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Kerbside find. Now what to do ...


Brisso57

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I found these sitting out in the rain on a kerbside.

The boxes looked solid, so I stopped to investigate.

Found these:

2 x B139

2 x B110

+ 4 x tweeters in ??? condition. (AMW Acoustic Labs Model A440's)

Fired them up just now. Woo-hoo! They work. (Just the boxes were crap.)

[ATTACH]14817[/ATTACH]

Now, suggestions about what to build with the B139 & B110 pairs.

I have a range of other tweeters in the cupboard, so let's assume I have that part covered.

I read the B139's like BIG boxes.

What the smallest box that likely to get good results from them?

Ideas?

Doug

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Great find. Yet another design utilising predominantly KEF drivers. The tweeter looks like a Coles 4001 or similar - I think Peerless units were used too. Wouldn't be surprised if the super tweet was Coles too.

They would be great for a KefKit build. Should be lots of info on the net. Or Falcon Acoustics in the UK may still supply the Kits. There are many designs out there.

Even with stuffed cabinets, the B139s and B110s can each fetch up to $200 a pair on a good day.

Recall seeing a pair for sale recently. Maybe they ended up on your kerbside. Great that someone with an interest found them.

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Nice find. AMW built, arguably, the best KEF based speakers ever. Crossovers and wiring were not the best, but, when they were working, they were very good indeed. Duplicate the cabinets exactly. along with the crossovers, add a Coles supertweeter and you'll enjoy superb sound quality.

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Hi Doug,

Great find............I used these drivers [originally Keff Concerto] with some success in several TL designs back in the early 70's and I'd still have the designs if you're interested. Let me know and I can scan and send them to you. As others have suggested a remake of the xover would be advisable.

Cheers,

Keith

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Take a close look at the picture above .... for those who haven't met Doug yet? let me explain he's a hobbit living on/in the side of the Kenmore Hills in a lovely warm and cosy hobbit hole. The speaker are larger than he is? one marvels at how he actually picked them up :):hiccup:D:o:cool:

A great find Doug .... I have the original plans for Pro 9 TL's from the mid 70's what used the B139's - these we're the first speaker I ever made and loved them dearly. I'd go as suggested - correct (old style) box but modern crossover - I'm sure Rob/Trevor would be happy to DEQX final build for you to give you a starting point.

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Hmmm. There does seem to be a school of thought to rebuild, with better XO's.

1. I have a large room: 6m W x 8m L, with a skillion ceiling rising from 2.8m to 5m.

What opinion is there about the max size room to which they would be suited?

2. The boxes are 780 x 430 x 300 overall - your classic monkey coffins.

Could the design tolerate going narrower and taller? (keeping the volume intact?)

Thanks

Doug

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Hi Doug - on a more utilitarian line you could simply add/glue a new more cosmetic outer skin onto the old boxes. Which would (1) strengthen them up and (2) add further damping etc. You would obviously need to make the existing openings bigger to allow the drivers to "breath" in their new position slightly more forward. Then you could rewire with better cable and connectors The outer skin could be developed into a floor stander solution??

If the box is a straight ported design, then as long as the volume remains, changing the ratio isn't to dramatic however one assumes the crossover would have been designed to account for baffle step/detraction etc. So changing the baffle width may mess up the sound if you keep the existing crossover?? - whats your plan there?

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The boxes are veneered chipboard ... which has been out in the rain. Sadly, they can't be retrieved.

The front baffle is ply in great condition, and perhaps could be cut away carefully and reused. It'd save a lot of rebating!

The design is ported, but the port length is the thickness of the ply: 20mm.

The B110 mid has a cardboard tube enclosure running from the front baffle to the rear board. I think careful removal will see it reuseable if I keep the new boxes the same depth. Therefore it's a matter of deciding H vs W to keep a constant volume.

Pondering further, I could trim the width of the existing baffle (~20 to 25mm either side) and add a strip at the bottom to increase the height. That would really be a time-saver.

