Mmmmm, .... I’ve been thinking... My first set of Concerto’s, I recapped with caps from Falcon Acoustics.
I still have to order some new Mundorf caps.
Would I get audibly a better result if I would remove the Falcon caps and use Mundorfs for my first set of Concerto’s as well?
They already sound good now , and I payed about 40 pounds for the Falcon caps.
Would the extra money for the Mundorfs make an audibly improvement?
Sorry for my bad English...
I still have to order some new Mundorf caps.
Would I get audibly a better result if I would remove the Falcon caps and use Mundorfs for my first set of Concerto’s as well?
They already sound good now , and I payed about 40 pounds for the Falcon caps.
Would the extra money for the Mundorfs make an audibly improvement?
Sorry for my bad English...
the falcons are great. if you use a PLAIN Mundorf mcap electrolytic cap for the 30uF in the mid section this will help the mids. don’t think of using other than electrolytic caps… you’d have to re-balance the whole crossover.
edit: sometimes falcon supplies film caps for the tweeter section (the two 4.7uF). to my ears this upsets the sound, go with two 4.7uF electrolytics “RAW” here… or try my mod (which implements the KEF aB upgrade for the T27 tweeter).
the Concertos can be much better than stock with the apt crossover, but —- see above.
hope that helps.
Thans you. Do you meen these (see picture please)?
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At Rumoh.be , they don.t sell the mundorf 4,7 RAW. Only the plain ones.
Can I remplace the 4,7 Falcon by the mundorf 4,7 Plain (see picture please)
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oh sorry… those are wrong (film caps). so please use ecaps
as I wrote above this will change the sound (to the worse) — use the (raw) electrolytic caps supplied by Falcon
edit: Mundorf ecaps, mcaps are polypropylene, so not suitable to directly replace electrolytics without further changes
I have listed up what you advised me to do. I hope I did it right?
For my first set of Concertos with the Falcon Alcaps, I should remove the 30mF Falcon Alcaps ,
and replace them by 33mF Mundorfs.
Also iT would be better as to remove the 5mF Falcon Alcaps and replace them by 4,7 mF electrolytics RAW.
However , I searched on the website of RumoH , and they don’t sell 4,7 MF Mundorfs RAW.
They only sell the 4,7 PLAIN.
Can I also use these instead of the 5mF Falcons?
Or do I just keep using these 5mF Falcon Alcaps?
For my second set of Concertos , I must replace the old original 80mF Kef caps by 82mF Mundorf Ecaps RAW.
I don’t have to replace the 4,7 mF Mundorfs glad ,by 4,7 mF RAW (which RumoH doens’t sell)?
See attached file please.
Thans you.
PS : since I’m not at home , I wrote everything down , instead of using a spreadsheet..
For my first set of Concertos with the Falcon Alcaps, I should remove the 30mF Falcon Alcaps ,
and replace them by 33mF Mundorfs.
Also iT would be better as to remove the 5mF Falcon Alcaps and replace them by 4,7 mF electrolytics RAW.
However , I searched on the website of RumoH , and they don’t sell 4,7 MF Mundorfs RAW.
They only sell the 4,7 PLAIN.
Can I also use these instead of the 5mF Falcons?
Or do I just keep using these 5mF Falcon Alcaps?
For my second set of Concertos , I must replace the old original 80mF Kef caps by 82mF Mundorf Ecaps RAW.
I don’t have to replace the 4,7 mF Mundorfs glad ,by 4,7 mF RAW (which RumoH doens’t sell)?
See attached file please.
Thans you.
PS : since I’m not at home , I wrote everything down , instead of using a spreadsheet..
Attachments
Hi Eric, first: apologies for the short and partly vague posts in the last two days, I was on a conference with very few time.
You CAN do what you suggest above (replace the 30uF Alcap by a 33uF Mundorf PLAIN), it will probably improve the mids and add some benign ripple effects into the remaining frequency spectrum.
