diminished with extended listening so I think I needed to retrain my hearing as I am so used to the Paradigms. Over time the KEFs sounded more balanced. The highs were there but a little muted compared to my other speakers. This makes them very easy on the ears though and leads to little ear fatigue. I could listen to these for hours.

I installed an SPL meter app and ran the speakers up to an 87dB average. NRC web site says that's safe for only about two hours of listening. I noticed no degradation in sound and they actually seemed to perform better when I gave them a good dose of power. If my daughter does not use these I would be happy to hang on to them. This would have been a great speaker in the '80s.

I have a pair of Electrovoice Interface 1 Series II speakers from the 80's (like below) that I purchased new. They need new foam surrounds on the woofers and tweeters to get them working. They use EVs Superdome tweeter and employ some of Neville Thiele's research in the design so would make an interesting comparison.

 

[Mark E. Long]

For speakers that are about 38 years old they sound pretty damn good. I did not recalibrate with Audyssey so tried Stereo mode which used the room correction for my Paradigms with subwoofer and then Pure Direct mode to bypass all processing which sounded a lot better of course. With a full range signal (no sub) these speakers have a lot of punch. They are bigger than my Paradigms and the extra cabinet volume and larger woofer produce satisfying bass.

I would describe them as being on the warm side with a rich bottom end. The soft dome tweeter compared to my Paradigms lacks brightness, so at first listen they sounded lacking in the higher frequencies. This diminished with extended listening so I think I needed to retrain my hearing as I am so used to the Paradigms. Over time the KEFs sounded more balanced. The highs were there but a little muted compared to my other speakers. This makes them very easy on the ears though and leads to little ear fatigue. I could listen to these for hours.

I installed an SPL meter app and ran the speakers up to an 87dB average. NRC web site says that's safe for only about two hours of listening. I noticed no degradation in sound and they actually seemed to perform better when I gave them a good dose of power. If my daughter does not use these I would be happy to hang on to them. This would have been a great speaker in the '80s.

I have a pair of Electrovoice Interface 1 Series II speakers from the 80's (like below) that I purchased new. They need new foam surrounds on the woofers and tweeters to get them working. They use EVs Superdome tweeter and employ some of Neville Thiele's research in the design so would make an interesting comparison.

Some times I do like a speaker with a somewhat muted high end . I’ve had jbl’s most of my life an older series I’ve used like l-26 up to l-100’s kind of have that sound kind of a restrained high end but if you would push them it was there that they really stood out . It might be my imagination but I .think most high caliber speakers from that era were built that way they all liked power .
My setup now is all jbl mostly pro based drivers in the cabs they can take a lot of power and I run a lot of power but they can tire your ears out at high levels. Most of my music listening is at the -35 level on the Yamaha avr and it’s great I’ve not put a meter on it to see what db levels Iam getting there but sometimes it gets to loud for conversation.
To me it seems to have more detail at lower levels or mabey I’ve got to many speakers at different angles surrounding me lol , what am I thinking you can’t have to many speakers ;-)

 

[Eppie]

Some times I do like a speaker with a somewhat muted high end . I’ve had jbl’s most of my life an older series I’ve used like l-26 up to l-100’s kind of have that sound kind of a restrained high end but if you would push them it was there that they really stood out . It might be my imagination but I .think most high caliber speakers from that era were built that way they all liked power .
My setup now is all jbl mostly pro based drivers in the cabs they can take a lot of power and I run a lot of power but they can tire your ears out at high levels. Most of my music listening is at the -35 level on the Yamaha avr and it’s great I’ve not put a meter on it to see what db levels I am getting there but sometimes it gets to loud for conversation.
To me it seems to have more detail at lower levels or maybe I’ve got to many speakers at different angles surrounding me lol , what am I thinking you can’t have to many speakers ;-)

Yes, some of the detail in the recordings seems to become more apparent at higher SPL levels. Not sure if that's by design or just a matter of approaching the level of live sound. I think I was at around -10 dB on my Denon with 115W/ch. Definitely too loud for conversations but it sounded sweet. My speaker collection is growing. After fixing the EVs I also have some Wharfdale picture frame panel speakers. Would like to try them as surrounds.

