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15 and 11 ohm Rogers LS3/5a's

 
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mech986
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Joined: 19 Oct 2004
Posts: 6
Location: La Habra, California USA

PostPosted: Sat Apr 15, 2006 3:55 am    Post subject: 15 and 11 ohm Rogers LS3/5a's Reply with quote

Here's a little information on the Rogers transistion from the "15 ohm" to "11 ohm" versions and why some Rogers look like they had B110B SP1057's.

Well, to be fair, the KEF B110C SP1228 looks very much like the B110B SP1057 because they use a similar looking flatter surround and have a smooth outer cone surface (the damping is on the back of the cone).

Having said that, Rogers made it a bit confusing by beginning to use the SP1228 based KEF LS3/5a redesign of 1987 but continuing to use the stock of 15 ohm based labels they had for the older B110 SP1003 version.

So there are a lot of "15 ohm" Rogers LS3/5a's (starting around 032000 IIRC through around 034000) that have the newer 11 ohm version parts (SP1228 and revised crossover). On the Yahoo! LS3/5a newsgroup, we call these "Psuedo 15 ohm" units.

Most ebay sellers don't really know or understand the difference and are reluctant to open the baffle to show the inner workings of their speakers (understandable). Also, per a friend who does a lot of buying and selling of LS3/5a's, British law prohibits him from describing the speakers as anything different from the manufacturer's ID labels.

Hope this helps to clarify or obsfucate!
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Bart
mech986
Yahoo! LS3/5a newsgroup moderator
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proffski
Über Contributor 1000+


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

PostPosted: Sun Apr 16, 2006 1:20 am    Post subject: Re: 15 and 11 ohm Rogers LS3/5a's Reply with quote

How absolutely true! Too many sharks and too many idiots on ePay keeping the prices so high.
Still, amazing when you think the following and worship that KEF has earnt from their creation in the foundry.
Not too many speaker manufcturers in the world with such a universal bunch of devoted apostles, is there?
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Parts
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Joined: 13 Jan 2006
Posts: 174
Location: Edinburgh

PostPosted: Sun Apr 16, 2006 9:35 am    Post subject: Reply with quote

Some people dont want to remember these were rated average plus at around £200 rrp once, they also don't seem to believe me when I say they used to be available during the mid/late 80's from £35 upwards a pair second hand as were kans , BC1 , Rogers studio moniters etc.

They seem to forget that before the internet , that due to size and power handling a lot of the old classics were deemed worthless by most and picked up by people with little income from second hand shops.

How the world has changed.
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ColinR
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Joined: 31 Jul 2004
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Location: Staffordshire

PostPosted: Sat May 20, 2006 10:45 am    Post subject: Reply with quote

Very Happy I upset someone yesterday Evil or Very Mad .

I only suggested that all 15 Ohm LS3/5a's currently being sold and any spares should have (slow speed - high resolution) B&K traces no older than a seven days attached, to show that they were still in specification Cool .

Quote:
rated average plus at around £200 rrp


That's a bit expensive, in 1982 I could have got them for £100-£125, but I bought the much better Ref 101's instead Shocked .
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Parts
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Joined: 13 Jan 2006
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Location: Edinburgh

PostPosted: Sat May 20, 2006 6:44 pm    Post subject: Reply with quote

Yes £200 according to 1981 hi fi choice ?

Interesting remark regarding the B&K check.

I have sudgested the specs of most of the old BC1's etc would not be correct today due to age.

I was also sure that the Rogers studio 1 was developed from the Export which was a development from the LS range, the LS7 developed from the Studio , and I was told these are nowhere near the performance of the BC1
.
I myself though the Export compaired well with the original alnico BC1.
I also read reviews which had the 1980's BC1 and Studio 1 as equal best buys with similar characteristics.

But I have since been told Rogers did not put the effort into their driver selection for the Studio range ?
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ColinR
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PostPosted: Sat May 20, 2006 7:40 pm    Post subject: Reply with quote

Quote:
I myself though the Export compaired well with the original alnico BC1


Most "olde world" dealers and myself would tend to agree.

Original Exports with the round Celestion HF1300 & HF2000 sound much better than the more common later versions with the square HF1300 & KEF T27 with a "BBC OB hammer protector" diffuser.

It's not the T27 for those not in the know, the accountant driven, square HF1300 is just not up to the same standard of the earlier version.

Quote:
Rogers did not put the effort into their driver selection for the Studio range


Probably, as they used a Dalesford unit for the Export. A case of could have done better?


Regarding the B&K check, I once asked a current ePay vendor who sells "KEF matched (sic) drivers" whether he supplied B&K and IMP waterfall traces with his serial number free >£300 products. Never got a reply Very Happy .
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proffski
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Joined: 22 Aug 2003
Posts: 1297
Location: Tewkesbury UK

PostPosted: Sat Jun 10, 2006 11:38 pm    Post subject: Reply with quote

Sad fact Colin is that there are obviously people out there not knowing as to what they are buying and why they are buying it.

I'd be very surprised if the vendor had any idea as to what a B&K graph is in the first place!

And as far as a waterfall in a speaker, the mind boggles... Shocked I'll bet they have no idea whatsoever.

I'd rather give away my surplus KEF collection if I was 100% sure that it would be used by a real enthusiast and not end up on ePay!!!
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