There is a chance that mids will become too prominent, as the series resistance (ESR) of the PLAIN cap is lower than that of the standard (RAW) Alcap one.
The Concerto's are already too strong on the mids to my taste. So be ready to put a 2 Ohm 10 Watt resistor in series with the new cap if the mids get too prominent.
The Alcap 30uF and the Mundorf eCap 33uF RAW are comparable in quality. The slight raise in capacity by 10% is within the tolerance range. So the only swap of one eCap against another one that makes an audible effect here is to put in a 33uF PLAIN.
No.
The original crossover circuit calls for 2x 5uF; 4.7uF is a working approximation for the cap values available today, as 5uF are rarely made nowadays (it is even possible that the Falcon 5uF are 4.7uF caps from a production run which has a slightly higher capacity).
Some of the Falcon caps seem to be Fischer&Tausche made, as are Mundorf's, so it is even possible that Alcaps and Ecaps RAW are identical.
What Mundorf / Fischer&Tausche today sell as PLAIN, Alcap once called LL (low loss), those are marked in the old KEF crossover schematics. There are non of those originally LL (aka PLAIN) caps in the Concerto schematics.
Fischer&Tausche is a cap manufacturer based in Husum, Northern Germany. They have just been acquired by one of the Cap industry giants.
No.
As the PLAIN caps have a lower ESR (see above) the highs would become too prominent, with ripple effects down the frequency spectrum.
Yes.
The other option is to replace the whole tweeter section with the aB tweeter section that KEF later used for that model of tweeter (T27). This is what I did in my modified crossover and it works well. KEF did this with the so-called AUSKEF crossover of the Concertos sold only in Australia for a short while with Concerto DIY kits.
I've never seen a schematics for that, though. There is scarce information on the web. From the few photos I found I guessed what the circuit could have been. It's a guess based on some photos and on my knowledge of the aB section developed by KEF and implemented by Falcon in some crossover designs with the T27, e.g. the improved Chorale crossover they once sold.
Falcon sold the AUSKEF crossover as No. 53 on PCB 11. It's possible someone there still knows about it or they'd even send a circuit diagram.
I can't upload pics right now but might start a new thread on the AUSKEF, as it might be useful to some.
Again (see above): I discourage you from using PLAIN eCaps in the tweeter circuit without further mods to the crossover.
You could get if you put resistors in all the crossover circuits whose ESR you lower by substituting the standard RAW Mundorf or Alcap caps with PLAIN ones. But then you are deeply into modification terrain and I'd encourage you to build one of the proved designs.
I ran extensive tests for months on that and my crossover resulted sounding very good to me in the end – but there where quite a couple of dead ends while experimenting (e.g. putting caps with a low ESR into the circuit without further adjustments).
Good luck!
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Hi Wieslaw, great, thanks. Where is this schematics from? To my eyes it shows the "simplified" aB section Falcon offered in their upgraded Concerto Crossovers. The AUSKEF version and my implementation have the full circuit with the fourth cap in parallel to a resistor and a different value for the small bypass film cap. see my reconstruction of the AUSKEF circuit attached.
It's from Falcon upgrade schematics here. I think you can find all the answers at the above speakertalk website. It is dedicated to classic KEF speakers. Good luck.
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Ah, that's helpful. Never found this. Thanks for posting! So Eric, this is the most easy-to-go upgrade which you can do. Proven design :- I might check it out on a remaining pair of the original crossovers and compare it to my more complex implementation of the aB network.
Hello again. I’m still abroad but I will certainly give it a closer look when I’m back home. THANK YOU VERY MUCH. . And also thank you Wieslaw.
Hello Mr. Eschenborn.
A good idea indeed to try out Mr Wieslaw Lipowski's schematics...
I'll give it a try when I have a few spare...
But for now, I'm going to keep it simple and only make the changes you've recommended.
