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Coda crossover
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proffski
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Joined: 22 Aug 2003
Posts: 1297
Location: Tewkesbury UK

PostPosted: Sun Aug 27, 2006 10:33 pm    Post subject: Reply with quote

Making your own inductors can be a pain.

Wilmslow still sell inductors!
Try https://secure.wilmslow-audio.co.uk/acatalog/Wilmslow_Audio_Inductors_51.html
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JimN
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Joined: 19 Dec 2005
Posts: 8
Location: London, England

PostPosted: Mon Aug 28, 2006 11:12 am    Post subject: Coda crossover Reply with quote

Hi,
Sorry, Proffski, for urging you to get out the test equipment Smile, but I must confess I would be most interested to see the results, so please post them.
And, Alex, I think most of your original questions have been answered apart from layout. Well, provided that you mount the two inductors at right angles to each other you should have no problems.
It's a shame that Falcon no longer supply inductors because, as Proffski says, they are a real pain to wind by hand, especially the larger values. Besides, I don't know of anywhere that sells the cores.
You could also try IPL Acoustics for ready-made inductors.
http://www.iplacoustics.co.uk/ipl_crossover_components.htm
Anyway, I wish you both luck with your tests/project.
Regards,
Jim
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proffski
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PostPosted: Mon Aug 28, 2006 12:14 pm    Post subject: Re: Coda crossover Reply with quote

Indeed, even with the help of an LCR meter, you cannot predict the 'Q' of an inductor which could have profound effects on the results.
I have a friend with a coil winding machine, must have words one of these days...

My small Coda KEFs are on loan at the moment, expected back any day now.
I simply will as mentioned, listen to them via white noise and pink noise switching the polarity of the HF unit. Then some massed choir, strings etc and see what the ears tell me.
I'd be tempted to do a frequency sweep, but not having automated B&K equipment or similar might take longer than I'm willing suffer.
Having all inductors at right angles to each other is always good engineering practice.
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Seymour
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Joined: 04 Jun 2007
Posts: 7
Location: Melbourne, Australia

PostPosted: Tue Jun 05, 2007 10:24 am    Post subject: Reply with quote

Hi all,

First time poster, long time reader.

I have a pair of Coda 1 cabinets that I purchased on e-Bay that are in excellent condition. Into these cabinets Iíve fitted brand new T27s & B110s and was wondering whether the following is correct. I know the B110s I've purchased are the last generation released by Kef and as such they are not the original part no but I am keen to give this set-up a go.

+ ------------C1---------------------I--------------------------------- +ve
................................................ I
................................................ I
................................................ I
............................................... L1
................................................ I
................................................ I
................................................ I
................................................ I
---------------------------------------I -------------------------------- -ve

T27 half section, 5uF, 0.25mH

+ ------------L1----------------------I--------------------------------- +ve
................................................ I
................................................ I
................................................ I
............................................... C1
................................................ I
................................................ I
................................................ I
................................................ I
---------------------------------------I -------------------------------- -ve

B110 half section, 0.8mH, 6uF
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CS
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proffski
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PostPosted: Tue Jun 05, 2007 7:02 pm    Post subject: KEF CS1 Reply with quote

The basic Coda crossover does the T27 SP1032 little favours... Shocked
Have you got the original crossovers?

Improvements were made to the crossover in the CS1 / CS1A kits.
However, they do sound different to the Coda.

The original unit in the CS1 kit used the B110 SP1057
Wheras the CS1A utilised the B110 SP1003, both different beasts.

Why not go for the full monty?

Please have a peep at the CS1 information under Technical on this site.
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Seymour
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Joined: 04 Jun 2007
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Location: Melbourne, Australia

PostPosted: Tue Jun 05, 2007 10:31 pm    Post subject: Reply with quote

proffski, thanks for the reply. I have considered the CS1 xover but I'm concerned with the impact of using the 6-ohm B110 that I have. Will try and look up the part no.

PS - Do you know whether the xover design in my original post is correct?

Thanks again.
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CS
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proffski
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Joined: 22 Aug 2003
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PostPosted: Tue Jun 05, 2007 11:28 pm    Post subject: KEF B110 Variants. Reply with quote

What is the KEF SP designation on your B110?
There should be a small white sticker on the back of the B110 somwhere.

I may still have the original Coda crossovers somewhere, but remember that they have been designed for 8 ohm impedance.

The specification for the SP1057 and SP1003 is eight ohms nominal impedance and 7.1 ohms DC resistance with the usual tolerances.

The crossover you propose is not wrong but neither does it resemble anything that KEF have produced as far as I know...
Half of it seems to be missing.

If the units you have are B110 A6340 - B110 A6362 - B110 SP1228 - B110C then sadly neither do I have any information on them nor do I know anything at all about them.
B110C

There is some information here: http://www.pinkfishmedia.net/forum/showthread.php?t=1132

Perhaps the two usual suspects may be able to help you out here?
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man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill
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Seymour
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Joined: 04 Jun 2007
Posts: 7
Location: Melbourne, Australia

PostPosted: Wed Jun 06, 2007 4:48 am    Post subject: Reply with quote

Proffski, they're B110 SP1228 (6-ohms). If I'm to take a calculated risk am I better proceeding with the original, simpler Coda 1 xover or will the CS1 prove to be an overall better option? Comments/feedback greatly appreciated.
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CS
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