Tannoy Cheviots

[Audio Al]

Hi

I acquired a pair of Chaviot's :D

One owner from new , the gent who sold the said from memory he purchased them from Laskey's in Totenham court road in the mid 1970's , He had to save for ages as he was a student

They have been through lots of relocation in the last 38 years , also residing in lofts when not in use due to space issues with a family taking priority

So cosmetics are not mint and like Geoff's the plinths are in poor condition , the veneering is coming off the chipboard

They need new foam rings fitted as you can see from the photos

Question ? where do I get the kit from ? all the ones I have seen are in Australia or USA , I would like good quality as these will be keepers :eyebrows:

Always wanted some old classic Tannoys

The speakers have never been out of the cases

They work as they are and he told me the foam has no impact on the sound ? I have also read this in other posts , is it true ?

Anyway here are the photos

http://img.photobucket.com/albums/v240/bigboobs/IMG_2435.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2435.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2436.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2436.jpg.html)
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:)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2437.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2437.jpg.html)
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;)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2438.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2438.jpg.html)
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:D
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2439.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2439.jpg.html)
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Can anyone explain the treble control roll off ?
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2440.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2440.jpg.html)
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Cheers :)

[DSJR]

As you well know, there's a wealth of information about refurbing these old timers.

Lockwoods suggest a complete recone with new COILS and cones, because the current ally coil former handles far more power. You can specify what surround you want as well I believe as unless I have it wrong, the foam was used to give a tad more bass extention at the cost of a little sensitivity which isn't at all an issue these days. While the drivers are in bits, the (hidden) pepperpot casting could be checked for casting flaws which I believe made issues with high frequency reproduction in this generation of drivers (far 'spikier' than they were a few years before).

Foams are certainly available should you wish to just repair what's there, but the switches will need either bypassing, or a damned good clean.

Good luck with the refurb. The Cheviots always sounded much better 'at home' than in the shop and modern crossover caps, wiring and a driver refurb can only make them far better..

[Macca]

Yer roll of knob will determine how high a frequency the tweeter will reproduce, yer level knob will determine how loud it goes - both within a comparatively small margin. unlikely that the perished foam won't affect SQ - you will have to get that fixed. Good buy - if it were me I'd get some custom cabs knocked up for them. Easier said than done, though.

[Gordon Steadman]

Yer roll of knob will determine how high a frequency the tweeter will reproduce, yer level knob will determine how loud it goes - both within a comparatively small margin. unlikely that the perished foam won't affect SQ - you will have to get that fixed. Good buy - if it were me I'd get some custom cabs knocked up for them. Easier said than done, though.

On Allen's lathe, he could turn up some giant, solid wood JR149 type cabinets. Should be an 'interesting' project eh Allen????:stalks:

[Macca]

On Allen's lathe, he could turn up some giant, solid wood JR149 type cabinets. Should be an 'interesting' project eh Allen????:stalks:

Yeah - make them out of a couple of tree stumps. Brilliant!

[Reffc]

Don't be tempted to use them with the foam in that condition. If the previous owner has done, you can be absolutely sure that the voice coils will be scrubbed. Best bet for under £300 is a complete refurb (new suspension, voice coils and cones) from Lockwood audio. I wouldn't just replace the foam surrounds precisely because the voice coils are likely to have been scrubbed.

Crossovers would likely need switches cleaning (resistance is very variable between pairs of these older units) and it'd be worth having the caps renewed too. If you get stuck, I can help you with that. Cable would also benefit from renewing usig OFC cable and the 4 pin connector bypassed for hard wiring or at least cleaned up.

Cabinet wise, the easiest (and best) way to restore them as long as the veneer's not flaked or missing anywhere is to rub them down gently with sand paper (240 grit) then apply a few coats of Danish oil using wire wool for the first few coats. This'll cover up most of the scratches. A final rub with Danish using a lint free cloth and you're done.

Great speakers so hope you get lots of enjoyment from them.

[walpurgis]

Best thing is to take the cones out and check them.

If the coils have been abraded by the magnet and horn pole piece it will be obvious. Chances are they'll be OK, but a light abrasion on the coil windings does no harm, just give it a very thin coat of epoxy laquer (even a thin smear of Araldite will do) where any copper is exposed. I personally am in favour of retaining the old cones where possible, as they will have been nicely run in over the years. New ones take months to years to 'bed in'.

My cones surrounds came from Australia and were a perfect fit. I would say don't use the adhesive that comes with the surrounds, as I did test patches of it and found it not resilient enough. If you choose to replace the surrounds instead of completely reconing, you'll find it's not a desperately hard job as long as you're practical. Your drivers are easier to work on as the entire cone assembly is only screwed in basically. Just pull out the foam strips at the front around the cone and you'll see what I mean.

