SpeakerTalk Forum Index SpeakerTalk
This forum has been set up to facilitate discussion of 1970s KEF speakers and drive units. The owner of the Forum has no connection with KEF Audio.
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

KEF 105/3 Restoration
Goto page 1, 2, 3  Next
 
Post new topic   Reply to topic    SpeakerTalk Forum Index -> KEF speakers
View previous topic :: View next topic  
Author Message
deckard
Intermediate Contributor 25+


Joined: 10 Sep 2012
Posts: 32

PostPosted: Mon Sep 10, 2012 9:18 pm    Post subject: KEF 105/3 Restoration Reply with quote

Hello all! This is my first post and I am looking for a little help and advice.

I recently acquired a pair of KEF 105/3's in fairly good condition. As they are, they sound fantastic! However, I have noticed a few things which I think need to be addressed:

1- The center woofer donuts have been replaced, but not with the typical foam ones you see on the web. They are some kind of woven fiber/fabric. They seem to be OK in the sense that they keep particles out of the coils, but there is no spring/tension to them. Also, one of them is not even attached to the rim of the plastic sheath around the rod. I have done this repair on a set of 104/2's using the foam donuts and it is my guess that they not only provide protection from dust, but also keep the woofers "suspended" so the coils don't bottom out. These speakers are much easier to work on than the 104/2's, so I am thinking it would be best to replace them with a set of standard foam donuts.

2- The tweeters were replaced and must have been within the time that KEF still offered originals, as they are NT25's. However, the job must not have gone smoothly, as evidenced by the fact that one of the UNI-Q midrange drivers is missing the plastic washer/guide that centers the tweeter. It has been replaced with a large metal washer which is glued in place. A hole was drilled through the edge of the washer to allow the wires to pass through. It works, but it 'aint pretty. Aside from all this, the question I have is, were these tweeters subject to the same issue with dried-up Ferrofluid as the T33's in the 104/2's? They do sound a little dim to me. I spoke with KEF in NJ and they do offer replacement tweeters, but they are a substitute part. Can anyone offer an opinion on the substitute tweeters?

3- One of the UNI-Q midranges has a slight voice-coil rub when depressed. You can hear a slight "tik-tik-tik", as if there is a bur or some particle rubbing on the coil wraps as it moves in and out. It does not appear to cause any audible problems, but I figure if I am doing a restoration, I may as well try to correct this. I have already rotated the driver in case it was caused by sag, so we'll see if that helps any. KEF no longer has any originals, nor do they even offer a substitute part at this point. However, they do offer a reconing service. Has anyone here ever used their service for something like this?

4- The bass response, while tight and accurate, is a bit lacking in slam. I have read mixed things about using the KUBE in that it can cloud the wonderful midrange. I believe the KEF museum makes note that the KUBE 200 was the one to be used with the 105/3. I have also read that it can be used in a bi-amp setup on the LF inputs only. This sounds like the best bet. Has anyone used this combination?

As I figure I'd have to spend a boatload of money to get anywhere near the quality of the 105/3's in a modern speaker, I think a couple hundred in parts and a Saturday afternoon would be worth it.

I would be most grateful for any tips or knowledge with regards to working on these speakers, or anything in general that would be helpful, as well as any other alternate resources for parts or places that specialize in servicing KEF.

Thank you for reading!
Back to top
View user's profile Send private message
proffski
Über Contributor 1000+


Joined: 22 Aug 2003
Posts: 1296
Location: Tewkesbury UK

PostPosted: Mon Sep 10, 2012 11:14 pm    Post subject: Re: KEF 105/3 Restoration Reply with quote

I shall try to read your missive in full when I am sober tomorrow.
However there are two proper experts out there somewhere who with luck will beat me to it, even though one seems to be on an extended cruise somewhere…

Welcome to the sanatorium! Wink
_________________
I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill
Back to top
View user's profile Send private message Send e-mail
clubsport911
Senior Contributor 100+


Joined: 26 Aug 2012
Posts: 157
Location: Cheltenham, UK

PostPosted: Tue Sep 11, 2012 1:11 am    Post subject: Reply with quote

Hi deckard (Blade Runner ?) - welcome to the forum and I'm only 3 weeks into 105/3 ownership myself so know only too well the path you are treading.

