Rebuilt Kef Codas

[Martyn Miles]

I have just built up a pair of Kef Codas for my eldest son, using cabinets and crossovers I found on the Internet.
A pair of B110s and T27s were acquired, the '110s costing only £40 for the pair. They are now up and running and I am surprised how good they sound. Using a Quad 34, with its comprehensive tone shaping controls, I achieved an excellent balance. The bass end is fairly light with the tone controls flat, but using the Quad controls I achieved an acceptable boost with no overhang.
Overall, a very good result.

[walpurgis]

Martyn, glad you like them. I had a couple of pairs of these and although they sounded OK, I thought the crossover (DN12?) was the weakest link. The drive units will do better with something a bit more advanced (modern?).

[Martyn Miles]

Martyn, glad you like them. I had a couple of pairs of these and although they sounded OK, I thought the crossover (DN12?) was the weakest link. The drive units will do better with something a bit more advanced (modern?).

The crossover is the Kef DN13/SP1035. I don't know of an upgraded crossover which suits the Kef B110 & T27 combination, but I wouldn't be surprised if somebody makes one.
Perhaps Falcon Acoustics make them. They do have a lot of replacement crossovers for sale.

[walpurgis]

I'm sure it would be well worth investigating. Basically, you have the ingredients for something approaching the LS3/5a, but the crossover is I'm sure holding things back a bit. I found the mid resolution on the Coda held back a bit and there was a 'busy' character, maybe caused by intermodulation due to the shallow crossover slopes. Somebody on AOS should have some experience with these drivers. As you say Falcon may be able to help. They are bound to have experience of crossovers for the B110/T27 pairing.

[walpurgis]

I don't know if this is suitable. But it may be. Doesn't quote impedance.

http://www.falconacoustics.co.uk/crossovers-ls35a-networks-filters-falcon/kef-1010-cs1-kef-b110-sp1057-t27-ab-crossover-network.html

[spendorman]

I don't know if this is suitable. But it may be. Doesn't quote impedance.

http://www.falconacoustics.co.uk/crossovers-ls35a-networks-filters-falcon/kef-1010-cs1-kef-b110-sp1057-t27-ab-crossover-network.html
Really the CS1a is better, it's for the B110 SP1003.

Don't see it listed now, but I bet they can do it.

[Martyn Miles]

I don't know if this is suitable. But it may be. Doesn't quote impedance.

http://www.falconacoustics.co.uk/crossovers-ls35a-networks-filters-falcon/kef-1010-cs1-kef-b110-sp1057-t27-ab-crossover-network.html

Thanks.
I looked at this Falcon crossover, but it is rather on the expensive side.

[spendorman]

KEF CS1a crossover for B110 SP1003 and T27 SP1032

http://www.hifiloudspeakers.info/Ana...A/KefCross.gif

That Martyn has older T27's won't make much difference.

[walpurgis]

Just spotted these Martyn. Could be fun putting a pair together.

http://www.ebay.co.uk/itm/pair-2pc-Rogers-KEF-loudspeaker-LS3-5A-Crossover-bare-PCB-15ohm-version-/191278013041?pt=UK_Sound_Vision_Valves_Vacuum_Tube s&hash=item2c890eda71

You could adjust values to suit 8 ohm.

[Martyn Miles]

Just spotted these Martyn. Could be fun putting a pair together.

http://www.ebay.co.uk/itm/pair-2pc-Rogers-KEF-loudspeaker-LS3-5A-Crossover-bare-PCB-15ohm-version-/191278013041?pt=UK_Sound_Vision_Valves_Vacuum_Tube s&hash=item2c890eda71

You could adjust values to suit 8 ohm.

Thanks, but for the moment I will stick with the SP1035 crossovers in the Codas.

I have another project on the way. I've bought an unusual pair of Rogers speakers. LS3/5a size cabinets, which have the look of the Rogers Studio 3 about them. White polypropylene bass/mid. drivers and SEAS tweeters. The tweeters are non-working, but replacements can be bought from Falcon Acoustics. The crossovers are Rogers, but not a design I have seen before. The input is by XLR, not 4mm. sockets.
New grilles will be required, so I will contact Sid Chaplin of Traditional Radio Grilles. He does a superb job.

It looks like an interesting project for the Autumn. I will report on progress here on TAOS Forum.

[Martyn Miles]

I'm sure it would be well worth investigating. Basically, you have the ingredients for something approaching the LS3/5a, but the crossover is I'm sure holding things back a bit. I found the mid resolution on the Coda held back a bit and there was a 'busy' character, maybe caused by intermodulation due to the shallow crossover slopes. Somebody on AOS should have some experience with these drivers. As you say Falcon may be able to help. They are bound to have experience of crossovers for the B110/T27 pairing.

