KEF Corelli crossover help

I picked up a pair of KEF Corelli speakers at a garage sale this weekend. When I hooked them up, one sounded "buzzy." It seemed mostly isolated to the tweeter, but the woofer sounded off as well. I finally got around to opening up the offending speaker and it looks like one of the caps is in bad shape.

There's another doodad (I'm still learning the ropes!) that appears burned as well. Just under the fuzzy cap there's something that appears to be wrapped in masking tape and it looks scorched.

I plan to recap these, but what is that scorched masking tape thing? Is it just tainted by the outgassing capacitor or is it toasted? Also, does anyone know if the fuzzy gray cap has the same specs as the one just above it (0.6uf 50V)? And finally, what should I look for on replacement caps (e.g. % variance)?

Thanks,
Tony

Those are inductors with the masking tape on them. Are you sure the grey component is a capacitor? Could be a resistor. Try a google search for the crossover schematic, or possibly the Kef website.

It might very well be a resistor. I found a schematic for a similar model and there was no second 0.6uf capacitor. I can't find a Corelli specific schematic, though.

Clumsily mashed out by my thumbs on a cell phone.

Read this,
http://www.diyaudio.com/forums/multi-way/189530-kef-104-kef-104ab-mkii-sp
They're not your speakers, but they use similar components, capacitors, inductors, ferrite coil, etc...
It also gives you which capacitors type and value as replacement, although the proper value should be for your own model, the Corelli.

Here's your schematic for your speaker.
http://www.hifiloudspeakers.info/Anatomy/Crossovers/DN17SP1052Corelli/Gallery/pages/corelli.htm

Although if you follow the arrow on the schematic, you will see that the cross-over is somewhat different than yours.

As a rule, the cross-over are not interchangeable from model to model.

It might very well be the same, but configured in a different patern. Look at the number behind yours and see if it's the same as the one shown in the picture, model SP1052

A bit more info for you, the cross-over are the DN-17 model, and should also mention SP-1052 on the back.

Thanks, moinau. Apparently I have the SP-1051 model. I'll try to pull the crossover tonight if i have time and read the back.
The gray fuzzy fella looks to be a resistor, though, based on the "almost" schematics I've seen.

Clumsily mashed out by my thumbs on a cell phone.

EDIT: I just learned that the speaker model is 1051, but the crossover has its own model number, presumably 1052. I'll double check my crossover model number later tonight.

I found a pair of Carlton lll's and I had a buzz, tracked it down to the woofer. Rotated the woofer, switched the woofers between speakers, still the buzz. Finally peeled the surround carefully off and resealed it using a 30hz test tone. No more buzz, with these woofers being around 40 years of age it could be the spider and surrounds sagging. Just a thought.

I had some corelli's in the house s year or two ago. They looked nice and sounded ok, but could've sounded much better. After seeing a pic of your crossover, I can see that I might've benefitted from a recap. You should probably replace ALL those old caps.

I will replace all of the caps before I judge these speakers. They are highly regarded, apparently, and it would be a shame to pass them on before I hear them at their best.

And moinau's first link is messed up. For posterity's sake, it's:
http://www.diyaudio.com/forums/multi-way/189530-kef-104-kef-104ab-mkii-spice.html

Sorry about that tyella, must of done something wrong when I sent it.

Lots of good info on this forum. They deal mainly about KEF from the 60s, 70s, and 80s.
http://www.hifiloudspeakers.info/speakertalk/

Your speaker is one of the same family as mine. I've the Calinda.

Wow! That forum is amazing for KEF information. Thanks, moinau! A few hours of research with a beer in hand (then another) and I'll be ready to tackle the job.
Expect more questions, but thanks for the answers so far!

Here's your best advice:

Take your digital photos and contact Jerry Bloomfield at Falcon Acoustics in Britain at http://www.falconacoustics.co.uk/ and email via http://www.falconacoustics.co.uk/contacts/.

Advise him that Bart from AudioKarma and Yahoo LS3/5a referred you (along with a dozen other AK members). He can come up with ALL of the components on the board if you're concerned they have been damaged or failed. I would certainly replace all the capacitors, and the resistor (which does get powdery with heat) and the suspect inductor(s).

Falcon can supply the exact replacements because founder Malcolm Jones was a KEF employee and engineer, and likely worked on the Corelli and finished the 104aB before he left to establish Falcon as an inductor supplier and crossover parts supplier, including to KEF. They have current equivalent electrolytic caps which will retain the correct parameters to voice the speakers as they were intended. In this case, substitution of films caps may alter that voicing. I'm very confident Falcon can come up with a kit of parts to make your crossovers as new.

It is important to try rotating the woofers or switch them from side to side to see if the issue is woofer or cabinet/crossover. However, with any British speakers of this vintage, time and time again many AK'ers have found the crossovers to have aged and affect the sound adversely. Many KEF, IMF, and Celestion speakers of this vintage really benefit from crossover refurbishment.

Search for speaker recap projects to get a feel for it, your are not too high in parts count so should be very straightforward.

Good luck!

moinau said:

Sorry about that tyella, must of done something wrong when I sent it.

Lots of good info on this forum. They deal mainly about KEF from the 60s, 70s, and 80s.
http://www.hifiloudspeakers.info/speakertalk/

Your speaker is one of the same family as mine. I've the Calinda.

Click to expand...

Yes, another great source of KEF info and discussion. I've got the KEF Cantata's, 101's, and various LS3/5a's and IMF's.

+1 on Falcon Acoustics in GBR,
Great place for LS3/5a, KEF, Rogers, and lots more, including crossover kit, and their famous T-27 replacement, not cheap by any mean, but of the highest quality.

Following up on this, now that I've had time to look at it again.
The inductor looks fried. Not only is it discolored, but its plastic spool is melted a bit and it's sagging.
Does anyone know the inductance value for it? There are many posts where folks say they will test the good one, but nobody has posted a follow up with the value. I don't have the gizmos to test inductance.
I don't want to sink a bunch of money into these speakers unless I think they're keepers. Honestly, I'm tempted to buy some old crossovers from that auction site and recap them.

Well, I picked up some working crossovers from eBay. I installed one in the damaged speaker and all is good!

In the somewhat near future I will replace capacitors, but I'm happy just to get them working. Some Restore-a-Finish followed by Feed and Wax and I'm delighted.

Now for those AR-1x speakers.....

These speakers have changed hands and are now mine found both of the 2 mh inductors on the green original boards were bad , they both had shorted winding's and the values had both drastically changed .The 30 uf caps had shorted so i replaced them and all the other caps with polypropylene .

None of the shown diagrams are correct , will draw it up latter and post the correct diagram here .

Right now i'm using them as near field monitors on my computer , driven by a HK PM665 amp

The Crossover uses three 10 uf caps , one .6 uf cap , one 3.3 uf and one 30 uf caps all the original are 50 volts non-polar electrolytic .

Mark

Glad you got them up and running correctly, Mark! I thought I had them good to go, but I guess either I don't have the ear, or my home acoustics are bad. Probably a little of both.

How do they sound now?

This crossover is wrong for these speakers http://www.hifiloudspeakers.info/Anatomy/Crossovers/DN17SP1052Corelli/Gallery/pages/corelli.htm

I drew the correct one




Will post some photos of the new inductors when i wind them