Ref the UniQ - I cannot answer all the questions on Ferrofluid but I know know that my previous owner replaced UniQ and HF unit 4 years ago and they fit perfectly. I would definately give Andy in KEF UK a call.. he's been there ~25 years and has built 105/3's - more than willing to help.

I have the 1353X HF units and they are an upgrade over the 1240's fitted as standard. Yours should have a gold edge to them... In terms of the "tick" sound, it could be a literal mechanical interference between the tweeter and the HF unit.

When I ripped mine apart, I was suspicious of the same, so I took off the little plastic cover, undid the bolt and loosened the HF unit, then rotated the tweeter. It all works fine.

For the bass units, I would 100% get all the units to the same spec as according to KEF you need to have electrical and mechanical equivalence for the best results in bass. I re-foamed mine with a kit sourced from the US. In addition, I had one of my units rewound and the repairer put on a KEF original surround, but this was a bad step because the compliance was different. Again, based on KEF advice, I ripped off the new surround and put on a new re-foam.

The centre donuts are not too critical, because most of the heqavylifting work on VC stability is done by the spider, but they do add stiffness to the suspension so again, worth getting them all the same.

On my speakers, I stripped out all the internal cable and replaced with heavy duty OFC cable. I added new polypropelyne caps to the crossover in C35 / C36 - the 7uf and 20uf caps in series with the tweeter. UK speakers builders Wilmslow Audio suggested that based on extensive messing about over years with the 105's they only ever replace these 2 caps as others have minimal effect. They never replace the chokes with air core.

I also took the time to add some additional damping on the exposed MDF cross member inside the bass cavity.

I replaced the grommits on the bass unit, and be aware that when repairing, the best sequence is the following

1) fit both bass units, but do not tighten to the cabinet
2) Tighten the force cancelling rod completely
3) tighten the upper unit so that the B200 sits firmly on the metal insert / grommits but no more
4) Do the same with the bottom unit

My final tweek was to remake all the joints everywhere with Silver solder

The re-furb took me 3 weeks - including waiting for parts and I only fired them up this weekend just past, and I'm utterly delighted with the sound.

Based on advice from KEF, I will be ordering a set of additional HF units because they are running out of them (enough for 2 years right now). These are from the KEF 109's ! (£20k per pair) and are an advanced derivative of the 1353's. Once these run out, the only alternatives are from the CI (custom install) range and not quite up to the std of the 1353's

Good luck with your upgrades.. and keep us all informed.

I have only one comment on the bass. Unlike my last large, 8" bass derived floorstanders, the KEF bass is much much more accurate (and they were good uns as well). Bass is not bloated, and even without KUBE, on my Musical Fidelity monoblocks, it runs deep. I thought at first they were bass light until I changed to program material where low bass was featured, then they came to life in front of my very ears. imaging and mid / treble detail is off the scale compared to my previous sound.

In other words, if it sounds naff, I wouldnt leap to blaming the speakers !

Cheers

Steve

PS - I'm NOT one of the experts proffski mentioned !


Last edited by clubsport911 on Tue Sep 11, 2012 4:45 pm; edited 1 time in total
Back to top
View user's profile Send private message
deckard
Intermediate Contributor 25+


Joined: 10 Sep 2012
Posts: 32

PostPosted: Tue Sep 11, 2012 3:34 pm    Post subject: Reply with quote

Um... Holy Crap! Thank you!!!