 

[Mark E. Long]

Yes, some of the detail in the recordings seems to become more apparent at higher SPL levels. Not sure if that's by design or just a matter of approaching the level of live sound. I think I was at around -10 dB on my Denon with 115W/ch. Definitely too loud for conversations but it sounded sweet. My speaker collection is growing. After fixing the EVs I also have some Wharfdale picture frame panel speakers. Would like to try them as surrounds.

The wharfdales would be interesting for sure I remember seeing a review on those a long time ago . They used to be a big player in the speaker game I don’t see much anymore although I have to admit I don’t look for many these days .
I think the age and quality of the recordings have a lot to do how they sound too older engineers mixed things differently and it wasn’t always for good home sound , mixed for radio I’d say .

 

[Eppie]

Wharfedale has some very nice speakers with their EVO line. They are employing AMT tweeters in the new designs. Haven't had a chance to hear any yet. The picture frame speakers I have originally came bundled with a small subwoofer. I tried them out and the sound was better than expected, but I would not use them for mains. I think they would be ok for surrounds. You can actually print a photograph on light weight paper and use a low tack adhesive to glue it to the front and it's not supposed to affect the sound.

I have a few artists that I prefer for testing speakers. Thomas Dolby has some very good sounding recordings with tight bass and drums and nice clear vocals. Uses a lot of synth as well and mixes in brass. Falls more in the vein of alternative music but most of my musician friends like his stuff as well. Bryan Ferry's recordings like Boys and Girls and Avalon sounds very nice too. Another is Crowded House. Their arrangements are not too complex so tracks where the drummer uses brushes are a good test and the vocals are very good too. I would add Steely Dan and Dire Straights to the list.

I know there are some great sounding jazz recordings but my collection is lacking in that regard. Dianna Krall has some great albums. I have a number of classical CDs and LPs but my room and system are not well suited to reproducing concert hall performances. Something I hope to work towards later.

 

[Eppie]

Interesting write up on these speakers. They mention increased output from 80-150 Hz which confirms my impressions above. Gratifying to know that my listening impressions match the measurements. Very well constructed in that both drivers are matched to each other, the crossover components are matched to the drivers and both speakers are matched to each other and sold as pairs. They retailed at $900 in 1984 which would be over $2,000 in today's dollars. I think they were well worth restoring.
http://www.hifi-classic.net/review/kef-model-103-2-327.html

 

[TLS Guy]

Interesting write up on these speakers. They mention increased output from 80-150 Hz which confirms my impressions above. Gratifying to know that my listening impressions match the measurements. Very well constructed in that both drivers are matched to each other, the crossover components are matched to the drivers and both speakers are matched to each other and sold as pairs. They retailed at $900 in 1984 which would be over $2,000 in today's dollars. I think they were well worth restoring.
http://www.hifi-classic.net/review/kef-model-103-2-327.html

I'm not surprised you like them. They were designed and manufactured before Raymond Cooke's untimely death. The KEF factory at Tovil, on the banks of the river Medway just outside Maidstone, produced some of the finest speakers in the world back then. Their tonal balance, like most decent UK speakers of that era, were strongly influenced by the balance favored by BBC engineering. Raymond Cooke with Peter Walker of Quad were the designers and builders of the active BBC active transmission line monitors. Jim Rogers and John Wright of TDL were also involved. Those speakers were considered for many years the finest and most accurate speakers on the planet. In the last few months four of the power amp modules that powered those speakers have come into my possession. Unfortunately one of the modules produces a sawtooth wave instead of a sine wave. I have some parts on the way from Europe, and hope to have that board restored. I think I know the problem. Those speakers had a major and overarching impact on the design of my right and left TL speakers.

Anyhow your speakers were produced at the dawn of the CD. The first CDs being released that year. So those speakers were designed in the LP era and the last thing you wanted in a speaker was HF excess and a forward character. So those speakers, if error they have, will be on the laid back side rather then the reverse.

Really the onset of digital media was a watershed moment for those of us designing speakers. It caused a back to first principles moment for all of us. Computer programs became increasingly prevalent, at least in the UK and then the US that year. That was the first year I used computer assistance in box and crossover design.

The digital age brought master tape quality to the home, with full power bandwidth throughout the audio spectrum, with no need for any dynamic compression.
This all occurred along with the further development of much more powerful solid state amps. So there really did demand significant changes in design approach.

