SpeakerTalk Forum Index SpeakerTalk
This forum has been set up to facilitate discussion of 1970s KEF speakers and drive units. The owner of the Forum has no connection with KEF Audio.
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Kef Cadenza's sp1019 dn14 crossover high tone problem
Goto page 1, 2  Next
 
Post new topic   Reply to topic    SpeakerTalk Forum Index -> KEF Speakers from the 1970s
View previous topic :: View next topic  
Author Message
Tinus74
Introductory Contributor


Joined: 25 May 2005
Posts: 8

PostPosted: Wed May 25, 2005 10:56 pm    Post subject: Kef Cadenza's sp1019 dn14 crossover high tone problem Reply with quote

Hello,

I'm living in The Netherlands and my father gave me his old Kef-Cadenza's.
There is however a problem with one of the cross-over filters (sp1019, dn14 dividing network): it does not filter the high-tones, the tweeters doesn't give any sound.
The tweeters are working properly when I connect them on the main input. Also, the mid/low filter works o.k.

Is anyone familiar with this high-filter problem? I bought a pair of crossovers on ebay and the suffer from the same problem...unfortunately.

Kind regards.

Martijn
Utrecht, The netherlands
Back to top
View user's profile Send private message
Gary
Senior Contributor 200+


Joined: 07 Nov 2004
Posts: 275
Location: Toronto, Canada

PostPosted: Thu May 26, 2005 1:58 am    Post subject: Reply with quote

So let me understand this a bit better.

The tweeters on BOTH of your speakers do not work? But the DO work if you bypass the speakers. Correct?

And it also happened the same way with the new crossovers?

Gary

(PS I am not an expert - just trying to help out. Smile )
_________________
Sometimes I lie awake at night, and I ask, "Where have I gone wrong?" Then a voice says to me, "This is going to take more than one night."
-- Charles M. Schulz (as Charlie Brown)
Back to top
View user's profile Send private message
ColinR
Über Contributor 1000+


Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Thu May 26, 2005 11:27 am    Post subject: Reply with quote

Sounds like one or both of the 5uF capacitors in the + side to the T27 are stuffed, the +/- 0.25mH inductor should be fine btw.

The Epay replacements exhibit the same fault as your originals as they are either the same age as your originals and/or have been "cooked" by a fairly big amplifier.

Worryingly even when capacitors are converted into resistors over time I would still expect some signal to get through, so turn down the wick a bit when you get them fixed.

So get a couple of ~100 Volt 5uF Elcaps, Polyester, 400 Volt Solens or whatever you have locally, do a bit of soldering and let us know how you get on.
Back to top
View user's profile Send private message
Tinus74
Introductory Contributor


Joined: 25 May 2005
Posts: 8

PostPosted: Thu May 26, 2005 3:30 pm    Post subject: Reply with quote

Quote:

The tweeters on BOTH of your speakers do not work?


No, the problem is with one of the speakers. When my father gave them to me, both tweeters were damaged. I replaced them. With the new tweeters one of the speakers still gave no sound through the tweeter although they work fine.

Quote:

But the DO work if you bypass the speakers. Correct?


Yes...so, the crossover of 1 speaker has a problem. Then I bought 2 new crossovers (needed only 1) at eBay. By my surprise, they suffer from the same problem (?) Strange. So, now I ended up by having three crossover with no high tones. Mid/low works fine.


Quote:

The Epay replacements exhibit the same fault as your originals as they are either the same age as your originals and/or have been "cooked" by a fairly big amplifier


Maybe, but not at my amp. I get them, installed them and they never worked proper. My amp is alright, that's not the problem. I'm pretty carefull with the cadenza's and one is still working ok.


Quote:

Sounds like one or both of the 5uF capacitors in the + side to the T27 are stuffed, the +/- 0.25mH inductor should be fine btw.

So get a couple of ~100 Volt 5uF Elcaps, Polyester, 400 Volt Solens or whatever you have locally, do a bit of soldering and let us know how you get on.


Well, that's beyond my knowledge. But I think that I understand what you mean. But...i'm double left-handed with soldering...and with electro-technique. However, thanks for the advise

Hoped maybe someone have 1 cross-over left.
Back to top
View user's profile Send private message
ColinR
Über Contributor 1000+


Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Thu May 26, 2005 7:51 pm    Post subject: Reply with quote

Unfortunately when your father blew the original T27's he fried the 5uF capacitors too - must have been some party.

The Epay item probably resulted from someone "parting out" a pair of speakers afer a similar event.

Unless you develop a sudden interest in Isaac Walton and The Compleat Angler, or are travelling between Manchester and Birmingham you've got to ask.