Yes, androids dream of electric beats... Wink

So, you think there might actually be some 105/3 UNI-Q midranges left in the UK? I think I may have read somewhere that KEF UK won't sell to KEF US though.
Corey at KEF in New Jersey says they only have tweeters now (which I will be ordering today). What's the best way to get in contact with Andy at KEF UK?
Even if I can't get parts through him, it might be helpful to have a chat. Wonder if I can get another plastic alignment washer instead of the jury-rigged metal one that's in there now.

Also, I wasn't given a part number for the new tweeters, only an SP#: SP1413. Can you confirm if that is the same as 1353X?

I did pull the tweeters out when I inspected everything originally (the missing plastic washer etc.) but the driver still made that ticking sound when depressed with the tweeter removed, so I think I've either got a particle in gap or a burr on the voice-coil. Fortunately there is no audible effect as far as I can tell.

Good point re: the spider. I don't feel that the donuts are that urgent now and can focus on the tweeters.

I like the idea of the silver solder and replacing the caps, but I'm wondering if I will notice any real difference with the gear I have currently.
However those seem to be pretty non-invasive and fairly straight-forward tweaks for the future! Can you provide links or more info on the caps you purchased?

Regarding the dampening material, the interior cavity should be empty, with the exception of the foam on the interior cabinet walls, correct?
What material did you use for the additional dampening on the cross braces?

My brother has a Krell KSA-150. He lugged it over for a test and the bass definitely became more solid/focused, but it's still not as deep as I have heard with other full- ranges.
However, my room is less than ideal, so I will be experimenting a little more with placement before attempting anything with the KUBE.

Again, thanks so much for the helpful info! I will update this thread as I progress.
Back to top
View user's profile Send private message
clubsport911
Senior Contributor 100+


Joined: 26 Aug 2012
Posts: 157
Location: Cheltenham, UK

PostPosted: Tue Sep 11, 2012 4:35 pm    Post subject: Reply with quote

Hi again

I'm in Japan right now, and my details on the speakers are at home. I'd be happy to chat.

Let's start basic.

I'd go for a full re-wire first. This takes time to make up a new loom to the front panel but worth it. Of course, whilst not being a fan of snake oil, I get the argument both ways that a chain is only as strong as it's weakest link, so I wince in incredulity at people using 1" thick super-conducting unobtanium cables" to then point out that in the speaker cabinet, someone has use a simple length of "el-cheapo" cable....

In my case, from the PCB on the amp right through to the pigtails on the speakers, I like to use decent cable. Can I hear a difference ? Is there a difference ? Well, I needed to kill the time awaiting parts so for me I thought "lets give these drivers the best possible chance to succeed" - hence the re-wire.

The caps come from a company called Wilmslow Audio. Check them out on the 'tinernet , ask for Terry - he will give you good advice. Interestingly the same day I contacted him asking "what do I need to change" he recieved in the post a set of 105/3 crossovers from France to upgrade.

The caps they show on the website are the polypropelyne versions. Can you hear the difference ? Well, it's another case of marginal gains. But as they claim, the series capacitors have the most effect on treble and upper mid quality.

More snake oil ? I'll not join the debate one way or another but as for replacing them... if you can affod it why not ? They costed ~£25 for the whole lot (both channels)

The driver airgap might need cleaning. I cleaned mine with a piece of 160g paper (quite thick) cut into an "I" shape then soaked it in switch cleaning fluid. I then inserted into the airgap (damp) and then moved up and down to clear debris (of course, moving the paper around the entire circumference of the airgap at the same time).

I then took the same spray (competely harmless to plastic, non residue forming) spray and used it to apply into the airgap. Once dry / drained, I then sprayed the airgap with my hobby airbrush and it just blew out all remaining liquid (and along with it...more crud).

Result.. when I re-inserted my paper shim, it went in / came out a lot easier ! along with a load of crud. Repeat until your airgap is clean. This might help your ticking speaker. Of course... in my case, I did this on woofers where the gap was heavily contaminated with loads of old foam. In the case of your UniQ MF unit, I doubt it's that contaminated.

