KEF B139 expert needed

[bumpy]

I have extracted a pair of KEF B139 drivers from some unloved vintage Radford cabinets. They look as if they have been in there for 40 odd years, but they are different, in that one has a rubber cone surround and one has an impregnated cloth surround. I will post pictures when I can, but I have two questions initially.

1. Was the KEF B139 ever made with impregnated cloth surround or is this likely to have been a very early repair?

2. I have read somewhere that Radford commissioned their own lightweight cone B139s. Is this true?

Thanks

[bumpy]

OK, can finally add some pictures

Rubber surround vs impregnated cloth surround, and an overall view

[spendorman]

All the B139s I've been though, and that's about 12, have have the rubber surround, but I believe that earlier ones have had cloth like one of yours, and I have seen pics of rotted early surrounds that might have been foam, though I'm not sure of this.

I read somewhere that Radford used a lighter cone on their two unit systems. I repeated it somewhere, can't remember where! And I don't remember where I got the original info!

It might be possible that both your units are original, if they were made at the changeover time for the surround type.

[bumpy]

All the B139s I've been though, and that's about 12, have have the rubber surround, but I believe that earlier ones have had cloth like one of yours, and I have seen pics of rotted early surrounds that might have been foam, though I'm not sure of this.

I read somewhere that Radford used a lighter cone on their two unit systems. I repeated it somewhere, can't remember where! And I don't remember where I got the original info!

It might be possible that both your units are original, if they were made at the changeover time for the surround type.

They certainly have the same aged appearance. Funnily enough vintage stereo Saba radios and radiograms often had slightly dissimilar driver construction, I think to exaggerate the stereo effect in the early days of stereo.

[walpurgis]

Not seen the fabric surround version before. No doubt it's early. There was also a version with clear/white foam surrounds, with the 'roll' convex, as opposed to the more usual concave.