I don't know if you've looked at the thread I did on my Cheviots, but it may be useful to you. It does point out a few pitfalls that you may not be aware of. You'd have to wade through quite a few member's posts, but the info is all there. See link:

http://theartofsound.net/forum/showthread.php?t=19555&highlight=%28vintage%29+Tannoys

The Cheviot cabinets are actually pretty rigid and work well with the 12" driver. Just about any veneer damage can be repaired with a bit of care, if you want to restore them.

Give me a shout, if you have any queries.

[Reffc]

Best thing is to take the cones out and check them.

If the coils have been abraded by the magnet and horn pole piece it will be obvious. Chances are they'll be OK, but a light abrasion on the coil windings does no harm, just give it a very thin coat of epoxy laquer (even a thin smear of Araldite will do) where any copper is exposed. I personally am in favour of retaining the old cones where possible, as they will have been nicely run in over the years. New ones take months to years to 'bed in'.

My cones surrounds came from Australia and were a perfect fit. I would say don't use the adhesive that comes with the surrounds, as I did test patches of it and found it not resilient enough. If you choose to replace the surrounds instead of completely reconing, you'll find it's not a desperately hard job as long as you're practical. Your drivers are easier to work on as the entire cone assembly is only screwed in basically. Just pull out the foam strips at the front around the cone and you'll see what I mean.

I don't know if you've looked at the thread I did on my Cheviots, but it may be useful to you. It does point out a few pitfalls that you may not be aware of. You'd have to wade through quite a few member's posts, but the info is all there. See link:

http://theartofsound.net/forum/showthread.php?t=19555&highlight=%28vintage%29+Tannoys

The Cheviot cabinets are actually pretty rigid and work well with the 12" driver. Just about any veneer damage can be repaired with a bit of care, if you want to restore them.

Give me a shout, if you have any queries.

If they've been run with perished surrounds, the coils almost certainly will be scrubbed. I've yet to see a pair run this way without damage to the coils but you're right, if it's light rubbing they can be re-laquered. New cones should not take years to bed in at all. They are made to perform to spec. They do take perhaps a few hundred hours IME for the new suspension and surround to bed in but that's it. I've compared the compliance of the suspension on an old pair verses the newly reconed ones, and after just 100 hours there was very little difference. One of the benefits of going with full refurb is that the newer voice coils allow greater power handling (not that they need much power to go loud though).

[Gordon Steadman]

Yeah - make them out of a couple of tree stumps. Brilliant!

Tree stumps hah! Allen's lathe would turn the whole tree:eyebrows:

[walpurgis]

If they've been run with perished surrounds, the coils almost certainly will be scrubbed. I've yet to see a pair run this way without damage to the coils but you're right, if it's light rubbing they can be re-laquered. New cones should not take years to bed in at all. They are made to perform to spec. They do take perhaps a few hundred hours IME for the new suspension and surround to bed in but that's it. I've compared the compliance of the suspension on an old pair verses the newly reconed ones, and after just 100 hours there was very little difference. One of the benefits of going with full refurb is that the newer voice coils allow greater power handling (not that they need much power to go loud though).

Paul, it wasn't the compliance of the cone suspension I was talking about when I mentioned running in/bedding in. It was the breakup modes/patterns of the cones themselves. That takes some time to establish itself and stabilise, which is why older drivers can and often do sound better than new.

[Audio Al]

Tree stumps hah! Allen's lathe would turn the whole tree:eyebrows:

:D:D;);)

[Audio Al]

Thanks for the advice so far :)

I will remove the speakers from the cabinets and have a look at the condition in the next few days

;)

[cooky]

They look pretty old to me, I often wonder what people think bass should sound like if they run them with rotted/missing part of the surrounds and say they work fine...
anyway re-cone them, spiders get shagged too, you'll end up with some pristine units good for another 15 years-if you just refoam by that time the spiders will be getting on for 50 years old.

Frank

[walpurgis]

Mine date from 1979 and the spiders are perfect.

[cooky]

Mine date from 1979 and the spiders are perfect.

On a quick look at your photo's they look to be sagging to me.
Lockwood and Tannoy recommend the replacement for good reasons.

[walpurgis]

On a quick look at your photo's they look to be sagging to me.
Lockwood and Tannoy recommend the replacement for good reasons.

They are fine.

Any 'droop' is due to the weight of the bonded metal attachment ring. I've overhauled plenty of speakers and there's nothing wrong with these. My Tannoys are working perfectly since their overhaul and sound superb. Should the spiders ever tire, I'll replace them. Suitable parts are available.

