Hi Rohan Thank you very much for your possitive opinion. I’ve always thought that these are lovely speakers bit a bit unfinished and with an enormous improving potential . They has to still being a pure KEF 105. I asked to some specialist, lot of googleing and finally asked to Jerry Broomfield of Falcon Acoustics and he guided me. I’ve purchased Solens 2% tolerance with some resistances to compensate the original caps resistance and the original xover schematics. The 207/2 are my parent’s speakers and the sound is clearly better than the 105’s, but now a bit closer. This was a very hard and unfair comparison, but the 105 ‘s did it very well The good news is that now I have a friend who is an engineer and we’re going to do the Evo II for the 40th anniversary. Mundorf Supreme caps for highs and mids, air core coils for highs and mids and better coils for lows to get them even closer to the sound of todays top speakers
Do you have a forum discussion talking about what you've done? I have a pair of these speakers and I'm not sure if I'll just leave them stock and listen as they are, or, take some measurements and see if some of the crossover components need to be replaced due to old age.
This is a remarkable project and I take my hat off to you for your dedication, expertise and vision. I have a few questions that hopefully you may answer. The first is, which capacitors did you choose for the replacement, and did you make any alterations to the crossover parameters? I can see that you have (I think) a pair of 207s there. Do you really use your 105 in preference to these? Again, great job. Congratulations.
Hi Rohan, sorry for being so late. The caps chosen were Solen, a good value caps, but in a few months I will do a new upgrade with Mundorf Supreme caps, air core coils in highs and iron core inductors in the bass section. The 207’s are my parents speakers and its sound is some steps forward Fram the 105’s, but they will be even closer soon. Due yo better room treatment, my system is performing better in soundstage and control, e hile the 207’s still more refined
Good morning, I admit I didn't understand all the changes you made. The result is magnificent. do you have the plans for the new crossover (1/1 size) and the black support at the base of the speakers?
Hello I made the changes in the bass enclosure to reinforce it internally in order to improve rigidity, improve the front baffle, which was one of the weak points of the 105/1 due to its lack of rigidity, and the floor was to recover the volume. internal lost and that was maintained in the original 70 liters. The base reinforces that soil weakened by the internal volume calculations and to house the crossover. The rest is only aesthetics If you want I'll send you the templates to make the filters, but I don't recommend the "EVO I" version because although it improves the original a lot, the EVO II filter with the Mundorf condensers and air coils is clearly better. As for the base, it is made with MDF boards. The upper and lower ones are 10mm and the 3 internal ones are 19mm. If I were to do it again it is possible that I would build it differently and leave more space to install air coils for the bass and leave more space inside the narrow area for the speaker terminals and wires. I can send you what you need without problem. Write me to the email that I have opened for the channel (audiobikerchannel@gmail.com) so that I can attach the files and list of components of the EVO II filter. The EVO I filter had a small crossover mismatch at 2500hz that should be fixed with the mod we introduced in the EVO II, changing C6 from 10nF to 15nF. We suppose that when modifying the filter with the new capacitors and altering the ESR, despite putting resistors to compensate it, there was a small defect. It could also be due to the old age of the drivers, but with the small modifications, the curve and the sound aesthetics are the same as the original but with a more refined, decisive and clean sound Everything has been measured in the laboratory of an engineer friend and the result is optimal
Hi Jerry Those resistors had been added as suggested by Jerry Broomfield of Falcon Acoustics, who did the calculations and supplied the Solen Caps. I don’t remember which the values are, but I’ll tell you tomorrow because I have to find the schematics. In the next few months, once finished the KEF 105 Subwoofer (video is coming soon), the xovers will be improved with Mundorf Supreme Caps, air core coils in Mids and Highs and Jantzen iron core c
@@audiobiker Fantastic! I'm refurbishing a set right now I got for free (!!). I went with Solen PB with a couple Bennic NP's for the really large values. I haven't added any series ESR comp resistors yet though. Going to refurb just one, and A/B the two first. Would really appreciate the schems if you can find them though. Not easy calculations. Cheers!
You are very lucky if you have taken them for free. I don’t know how to send you the schematics in this platform. You have to take in account seriusly some points with these marvellous speakers: 1- These speakers are ultra Hi End and power hungry, and must be paired with popper electronics. 2- The 40 - 200 w rating is not true. If you want to enjoy the actual potential of them, you’ll need at least 200w high current amplifier. Lesser amplifiers will be clipping often and not getting the true sound that these speakers are capable. Luxman L11 100w had serious problems, Primare A32 250w sounded wonderdul, but with McIntosh MC402 the magic appeared. Musical Fidelity A308, TriVista 300, etc, Electrocompaniet, Krell, Bryston, Primare are good choices. 3-Kef 105 are wide dispersion speakers and in order to get big soudstages and clean sound, they need space arround to breed and good room acoustics to achieve the best performance
Hi Jerry. I’ve just uploaded a new video for you with the schematics and the resistor values gived by Falcon Acoustics. In this video appears the new coils for de bass crossover that I’m testing and the 105’s partners, the center channel amd the new 105 Subwoofer
its disgraceful when i see so called High End Speaker manufacturers charge in excess of $30,000 for a pair of speakers and give us woeful parts in the crossover . When great parts dont cost an arm an a leg . DIY is the future .
These speakers were launched 45 years ago, when available parts were different from today and nobody cares about cables. I’ve spent more than 1500€ in components in these speakers. Quality isn’t cheap Today’s KEF Reference series still very well engeneered and prices remain quite afordable for a range of speakers for the highest performance. KEF Reference 3 is the equivalent current model and is priced arround 12.000€
Hi Rohan
Thank you very much for your possitive opinion.
