KEF 104/2 - The speaker gods have spoken
- Thread starter baco99
- Start date
robn
New Member
Hello everybody,
I've just bought a pair of these to scratch a 35 year itch! It's been so helpful finding this thread to help me work out what to do, thank you all
For the past few years I've been mainly using a pair of Quad ESL63s which I like very much and will be keeping. Their only weaknesses for me are the size they present which is disproportionate to my lounge and the slight limitations on volume and bass 'weight'. I've always been fascinated by the 104/2 since their launch, so I sold a pair of old little used Ditton 44s to help buy a SH pair. For now they will be driven by an Exposure Super XVIII power amp.
My 104/2s appear to be very early, the woofers have rubber surrounds and somehow (maybe low exposure to light) the donuts are not rotten? Maybe they were replaced already but they do look old? The serial numbers A002793 & A002893 are strange with both being As and the numbers having 3 out of 4 digits in common, maybe a mistake in the factory?
They already sound good but even at rest the tweeters hiss more than I would expect and on streamed music the levels of hiss increase as other instruments come in, maybe this is an artefact from compression being exaggerated by the dried up tweeters, I don't hear this with the records I play.
I've ordered replacement tweeters from MidWest Speaker Repair, after these are fitted I'll try to clean out and renew the ferrofluid in the originals, maybe I'll refit them if MidWest's clones sound inferior.
Further ahead I will inspect the woofers, tighten up the bolts & clean out. I'd also like to remove the various layers of varnish etc & oil the veneer but this is not urgent. The Grilles are shabby and one of them is lacking the badge but am happy without them.
Once the tweeters are sorted I'll have a good listen and try decide whether to bother replacing the caps. I've yet to read any compelling accounts of why - unless there is an obvious problem - they should be changed?
I'd like to post a few photos but not sure how to
Cheers, Rob
I've just bought a pair of these to scratch a 35 year itch! It's been so helpful finding this thread to help me work out what to do, thank you all
For the past few years I've been mainly using a pair of Quad ESL63s which I like very much and will be keeping. Their only weaknesses for me are the size they present which is disproportionate to my lounge and the slight limitations on volume and bass 'weight'. I've always been fascinated by the 104/2 since their launch, so I sold a pair of old little used Ditton 44s to help buy a SH pair. For now they will be driven by an Exposure Super XVIII power amp.
My 104/2s appear to be very early, the woofers have rubber surrounds and somehow (maybe low exposure to light) the donuts are not rotten? Maybe they were replaced already but they do look old? The serial numbers A002793 & A002893 are strange with both being As and the numbers having 3 out of 4 digits in common, maybe a mistake in the factory?
They already sound good but even at rest the tweeters hiss more than I would expect and on streamed music the levels of hiss increase as other instruments come in, maybe this is an artefact from compression being exaggerated by the dried up tweeters, I don't hear this with the records I play.
I've ordered replacement tweeters from MidWest Speaker Repair, after these are fitted I'll try to clean out and renew the ferrofluid in the originals, maybe I'll refit them if MidWest's clones sound inferior.
Further ahead I will inspect the woofers, tighten up the bolts & clean out. I'd also like to remove the various layers of varnish etc & oil the veneer but this is not urgent. The Grilles are shabby and one of them is lacking the badge but am happy without them.
Once the tweeters are sorted I'll have a good listen and try decide whether to bother replacing the caps. I've yet to read any compelling accounts of why - unless there is an obvious problem - they should be changed?
I'd like to post a few photos but not sure how to
Cheers, Rob
The earliest versions of the 104/2 used foam surround and foam donuts with single binding posts. Then KEF switched to rubber around the outside. Then, when they allowed for bi-amping, the woofers got their foam back again. Those do look early and possibly were not matched A/B when they were sold by the retailer. Or could have been part of a larger setup that was broken up. In either case, A/B doesn't matter. What matters is how amazing they are. Congrats!
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BobbyN
Well-Known Member
Congrats! You won't be sorry. So the cap question, should they be replaced or not. You could probably get a thousand responses and opinions on that. For repairing anything, if you replace a perfectly good part with a new perfectly good part, then you'll get no change.
If you suspect you need new caps and want to replace them, you can always save your originals and put them back if you desire. You've only lost time.
Another suggestion is don't crank it up too loud since you don't know the condition of the ferrofluid in the tweeters. You don't want to overheat the coils in them. When you're ready to take some serious listening I would give it several weeks before you make any decisions on what you want to do. I feel that's what it takes for you to take a serious listen to your music. That's just my 2 cents.
Can't wait to hear you report back.
Bob
If you suspect you need new caps and want to replace them, you can always save your originals and put them back if you desire. You've only lost time.
Another suggestion is don't crank it up too loud since you don't know the condition of the ferrofluid in the tweeters. You don't want to overheat the coils in them. When you're ready to take some serious listening I would give it several weeks before you make any decisions on what you want to do. I feel that's what it takes for you to take a serious listen to your music. That's just my 2 cents.
Can't wait to hear you report back.
Bob
robn
New Member
Hi Again! Thanks for the comments.
