Uh oh, bad sounds from my old Tannoys

I have an old (ca. 1982) pair of Tannoy T185 Dorset. I've enjoyed them for about 15 years now, but I think one of them has developed a rub in the voice coil or possibly the black rubber surround is coming away from the plastic cone.

The noise is like a fuzz on certain sounds, especially on low to midrange piano notes. Also noticeable on acoustic and electric bass as sort of a fuzz riding on top of the note. It's started driving me crazy.

I'm hoping someone here knows of a shop accessible from NYC that can repair these old Tannoys. Or maybe I'll need to ship the drivers. At any rate... Any recommendations?

Many thanks in advance...

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Thanks for your vote of confidence. Well...

How to proceed? First is diagnosis. I think the problem might be a misaligned coil in the gap, due to surround "sag." Does this sound correct to you?

Fixing this requires careful realignment of the coil in the gap, correct? I've tried this on less expensive speakers, and found that I could only get them working for a little while until the problem recurred. It might be that I don't know what I'm doing.

Any pointers for aligning the voice coil in the gap?

Is it possible the surrounds have softened up so much that the cones are misaligned? I've rotated the drivers in their cabinets several times over the years, but this one is not responding to that treatment any more.

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In this case forget what I just posted!

Well, it could be that a really humid warm front came in and caused the problem to flare up. I rotated the driver around last night, so maybe it will take a day or two to "take". I'm hopeful.

In the meantime, I really don't know of any reputable speaker repair shops that can handle something like a 30 year old Tannoy. There are lots of speaker recone shops that can handle guitar amp and PA speakers. Maybe even car stereo subwoofers. But this really nice old Tannoy? I dunno...

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Hi,

First look for the easy problems to fix, loose dust caps, loose surounds
etc, obviously if it voicecoil rubbing that is not easy to fix at all, and
can be caused by too much power delaminating the voicecoil, when
this happens the coil is far more likely to simply burn out, which will
happen eventually if they are given too much stick.

rgds, sreten.
 

Face

Member
2007-05-23 8:38 pm
I've flipped vintage Tannoy drivers 180* before and it's done the trick.

I purchased a pair of Tannoy HPD's a few years ago that were re-coned by someone in CT, I'll look for the receipt.

If you don't mind shipping your drivers, check out Lockwood Audio and Speakerbits.
 
Hi,
First look for the easy problems to fix, loose dust caps, loose surounds
etc,

Dust caps are good. I think there's a spot on the surround that is coming off from the cone (diaphragm). What's a good glue to use for this? The cone is black plastic, the surround is black butyl rubber. Very 1980s British. I wouldn't want to use a glue that would eat away at the materials, but I would like it to stick...

obviously if it voicecoil rubbing that is not easy to fix at all, and
can be caused by too much power delaminating the voicecoil, when
this happens the coil is far more likely to simply burn out, which will
happen eventually if they are given too much stick.

The good news is that I really doubt it could be this. The speakers have only ever been powered by my two low power triode amps (one's 10wpc, the other 6wpc) playing jazz and classical mostly.

Thanks for the tips on Lockwood and Speakerbits, I'll check them out.
 
Hi
Just wondering if you have fixed the problem with your Tannoy Dorsets yet?

I had the same problem and found an easy test and fix.

I removed the bad driver and disconected the wiring then with the cabinet lying on its back I lay the driver over it's own apature face down.
Now by tapping on the ABR you can make the cone move inwards and if the voice coil is rubing it is easy to detect.
Using the ABR in this way moves the driver very evenly in and out.
Other culprits can be the two wires from the conector block to the cone or loose bolt on magnet or loose conector block.
If you do finde it is the voice coil this may just be sag through age and on these old Tannoy drivers can be fixed because they are bolted together and not glued like many modern drivers.
At the rear of the cone you will finde the suspenshion held by for small bolts,
I removed these bolts and gently puled the suspension forward you can now see the voice coil in the gap, a few gental in and outs will help remove any dust build up.
Now reinstal the bolts to finger tight, sit the driver back over it's apature on the cabinet use the ABR to hear if the coil is rubing and manover the rear suspension about using it's outer metal ring until the voice coil stops rubing then tighten the bolts.
Job Done
If you canot find a spot where the coil does not rub it will be a distorted coil that has gone oval but as you say unlikly, or a large amount of dust between coil and magnet or HF horn.
This could happen if the speakers are in a damp atmosphere as the aloy horn could oxidise.
A old simple fix for dust is to face the speaker cab face down on blocks and play some bass heavy music and the driver movement may vibrate the paticals out the front, a good idea but if the coil is rubing eventualy you will rub through the thin insulating paint/lacker and cause the speaker to short and if you are using a transitor amp you will blow that as well, not so good.

A mate of mine got some Dorsets in the summer and could hear a rattle on one cabinet when opened he found an offcut of wood under the acoustic foam it seems it had been there 32 years and the previous owner had not noticed!

I Hope this is helpful to you or anyone else with a similar problem the ABRs are very usefull here.

Cheers Rod
 
Have had my T185 Dorset's for about 4 yrs and never checked them as they sounded fine.

Mine recently developed a muzzled sound and was quickly diagnosed as a connection breaking away from the driver. Re-soldering that and the connection to the cross-over that was also broken brought it back to life, even better than the other. So went and checked that to find a very "thin" connection to the crossover (black cable in photo) that broke away as soon as I gave it the slightest tug. A quick re-solder and both are now 20% better than ever before.
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Thanks for the updates!

I'll have to look into refreshing solder joints on the drivers and crossover. Certainly can't hurt (if done correctly...).

It seems regular rotation of the drivers has helped a lot. I have to remember to rotate the drivers a quarter-turn, every three months or so. On the speaker I use for the left side, the weight of the cone makes the driver sag and the rubbing noise starts up again.

I hadn't rotated my right side speaker for a long time (it doesn't make any bad noises, so it hadn't called attention to itself). I took a close look at it, and the black rubber (butyl?) surround had gone very soft on the side of the driver that was closest to the floor. It looked sort of flat in shape - it had lost its curvature.

I wonder if the 'cone sagging' problem is due to the surrounds getting softer and overly compliant with age?

At any rate, regular rotation of the drivers seems to be keeping things going. That's a good thing too, because I really love these old speakers.

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Hi,
I'm so grateful I found this thread. My right speaker came up with this problem and it grew worse. Today I had it throughout a complete CD which seems to consist a lot of the frequencies which cause this problem.

I rotated the driver a quarter-turn as recommended and tightend the screws again which were quite loose. A few hours later I'm playing the same CD without any problems.

As you can imagine I was already going through a bunch of worst case scenarios as I bumped into this thread this morning :).

BTW my drivers don't have solder joints like the one on the picture above but a plastic connector clamp instead.