Any Walloons or Dutchers out there who can solder?

Alternatively it looks like an expensive International soldering job, but as you have no aptitude in this area you will have to investigate suitable automotive "piggy back" connectors and 5 Amp electrical "chocolate blocks" too.
Back to top
View user's profile Send private message
Tinus74
Introductory Contributor


Joined: 25 May 2005
Posts: 8

PostPosted: Thu May 26, 2005 9:13 pm    Post subject: Reply with quote

Only the Walloons knew who Isaac Walton was. But these belgium people also think that Kef is a kind of fish.
In the mean while they started in the Netherlands a solder-addiction-talking group. Sharing the knowledge with non-solders seems to be the hardest problem. They just kept on talking to their own niche. Strange behaviour for fishermen. But it helped me a lot, though. Just need some tape and a 5mFd Low Loss.
Back to top
View user's profile Send private message
Wouter
Intermediate Contributor 50+


Joined: 18 Jun 2004
Posts: 60
Location: Ramsel (Belgium)

PostPosted: Thu May 26, 2005 9:17 pm    Post subject: Reply with quote

Hello,

It's a quite common problem with these old crossovers.
When I bought my concerto's two years ago, none of the tweeters were working. When I connected them directly to the amplifier's output, they worked fine.
After I replaced both 5uF's on both crossovers, everything was OK.

The problem is, that 5uF is an uncommon value, you have to use 4,7uF and 0,33 in parallel.

I'm living i the north of Belgium and I'm willing to help you, but believe me: If you take the crossover to an electronic shop nearby your hometown, they will help you with the replacement of the caps.

My best advice is to replace all of the capacitors.
Electrolytes have a bad lifetime. All of the caps have reached a value, far away from the original value! Electrolytic capacitors are not good for crossover networks, but they are cheap....

For my concerto's, I changed the electrolytics into MKP and the ferrite coils into air-coils.
The difference is unbelievable!

Best regards,
Wouter
Back to top
View user's profile Send private message Send e-mail
Wouter
Intermediate Contributor 50+


Joined: 18 Jun 2004
Posts: 60
Location: Ramsel (Belgium)

PostPosted: Thu May 26, 2005 9:19 pm    Post subject: Reply with quote

Hoohoo, these Belgium people think that Kef is a kind of fish.......???????
Back to top
View user's profile Send private message Send e-mail
Tinus74
Introductory Contributor


Joined: 25 May 2005
Posts: 8

PostPosted: Thu May 26, 2005 10:14 pm    Post subject: Reply with quote

Quote:

Hoohoo, these Belgium people think that Kef is a kind of fish.......???????


Razz Regarding to Isaac Walton: the Flemish don't

(Niet persoonlijk bedoelt hoor Wouter, maar ik vond dat het berichtje waarop ik reageerde een beetje uit de toon was en was daardoor lichtelijk geirriteerd)

Thank you for your tips. The solder-thing is not a real problem though.
It's growing a bit out of proportion right now. But, it would just be handier if someone has a crossover left.

You advised me to replace all of the capacitors.
Well, I surely can try this (since I have three crossovers to try). But still, aren't the caps, besides the decay, very important for the balanced sound of the old speakers?

I also get an email from Falcon (http://www.falcon-acoustics.co.uk/) you problably all know of. They can send me the 'original' caps.
They suggest:

6mFd Low Loss
16mFd standard
4.7mFd Low Loss or Polyester
5mFd Low Loss or 4.7mFd Polyester +5% to +10% Tol.

So, that looks a bit like chinese to me, but I see the same on my pcb. Would this be better to do compared to the electrolytic caps you mentioned?


Last edited by Tinus74 on Fri May 27, 2005 9:00 am; edited 1 time in total
Back to top
View user's profile Send private message
Wouter
Intermediate Contributor 50+


Joined: 18 Jun 2004
Posts: 60
Location: Ramsel (Belgium)

PostPosted: Fri May 27, 2005 6:40 am    Post subject: Reply with quote

Hi Martijn

Well, it's hard to say.
Changing the caps will surely change the sound in a certain way.
It's hard to say HOW it will change.
But if the change means an improvement, I wouldn't complain...?
And since electrolytics and ferrites are not my favourite toys, I usually replace them.

Anyway, you have to change the broken capacitors. That's for sure. And if you want to stick as close as possible to the original design, you should better use the electrolytics.

If Falcon can deliver you a 5uF capacitor, I think, this should be a good choice, because the value of the capacitor is important to get the correct crossover-point.
Is there a great price difference between the 5uF and 4,7uF?