Of course, the main inner cavity was empty of all insulation save the KAF applied black stuff and here, all I did was paint the flat section where the driver sits matt black (you can see it throgh the port)

I did however cover the MDF cross brace with some sound absorbent material (because I could.. no reason) and also covered any gaps in the insulation with a small cut section of the same.

I got car sound deadening sheet from oBey and it has the same finish as the dense foam already in the cavity. Looks nice too ! ~Easy to cut, self adhesive backed.

Drivers. I think the 1413's are NOT the ones you need.. but I need to check my notes...from memory they have an alumimium dome and not as good as the SP1353x's (according to KEF) - but differences are marginal (experts might have another opinion of course)

I would ring them (Andy) up and plead for the revised tweeters from the 109 but please please do not propogate too widely..... You will have to work hard on charm and be patient to get them. if you get the last 2 I'll go mad because I have planned to purchase them when I get back from Japan ! about £55 each + VAT + shipping.

PM me with your contact details (ph etc) if you want a chat.. I kept a photo log of the whole experience.

Cheers

Steve


Last edited by clubsport911 on Tue Sep 11, 2012 4:47 pm; edited 2 times in total
Back to top
View user's profile Send private message
deckard
Intermediate Contributor 25+


Joined: 10 Sep 2012
Posts: 32

PostPosted: Tue Sep 11, 2012 4:39 pm    Post subject: Reply with quote

Well... figured since it was still afternoon across the pond, I'd try calling KEF UK using the number on on the contact page.

Lo and behold, I was able to get Andy in service! He did confirm my suspicion that there are indeed no more UNI-Q midrange drivers or substitutes available for the 105/3. Sad However, he actually did have a set of the plastic UNI-Q alignment washers and is sending them to me FOC!!! Very Happy

He said the tweeters and the caps would be the most important updates at this point. He confirmed that the SP1413 is in fact the 1353X, but stated I would have to buy them from KEF US (no big deal). Yes, they are not "matched" as they normally would be for a Reference speaker, but I think this is an acceptable compromise.

Regarding the UNI-Q midrange voice-coil issue I described, he said it probably won't cause an audible problem, but did say to give a closer look at not just the coil, but the spider, the leads, etc. which I will do when I have them apart again.

One thing he mentioned that I found very interesting regarding internal dampening; there was a variant of the 105/3 that had large foam donuts on the force-cancelling rods, same as on the 104/2's I have seen. However, this was only for certain dealers that claimed there was some sort of benefit and to his knowledge, none of the 105/3's in the UK had the extra donuts installed.

He also said that the main purpose of the woofer donuts was to keep dust out of the coil, but they do provide some suspension as well, so he suggested I do replace the fabric ones with foam.

So I think I'm good to go for the time being!
Back to top
View user's profile Send private message
deckard
Intermediate Contributor 25+


Joined: 10 Sep 2012
Posts: 32

PostPosted: Tue Sep 11, 2012 4:57 pm    Post subject: Reply with quote

Hi Steve - was in the middle of my last post when I saw you replied. I wouldn't worry about the tweeters as I can't order from the UK, but Andy definitely confirmed that the 1413 is the 1353X. Maybe you can ask him to elaborate a bit more when you speak to him next.

I hear you on the wiring. I tend to get pretty obsessive (ahem... anal) with gear and while I could see myself doing the same, I have to sometimes stop myself or I'll never get to a point where I can just sit, listen and enjoy. Wink

Good tip on soaking a piece of paper with cleaning fluid - will (carefully) give that a go.

Going to start a dialog with Wimslow on the caps as well.

Would LOVE to see your pics! I'll PM you.

Thanks again!
Back to top
View user's profile Send private message
deckard
Intermediate Contributor 25+


Joined: 10 Sep 2012
Posts: 32

PostPosted: Tue Sep 11, 2012 10:03 pm    Post subject: Reply with quote

clubsport911 wrote:

I would ring them (Andy) up and plead for the revised tweeters from the 109 but please please do not propogate too widely..... You will have to work hard on charm and be patient to get them. if you get the last 2 I'll go mad because I have planned to purchase them when I get back from Japan ! about £55 each + VAT + shipping.