About my first set of Concertos, from which the capacitors have been replaced by the 'Falcon kit': I think I will make no changes and leave these crossovers as they are.
As you wrote : I MIGHT replace the 30µF Alcap, by a Mundorf 33µF PLAIN, but then I would have to put a 2 Ohm 10 Watt resistor in series with the new cap if the mids get too prominent.
But would this make a big audible difference ? (as it sounds good to me already.)
So for my 2nd set of Concertos, I'm going to replace the Mundorf 82µF plain , by Mundorf 82µF raw.
That's no problem. I can now also order these @ Rumoh.be.
https://www.rumoh.eu/crossover-parts/capacitors/mundorf-ecap-raw/1158/82.0uf-5-ecap100-raw
The Mundorf ecaps 4.7µF plain , I should replace by Mundorf(?) ecaps 4.7µF raw.
Or as you wrote : "go with two 4.7uF electrolytics “RAW”.
And that's a problem for me... I can't order such capacitors anywhere (in Belgium or the Netherlands)...
Or perhaps you can recommend me other capacitors from another brand?
Or perhaps you are able to find such 'other' capacitors on Rumoh.be?
I'm asking al lot here, I know ...
And since you advise me to replace the Mundorf 4.7µF plain for the Concert’o's by 4.7µF electrolytics raw ...
does that mean I should do the same for my 2 pairs of Kef Cadenza's ???..
(see attched files) .
Other question :
Are all Falcon alcaps raw?
Thanks in advance.
Have a nice day.
Eric
A good idea indeed to try out Mr Wieslaw Lipowski's schematics...
I'll give it a try when I have a few spare...
But for now, I'm going to keep it simple and only make the changes you've recommended.
About my first set of Concertos, from which the capacitors have been replaced by the 'Falcon kit': I think I will make no changes and leave these crossovers as they are.
As you wrote : I MIGHT replace the 30µF Alcap, by a Mundorf 33µF PLAIN, but then I would have to put a 2 Ohm 10 Watt resistor in series with the new cap if the mids get too prominent.
But would this make a big audible difference ? (as it sounds good to me already.)
So for my 2nd set of Concertos, I'm going to replace the Mundorf 82µF plain , by Mundorf 82µF raw.
That's no problem. I can now also order these @ Rumoh.be.
https://www.rumoh.eu/crossover-parts/capacitors/mundorf-ecap-raw/1158/82.0uf-5-ecap100-raw
The Mundorf ecaps 4.7µF plain , I should replace by Mundorf(?) ecaps 4.7µF raw.
Or as you wrote : "go with two 4.7uF electrolytics “RAW”.
And that's a problem for me... I can't order such capacitors anywhere (in Belgium or the Netherlands)...
Or perhaps you can recommend me other capacitors from another brand?
Or perhaps you are able to find such 'other' capacitors on Rumoh.be?
I'm asking al lot here, I know ...
And since you advise me to replace the Mundorf 4.7µF plain for the Concert’o's by 4.7µF electrolytics raw ...
does that mean I should do the same for my 2 pairs of Kef Cadenza's ???..
(see attched files) .
Other question :
Are all Falcon alcaps raw?
Thanks in advance.
Have a nice day.
Eric
Attachments
Dear Mr. Wieslaw,
I have read the link 4 times.
Although I am not an 'electronic engineer', I understand most of what is stated.
But I can't link an answer to my specific question to this article. Unless perhaps the part that mentions the use of a Monacor 2%.
Maybe I can buy a Monacor 4.7µF raw somewhere.
Should I have a few extra DN12-crossovers , I see myself able to execute the 'Falcon upgrade schematics'.
But then I would need the complete parts list. (including indication of whether the capacitors should be 'plain' or 'raw'.)
But for now I will stick to replacing Mundorf 4.7µF plain by …. 4.7µF raw.
Or put in Mundorf 4.7µF PLAIN in anyway ?