Best regards,
Wouter

PS. Utrecht is a lovely town! I visited it some time ago while was nearby when I was collecting a pair of B139's...
Back to top
View user's profile Send private message Send e-mail
Tinus74
Introductory Contributor


Joined: 25 May 2005
Posts: 8

PostPosted: Fri May 27, 2005 7:42 am    Post subject: Reply with quote

Quote:

s there a great price difference between the 5uF and 4,7uF?


Well, I don't know yet. And know the guy at Falcon is on a holiday for 2 weeks. But since I have three crossovers I can try both. I think I'm going to a electro-shop today and ask them what they can do for me.
So, the main thing I have to ask them is to change the electrolytics into MKP's and the ferrite coils into air-coils?

Quote:

Utrecht is a lovely town! I visited it some time ago while was nearby when I was collecting a pair of B139's...


Yes, sure it is. But I like Antwerpen very much! I was born in the south-west of the netherlands near the belgium border. 20 minutes from Antwerpen Wink
Back to top
View user's profile Send private message
Tinus74
Introductory Contributor


Joined: 25 May 2005
Posts: 8

PostPosted: Fri May 27, 2005 1:33 pm    Post subject: Reply with quote

Today, I went to the electro-shop here in the city. Too bad they hadn't any 0,33 mF. So he replaced both the 5mF for a 4,7mF.
The question is: do I hear the difference. It's the 2.20 euro worth to try.
And...the speaker works fine! And I don't know if I hear the difference.

By the way, he measured for fun the 5mF with an old-skool device. The one that was damaged gave 0.001 or something.
But the other one gave 7.xxx. It should be 5.xxx. So as you guy's mentioned, the original value isn't there anymore. It's even higher...(?)

But still, what difference would it make for the ear to hear the 0.33mF ?
Maybe I just had to replace them all, as you already mentioned Wouter.
They didn't recommend me though to replace the coils: the decay of those would be minimal.
He didn't have any MKP's above 1mF. And 5 of those blocks...?

So: is it really advisable to replace all of the elko caps for MKP's ? And where do I find MKP's of 5,6 and 16mF? And what about the coils. Can you explain me what's making the difference changing them to air-coils?

Thanks you all for your advise. I have sound again.
Back to top
View user's profile Send private message
ColinR
Über Contributor 1000+


Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Fri May 27, 2005 4:25 pm    Post subject: Reply with quote

For the "techies" the T27 leg of the Cadenza crossover is a 24dB/octave Bessel configuration where L4 is zero! Rolling Eyes

Lowering capacitor values by 0.33uF will increase the effective crossover frequency by ~100Hz.

So you won't hear much difference. Smile

Do change all the capacitors, if one's gone senile the others will surely follow. Crying or Very sad

Make sure that they are at least 100V working in the bass leg and 50V in the treble.

Air core inductors saturate less easily, are more linear and have greater power handling capacity.

Sonically those who have modified the Ref 104 weren't impressed (do a "google" on newsgroups) as they gained nothing apart from an empty wallet.

The Cadenza may be the same. Crying or Very sad

The Concerto and it's many varients do benefit from the use of air cores, if you can be bothered to import them from the U.S.A.
Back to top
View user's profile Send private message
Tinus74
Introductory Contributor


Joined: 25 May 2005
Posts: 8

PostPosted: Fri May 27, 2005 10:06 pm    Post subject: Reply with quote

ok, so...leave it this way with the 4.7 and replace all of them..unless you're 'think' you hear the difference and are willing to empty your wallet.
ok.
One thing that can be beneficial for the cadenza's: my ears are probalbly not what they use to be Shocked

But still, ColinR, would you replace all the caps without any reason, I mean: without any hearable damage in the speaker?
I think i'ts a tricky question among sound-purists. What's the level of perfection if only the mind knows about it and the ears don't hear?
Back to top
View user's profile Send private message
ColinR
Über Contributor 1000+


Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Fri May 27, 2005 11:33 pm    Post subject: Reply with quote

Yes I would recommend that you replace all the capacitors in this instance as you have had some damage to the treble components, your electro-shop verified this, therefore there is a high probability that the bass capacitors will also be operating out of specification.

This won't affect the sound seriously as the inductors are doing their job, but the "off spec" capacitors may present your amplifier with an odd load at some frequency or other, which may or may not cause a problem in the future.

So, while your in there poking around, you may as well do a proper job, then you can forget them for about twenty odd years.

My personal approach would be different in that !'ve got a very expensive LCR meter, so I can measure all crossover component values to determine whether a replacement is required or not.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    SpeakerTalk Forum Index -> KEF Speakers from the 1970s All times are GMT + 1 Hour
Goto page 1, 2  Next
Page 1 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group