 

[Eppie]

I'm not surprised you like them. They were designed and manufactured before Raymond Cooke's untimely death. The KEF factory at Tovil, on the banks of the river Medway just outside Maidstone, produced some of the finest speakers in the world back then. Their tonal balance, like most decent UK speakers of that era, were strongly influenced by the balance favored by BBC engineering. Raymond Cooke with Peter Walker of Quad were the designers and builders of the active BBC active transmission line monitors. Jim Rogers and John Wright of TDL were also involved. Those speakers were considered for many years the finest and most accurate speakers on the planet. In the last few months four of the power amp modules that powered those speakers have come into my possession. Unfortunately one of the modules produces a sawtooth wave instead of a sine wave. I have some parts on the way from Europe, and hope to have that board restored. I think I know the problem. Those speakers had a major and overarching impact on the design of my right and left TL speakers.

Anyhow your speakers were produced at the dawn of the CD. The first CDs being released that year. So those speakers were designed in the LP era and the last thing you wanted in a speaker was HF excess and a forward character. So those speakers, if error they have, will be on the laid back side rather then the reverse.

Really the onset of digital media was a watershed moment for those of us designing speakers. It caused a back to first principles moment for all of us. Computer programs became increasingly prevalent, at least in the UK and then the US that year. That was the first year I used computer assistance in box and crossover design.

The digital age brought master tape quality to the home, with full power bandwidth throughout the audio spectrum, with no need for any dynamic compression.
This all occurred along with the further development of much more powerful solid state amps. So there really did demand significant changes in design approach.

Thanks very much, I really appreciate your insights into these speakers. I can't help but wonder how much of what I hear is personal bias, so it is reassuring to know that the slightly pronounced bottom end and slightly muted highs that I am hearing are supported by the hifi-classic article and your own personal knowledge of these speakers. After your nice response I am almost reluctant to let these go.

For a while I was concerned that age had affected the crossovers, but they appear to be in pristine condition. It's reassuring to know that the laid back character of the highs is characteristic of this model. Hopefully the Bextrene cones still have a few years left in them and my repair will prevent any further delamination of the one cone. I have some stands on order and plan to take these out east for my daughter. They live in an apartment so I don't expect her to drive them too hard. They also have a cat and with wood veneer I need to get these up off the floor so that my hard work does not result in an expensive scratching post!

I was surprised to find the polarity wrong on one of the speaker's internal binding posts (the one with the crappy solder job). They would have been out of phase. Can't help but wonder if someone else had been poking around in there years ago. I doubt that QC at KEF would have allowed these to ship like that. I double checked the polarity with some listening tests and they're all good now. I'm rather tempted to hook them up again and rerun Audyssey on my AVR just to see how they sound with some room EQ. Would have been nice to compare these to my Electrovoice Interface 1 speakers from around the same era but I need to order some refoam kits from NY to gets those operational. Probably give those to my son.

 

[Eppie]

The KEFs in their new home. Got her a pair of 23" VIVO premium stands. Glass top and glass base plate. The bottom plate is nice and thick and heavy. Top plate is little thinner. Comes with metal spikes and rubber feet. The metal for the tube is on the thin side but there is a steel rod down the centre to hold the plates together and reinforce it. Best for medium or light weight speakers. For heavy bookshelves I would recommend something a little more heavy duty. They do look quite nice though.

 

[Mark Caudill]

I have a pair of pristine 103.2 Kefs. Well, they used to be pristine until I over drove them. On one speaker the protection light came on and the woofer stopped working. The other one works fine. I felt terrible. Fast forward 9 months to now. I finally decided to determine if it's the driver or the protection circuit. NOW with music playing, the same woofer still doesn't work but the protection circuit light is off. I planned to swap the woofers or just apply a bit of signal to the silent one. How the heck do the woofers come out? Removing the 3 bolts doesn't do it. I've tried a few things and they just don't want to come out. HELP!!!

 

[TLS Guy]

I have a pair of pristine 103.2 Kefs. Well, they used to be pristine until I over drove them. On one speaker the protection light came on and the woofer stopped working. The other one works fine. I felt terrible. Fast forward 9 months to now. I finally decided to determine if it's the driver or the protection circuit. NOW with music playing, the same woofer still doesn't work but the protection circuit light is off. I planned to swap the woofers or just apply a bit of signal to the silent one. How the heck do the woofers come out? Removing the 3 bolts doesn't do it. I've tried a few things and they just don't want to come out. HELP!!!

