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KEF 105/3 Restoration
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speakerguru
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Joined: 18 Nov 2005
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Location: Green Hut, Tovil

PostPosted: Sun Dec 09, 2012 11:44 am    Post subject: Reply with quote

Headrush wrote:
Hopefully someone will step in here and tell me not to be so stupid and go stand in the corner Embarassed


Yeah, please do. Make yourself a big pointy hat while you're at it.Wink

Your post instantly sent me into grumpy old git mode. If something as simple as putting some extra holes in the box could give any worthwhile improvement to the system performance, don't you think that the engineers at KEF with their computers simulations and ready access to countless prototype cabinets would have discovered that and done something about it? Rest assured that for any given box size and choice of drivers, those KEF systems had the most possible bass extracted out of them. If you want more without going to a larger box, get a KUBE.
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clubsport911
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Joined: 26 Aug 2012
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Location: Cheltenham, UK

PostPosted: Sun Dec 09, 2012 4:27 pm    Post subject: Reply with quote

Smile Of course, it's Rockwool ! ( I used to work for Rockwell !)... apologies.

So how much to put in ? Well, not sparse and not stuffed - but somewhere in between. There is a formula somewhere, but I just packed it in until it looked right (how unscientific is that !)

Ref the "drilling holes in the bass sections"... Crikey, I have to say, I've trodden in your shoes and asked the exact question not a few weeks ago on this very forum.

Apart from custard pies and rotten fruit, I had all sorts of advice thrown at me - mostly in the "not at all " sense.

KEF themselves did use an "interport" foor the models that followed on from the 105/3 (Reference 1-4) whereby they vented the sealed system to the main cavity with a small port, but according to the experts it was incredibly complicated to do this, and the crossover / drive units were all matched accordingly.

Oddly enough, whilst mine were apart recently, I re-sealed the bottom crossover hatch and the main sealing on the front panel. It seems they (the speakers) work at their very best when all the bass system is sealed as tight as a drum.

Odd that... for me, it's counterintuitive, but there you have it... perhaps that's why I'm not a speaker designer ! Laughing

Cheers

Steve
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deckard
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Joined: 10 Sep 2012
Posts: 32

PostPosted: Tue Dec 11, 2012 10:00 pm    Post subject: Reply with quote

Hi Headrush - Welcome and thanks for the detailed post!

Regarding the optional source for 1353's, I did look into that myself, but I believe they are slightly different (mounting-wise) than the NT24/1353 offered for the 105/3. At least, I know the UNI-Q driver in the 90/100 is different from the UNI-Q in the 105/3. I could probably get them to fit, but hopefully I won't have to resort to this as I myself am waiting on a pair of 1414's. Since I am across the pond, special consideration was made for me, but I am definitely the Yank at the end of the line...

As a side note - a pair of replacement tweets I got from KEF US directly some time ago (part # on the box started with "RX") for an old pair of 104/2's also say 1353 on them. But again, the mount is completely different. They have a metal faceplate around them to make them fit in the cutout on the back of the baffle where the T33 magnet would sit. Unlike the ones in the Model 90/100, these would not work at all in a UNI-Q driver.

Since you've dealt with KEF UK directly and now have some experience with the 105/3, I figured I'd ask if you have or have a line on any other spare parts. As I mentioned earlier in this thread, I have a midrange with a slight voicecoil rub that may need to be replaced at some point. It's a B160, but has the UNI-Q cutout. The part number is SP1258.

Anyway, I hope to get some new tweets for Xmas! Will continue to post here once work commences.
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Headrush
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Joined: 10 Nov 2012
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Location: Nottingham

PostPosted: Wed Dec 12, 2012 4:29 pm    Post subject: Reply with quote

deckard wrote:
I know the UNI-Q driver in the 90/100 is different from the UNI-Q in the 105/3.


The tweeter in the Model 90 is not a compatible replacement although it will probably fit. The tweeters from the Model 100 & 200C are compatible. As you say, the whole driver cannot be used because it's a different shape but the tweeters are exactly the same as the ones KEF have supplied as alternatives to the original NT25 SP1240. The main physical difference between the 1240 and the 1353 is the rear threaded stub on the 1353 is much shorter so presumably one would need to use a longer bolt. I can't be 100% on this because I never fitted the tweeters myself but I can't imagine KEF changed the whole driver, because I was only charged for the tweeters.

I noticed you metioned a NT24, I assume you meant NT25. I sent an email to KEF asking about the B160 midrange driver. If I get no reply, I will pop in next time I'm passing.
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deckard
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PostPosted: Wed Dec 12, 2012 5:57 pm    Post subject: Reply with quote

Headrush wrote:

The tweeter in the Model 90 is not a compatible replacement although it will probably fit. The tweeters from the Model 100 & 200C are compatible.


Thanks for the clarification - I used to be a KEF dealer/custom AV installer back in the early 90's and installed a lot of Model 90 and 100 centers so I had that stuck in my head when I replied.

Headrush wrote:

I noticed you metioned a NT24, I assume you meant NT25. I sent an email to KEF asking about the B160 midrange driver. If I get no reply, I will pop in next time I'm passing.