Ugh.... Well I called Corey at KEF US today to order the tweeters. I asked him if the 1413's were the same as the 1353X's.
He said no, the 1353X's are a soft-dome tweeter and the 1413's have aluminum domes, but the 1353X's are no longer in stock... Mad

I mentioned reading that there was a revised tweeter for the 109 "Maidstone" that would be a better substitute. He spent some time trying verify this, but ultimately could not find any info on this part. Were the Maidstone's UK issue only? Could that be why Andy didn't bring this up? Corey said he was going to email Andy to try and find out more. I think I'm SOL... I really don't want to go to an aluminum-domed tweeter...

Maybe you could put in a good word for me? Laughing
Back to top
View user's profile Send private message
clubsport911
Senior Contributor 100+


Joined: 26 Aug 2012
Posts: 157
Location: Cheltenham, UK

PostPosted: Wed Sep 12, 2012 12:23 am    Post subject: Reply with quote

Hi again. When I get back to blighty, I'll look @ my detailed notes that I made with Andy and confirm the tweeters I'll be ordering. Of course, when I do that I'll have a set of 4 year old, mint condition 1353's going spare.

Would you be interested ?

S
Back to top
View user's profile Send private message
deckard
Intermediate Contributor 25+


Joined: 10 Sep 2012
Posts: 32

PostPosted: Wed Sep 12, 2012 12:29 am    Post subject: Reply with quote

Absolutely - sent you another PM.
Back to top
View user's profile Send private message
deckard
Intermediate Contributor 25+


Joined: 10 Sep 2012
Posts: 32

PostPosted: Fri Sep 21, 2012 3:04 pm    Post subject: SP1258? Reply with quote

Much has happened since my last post. I am awaiting a few more parts until I start working on these again. I still plan on posting my progress here.

In the meantime, I would like to ask: does anyone here have or know where I might find a spare UNI-Q midrange driver for the 105/3?

One of mine has a rub and while it's not causing any audible problems at the moment, I'd love to have a second unit on hand.

It's a B160, but has the UNI-Q cutout. The part number is SP1258.

I would appreciate if my fellow KEF fans here would keep an eye out and drop me a note if an SP1258 surfaces.

Thanks!
Back to top
View user's profile Send private message
Headrush
Junior Contributor 10+


Joined: 10 Nov 2012
Posts: 18
Location: Nottingham

PostPosted: Fri Dec 07, 2012 8:02 pm    Post subject: Reply with quote

Hello deckard et al.. As a 105/3 owner for just over 5 years I decided to chime in with a few thoughts of my own. I am not an expert on speakers, my greatest achievement was re-foaming a set of 107/2 base drivers but I know nothing about the electronic side of things.

I bought my speakers as faulty. One of the upper base drivers was ripped around the outer foam causing a nasty distortion, so I contacted a guy who suggested having all four refoamed, which I have regretted ever since because he used really thick rubber surrounds. If I had known then what I know now, I would of done them myself with foam.

They had the original SP1240 tweeters but I can't say how good they were because I broke one soon after getting them. So I took the Uni-Q drivers to KEF where I met Andy. He replaced them with a pair of SP1353s which both popped 2 years later so he replaced them again for free but they popped again just over a month ago so back I went expecting a big bill but found I was still on a 5 year warranty, just.

As you are now aware, there are no more SP1353s left and the alternative is the 1413s which Andy explained were made in China in a way that made me feel I was getting second best. But then he went on to say that they had this pair of tweeters which were redesigned for the Maidstones which he thought were better, I'm fairly sure he said they were 1414s and just happened to be laying in the spares box if I wanted to take a chance with them. I agreed and he sent me on my way with a wagging finger and told me to not break these ones. I got the impression next time I will have to cough up some folding stuff.