Or put the old ones back ... ?
I have sent an email to Rumoh.be, asking if they didn't sell electrolytic 4.7µF 'raw' capacitors, but they don't sell such capacitors and unfortunately , I am not one step further with their answer:
“Hello Eric.
The raw only starts at 10.0µf, so just take the smooth (plain) one for that.
Why the advice is given to take raw instead of plain is strange to me because smooth is always better.
Raw is more of a cost/benefit story and the values run higher.
Sincerely, Rudy Holtrop”
But of course I fully believe the advice Mr. Eschenborn has given me.
NO DOUBT ABOUT THAT.
Rumoh is just a seller and does not have these capacitors, so he just wants to sell me some other capacitors … (imho).
Kind regards,
Eric
I have read the link 4 times.
Although I am not an 'electronic engineer', I understand most of what is stated.
But I can't link an answer to my specific question to this article. Unless perhaps the part that mentions the use of a Monacor 2%.
Maybe I can buy a Monacor 4.7µF raw somewhere.
Should I have a few extra DN12-crossovers , I see myself able to execute the 'Falcon upgrade schematics'.
But then I would need the complete parts list. (including indication of whether the capacitors should be 'plain' or 'raw'.)
But for now I will stick to replacing Mundorf 4.7µF plain by …. 4.7µF raw.
Or put in Mundorf 4.7µF PLAIN in anyway ?
Or put the old ones back ... ?
I have sent an email to Rumoh.be, asking if they didn't sell electrolytic 4.7µF 'raw' capacitors, but they don't sell such capacitors and unfortunately , I am not one step further with their answer:
“Hello Eric.
The raw only starts at 10.0µf, so just take the smooth (plain) one for that.
Why the advice is given to take raw instead of plain is strange to me because smooth is always better.
Raw is more of a cost/benefit story and the values run higher.
Sincerely, Rudy Holtrop”
But of course I fully believe the advice Mr. Eschenborn has given me.
NO DOUBT ABOUT THAT.
Rumoh is just a seller and does not have these capacitors, so he just wants to sell me some other capacitors … (imho).
Kind regards,
Eric
Old Falcon/Kef electrolytics were rather of "raw" than "plain" family. Be careful especially with the 80uF shunt caps going to ground. If you have to use plain, insert about 1R -2R resistors in series with them. Good luck, Eric.
Thank’s for your advice Mr. Lipowski.👍
Yesterday, I received the Mundorf 82µF RAW and the 4.7µF plain. (as I couldn’t find any 4.7µF electrolytics raw…😢)
But I managed to also put the 82µF RAW on the back of the PCB , next to the other components. 🙂
(as the 82µF raw is so much smaller then the 82µF plain as Mr. Eschenborn said - see attached pictures).
Just enough space (see photos).
The legs of the ecap were also just long enough to solder (lucky me...)
So next step will be to replace the (corroded) connectors...
Have an nice week-end.
All of you!
Eric
PS : I also bought another pair of Kef Cadenza's today.
My intention is to replace the Morel Cat 298's from my other Concertos , with the original T27's (SP1032)...
The nostalgic feeling would be completely back that way 😏😎
Yesterday, I received the Mundorf 82µF RAW and the 4.7µF plain. (as I couldn’t find any 4.7µF electrolytics raw…😢)
But I managed to also put the 82µF RAW on the back of the PCB , next to the other components. 🙂
(as the 82µF raw is so much smaller then the 82µF plain as Mr. Eschenborn said - see attached pictures).
Just enough space (see photos).
The legs of the ecap were also just long enough to solder (lucky me...)
So next step will be to replace the (corroded) connectors...
Have an nice week-end.
All of you!
Eric
PS : I also bought another pair of Kef Cadenza's today.
My intention is to replace the Morel Cat 298's from my other Concertos , with the original T27's (SP1032)...
The nostalgic feeling would be completely back that way 😏😎
