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Crossover details for Coles 4001?

 
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rodb
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Location: Canberra Australia

PostPosted: Wed May 05, 2010 1:23 pm    Post subject: Crossover details for Coles 4001? Reply with quote

I have had a set of Baileys TLS speakers since I built them over 30 years ago and still love them...
I have decided to build another set with a slightly different physical configuration and I have bought some speakers for them. They are B139, B110, T27 and included in the purchase are two Coles 4001 tweeters. I haven't been able to find out much about the Coles, particularly what is needed for the crossover for them. I have the details for the KEF drivers however.

Does anyone know what crossover is required?

Cheers...Rod
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ColinR
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PostPosted: Wed May 05, 2010 3:05 pm    Post subject: Reply with quote

Neutral The 16 Ohm Coles 4001G used in Cambridge R50s & knockoffs, Spendor BC and SP 1s, B&W DM 2 and 4.

Either use a half-section; 0.47uF in series with and 0.3mH across the drive unit.

Or the alternative Spendorish topography of a 1uF, 0.1mH, 1uF tee-section.


The 8 Ohm 4001K like the Celestion HF2000 uses a 2.2uF capacitor in series, which suggests the half-section 2uF in series and 0.18mH across the drive unit is also applicable.

The published tee-section for a HF2000 in a Ditton 66 is good from 5kHz, but a Coles K or G is only good from 7kHz so you'd have to come up with your own figures as both drive units have limited power handling capacities below ~9kHz, hence they're all best crossed over at 10kHz or above just like all the examples I've given Cool .
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rodb
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Location: Canberra Australia

PostPosted: Thu May 06, 2010 10:21 am    Post subject: Reply with quote

Thanks for the info, as all 8 speakers came from the same boxes (don't know which ones) I'll start with using 10khz and see what happens.

Cheers
Rod
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ColinR
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PostPosted: Thu May 06, 2010 1:46 pm    Post subject: Reply with quote

Just for completeness here are the specifications for the ITT/STC/Coles 4001 K & G.


Frequency Range 1.2KHz - 35KHz
Useable Frequency Response 8KHz - 35KHz; 5KHz - 25KHz +/-2dB.
Free Air Resonanance 1.6KHz
Nominal Impedance /K = 7 OHM /G = 16 OHM
D.C. Resistance /K = 6 OHM /G = 23 OHM
Sensitivity (dB for 1 Watt @ 1 Metre): /K 87dB 15K /G 85dB 15K

As I've got a "proper" B&K frequency plot, i.m.h.o. the units are only really useable above ~9kHz.
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TL 200
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Location: Emmer-Compascuum The Netherlands

PostPosted: Fri Jun 04, 2010 11:48 am    Post subject: Reply with quote

Here is a link to original Coles 4001 documentation.http://new-hifi-classic.de/Gallery_MO/displayimage.php?album=search&cat=0&pos=0 last two pics, first is CE 4001
Lots of documents and brochures on this site, all vintage, have fun.
link to homepagehttp://new-hifi-classic.de/Gallery_MO/index.php
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ColinR
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PostPosted: Wed Jun 09, 2010 5:02 pm    Post subject: Reply with quote

One slight problem, the first link goes to "no image" and there's no ITT/STC/Coles in the list.
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audiolabtower
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PostPosted: Wed Jun 09, 2010 5:19 pm    Post subject: Reply with quote

I had the same problem, but if you put "coles" in the search box you should get 3 pages of scans.
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TL 200
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PostPosted: Wed Jun 09, 2010 5:48 pm    Post subject: Reply with quote

audiolabtower wrote:
I had the same problem, but if you put "coles" in the search box you should get 3 pages of scans.

You're right, something weird is going on, link works fine to me, suddenly doesn't, sometimes does Confused
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TL 200
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Location: Emmer-Compascuum The Netherlands

PostPosted: Thu Jun 10, 2010 8:30 am    Post subject: Reply with quote

ColinR wrote:
One slight problem, the first link goes to "no image" and there's no ITT/STC/Coles in the list.


Look for IMF Colin, there are the datasheets and brochures.
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