Right... NT25. I'm getting old...

When I last spoke to KEF on the 1258's they told me there were absolutely none left, nor were there any substitutes available. But again, they may be more willing to hook up a UK customer, as I had to go through some hoops to get the 1414's. If you have different results, I would gladly fork over the cost plus shipping if that's OK with you.
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clubsport911
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Joined: 26 Aug 2012
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PostPosted: Wed Dec 12, 2012 6:45 pm    Post subject: Reply with quote

As a 1253 to 1414 convert, I can report that Indeed you do need a longer M5 bolt to catch the thread on the shorter 1414 stub. As for the move from 1240 to 1253, I had assumed compatability.

There was also another difference. The 1414 had a 2mm thick washer surrounding the stub, making the bolt reach even more important.

@deckard... Why not get that rubbing upper mid-bass unit rewound or repaired ?
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deckard
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PostPosted: Thu Jan 03, 2013 10:21 pm    Post subject: Reply with quote

Well I got my tweets over the holidays. They have reportedly been matched, however, I haven't had a chance to install them yet. Regarding the M5 bolt, my local hardware store only has lengths of 25mm and 30mm. If I need longer than that I'll likely have to order something. Can anyone confirm the required length before I start taking everything apart?

As for getting the mid-bass repaired, I guess I'm hesitant to do this because I have no way of knowing if the repaired driver will sound the same. I could call around to some places that have mentioned repairing KEF drivers, but I'm going to wait and see what I find when I swap the tweeters. It might be something as simple as the lead from the spider or the foam insulation around the basket.

Also, for anyone interested, my brother got me this for Christmas: http://www.amazon.com/KEF-50-Years-Innovation-Sound/dp/988154274X

Lots of great info and I am thoroughly enjoying it!
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proffski
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Joined: 22 Aug 2003
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PostPosted: Fri Jan 04, 2013 1:38 am    Post subject: Reply with quote

My sentiments regarding the KEF publication have already been posted here on another thread. As have my comments on Amazon UK, I am so pleased that we both agree! Smile

Link: http://www.amazon.co.uk/product-reviews/988154274X/ref=dp_top_cm_cr_acr_txt?ie=UTF8&showViewpoints=1
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speakerex
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Joined: 22 Jan 2013
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Location: TAMPA, FL USA

PostPosted: Wed Jan 23, 2013 6:46 pm    Post subject: KEF SP1353 Reply with quote

The SP1353 can be replaced with the SP1413 we we can order for you. We also have the center donut foams.
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clubsport911
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PostPosted: Thu Jan 24, 2013 11:38 pm    Post subject: Reply with quote

The 1253 can indeed be replaced by the 1413 but the tweeter is quite different having an aluminium dome instead of fabric. The latter does have a (claimed) extended response but the sound chracteristic will be different.

Whether you can detect it, is another matter !
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speakerex
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PostPosted: Fri Jan 25, 2013 4:42 pm    Post subject: Reply with quote

I agree with both points. I should have mentioned the difference in the domes. sorry about that.
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deckard
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PostPosted: Fri Feb 15, 2013 9:20 pm    Post subject: Donuts Reply with quote

I was reading some other posts here about the rotting donuts and someone mentioned "leaks"... Early on I explained how the ones in my 105/3's had already been replaced, but with a woven fiber/fabric instead of foam. I have the correct foam donuts but have not installed them yet.

My question is, do the domes have anything to do with keeping the speaker sealed? I mean sealed in the sense of keeping air in the speaker cavity. I know they keep dust and debris out of the coils/gaps and provide some stability, but do they also keep the speaker airtight? I assumed that this is done where the spider meets the cone and where the surround meets the frame, not at the coil/dustcap (donut).

If they do in fact help with keeping the speaker sealed, then I'm guessing I should jump on replacing mine ASAP as the fabric ones are likely not airtight.

Can someone please clear this up?

Here's a pic of what mine look like:

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speakerguru
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PostPosted: Sat Feb 16, 2013 1:26 am    Post subject: Reply with quote

Yes, they should be sealed.
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speakerex
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PostPosted: Mon Feb 18, 2013 6:18 pm    Post subject: Reply with quote

Usually there is a cup that fits under the donut and around the pole piece.
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clubsport911
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PostPosted: Tue Feb 19, 2013 7:22 am    Post subject: Reply with quote

@Deckard, as we already spoke off forum, I think the woven ones should be replaced and indeed would echo that the cabinets should be sealed. In terms of your question:- "do the donuts act as a seal" then the answer is yes... sort of.

There is a way for air to get out of the cabinet via the donut, but in this instance, the internal air has to travel via the spider, past the voice coil and out through the airgap.

The spider on my 1245's were a woven fabric material and are definately not a seal.

Changing subject... looking at your speaker internals, I notice that compared to my 1053's two items stand out.

1) The internal rod on mine is matt black (wonder why Kef changed this...)
2) The internal cavity foam material is slightly different. Mine have some sort of hard-ish covering over the foam, and the foam itslef seems slightly denser and black in colour

Anyone got any clues ?
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