Cambrudge R50/Ex Baobab speakers - diyAudio
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Old 18th May 2013, 02:00 PM   #1
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Default Cambridge R50/Ex Baobab speakers

Although I do really like my Paralab 40s for some reason I have now become the owner of a pair of Cambridge R50s.
These appear to have had an unhappy past and now I am hoping to restore them to their former glory, lets wait and see.
These speakers were previously owned by a HiFi fan(?) and they are shown on his web site baobab-audio.com. Take a look. They were then sold to two others and now it is my turn. They arrived with me as cabinets only with R40 crossovers, fortunaly not the B&O ones previously fitted! Pictures will be added.
They look to be fairly original but with added speaker connections front and rear, none of them seem to be in line fully, the back ones will have to stay as they are drilled through formica and I am not going to make things worse.

If anyone knows how the fibrous panels were originally fitted please let me know and whether the R50s had the foam plug in the vent for the B110 chamber. The hole for the T27 has been butchered so will try to plug it and redrill it if I can get the original bass units.
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Last edited by ParalabFan; 18th May 2013 at 06:41 PM. Reason: Add picture
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Old 18th May 2013, 02:05 PM   #2
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Default Forgotten Pics

Oops I forgot to add the pics showing the cabinet makers initials.
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File Type: jpg DSC_0015small.jpg (58.4 KB, 43 views)
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Old 20th May 2013, 09:14 PM   #3
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Default Stuffing?

Does anyone have, or actually seen this type of filling in their R50s.

They are no doubt early models as they had the Racetrack style B139s,
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Old 21st May 2013, 03:56 PM   #4
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On Sunday night I was chasing a pair of Large speakers for my restoration, no names given so as not to alert too many people, After some frantic bidding I lost out and kicked myself for not putting in a larger amount sooner! Never mind I thought to myself I am bidding on some complete units which looked promising and some speakers with broken cabinets for the tweeters.

Hooray I won the complete speakers I wanted and then double checked the maker's Museum pages to discover that the speakers were rated at 15 Ohms, oh b***er I said to myself several times. Never mind they only cost me 25.00 plus 15.00 postage, less than the 45.00 before postage for the 2 I didn't win.

They arrived today, connected them up and for the size of the cabinet sounded quite good. Lets have a look inside, so undo all the screws and take off the backs remove the loft insulation and what do I see..... a lovely sticker that says 8 Ohms, someone is smiling on me at the moment. All shiny and as good as new!

Now if the broken cabinets arrive and the tweeters are good they will have cost me a fraction of the cost of others offered! Fingers crossed.

I feel sad that I will be breaking up a perfectly good pair of speakers but will try to sell on the T15s a a sensible price. Some of the most solid cabinets I have ever seen.
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Old 24th May 2013, 12:54 AM   #5
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I think I have found the source of that wierd looking fibrous stuff!

Le forum Audio Vintage • Afficher le sujet - B&W DM2 I

On this French forum there is a repair project for some B&W DM2s and the pieces appear to be from thesse. I have copied the pic,
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Old 24th May 2013, 07:22 AM   #6
DrBoar is offline DrBoar  Sweden
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The R50 is the B.J. Webb TLS and according toe Webb one kg of lambs wool per cabinet evenly distributed is the damping. The Webb design states that a plug of open foam should complety fill the opening of the midrange pipe. No qualities or measures are given but on the drawing the plug appear to be about 6 cm deep

With the whole pipe filled the design will work as a closed box with some resisitive venting. And clearing the last half of the pipe of damping material will not give that much of quarter wave behavior as the final section is only 1/3 of the driver area I expect the pipe itself to have substantial resistive losses.
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Old 24th May 2013, 11:15 AM   #7
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Thanks. It appears that, as the cabinets were built, not by Cambridge, that just the space behind the B139 and the last part of the line has wool in. The first part of the line has a thin layer of foam attached to the rear of the cabinet. I intend to staple foam carpet felt to the side walls and botton of the lower chamber in the hope it will help. I am still hoping that someone will answer my requests for pics of the inside of good R50s to help, lets wait and see.
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Old 24th May 2013, 11:41 AM   #8
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Managed to clean up the baffle boards, getting the old wiring loom out of the slot cut for it was a pain, but I have managed to keep the cloth from the vents for the B110 ports. The wiring looms were pretty well built all neatly tied together.
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File Type: jpg Baf3.jpg (79.8 KB, 16 views)
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File Type: jpg Baf4.jpg (72.5 KB, 15 views)
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Old 27th May 2013, 12:29 AM   #9
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Just been flicking through some old hi-fi news' and the earliest Ad for Cambridge R50s seems to be March 1973, they were for sale at C C Goodwin for 98.00. They also sold the B139 for 12.22, B110 at 7.58 and T27 at 6.00. Herts Hifi had the R50s at 164 a pair so the Goodwins price may have been each!

Not found a price for the Coles 4001 so was probably only available at specialist shops.
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Old 30th May 2013, 12:58 PM   #10
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Default Progress

I have now built up the new crossover from Falcon and started to put together the wiring while I get the drive units.
I have decided to make sure the baffle can be easily removed from the speaker so have bought some XT60 connectors. I think they are used in RC models bit are a gold plated and appear to have a very good current rating. Photos below.
Still looking for Kef B110s at sensible prices so, pehaps foolishly, I have ordered a pair of MONACOR SPH-135C units, but they were inexpensive. I can see myself getting a pair of new B110s from Falcon if all else fails and perhaps some new Coles 4001 as well.
Attached Images
File Type: jpg Connectors 1 R50.jpg (94.7 KB, 17 views)
File Type: jpg Connectors 2 R50.jpg (68.0 KB, 13 views)

Last edited by ParalabFan; 30th May 2013 at 12:59 PM. Reason: Bad spelling!
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