I've only ever seen one pair of Tannoy cones with damaged spiders and that was due to rough handling by Lockwood. To be fair, they were cones from drivers that were in for replacements and they thought the old cones were going to be binned, but they were rescued and I repaired those too.

Lockwood no doubt recommend replacement complete cone assemblies, as that is all they sell. No separate component parts as far as I'm aware. I believe they don't even sell the cones now unless they fit them. They are in it to make money. That's not a criticism, it's just business.

[cooky]

From Klippel;
http://www.klippel.de/fileadmin/klippel/Files/Know_How/Literature/Papers/Aging%20of%20loudspeaker%20suspension_Klippel.pdf
Spiders, surrounds and other soft parts used as a mechanical suspension in electro-acoustical transducers vary significantly over time. Variation of the stiffness K(x=0) at the rest position affects the fundamental resonance frequency and the alignment of the drive unit in a vented enclosure. A loss of stiffness increases the peak displacement which may result in hard limiting of the voice coil former at the back plate or coil rubbing at the pole tips. In combination with a nonlinear force factor characteristic Bl(x) a softer suspension may also cause a motor instability which generates an excessive DC displacement (“coil jump out effect”) above resonance frequency.
The time varying properties of the suspension are caused by reversible processes such as the viscoelastic behavior of the suspension. The temporary decrease of the stiffness after large peak displacement recovers slowly after removing the stimulus. The stiffness also varies with the ambient temperature, humidity of the air and the absorbed moisture in the suspension material.
Non-reversible changes which can be interpreted as an “aging” of the suspension have the following causes:
 Initial exposure to mechanical load opens some bonded joints in the impregnated fiber structure (break-in effect).
 Accumulated mechanical load causes slowly growing cracks, destruction of the micro-fibres and other mechanical deformations (fatigue).
 High ambient temperature or voice coil heating changes the suspension properties permanently.
 Humidity, direct water contact and reaction with other chemicals change the material
properties.
 Gravity changes the geometry of the
suspension part and the coil’s rest position if the loudspeaker is mounted in horizontal position.
 Instability of the chemical compounds causes decomposition over time.
 UV light promotes chemical reactions and decay processes in diaphragms and surrounds.

[Reffc]

Paul, it wasn't the compliance of the cone suspension I was talking about when I mentioned running in/bedding in. It was the breakup modes/patterns of the cones themselves. That takes some time to establish itself and stabilise, which is why older drivers can and often do sound better than new.

I see...understood. There's so many factors involved that I must admit that I'd find it hard to pin down just what was better about older units. Its easier to address obvious deficiencies though such as crossover units, worn coils and suspension. I wouldn't expect several years on a cone to make any significant difference to SQ over a few hundred hours tbh.

[walpurgis]

Yes Frank, I have an engineering background and am well aware of how materials work (or don't).

It doesn't alter the fact that my spiders are fine.

[cooky]

Yes Frank, I have an engineering background and am well aware of how materials work (or don't).

It doesn't alter the fact that my spiders are fine.

I just post the evidence of an understood effect/problem with loudspeaker suspension systems from the most respected research/measurement company in the business. So that's Kippel, Tannoy, Lockwood, JBL(first thing to check on a vintage JBL bass driver) to mention a few who are acutely aware of the issue.

I'll accept your Tannoys may have had a very sheltered life and the droop I can see towards the voice coil former is just down to the photography.

[walpurgis]

This thread is like being back at school. I expect I'll get a pat on the head shortly (that's not allowed now of course) and be told to revise for exams.

I'm pretty sure I'm likely to have designed and built more speaker systems than any other non professional AOS member. Over fifty pairs to date, mostly good ones, but one or disastrous experimental jobbies on the way.

Here's a thumbnail of what I was building thirty years ago (poor quality picture and part finished speaker temporarily wired). Full sized 1/4 wavelength constant width folded horns using Coral Beta 10 drivers. A serious speaker, half as big again as a Lowther Acousta.

[southall-1998]

This thread is like being back at school. I expect I'll get a pat on the head shortly (that's not allowed now of course) and be told to revise for exams.

I'm pretty sure I'm likely to have designed and built more speaker systems than any other non professional AOS member. Over fifty pairs to date, mostly good ones, but one or disastrous experimental jobbies on the way.

Here's a thumbnail of what I was building thirty years ago (poor quality picture and part finished speaker temporarily wired). Full sized 1/4 wavelength constant width folded horns using Coral Beta 10 drivers. A serious speaker, half as big again as a Lowther Acousta.

That is one sexy drive unit Geoff :eyebrows::stalks:

[Macca]

I thought I had best check my spiders. The one that lives in the gap between the bath and the wall is fine but the big one in the porch seems to have disappeared and his web looks like it hasn't been slept in. Should I be concerned?