Thanks for that. I have owned ( and built ) LS3/5as in the past, but now use Harbeth P3ESRs and an early pair of Harbeth HL Monitors.
The Codas are currently sitting on top of the HLs and I have been listening them for a few days. The HLs are smoother, with that lovely 'BBC' midrange and, of course, a deeper bass.
Currently listening to solo guitar and the reproduction is almost 'intimate' from the Codas. Reminds me a little of the LS3/5a and is a definite improvement on the original Wharfedale Diamonds. I owned a pair for years, used daily in my University Lab.
I'm really pleased with them...

[spendorman]

Thanks for that. I have owned ( and built ) LS3/5as in the past, but now use Harbeth P3ESRs and an early pair of Harbeth HL Monitors.
The Codas are currently sitting on top of the HLs and I have been listening them for a few days. The HLs are smoother, with that lovely 'BBC' midrange and, of course, a deeper bass.
Currently listening to solo guitar and the reproduction is almost 'intimate' from the Codas. Reminds me a little of the LS3/5a and is a definite improvement on the original Wharfedale Diamonds. I owned a pair for years, used daily in my University Lab.
I'm really pleased with them...

Good that you are really pleased with the Coda's. I was not that happy with them. I still feel that the CS1a crossover is likely to be a very good upgrade. It was for me. I made the crossovers from Falcon parts and the result with B110 SP1003 and T27 SP1032 was very good. In fact, not much different to my Chartwell LS3/5a's.

The CS1a crossover was computer designed by KEF as a simplified LS3/5a type crossover, not requiring the tapped inductors, so much easier to build.

[Martyn Miles]

Good that you are really pleased with the Coda's. I was not that happy with them. I still feel that the CS1a crossover is likely to be a very good upgrade. It was for me. I made the crossovers from Falcon parts and the result with B110 SP1003 and T27 SP1032 was very good. In fact, not much different to my Chartwell LS3/5a's.

The CS1a crossover was computer designed by KEF as a simplified LS3/5a type crossover, not requiring the tapped inductors, so much easier to build.

Well, you've set me thinking now...

[spendorman]

CS1 crossover was to build sort of equivalent to 11 Ohm LS3/5a

CS1a crossover was to build sort of equivalent to 15 Ohm LS3/5a

[spendorman]

I suppose an idea would be to bring the Coda tweeter and bass unit wires out of the cabinet and try different crossovers. I suppose that the most expensive might be the Cicable ones!

How much difference in sound quality between these and some CS1a crossovers, I'm not sure.

[walpurgis]

It must be possible to adjust component values to work with 8 ohm drive units. Falcon could advise on that.

[spendorman]

It must be possible to adjust component values to work with 8 ohm drive units. Falcon could advise on that.

The CS1a crossover is correct for the B110 SP1003, I believe that Martyn is using that.

It is also correct for the T27 SP1032, but I understand that Martyn is using the earlier model T27, but I think it should be fine. I suspect that Falcon may say the same, but I could be wrong.

[walpurgis]

The CS1a crossover is correct for the B110 SP1003, I believe that Martyn is using that.

It is also correct for the T27 SP1032, but I understand that Martyn is using the earlier model T27, but I think it should be fine. I suspect that Falcon may say the same, but I could be wrong.

I think that is true. When KEF revised the T27 design, as far as I recall the crossovers in their speakers remained unchanged.

[Martyn Miles]

I think that is true. When KEF revised the T27 design, as far as I recall the crossovers in their speakers remained unchanged.

Yes, I understand they stayed the same.
Thinking it over, I would like to make up some CS1a crossovers. Falcon ones are a little too expensive for me...

[spendorman]

Martyn, did you find the CS1a crossover on the Falcon site? When I looked the other day I could only see the CS1.

Anther point, but small, from memory, the CS1a data sheet suggests rear mounting the B110, as in the LS35a, the Coda B110 is front mounted, but recessed slightly into the baffle. I don't think this will make much difference.

[spendorman]

I had a hard copy of this leaflet years ago and mislaid it, just found on the internet:

http://kef.com/uploads/files/en/museum_pdf/80s/Constructor_%20Series_Model_CS1A.pdf

[Martyn Miles]

I had a hard copy of this leaflet years ago and mislaid it, just found on the internet:

http://kef.com/uploads/files/en/museum_pdf/80s/Constructor_%20Series_Model_CS1A.pdf

Thank you. Now, where is the best place to obtain the components from ? Also, can you get away without a dedicated printed circuit board ?

