SpeakerTalk

andy ashworth · Posted: Thu Nov 20, 2003 3:31 pm Post subject: DIY LS3/5A subwoofers

Does anyone know where I can source NOS B139 and B200 drivers for a project ?

I would consider very good used drivers if available.

I know they are often available on ebay but it seems a little mercenary of the seller to buy classic speakers, then sell the drivers for profit (maybe I'm being silly/naive).

If anyone has any tips on using these drivers, that too would be appreciated.

Cheers,
Andy Ashworth.

terry · Posted: Fri Nov 28, 2003 10:10 pm Post subject:

Andy

I agree, I hate to see old KEF speakers being broken up for the drive units. I suppose that is why I have a loft full of old KEF speakers.

Have you tried Falcon? The URL I have provided here takes you straight to a section where there are some on sale.

Terry

andy ashworth · Posted: Wed Dec 03, 2003 12:41 pm Post subject:

I have spoken to Falcon and have also contacted the people selling items through their small ads section. As yet I have had no success.

The market for old KEFs appears to be dominated by a few individuals on Ebay who buy the speakers relatively cheaply, break them up and then sell the pairs of drivers seperately. Usually with a high reserve. I think a lot are trading on the coat-tails of the ls3/5a, usually advertising T27s and B110s as suitable replacements. To my knowledge, to satisfy the design parameters of this speaker, they would have to be very lucky to find a driver within the spec that had previously been fitted to a speaker other than the ls3/5a.

I love the LS3/5a, I have a pair of Kef 'Raymond Cooke' edition in my system but I do wonder how cheaply you could find any KEF drivers if it were not for these 'Little Legends' - ho hum.

Best regards,
Andy.

PS - Is there a 'best' version of the B139 and B200 ?

terry · Posted: Wed Dec 03, 2003 4:34 pm Post subject:

Andy

Although the LS3/5a has a devout following, that is really only a small part of the equation. There are incredible numbers of people still using Cadenzas, Concertos and the smaller speakers from the early C Series.

I am astounded by the number of people who email me asking about replacement ABRs for Cadenzas for example.

The B110s and B139s are also used widely in diy speakers including transmission line designs not to mention KefKits and Constructor series.

Then of course we have the Linn range (Isobarik, Kan etc).

The B139s are now popular items in subwoofer designs like the 'coffin'. I have more requests for information about where to buy or repair B139s than anything else.

As much as the LS3/5a is loved by a large number of people it is only a very small part of the equation when it comes to second-hand sales of the old drive units.

Terry

terry · Posted: Wed Dec 03, 2003 4:44 pm Post subject:

andy ashworth · Posted: Wed Dec 03, 2003 7:34 pm Post subject:

Thanks for the info, I'll keep my eyes open for a good pair of SP1044s.

I'll post my experiences with the project 'as and when'.

Best regards,
Andy Ashworth.

terry · Posted: Wed Dec 03, 2003 8:26 pm Post subject:

Andy

B139 SP1044 on eBay. The seller is calling them ABRs but they are not ABRs. This could confuse some people and you could get a bargain.

Terry

andy ashworth · Posted: Thu Dec 04, 2003 10:55 am Post subject:

Cheers, I am now watching them.

Andy.

andy ashworth · Posted: Mon Mar 15, 2004 5:30 pm Post subject: DIY LS3/5a subwoofers

Well I finally managed to get hold of some B139s (SP6167) for a 'bargain' price (4 for £80 on ebay). All that remains is to find a suitable set of plans for the cabinets and crossovers. KEF recommend a volume of 39.8 litres for an infinite baffle enclosure and around 60-70 litres for a ported one.
I think I would prefer the former as I have always found ported boxes seem to be unpredictable in smaller rooms. Being relatively compact is of primary importance I'm afraid, otherwise I'd be building a coffin !

Has anyone got or know of any info on such a project ?

Did kef manufacture a 3-way speaker that wasn't ported ?
The reason for this is that if the low-pass section had a cutoff at around 400hz, I could build an enclosure to match the volume for which the crossover was originally designed. As for the high-pass to the LS3/5a, that's going to take a bit more headscratching.
I know of the DN12 crossover but I don't think this would be suitable because of the different characteristics of the 2 enclosure types.

Maybe I should bite the bullet and bi-amp the lot, using simple low-pass and high-pass filters between the pre-amp and power-amps. At least that would solve the impedance and phasing problems Idea

!

Thanks,
Andy Ashworth.

terry · Posted: Mon Mar 15, 2004 5:44 pm Post subject: Re: DIY LS3/5a subwoofers

andy ashworth · Posted: Tue Mar 16, 2004 12:47 pm Post subject:

Thanks Terry, I must have missed that one when I looked a while back. It even looks like the low-pass section is available seperately so it could be ideal. I'll be contacting Falcon and picking their brains with regard to phase error, volumes, etc.

Regards,
Andy.