[walpurgis]

That is one sexy drive unit Geoff :eyebrows::stalks:

Sure is. One of the finest full range drivers ever made. Wish I still had them.

[chelsea]

They do look very nice units.

[cooky]

I'm pretty sure I'm likely to have designed and built more speaker systems than any other non professional AOS member. Over fifty pairs to date, mostly good ones, but one or disastrous experimental jobbies on the way.



That's a lot of speakers!, I for one would be well interested in seeing some of them, you should post some pics on the diy speakers thread.

[Reffc]

Sure is. One of the finest full range drivers ever made. Wish I still had them.

Lovely. How did they compare with your DC's Geoff?

[Audio Al]

Just removed the driver units :)


Looking good , will do some photos later

[walpurgis]

Frank, I haven't built a serious pair of speakers for years, and all have been moved on. I haven't even kept many photos. I'll have a look though, there may be one or two. I do have a couple of projects in the pipeline and I thought I'd get back into building speakers again.

Paul, back then my main Tannoys were a pair of Eatons, very nice they were too. The Corals were a totally different sound, very tight and fast with huge impact and at 102db sensitivity you had to choose amps carefully, as any hiss or hum showed.

Allen, sorry to hog your thread. I'd like to see the shape your drivers are in. Especially the cones once you take them out. You're not a huge distance from me, so if you're interested you could pop over and I could give you a hand with replacing the surrounds if that's what you choose to do.

[Audio Al]

Back on topic :)

Here are the photos of the units

They are stamped June 1978 in the cases

http://img.photobucket.com/albums/v240/bigboobs/IMG_2461.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2461.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2460.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2460.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2459.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2459.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2458-2.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2458-2.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2457.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2457.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2456.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2456.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2455.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2455.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2454.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2454.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2451.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2451.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2450.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2450.jpg.html)
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One has A marked on it in pencil the other B

Look OK to me , but then I don't know what I al looking at :lol:


Is it OK to remove the magnet cover , is there any need too ?

[Reffc]

Back on topic :)

Here are the photos of the units

They are stamped June 1978 in the cases

http://img.photobucket.com/albums/v240/bigboobs/IMG_2461.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2461.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2460.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2460.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2459.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2459.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2458-2.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2458-2.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2457.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2457.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2456.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2456.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2455.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2455.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2454.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2454.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2451.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2451.jpg.html)
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http://img.photobucket.com/albums/v240/bigboobs/IMG_2450.jpg (http://smg.photobucket.com/user/bigboobs/media/IMG_2450.jpg.html)
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One has A marked on it in pencil the other B

Look OK to me , but then I don't know what I al looking at :lol:


Is it OK to remove the magnet cover , is there any need too ?

They don't look too bad but you can't tel what state the coils are in without removing the bolts holding the spiders in and removing the whole cone, which is what I'd do as they need re-foaming anyway. You can test the coils. LF should be around 6Ohms DC and HF should be between 10 and 11 Ohms DC.

That's no indication of specific condition but gives you an idea. I'd remove them and check the lacquering/re-lacquer if you don't intend on re-coning.

No need at all to remove the plastic magnet cover. All you'll see is the HF wiring and the magnet. Nothing to do there.

A 1978 date means that they were post-London manufacture and most likely the drive units came from the Coatbridge works.

[walpurgis]

Strange that one driver has bolts retaining the spider, whilst the other appears to have studs and nuts, even though the serial numbers are reasonably close. Tannoy were consistant in their inconsistancy!

Take great care unbolting the spiders. It's easy for washers to get drawn into the magnet gap and extremely difficult to get them out again.

The screw fixing for the cone roll surrounds should be visible once the foam strips are pulled out. Probably easiest initially just to cut through the remains of the old surrounds as I did prior to lifting the cone out.

[walpurgis]

Just a thought. Be very careful unsoldering the cone/coil lead out wires from the socket terminals as they are fairly fragile. It may pay to buy some desoldering braid to remove excess solder and allow you to unwrap the wires from the posts more easily.

[synsei]

Just a thought. Be very careful unsoldering the cone/coil lead out wires from the socket terminals as they are fairly fragile. It may pay to buy some desoldering braid to remove excess solder and allow you to unwrap the wires from the posts more easily.

...or a decent solder sucker ;)

[walpurgis]

Sure is. One of the finest full range drivers ever made. Wish I still had them.

Just spotted a pair for sale on eBay in Australia!

http://www.ebay.co.uk/itm/CORAL-BETA-10-Full-Range-Speake-ONE-OF-THE-BEST-FULLRANGE-SPEAKER-MADE-IN-JAPAN-/370815080317?pt=AU_Electronics_Vintage_Electronics&hash=item56564d177d

Only the second pair I've seen in about ten years.