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Wharfedale Sand Filled Baffle SFB/3

Tony L

Administrator
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I now own one! I don’t really do mono, but it looks like I have the basis of a state of the art 1950s mono rig here as I landed the solo Leak TL12 Plus at the same time! I mentioned I knew where a cheap SFB was here a few weeks ago and got no interest, but I just couldn’t walk away as it was very cheap (£30) and I have a feeling it had an uncertain future if I didn’t grab it. Cosmetically it is superb, really tidy condition, museum grade to be honest, though the drivers all need re-foaming as what was there has long turned to dust.

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It was filthy inside with a mix of decades of dust and the disintegrated foam surrounds (photo is after I’d dusted the worst of it). Not sure what I’ll do with it yet, probably just store it for a while until I decide. I’ve always really wanted to hear this speaker as I’ve a lot of respect for Gilbert Briggs and this was arguably his finest/most famous design, so I’m tempted to get the drivers rebuilt and then sell it on as a fully working example once I’ve enjoyed it for a while.

Anyone know anything about this speaker and who might be able to do driver rebuilds that are close to original spec? I suspect the cones may be alright and I get (somewhat intermittent) impedance readings from all three drivers so I assume the coils are intact. I’m in no rush, but it would be nice to get it fully restored.
 
Troels’ design is interesting, but to my mind loses much of the appeal of the original (the remarkably inert sand filled baffle, the efficiency and real ease of drive). Still like to hear them though.

Does anyone here know anything about the Wharfdale units in the SFB/3s? I assume it won’t be a typical refoam job given they are designed for free-air loading?
 
I recall reading an on-line article about the special requirements for a woofer used for open baffle bass and how Wharfdale had managed it all those years ago in the SFB/3... but no more than that... so not much help really other than informing you that such an article exists, cos I've seen it!
 
I have a single one looking for a partner ,I had new surrounds and the mid re-coned at Wembley Loudspeakers a few
years ago .
 
I have never heard one, but reading this thread it occurs to me to suggest that you might open up the chassis, remove the sand and dry it out in the oven before returning it. Otherwise it might rot the wood in due course.

I use sand- filled stands as (part) of my concrete 'Mulebenches'. These seem about as acoustically inert as it gets, but I have no measurements. However I sealed the internal surfaces before filling with oven- dried sand.
 
By the fact there is no pool of sand on my floor or in the speaker I suspect it is very well glued /sealed in. I’ve no intention of getting that far into it to be honest as I’d likely do more damage than good. There is no evidence that it has ever got damp, it really is in nice condition, it was just full of dust and foam surround gunk. I gave it a good spray with some highly toxic woodworm prep last night and a good polish again with a woodworm repelling wax - no signs, though I have had a problem in my house recently (allegedly treated and now insured) but given it is exactly the sort of thing the beetles love I thought better to be on the safe side.

I have now managed to carry the damn thing upstairs, which was a fundamentally stupid thing to attempt on my own given the weight, unwieldiness and steepness of my stairs but I managed one step at a time without dropping it! I’m still getting my breath back now to be honest! It is now stashed in a safe place on my landing where it looks rather cool. It can stay there as long as it takes me to decide what to do with it, which may be many years!

My feeling is it could really do with finding its way to a museum at some point as to my mind it is a rather significant piece of UK audio history and in lovely condition (I feel the same way about my Lockwood cabs which also have interesting provenance), but at this point in time museums aren’t really thinking about this area of conservation. I would like to get it working if possible as I would love to hear it, but only if it can be done right. Otherwise I’ll just keep it as an ornament (at least until I want to move to a smaller house later in life). It only owes me £30 so it can stay as long as it likes really.
 
They are big heavy beasts aren't they!i spent £330 getting mine sorted then it wasn't welcome in the house,so I only played with it for a limited time.I was impressed with what I did hear ,amazing what he achieved with three drive units and one capacitor and no computer.Creating new surrounds with similar foam to the original is the difficult bit Wembley used a denser type of foam which may have made a difference.I never touched the sand in mine it came straight out of an aged audiophiles listening room it had been superceded by ELS57s when stereo came fashionable.
 
Interesting SFB review on Inner Magazines, which I’d never heard of, here. Anyone shed any light of the comment the drivers don’t have spiders? If not how the hell do the coils stay centred in the magnet gaps?

PS Mine had real spiders, dead, now in hoover.
 
A certain stylistic similarity to the ESL 57, at least to me.

It was actually Gilbert Briggs’ answer to the Quad ESL prototype he had heard! The ESL renewed his interest in dipoles so he developed drivers for free-air load and built an open baffle variant of the sand-filled corner cabinets Wharfedale had been using previously. I get the impression it surprised everyone by how good it was!

I’ve been reading up everything I can find on it, which is sadly very little. I found a review in the May 1957 issue of Gramophone (I have a full set 55-78) and there is some mention in the rather excellent A Pair Of Wharfedales book by David Briggs (I recommend grabbing a copy whilst they can still be had cheap, it is a good hefty and well researched hardback book), plus there is another review on Troels’ site via a link here. There are some great pictures of them in the Pair Of Wharfedales book being used in the various ‘live vs. recorded’ dems in big concert halls in the late-50s. I also note that The Science Museum do have Raymond Cooke’s pair of SFB/3s in their permanent collection (link).

I’m still not finding anything with any advice as to how to correctly approach a refoam that retains the original compliance spec though, so sadly I suspect mine will remain silent for the foreseeable future.
 
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I found a couple of threads over on Audio Karma here and here (you need to be logged in to see the pics, it is a very good forum so worth joining!). The first thread does actually cover refoamimg, which looks like a real nightmare to be honest, especially the tweeter! Looks like he got there eventually though, but what compliance etc I’ve no idea. The lack of spider really confuses me, I don’t understand how they stay centred at all.
 
I heard a pair of these in a dealer's showroom in Glasgow back in 1962 (Leak amps too), but memory dims over the years.

Valvebloke over on the Wam has a pair which he's been 'getting around' to restoring for quite a few years now. As smithy has said, Wembley Loudspeakers seems to be the place to go if you lack the DIY skills to refoam them.
 
Might it be that Gilbert Briggs' own books and publications from that era contain enough details to help restoration?
 
I think I read somewhere that the dimensions of SFB and Quad 57 went somewhere towards the excellent sound reproduction.
A very nice example that Tony.
 


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