M Miles.

[Martyn Miles]

Martyn, did you find the CS1a crossover on the Falcon site? When I looked the other day I could only see the CS1.

Anther point, but small, from memory, the CS1a data sheet suggests rear mounting the B110, as in the LS35a, the Coda B110 is front mounted, but recessed slightly into the baffle. I don't think this will make much difference.

Sorry, missed this post. No, I only saw the CS1 . If I said earlier I had seen the '1a it was a mistake.
Martyn.

[spendorman]

Thank you. Now, where is the best place to obtain the components from ? Also, can you get away without a dedicated printed circuit board ?

M Miles.

My CS1a crossovers were a kit of parts from Falcon, and I think they used a universal board that Falcon provided. Don't think it was a dedicated board. It was years ago, will search my PC for pics of the crossovers.

[spendorman]

Well I was wrong, I got the kit of parts from Wilmslow Audio, I remember now, I had meant to order from Falcon. The pics must be about 10 years ago, and I bought the kit of parts well before that.

I suspect that Falcon may have supplied parts to Wilmslow though.

[spendorman]

Wrong again, well a bit anyway, In the literature KEF mention that the CS1 is based on the KEF Reference 101.

[Martyn Miles]

Wrong again, well a bit anyway, In the literature KEF mention that the CS1 is based on the KEF Reference 101.

Ah yes, I picked that up...

[spendorman]

But what is the 101 based on! Probably the LS3/5a

[Gordon Steadman]

But what is the 101 based on! Probably the LS3/5a

Yes, as I understand it. I remember reading that somewhere. Certainly our 101s have most of the hallmarks of the LS35As but with slightly more freedom in the bass and a slightly less smooth top end. I assume the crossovers are somewhat simpler.

We both still enjoy them very much. They are now out on computer duty as I got tired of the Diamond 7 Pros which never sounded natural enough.

[spendorman]

Yes, as I understand it. I remember reading that somewhere. Certainly our 101s have most of the hallmarks of the LS35As but with slightly more freedom in the bass and a slightly less smooth top end. I assume the crossovers are somewhat simpler.

We both still enjoy them very much. They are now out on computer duty as I got tired of the Diamond 7 Pros which never sounded natural enough.

You could put the LS3/5a perforated metal tweeter grilles over the tweeters in the 101's, this tends to tame the T27 a bit, also protects them.

Not that cheap, available from Falcon etc.

http://www.falconacoustics.co.uk/ls3-5a/falcon-ls3-5a-b110-drive-units/ls35a-tweeter-grilles-t27.html

they have some seconds too:

http://www.falconacoustics.co.uk/ls3-5a/falcon-ls3-5a-b110-drive-units/ls35a-tweeter-grilles-t27-seconds.html

On ebay too:

www.ebay.co.uk/itm/LS3-5a-T27-TWEETER-GRILLES-PAIRS-ORIGINAL-BBC-SPECIFICATION-/161143643548

[Gordon Steadman]

You could put the LS3/5a perforated metal tweeter grilles over the tweeters in the 101's, this tends to tame the T27 a bit, also protects them.

Not that cheap, available from Falcon etc.

http://www.falconacoustics.co.uk/ls3-5a/falcon-ls3-5a-b110-drive-units/ls35a-tweeter-grilles-t27.html

they have some seconds too:

http://www.falconacoustics.co.uk/ls3-5a/falcon-ls3-5a-b110-drive-units/ls35a-tweeter-grilles-t27-seconds.html

That looks interesting. Might just try those and see what they do to the 101s. Quite fancy trying the felt round the T27s too.

[spendorman]

That looks interesting. Might just try those and see what they do to the 101s. Quite fancy trying the felt round the T27s too.

Yes, that's a good idea too.

[Martyn Miles]

Yes, that's a good idea too.

Trying LS3/5a tweaks on the 101s might lead to dissatisfaction. I assume Kef decided to leave the T27 how it was for reasons of their own.
Some people prefer the 101 to the LS3/5a...

[Martyn Miles]

Good that you are really pleased with the Coda's. I was not that happy with them. I still feel that the CS1a crossover is likely to be a very good upgrade. It was for me. I made the crossovers from Falcon parts and the result with B110 SP1003 and T27 SP1032 was very good. In fact, not much different to my Chartwell LS3/5a's.

The CS1a crossover was computer designed by KEF as a simplified LS3/5a type crossover, not requiring the tapped inductors, so much easier to build.