I’ve always thought that these are lovely speakers bit a bit unfinished and with an enormous improving potential . They has to still being a pure KEF 105. I asked to some specialist, lot of googleing and finally asked to Jerry Broomfield of Falcon Acoustics and he guided me. I’ve purchased Solens 2% tolerance with some resistances to compensate the original caps resistance and the original xover schematics.
The 207/2 are my parent’s speakers and the sound is clearly better than the 105’s, but now a bit closer. This was a very hard and unfair comparison, but the 105 ‘s did it very well
The good news is that now I have a friend who is an engineer and we’re going to do the Evo II for the 40th anniversary. Mundorf Supreme caps for highs and mids, air core coils for highs and mids and better coils for lows to get them even closer to the sound of todays top speakers
Do you have a forum discussion talking about what you've done?
I have a pair of these speakers and I'm not sure if I'll just leave them stock and listen as they are, or, take some measurements and see if some of the crossover components need to be replaced due to old age.
This is a remarkable project and I take my hat off to you for your dedication, expertise and vision.
I have a few questions that hopefully you may answer. The first is, which capacitors did you choose for the replacement, and did you make any alterations to the crossover parameters?
I can see that you have (I think) a pair of 207s there. Do you really use your 105 in preference to these?
Again, great job. Congratulations.
Hi Rohan, sorry for being so late. The caps chosen were Solen, a good value caps, but in a few months I will do a new upgrade with Mundorf Supreme caps, air core coils in highs and iron core inductors in the bass section. The 207’s are my parents speakers and its sound is some steps forward Fram the 105’s, but they will be even closer soon. Due yo better room treatment, my system is performing better in soundstage and control, e hile the 207’s still more refined
Good morning, I admit I didn't understand all the changes you made. The result is magnificent. do you have the plans for the new crossover (1/1 size) and the black support at the base of the speakers?
Hello
I made the changes in the bass enclosure to reinforce it internally in order to improve rigidity, improve the front baffle, which was one of the weak points of the 105/1 due to its lack of rigidity, and the floor was to recover the volume. internal lost and that was maintained in the original 70 liters. The base reinforces that soil weakened by the internal volume calculations and to house the crossover. The rest is only aesthetics
If you want I'll send you the templates to make the filters, but I don't recommend the "EVO I" version because although it improves the original a lot, the EVO II filter with the Mundorf condensers and air coils is clearly better.
As for the base, it is made with MDF boards. The upper and lower ones are 10mm and the 3 internal ones are 19mm. If I were to do it again it is possible that I would build it differently and leave more space to install air coils for the bass and leave more space inside the narrow area for the speaker terminals and wires.
I can send you what you need without problem. Write me to the email that I have opened for the channel (audiobikerchannel@gmail.com) so that I can attach the files and list of components of the EVO II filter. The EVO I filter had a small crossover mismatch at 2500hz that should be fixed with the mod we introduced in the EVO II, changing C6 from 10nF to 15nF. We suppose that when modifying the filter with the new capacitors and altering the ESR, despite putting resistors to compensate it, there was a small defect. It could also be due to the old age of the drivers, but with the
small modifications, the curve and the sound aesthetics are the same as the original but with a more refined, decisive and clean sound
Everything has been measured in the
laboratory of an engineer friend and the result is optimal
Do you have any info on what series resistors you added to compensate for cap ESR? Looks like you've added them, smart!
Hi Jerry
Those resistors had been added as suggested by Jerry Broomfield of Falcon Acoustics, who did the calculations and supplied the Solen Caps. I don’t remember which the values are, but I’ll tell you tomorrow because I have to find the schematics. In the next few months, once finished the KEF 105 Subwoofer (video is coming soon), the xovers will be improved with Mundorf Supreme Caps, air core coils in Mids and Highs and Jantzen iron core c
@@audiobiker Fantastic! I'm refurbishing a set right now I got for free (!!). I went with Solen PB with a couple Bennic NP's for the really large values. I haven't added any series ESR comp resistors yet though. Going to refurb just one, and A/B the two first. Would really appreciate the schems if you can find them though. Not easy calculations. Cheers!
You are very lucky if you have taken them for free. I don’t know how to send you the schematics in this platform. You have to take in account seriusly some points with these marvellous speakers: 1- These speakers are ultra Hi End and power hungry, and must be paired with popper electronics. 2- The 40 - 200 w rating is not true. If you want to enjoy the actual potential of them, you’ll need at least 200w high current amplifier. Lesser amplifiers will be clipping often and not getting the true sound that these speakers are capable. Luxman L11 100w had serious problems, Primare A32 250w sounded wonderdul, but with McIntosh MC402 the magic appeared. Musical Fidelity A308, TriVista 300, etc, Electrocompaniet, Krell, Bryston, Primare are good choices. 3-Kef 105 are wide dispersion speakers and in order to get big soudstages and clean sound, they need space arround to breed and good room acoustics to achieve the best performance
I know that all of that is quite complex to get, but these speakers do worth the effort. The more you vive them, the more return.
Hi Jerry. I’ve just uploaded a new video for you with the schematics and the resistor values gived by Falcon Acoustics. In this video appears the new coils for de bass crossover that I’m testing and the 105’s partners, the center channel amd the new 105 Subwoofer
its disgraceful when i see so called High End Speaker manufacturers charge in excess of $30,000 for a pair of speakers and give us woeful parts in the crossover . When great parts dont cost an arm an a leg . DIY is the future .
These speakers were launched 45 years ago, when available parts were different from today and nobody cares about cables. I’ve spent more than 1500€ in components in these speakers. Quality isn’t cheap
Today’s KEF Reference series still very well engeneered and prices remain quite afordable for a range of speakers for the highest performance. KEF Reference 3 is the equivalent current model and is priced arround 12.000€