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Coda crossover
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Alex
Introductory Contributor


Joined: 27 Jul 2006
Posts: 5

PostPosted: Thu Aug 24, 2006 2:25 pm    Post subject: Coda crossover Reply with quote

Hi, Have B110s and T27s and consructing spkrs based on Coda design. I see that Falcon offer c/o to original Coda spec. ( £9.50 ) these would be fine but would prefer to wire up myself.... would much appreciate layout and values of components. Also wire spec. for inductors if it is necessary to make these up.
Thank You
Alex
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proffski
Über Contributor 1000+


Joined: 22 Aug 2003
Posts: 1297
Location: Tewkesbury UK

PostPosted: Thu Aug 24, 2006 5:45 pm    Post subject: Re: Coda crossover Reply with quote

All you need to know is on this most excellent website already!
If you missed the technical bit have a long browse on: http://hifiloudspeakers.info/Anatomy/Anatomy.html

You will then see not only original KEF information regarding the Coda, but pictures as well as details regarding the crossover components, cabinet etc from the KEF CS1 Kit. All you could possibly want.

A suberb source of knowledge and information...
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ColinR
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Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Thu Aug 24, 2006 8:32 pm    Post subject: Reply with quote

Quote:
details regarding the crossover components


No you won't Shocked .

As it's elsewhere Smile, as I couldn't be bothered to draw the schematic Rolling Eyes .

B110 half section, 0.8mH, 6uF.

T27 half section, 5uF, 0.25mH.


Inductor RDC ~0.3 Ohm, Capacitors 50V L.L.

That's assuming you're going to use some form of low powered SAD valve amplifier.

Greater performance will be achieved by using an aB treble section and a more complex bass section Very Happy .
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proffski
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Joined: 22 Aug 2003
Posts: 1297
Location: Tewkesbury UK

PostPosted: Thu Aug 24, 2006 9:16 pm    Post subject: Reply with quote

What? Me? Wrong? Embarassed Never been known!

Trouble with assumptions that using Acoustic Butterworth would come as obvious to all and sundry! Why stop at second order crossover?

Small increase in cabinet volume within reason is beneficial without causing too much havoc in the bass region.

Good Luck!
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Gary
Senior Contributor 200+


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

PostPosted: Fri Aug 25, 2006 10:44 pm    Post subject: Reply with quote

This is a great site and all but sometimes I have no idea what people are talking about. Embarassed

On the other hand, I learned recently that you hold a screwdriver by the thick end, not the skinny end. Rolling Eyes
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proffski
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Joined: 22 Aug 2003
Posts: 1297
Location: Tewkesbury UK

PostPosted: Sat Aug 26, 2006 12:05 am    Post subject: Weller. Reply with quote

Hi Garry!

Pro Noblem! Being moved to paper pushing for a year I found it a shock when I picked up my trusty Weller Soldering Iron by the wrong end... Confused

Damned good site though eh?

Gary wrote:
This is a great site and all but sometimes I have no idea what people are talking about. Embarassed

On the other hand, I learned recently that you hold a screwdriver by the thick end, not the skinny end. Rolling Eyes
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Gary
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Joined: 07 Nov 2004
Posts: 275
Location: Toronto, Canada

PostPosted: Sat Aug 26, 2006 1:24 am    Post subject: Reply with quote

Yes, I've grabbed an iron by the wrong end, too! Know how to prevent bad blisters? Soak the burn in Javex bleach and water!

Fantastic site! Smile
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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)
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terry
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Joined: 22 Apr 2003
Posts: 262
Location: UK

PostPosted: Sat Aug 26, 2006 10:18 am    Post subject: Could be better Reply with quote

Thanks all. Very Happy Site could be a lot better though if I could find the time to publish the wealth of contributed information sent to me. Embarassed Sorry about that folks. Sad
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ColinR
Über Contributor 1000+


Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Sat Aug 26, 2006 10:19 am    Post subject: Reply with quote

Cool


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


A half section
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proffski
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Joined: 22 Aug 2003
Posts: 1297
Location: Tewkesbury UK

PostPosted: Sat Aug 26, 2006 2:31 pm    Post subject: Reply with quote

2nd order 12db octave...
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JimN
Introductory Contributor


Joined: 19 Dec 2005
Posts: 8
Location: London, England

PostPosted: Sun Aug 27, 2006 12:08 am    Post subject: Coda crossover Reply with quote

Hi,
A small point worth mentioning is that with half section networks the drivers are usually connected out of phase. However, the Coda units are connected in phase.
I assume the B110 is SP1003 and as such it might be better to use the CS1A crossover, and rear mount the driver. The CS1 crossover is better suited to a front mounted SP1057/SP1032 combination.
Regards,
Jim
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proffski
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Joined: 22 Aug 2003
Posts: 1297
Location: Tewkesbury UK

PostPosted: Sun Aug 27, 2006 12:50 am    Post subject: Re: Coda crossover Reply with quote

Ah yes, but look at the design, it is 3rd order with the clever ab stuck on.
18db octave with the inevitable phase anomaly. Therefore that is correct!
So, all the answers are in the website after all... As expected.
Yum!



JimN wrote:
Hi,
A small point worth mentioning is that with half section networks the drivers are usually connected out of phase. However, the Coda units are connected in phase.
I assume the B110 is SP1003 and as such it might be better to use the CS1A crossover, and rear mount the driver. The CS1 crossover is better suited to a front mounted SP1057/SP1032 combination.
Regards,
Jim
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JimN
Introductory Contributor


Joined: 19 Dec 2005
Posts: 8
Location: London, England

PostPosted: Sun Aug 27, 2006 8:55 am    Post subject: Coda crossover Reply with quote

Hi,
Yes, but I was referring to the original Coda crossover (2nd order, 12dB/octave). It is usual to connect the units out of phase with 2nd order networks, but KEF, it seems, chose to do otherwise and probably with good reason.
The CS1 and CS1A crossovers are, as you say, correct and were only really mentioned as possible improvements, depending on the B110 type.
Regards,
Jim
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proffski
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Joined: 22 Aug 2003
Posts: 1297
Location: Tewkesbury UK

PostPosted: Sun Aug 27, 2006 11:03 am    Post subject: Re: Coda crossover Reply with quote

Interesting, a fact I had not been aware of!

I'll dig up mine and do some tests with pink & white noise as well as musical input.

Now look at what you have started! Laughing
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Alex
Introductory Contributor


Joined: 27 Jul 2006
Posts: 5

PostPosted: Sun Aug 27, 2006 9:23 pm    Post subject: Reply with quote

Many thanks to all who responded to my crossover queries....info. most helpful and a useful intro. to a very excellent site. One has also to include the to and fro banter re. screwdrivers and first aid advice on the treatment of soldering iron burns. Handy to know that!
I'm a new kid to this game (but an old one) with pretty scant knowledge on matters technical or theoretical but capable of following constructional details. No soldering burns (yet!!). However, interest in making x/over coils has run aground and evaporated since turning up a web site " Wouter's Homebrew Crossovers" on http://retro.co.za/audio/xover.html
Full details on coil construction but complicated.

Has anyone any info on coil suppliers....I understand that neither Falcon nor Maplins stock them now.

Regards. Alex.
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