The driver is front loaded and will come out. The gasket has turned to glue. You will have to use controlled brute force. The best bet is to get two flat blades, placed opposite each other and lever the driver out. This may take quite a bit of force, and you may do a little cosmetic damage. It would also be a good idea to give some taps round the edge of with woofer with a soft impact hammer, prior to levering the driver out.

Most likely the protection circuit has failed. Your clue will be a couple of leaked caps. What most do is to remove the protection circuit. You don't want to dive those speakers hard anyway at that age. The cones of those drivers are well known for cracking as they age, and then you will be out of luck.

Marantz DV 9600 Oppo BD-83 Marantz AV 8003 Quad current dumping amps X 7 Direct TV HD 20 HD DVR Carter audio workstation RME Fireface 800 Fujitsu 50XHA40 Front left and right Carter dual transmission line studio monitors MK II. Center Carter coaxial transmission line center speaker Rear Carter NFM-1s Center backs Carter dual transmission line studio monitors MK I.
My System: http://mdcarter.smugmug.com/gallery/2424008_RKGvb#127077317_Pufg7

 

[Eppie]

I have a pair of pristine 103.2 Kefs. Well, they used to be pristine until I over drove them. On one speaker the protection light came on and the woofer stopped working. The other one works fine. I felt terrible. Fast forward 9 months to now. I finally decided to determine if it's the driver or the protection circuit. NOW with music playing, the same woofer still doesn't work but the protection circuit light is off. I planned to swap the woofers or just apply a bit of signal to the silent one. How the heck do the woofers come out? Removing the 3 bolts doesn't do it. I've tried a few things and they just don't want to come out. HELP!!!

You can see from my photos above that there is gasket underneath the woofer and tweeter as this is a sealed design. As TLS Guy stated, the woofer is likely stuck to the gasket. Before prying up on the woofer from the edge and possibly damaging the cabinet, I would insert a rod into the screw hole location and apply lateral force to break the speaker rim free, or use a wooden dowel or screw driver against the side of the screw hole and tap it with a hammer. If that won't break it free then you'll need to pry up from under the rim, but try and protect the wooden edge as best you can.

Hopefully just the protection circuit is defective and the woofer is ok. I never managed to light the LED up but those speakers are 39 years old now after all. The crossover is located on the bottom of the cabinet and secured with 4 nuts, one in each corner, so easiest to remove with a tall slim socket. The protection circuitry is located around the relay, which might be stuck closed. Most parts are serviceable except for the grey ceramic module labeled Mod1. If that's gone then you'll likely have to bypass the protection circuit. I don't have schematic but hopefully there's one available.

 

[highfigh]

The KEFs in their new home. Got her a pair of 23" VIVO premium stands. Glass top and glass base plate. The bottom plate is nice and thick and heavy. Top plate is little thinner. Comes with metal spikes and rubber feet. The metal for the tube is on the thin side but there is a steel rod down the centre to hold the plates together and reinforce it. Best for medium or light weight speakers. For heavy bookshelves I would recommend something a little more heavy duty. They do look quite nice though.

I didn't see this thread until a few minutes ago, but I have to comment on "crappy binding posts". Those are absolutely fine and are easy enough to use, as you know how- a hex socket will fit onto the red and black nuts, so that's no big deal. They were also made to accept banana pugs that were paired in a piece of plastic so the wires could be connected in one motion, rather than using all metal plugs that can touch. They're still available in that configuration and until the marketing BS storm of the '80s, this type (not the ones in the photo) were the standard unless they were used to connect equipment that didn't have pairs.

 

[highfigh]

I have a pair of pristine 103.2 Kefs. Well, they used to be pristine until I over drove them. On one speaker the protection light came on and the woofer stopped working. The other one works fine. I felt terrible. Fast forward 9 months to now. I finally decided to determine if it's the driver or the protection circuit. NOW with music playing, the same woofer still doesn't work but the protection circuit light is off. I planned to swap the woofers or just apply a bit of signal to the silent one. How the heck do the woofers come out? Removing the 3 bolts doesn't do it. I've tried a few things and they just don't want to come out. HELP!!!

Buy a good set of pick tools. Insert the L-shaped one into the gap between the woofer frame and cabinet, then turn the tip toward the flange once it reaches the bottom. Work it around the woofer's circumference and eventually, it will release.