I have a set of jr149 speakers that are showing their age a bit. I purchased them new back in the 70's.
I am wondering if it would be worthwhile rebuilding them with some more modern components and if so what would you suggest. The woofers are the Kef B100 and I am not sure what the tweeters are. I do not want to alter the cabinets at all so I can retain the originality by simply replacing the old parts if needed (probably not, but not a bad idea).
Any suggestions would be appreciated.
Thanks
Jeremy
I am wondering if it would be worthwhile rebuilding them with some more modern components and if so what would you suggest. The woofers are the Kef B100 and I am not sure what the tweeters are. I do not want to alter the cabinets at all so I can retain the originality by simply replacing the old parts if needed (probably not, but not a bad idea).
Any suggestions would be appreciated.
Thanks
Jeremy
You do realise your speakers something of a collectors item? They are worth a small fortune over here. Rebuilding them with "modern components"is a bad idea. Really.
Indeed they are collectors items by now.
I'd sell them and build something better with the profits.
I'd sell them and build something better with the profits.
Hi,
The drivers are the high impedance KEF B110 and T27 used in the original
high impedance BBC LS3/5A and as such are highly desirable as spare parts.
You may be able to sell the drivers (and c/o) as parts for more than the
speakers. If so the cabinets would make a nice basis for a project.
rgds, sreten.
The drivers are the high impedance KEF B110 and T27 used in the original
high impedance BBC LS3/5A and as such are highly desirable as spare parts.
You may be able to sell the drivers (and c/o) as parts for more than the
speakers. If so the cabinets would make a nice basis for a project.
rgds, sreten.
Only chipping in because Jim Rogers was a bit of a legend. He based the JR149 on the famous tiny BBC LS3/5A which he also designed IIRC. Better cylindrical metal cabinet and a bit more bass extension.
Lots of info available like this site: jr149
Looks like the original design was very crossover equalised for the KEF B110 SP1003 bass and T27 treble. Baffle step, some reduction of peaks and Zobels an all. Later designs used a Focal 110mm unit and scanspeak tweeter with simplified 3rd order filters. Nothing there that ought to deteriorate too badly except the usual glue and surrounds and covering foam, I'd reckon. 🙂
Lots of info available like this site: jr149
Looks like the original design was very crossover equalised for the KEF B110 SP1003 bass and T27 treble. Baffle step, some reduction of peaks and Zobels an all. Later designs used a Focal 110mm unit and scanspeak tweeter with simplified 3rd order filters. Nothing there that ought to deteriorate too badly except the usual glue and surrounds and covering foam, I'd reckon. 🙂
Hi,
Different version of the B110 I believe to the later version, T27 the same.
There are four versions of the B110, all "standard" 8 ohm.
The 11 ohm version requires matching drivers and c/o, as driver
variation to some extent was compensated in each crossover.
PITA having to check something true because being contradicted. Pre
1987 T27's are still worth more even though they are nominally the same.
Whatever the details (and there are lots more to argue about) the
drivers are worth a lot in the far east, if correct type and vintage.
rgds, sreten.
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B110 SP1003 is an 8 ohm driver -- essentially what i stated.
http://p10hifi.net/planet10/TLS/drivers/images/B110/B110_SP1003.gif
Yes, there are no high impedance B110 (or T27)
dave
http://p10hifi.net/planet10/TLS/drivers/images/B110/B110_SP1003.gif
Yes, there are no high impedance B110 (or T27)
dave
Hi,
Post #4 didn't come out right. The versions are the same as in the high
impedance version of the LS3/5A, not high impedance driver versions.
(Though some LS3/5A'ers might refer to them that way).
rgds, sreten.
Post #4 didn't come out right. The versions are the same as in the high
impedance version of the LS3/5A, not high impedance driver versions.
(Though some LS3/5A'ers might refer to them that way).
rgds, sreten.
Thanks to all for your information. I will have to now consider what to do with these speakers if they are worth preserving, or selling the parts. I will take a closer look at them and find out exactly which model or year they are. The foam covers have gone completely, just rotted away and turned to dust but the rosewood cabinets are in excellent condition.
Keep them and use them, or sell them as is. It's a shame to see classic speakers parted out unnecessarily, but it's your money.
Vintage HiFi is a pleasure all in itself. Those older engineers understood how to get the various parts working together nicely. BBC designs were often tailored for matching components, and when you got it right, they just SANG! 😀
God bless my soul. What I would give for my old Garrard 401/SME tonearm with Decca London MC cartridge, Radford STA25 valve amp and simple Goodmans box 2-way speakers with 5 Amp cablewire! Magic! 😎
God bless my soul. What I would give for my old Garrard 401/SME tonearm with Decca London MC cartridge, Radford STA25 valve amp and simple Goodmans box 2-way speakers with 5 Amp cablewire! Magic! 😎
Later versions of the JR149 used Focal drivers.
Falcon Acoustics is a good source of materials for them. They used to import Focal drivers and the founder of Falcon worked for KEF. The company used to supply crossovers for the Goodmans and RAM versions of the LA3/5a LS3/5A.
Falcon Acoustics | The Leading DIY Speaker Parts and Kit Supplier since 1972
Rogers JR149 Mk1 and Mk2 Replacement Capacitor set
They also have a cabinet kit for the LS3/5a to approved BBC spec (and it's not the most expensive out there, either)
LS3/5a cabinet kits, drivers, crossovers and parts.
Falcon Acoustics is a good source of materials for them. They used to import Focal drivers and the founder of Falcon worked for KEF. The company used to supply crossovers for the Goodmans and RAM versions of the LA3/5a LS3/5A.
Falcon Acoustics | The Leading DIY Speaker Parts and Kit Supplier since 1972
Rogers JR149 Mk1 and Mk2 Replacement Capacitor set
They also have a cabinet kit for the LS3/5a to approved BBC spec (and it's not the most expensive out there, either)
LS3/5a cabinet kits, drivers, crossovers and parts.
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Ooh, yes. Good link! 😀
I'd assumed the caps would be polypropylene or something nice for the most part. They're not. 20-y-o non-polar electrolytics have gotta only be fit for the dustbin. REPLACE IMMEDIATELY! 😎
My red bottom JR149 are original. The caps are NOT ElCrap electrolytic. They use the tan colored STC Polycarbonate caps for the 3.3uf locations and two Mullard Tropical Fish 1.5uf in the B110 circuit. The 1.5uf used to shunt, was physically cracking at both ends in both speakers. While they still tested good on my Sprague TO-5, I went ahead and replaced them with 1.5uf 250v green ERO caps. I have a bag full of these - NOS - and have seen these used in these crossovers... so, they remain authentic. The two 1.5uf tropical fish that are in series with the B110 were completely good and they were put back in. I removed each component individually, tested it, and reinserted with firm connection and new soldier. My point is, not all of these used electrolytic caps. So, perhaps Mr. Rogers voiced them with metalized Polycarbonate and Polyester caps originally.
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