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Kef 103.2 blown driver?

At least the original T33 used in the 103.2 has no ferro-fluid to worry about, that came around with the Mk II in the 103.3 era. That series can be a handful but the earlier ones are pretty good considering their age.
 
kymers said:
This
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Got it. Thanks guys. Remove rubber surround and re-glue using rubber based glue, with shims in place, right? Is it a must to remove the dust cap? Does this afford for easier re-centring? Can it be done with dust cap in place? Thanks a lot, Jon
 
It can usually be done without removing the dust cap. I use the standard speaker glue.
 
If that doesn't work, keep in mind the leaking caps. I still think that's going to be the issue with mine, anyway...happened on one of my speakers, sounded exactly like this one does before it was repaired. Hope to get to my repair, soon.
 
Haven't recapped mine yet but just put the 103.2's back into rotation in the office, in the nearfield, on stands. They were across the room, stacked on my Bozak 305's. Wow, I forgot how good they are in the nearfield! The imaging, the tight bass! Really enjoying them, not noticing any distortion today but still planning a re-cap in the near future. :music:
 
Update on an old thread. I took the plunge and simply removed the rubber surround as Baco99 suggested. It came apart easily and I re-centred the cone with the driver facing upwards. Re-glued and checked centring by playing music whilst the glue dried. Simple as that- job done! Driver sounds as good as new with absolutely no cone rub! Thanks for the tip!
 
Jon_Bawn said:
Update on an old thread. I took the plunge and simply removed the rubber surround as Baco99 suggested. It came apart easily and I re-centred the cone with the driver facing upwards. Re-glued and checked centring by playing music whilst the glue dried. Simple as that- job done! Driver sounds as good as new with absolutely no cone rub! Thanks for the tip!
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Nice, probably re entered the cone sufficiently taking into account the original spider's wear and sag. Hopefully will not need to again, or maybe could do a yearly rotation of the driver.
 
I bought a pair of 103.2s in April 2016. I drove each with a bridged NAD 2155 Amp, 150 WPC peak. After a couple of months one speaker sounded like it had been blown. I finally removed the woofer last week and now think that it might just be spider sag. When I move the speaker in and out on each of 2 sides, I hear the noise but not when the third side is expanded/compressed. Does this sound like speaker rub? Thanks.
 
It sounds like it to me. Have you tried remounting it in a different orientation to see if it sounds better?
 
Yep sounds like it to me too! First try rotating the driver, if that doesn't work, try re-centring and re-gluing the surround as I did above. It's a small driver so there's no need to remove the dust cap and centre the voice coil with spacers... An easy job!
 
chipobrien said:
I bought a pair of 103.2s in April 2016. I drove each with a bridged NAD 2155 Amp, 150 WPC peak. After a couple of months one speaker sounded like it had been blown. I finally removed the woofer last week and now think that it might just be spider sag. When I move the speaker in and out on each of 2 sides, I hear the noise but not when the third side is expanded/compressed. Does this sound like speaker rub? Thanks.
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So, digging up this old thread reminded me of the problem, and I checked my repair. With closer listening and a good in-out physical check it seems that all is not well with the driver. Although there is no apparent voice coil rub, the driver just doesn't seem to have the same travel (and therefore bass response) of the other, healthy one. Is this a repairable issue? Or does it mean the bextrene is just past it's best, stiff, as it were?
 
The bextrene is in the cone, what would limit travel is the rubber surround. Poking it with your finger does the surround from the bad driver seem different from the good one? If not it could be a voice coli or spider issue, just off the top of my head.
 
Raynald said:
The bextrene is in the cone, what would limit travel is the rubber surround. Poking it with your finger does the surround from the bad driver seem different from the good one? If not it could be a voice coli or spider issue, just off the top of my head.
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Hi Raynald, thanks for your help. The surround seems fine in itself. Only the cone doesn't have much travel and the whole unit doesn't seem to move in-out well (even though there is no rub to speak of). I also realised that a visiting toddler had nicely pushed the dust cap in too, which wouldn't have been helping! So I bit the bullet and purchased a used driver from the auction site yesterday for $30. It's not in mint cosmetic condition but sold from a store, apparently in fine working order. I'll see how that works! Cheers, Jon PS- Whats the best thing to clean these drivers with to remove dust and maybe even to return faded colour to proper black? Stupid to use "back to black" that works on car tyres?
 
Removing the 300uf lytics should have no ill effect on the speaker if the S-Stop parts are removed. In fact bass will be more extended because the rollout will be 12db per octave instead of 18db. The real reason they’re there (nobody else does it anymore these days) is to cut out subsonics that would otherwise trip the S-Stop relay. This little known secret came from an old B&W importer as some of their models from the 80s with protection relays had them too. Removing the big coupling caps will also make the speaker sound more transparent. You can do that on the KEF 103.2 without screwing up the phase response because the caps are in series with BOTH woofer and tweeter. Not so on the B&Ws - their tweeters are not in the same circuit. Very important difference!
 
Update for you folks. Bought a pair of 103.2's with speaker sag/rub in one driver and thanks to this thread I removed and re-glued the surround adjusting to eliminate any rubbing probing gently in a circle around the dust cap and adjusting the surround correspondingly and was 100% successful. With the voice coil rub any test tones 200 hz and below sounded like a car engine running i.e. rattly and horrific. After adjustment I just hear pure test tone. I'm pretty confident that any speaker sag can be re-mediated in this manner.

To address the question in the thread posted by Jon_Bawn in mid 2017 (better a late answer than never right?) regarding a potentially diminished output on his driver where the surround was re-adjusted I will provide my suspicions.

1. Since the spiders have sagged the upper part of the surround has stretched over time slightly due to gravity and it's resistance.
2. For anyone that hasn't done a refoam by touch the process basically involves poking around the dust cab to look for voice coil rub. If you picture yourself looking straight at the woofer i.e. it's on it's side with the dust cap facing you:
a. If you poke a few centimeters above your cone and you feel rubbing/resistance then to remedy it you would move your finger to the bottom of the surround while the glue is still tacky and shift it downwards/lower to compensate.
b. If you were to feel rubbing below the dust cap you would go to the top of the surround and move it up.
c. You would keep making these adjustments until you felt no rub.

So here's the problem. If there is sag and rub you may have to move your surround edge pretty far down or up to compensate in centering the speaker/voice coil. As a result depending on how far you have to drag your surround edge out of spec to correct the sag you may be diminishing the size of the roll on the surround and thus reduce the limit of it's excursion.


I'm not sure if what I said made sense or if I articulated it well but even though you can solve the voice coil rub/sag issue fairly easily you may be slightly reducing the excursion capability due to the procedure I mentioned.

I think it's a small price to pay for operational KEF 103.2's and since I complement with a pair of subs to take the burden of reproducing extremely low frequencies it has little impact on me.
 
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