Well what can I say? These tweeters are brilliant. The only way I can describe it, as I'm not fluid in snake oil lingo, is that they are softer but still incredibly detailed, and so much easier to listen to at high volume levels. The softer sound may not suit everyone but it definately suits me Sir. I do hope they were not the last pair clubsport911 :p

Regarding the bass: It's a long story, I was unhappy for a long time but it's getting there and hopefully will be worth the effort and patience. I read with great interest some of the tweaking info above so thanks for that.

My tips: If you refoam the bass drivers, don't use rubber. I bought the surrounds and doughnuts for the 107/2s from http://www.speaker-repairs.co.uk/shop/refoam/kef.html - the material is very similar to the foam surrounds found on the 104/2s and only after a few hours of playing time, the bass was perfect.

If you get tired of listening to 1353s, snap up a pair of 1414s, it worked for me.

When bolting the front driver assembly onto the bass box, I found the original seal to be useless. Use some thin sticky back draught excluder around the driver recess holes and the small terminal hole on the bass box. It will eliminate any farting (can I say that here?) and helps to dampen/decouple the assembly from the bass box. Also place some foam plugs in the wiring channels on the driver assembly to stop air moving from one compartment to another.

I look forward to reading more from you all and good luck with your endeavours...
Back to top
View user's profile Send private message
Headrush
Junior Contributor 10+


Joined: 10 Nov 2012
Posts: 18
Location: Nottingham

PostPosted: Fri Dec 07, 2012 8:40 pm    Post subject: Reply with quote

deckard wrote:

Ugh.... Well I called Corey at KEF US today to order the tweeters. I asked him if the 1413's were the same as the 1353X's.
He said no, the 1353X's are a soft-dome tweeter and the 1413's have aluminum domes, but the 1353X's are no longer in stock... Mad


Two places I know where you can find 1353s. In the Reference 100C and 200C center speakers. I've seen 100Cs go for as little as £40 on eBay, less than the price of a new 1353 on its own Wink
Back to top
View user's profile Send private message
clubsport911
Senior Contributor 100+


Joined: 26 Aug 2012
Posts: 157
Location: Cheltenham, UK

PostPosted: Fri Dec 07, 2012 10:55 pm    Post subject: Reply with quote

Great post headrush. Where you been hiding ? Anyhow, I've just swapped out 1353's to the (rare as you like) 1414's and my posts elsewhere on this site give a clue to my thoughts.

I'm happy.. And then some

Anyhow, I can only agree with the sealing trick and also, the swap out of the white BAF to Rockwell has worked nicely.

After many weeks of messing around with Refoams, rewiring, new tweeters, a couple of polypropylene caps in the crossover, removal of all the connectors in favour or directly connected silver solder joints..... I have to suggest that these speakers are stunning

Apart from the lack of the very deepest bass (but what is there, is accurate) I am totally enchanted.

Don't kill those 1414's !
Back to top
View user's profile Send private message
Headrush
Junior Contributor 10+


Joined: 10 Nov 2012
Posts: 18
Location: Nottingham

PostPosted: Sat Dec 08, 2012 7:38 pm    Post subject: Reply with quote

clubsport911 wrote:
the swap out of the white BAF to Rockwell has worked nicely.


Thank you for the warm welcome. This 'Rockwell' stuff you mention, where can I find it? Or did you mean 'Rockwool', the stuff they use in loft insulations. Also, how much did you pack in? Did you ram it in or just loosely fill the cavity? I'm thinking it must of changed the bass for you in some way.

I know this is going to sound mad, but I often wondered what would happen if one was to drill port holes in the rear of each bass cavity. Of course it would be a crazy arse thing to do to a pair of nice cabinets and one would have to be sure of the size and depth of the port. Hopefully someone will step in here and tell me not to be so stupid and go stand in the corner Embarassed
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    SpeakerTalk Forum Index -> KEF speakers All times are GMT + 1 Hour
Goto page 1, 2, 3  Next
Page 1 of 3

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group