Doug

PS If you're at home Phil, give me a call.

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Then you could rewire with better cable and connectors The outer skin could be developed into a floor stander solution??

You're spot on about the wiring. It's fairly cheap & nasty. Also, the binding posts are crap.

The other enhancement would be to allow a slightly bigger replacement box so a P-10 style holey brace could be put behind the B139.

Doug

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The KEF Model 139 (Specification SP 1044 )gives its best results in a reflex box of 155 Litres internal volume with an Fb of 25Hz. This is a large box but equivalent to the so-called transmission lines in comparision.I would have the speaker examined firstly, for cracks in the roll suspension and secondly for the coil former to polystyrene cone bond to see that it is fully intact.Failure to do this could end up being a futile excercise as I believe spare parts are non-existant or in very short supply.The B110,also should be examined as the coated bextrine cone may be splitting or simply going soft.And yes a better xover is very worthwhile as is a modern tweeter.

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The lower tweeter is a Celestion HF1300. If the right one, quite valuable.

dave

OK, Dave. You've piqued our interest. Which is the desirable one and how is it distinguished from the also-rans?

Cheers

PS It appears one of the supertweeters isn't original. The one I have removed and inspected is an alnico Peerless.

Doug

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Hi Doug - on a more utilitarian line you could simply add/glue a new more cosmetic outer skin onto the old boxes. Which would (1) strengthen them up and

That's what i did to my old Coral speakers . I used just thin plywood and stained it to cover the existing chipboard.

[ATTACH=CONFIG]14894[/ATTACH]

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[ATTACH]14916[/ATTACH][ATTACH]14917[/ATTACH][ATTACH]14918[/ATTACH][ATTACH]14919[/ATTACH]

The lower tweeter is a Celestion HF1300. If the right one, quite valuable. Can you post a close up of the super tweeter? It doesn't look like a Coles.

dave

One "supertweeter", obviously not original, is a SEAS 5TV HF.

The other (appears to be original) is a peerless without any numbers or letters. Black shiny dust cap, with 8ohms painted on the outer face of the cone. Square frame, 57mmx57. Mounting hole PCD is ~64mm. Sealed rear.

The celestion has no markings except "Made in England", and an inspection sticker.

Doug

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OK, Dave. You've piqued our interest. Which is the desirable one and how is it distinguished from the also-rans?

The desirable ones are the big magnet, 8 ohm units that can be sold as replacement parts to guys with the big IMFs, Spendors etc,

There are also small magnet ones, and different impedances IIRC, take me a bit to dig out my archives & pictures.

dave

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One "supertweeter", obviously not original, is a SEAS 5TV HF.

The other (appears to be original) is a peerless without any numbers or letters. Black shiny dust cap, with 8ohms painted on the outer face of the cone. g

Doug,

At one point SEAS was part of one of the Danish companies, and a lot of cross production seems to have happened. The Peerless was an outstanding tweeter, partially due to the very thin, damped aluminum dustcap. Once it is damaged it won't have the extension.

The HF1300 pictured are the small magnet version. I might be interested in them to see if i could transplant the diaphrams into the set of dead big magnet ones i have here.

dave

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Thanks Dave.

I 'm going to keep them at this stage.

From listening to the speaker, even allowing it's water-damaged box, I think I'll have a go at building replacement cabinets.

It appears I'll need at least one Peerless replacement. What's your guess as to it's ID?

Doug

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6.8uF. That is the least of your worries. It will be fine.

Thanks Zaphod.

All the rest of the caps are "ELCAP"'s.

50V NP of the following values:

2, 2, 4, 20, 30, 60 and 20 microfarad.

Are these of lasting quality? or should I just replace the lot?

If yes, with what brand?

(BTW, I cranked up the speaker I haven't taken to bits, and the sound was impressive ... so I think there's a fair chance the caps in both XO's are OK.)

cheers

Doug

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