Dear 'Spendorman',
I have decided to go for a crossover upgrade. The Falcon CS1 was my first choice, as you suggested. Then I discovered a friend, who has exactly the same Codas, is planning to use the Falcon 23 c'overs. His Codas use the SP1032, but as has been mentioned here, my earlier model T27 tweeters should not make a difference.
Any thoughts on which crossover to go for ? As the CS1 appears to have a good 'track record' with the B110/T27 combination it may be the best choice.
Any ideas will be most welcome.
Thanks. M Miles.

[Gordon Steadman]

Trying LS3/5a tweaks on the 101s might lead to dissatisfaction. I assume Kef decided to leave the T27 how it was for reasons of their own.
Some people prefer the 101 to the LS3/5a...

I am one of those people. However, out of interest I ordered the grilles and felt. Falcon managed to get the order wrong. The grilles arrived but the wrong felt. However, I have fitted the grilles and I like the result very much. The sound has less edge and seems better focussed somehow. Very natural sounding and terrific when used with the REL Quake to fill in the bottom end. I keep turning the sound up to silly levels that annoy Ronnie as it all seems so clean now. Mind you, she has ears that still work at whisper levels - I need a bit of oomph these days.

[spendorman]

Dear 'Spendorman',
I have decided to go for a crossover upgrade. The Falcon CS1 was my first choice, as you suggested. Then I discovered a friend, who has exactly the same Codas, is planning to use the Falcon 23 c'overs. His Codas use the SP1032, but as has been mentioned here, my earlier model T27 tweeters should not make a difference.
Any thoughts on which crossover to go for ? As the CS1 appears to have a good 'track record' with the B110/T27 combination it may be the best choice.
Any ideas will be most welcome.
Thanks. M Miles.

You really should have the CS1a crossover, not the CS1 which if for the later B110. The type 23 crossovers should be very good, but will likely be a fair bit more expensive than the CS1a. You may have to ask Falcon if they can do the CS1a crossover.

[spendorman]

I am one of those people. However, out of interest I ordered the grilles and felt. Falcon managed to get the order wrong. The grilles arrived but the wrong felt. However, I have fitted the grilles and I like the result very much. The sound has less edge and seems better focussed somehow. Very natural sounding and terrific when used with the REL Quake to fill in the bottom end. I keep turning the sound up to silly levels that annoy Ronnie as it all seems so clean now. Mind you, she has ears that still work at whisper levels - I need a bit of oomph these days.

Great that you liked the result. I used the grilles on Tangent RS2's, which also use the T27, and thought it a slight improvement. I also fitted them to my clone LS3/5a's. My Chartwell LS3/5a's, of course, had them from new.

My Rogers LS3/6 also has them as standard on the Celestion HF2000's

[Martyn Miles]

You really should have the CS1a crossover, not the CS1 which if for the later B110. The type 23 crossovers should be very good, but will likely be a fair bit more expensive than the CS1a. You may have to ask Falcon if they can do the CS1a crossover.

Thank you Spendorman.
As you mentioned the CS1a crossovers came from Wilmslow, I wonder if they can supply the necessary components and suitable boards. Then I can build the ones shown on the Kef leaflet you put in a previous post.

[spendorman]

I would prefer to use Falcon, I think that they used to supply the CS1a crossover or parts to build it.

Wilmslow seemed to get expensive, and suggested some strange unit replacements. One was a Vifa as a replacement for a BC1 bass unit. To my ears, that did not work.

[Martyn Miles]

Good that you are really pleased with the Coda's. I was not that happy with them. I still feel that the CS1a crossover is likely to be a very good upgrade. It was for me. I made the crossovers from Falcon parts and the result with B110 SP1003 and T27 SP1032 was very good. In fact, not much different to my Chartwell LS3/5a's.

The CS1a crossover was computer designed by KEF as a simplified LS3/5a type crossover, not requiring the tapped inductors, so much easier to build.

I have found a company to supply the components for 2 x CS1A crossovers. Total cost just under £44.
Post Christmas I hope to order them, and obtain boards to mount them on.

[spendorman]

I have found a company to supply the components for 2 x CS1A crossovers. Total cost just under £44.
Post Christmas I hope to order them, and obtain boards to mount them on.

That's good. I hope that they result is to your liking.

Who is supplying the components?

I have taken out of storage a pair of KEF Corellis, not bad at all, B200 and T27. Cabinets made well, bitumen damping panels on the cabinet walls, like LS3'5a. The crossover is pretty good, does a fine job of integrating the units.

[Martyn Miles]

That's good. I hope that they result is to your liking.

Who is supplying the components?

I have taken out of storage a pair of KEF Corellis, not bad at all, B200 and T27. Cabinets made well, bitumen damping panels on the cabinet walls, like LS3'5a. The crossover is pretty good, does a fine job of integrating the units.

The company is Audio Components.
Very helpful indeed.

[spendorman]

That looks interesting, I checked prices for some capacitors, and they seem very reasonable, free P&P too.

Thanks.

[DSJR]

Corelli's were better integrated than the previous Chorale's, despite using (I think) the same drivers. Sold a good few in my time and I believe they were derived from the 104ab crossover, but could be wrong here. They certainly didn't screech like the original 104 pre the 'ab' crossover change could on female vocals.

[spendorman]

Corelli's were better integrated than the previous Chorale's, despite using (I think) the same drivers. Sold a good few in my time and I believe they were derived from the 104ab crossover, but could be wrong here. They certainly didn't screech like the original 104 pre the 'ab' crossover change could on female vocals.


Yes, did not like the Chorale's, B200 bass unit in the Corelli's is slightly different to the usual one in the Chorale, it was either aluminium coil former or coil, or both. And yes, the Corelli crossover is more complex than the Chorale.

Incidentally, I'm looking for a Corelli crossover diagram. I'm not sure that the one I found on the internet is correct.

[DSJR]

Check the 104ab one and look for similarities... Falcon Acoustics have years of experience and may be able to assist with details, as may Wilmslow Audio, who used to manufacture replacement ab crossovers as well as improved ones for the Concerto. At least the B110 and T27 are now being re-manufactured by Falcon and I'm sure good business could be made if the B200 was re-made too (I think Harbeth ditched the tooling some time ago - they acquired the tools for the old KEF drivers when the Chinese took KEF over I think).

[spendorman]

Check the 104ab one and look for similarities... Falcon Acoustics have years of experience and may be able to assist with details, as may Wilmslow Audio, who used to manufacture replacement ab crossovers as well as improved ones for the Concerto. At least the B110 and T27 are now being re-manufactured by Falcon and I'm sure good business could be made if the B200 was re-made too (I think Harbeth ditched the tooling some time ago - they acquired the tools for the old KEF drivers when the Chinese took KEF over I think).

Thanks, I have already checked the 104ab crossover, and there are similarities, but I still need the correct diagram. I may contact Falcon.

[Gordon Steadman]

Trying LS3/5a tweaks on the 101s might lead to dissatisfaction. I assume Kef decided to leave the T27 how it was for reasons of their own.
Some people prefer the 101 to the LS3/5a...

The felts arrived today and I've just fitted them. Its finished off what the grilles started. very smooth without loss of life and natural sounding. So i like them even more better than the LS35As now:)

I would definitely recommend that anyone with T27s tries these. The felts are self adhesive and that can always come off if you don't like it. The grilles I stuck on with pritstick to try them out and will now make them permanent. They come from Falcon of course.

[Martyn Miles]

As the build of speakers ( including upgraded crossovers ) goes on, I now have two, brand new and unused ( still-in-their-boxes ) Falcon Acoustics FB110s now surplus to requirements.

If anyone is looking for a pair I wil let them go for 10% less than the price Falcon sells on their web site.
Buying on eBay they are more expensive.
Collect or I can ship.
I live 12 miles west of Oxford.
Thanks.
M Miles

[Martyn Miles]

As the build of speakers ( including upgraded crossovers ) goes on, I now have two, brand new and unused ( still-in-their-boxes ) Falcon Acoustics FB110s now surplus to requirements.

If anyone is looking for a pair I wil let them go for 10% less than the price Falcon sells on their web site.
Buying on eBay they are more expensive.
Collect or I can ship.
I live 12 miles west of Oxford.
Thanks.
M Miles

As I have now bought a complete Falcon LS3/5a kit, I now have two T27s, the CS1A crossover components and two brand new FaLcon LS3/5a cabinets for sale .
Anyone interested ?
Thanks.
M Miles .

[Martyn Miles]

As I have now bought a complete Falcon LS3/5a kit, I now have two T27s, the CS1A crossover components and two brand new FaLcon LS3/5a cabinets for sale .
Anyone interested ?
Thanks.
M Miles .

The Falcon Acoustics LS3/5a kit is now completed and sold, but I now still have the components mentioned above to sell.
The Falcon cabinets are cherry finish, as I used the walnut ones for the kit build

They will be going on eBay in the next few days...

[PaulStewart]

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