Well the copy tweeters from Mid-West Speaker Repairs arrived yesterday. I'd become used to and very happy with the sound with the original tweeters, they did sound a bit rough when cold but soon warmed up. From what my ears are telling me the new ones give a little more definition but not as big a change as I was expecting. I hope this is in keeping with the forum rules to post a short old and new tweeter comparison video which is here: https://www.youtube.com/watch?v=&feature=youtu.be
The recorder is hindered by the onboard basic mics, can anyone else hear a difference?
Cheers
Rob
Well the copy tweeters from Mid-West Speaker Repairs arrived yesterday. I'd become used to and very happy with the sound with the original tweeters, they did sound a bit rough when cold but soon warmed up. From what my ears are telling me the new ones give a little more definition but not as big a change as I was expecting. I hope this is in keeping with the forum rules to post a short old and new tweeter comparison video which is here: https://www.youtube.com/watch?v=&feature=youtu.be
The recorder is hindered by the onboard basic mics, can anyone else hear a difference?
Cheers
Rob
Crang
Well-Known Member
Picked up my next project yesterday- a set of KEF 104/2 for the princely sum of $50. The grills are about the only thing that dont need work lol. They came with a new set of MW Audio MT1911 tweeters in them and the previous owner had refoamed the woofer donuts before he ran out of steam on the projects. So thats the good.
He said the guy who tried before him was a hack. The mids dust caps badly glued in. Im trying to undo them now. A whole randomly drilled in the cabinet top with 2 wires through it, but only on one cabinet. Curious. So a couple questions-
I got the original T33 tweeters along with them. I tested them at 3.1 ohms each. Seems like they should be more like 4? Before I go through the trouble of of opening them up and changing the fluid figured I should ask.
Also the mids had issues. One had no throw due to the dust cap replacement being glued in a totally sealed fashion. It was locked in place with no motion possible. The others were all on badly enough with holes around them they all had some throw to them. Looked like a drunk monkey worked them over. I cut the dustcaps off the one that had no throw and it fixed it. I assume the originals were vented in some way? Anyone have a source for OEM ones? Unfortunately when I cut them off they took a protective layer off the cones, but that was the only way to do it. Pic below. At least they all test 7 ohms.
Figure I'll order the recap kit from Falcon. Still have to look at the crossovers. Should give me time to refinish the cabs while they are in the mail. Anyone try matching the paint on the pods? Pretty scratched up so going to spray them with something. Never heard these before so hopefully they sound right when Im done!
Put an ad up in Bartertown as well. Need to track down the bass port caps.
He said the guy who tried before him was a hack. The mids dust caps badly glued in. Im trying to undo them now. A whole randomly drilled in the cabinet top with 2 wires through it, but only on one cabinet. Curious. So a couple questions-
I got the original T33 tweeters along with them. I tested them at 3.1 ohms each. Seems like they should be more like 4? Before I go through the trouble of of opening them up and changing the fluid figured I should ask.
Also the mids had issues. One had no throw due to the dust cap replacement being glued in a totally sealed fashion. It was locked in place with no motion possible. The others were all on badly enough with holes around them they all had some throw to them. Looked like a drunk monkey worked them over. I cut the dustcaps off the one that had no throw and it fixed it. I assume the originals were vented in some way? Anyone have a source for OEM ones? Unfortunately when I cut them off they took a protective layer off the cones, but that was the only way to do it. Pic below. At least they all test 7 ohms.
Figure I'll order the recap kit from Falcon. Still have to look at the crossovers. Should give me time to refinish the cabs while they are in the mail. Anyone try matching the paint on the pods? Pretty scratched up so going to spray them with something. Never heard these before so hopefully they sound right when Im done!
Put an ad up in Bartertown as well. Need to track down the bass port caps.
Attachments
darkblue94
The Devil made me do it.
Best of luck with these speakers, they deserve the finest effort in restoration. Starting with a fairly mangled pair is unfortunate but $50 is an excellent deal. Remember that the tolerances are tight and important to replicate. When properly restored and powered by high quality amplification they will reward with wonderful sound.
Measuring a tweeter with a multimeter will give you the DC resistance, not the impedance. 3.1 DCR is appropriate for a 4 ohm driver. Definitely change the fluid.
As you probably know by now, those mids are held together by the MDF pods, glue, and foam. There's no traditional "basket/frame" for the driver to sit in. It's part of what makes the 104/2 so special. The dust caps are not vented. They are a coated felt. You can get a standard felt dust cap and paint it with something like FlexSeal and get a very similar result. Taking the "protective layer off the cone" for the midranges, is a bad thing. I don't see that in your photos. Would need a clearer picture to help here.
You can use any standard spray paint with a "sand finish" and then cover that with satin black to get the desired effect.
And yes, you need the bass ports to reduce port noise.
Crang
Well-Known Member
Baco-thanks. I changed the fluids yesterday and all went well. I was confused as when I test MW Audios T33 replacement it tests a perfect 4ohms and the OEM T33s test 3.1. Did it anyway. Didnt realize how many kinds of black spray paint I had till I went looking and tried a half dozen to match. Simple rustoleum flat black was the best match. They look pretty sharp. Definitely on the hunt for bass port caps- anyone feel free to PM me. Falcon order placed and new set of crossover caps on the way.
Yeah- the mids are where the work will be. Really appreciate the info on the dust caps. Trying to source some OEM ones now but felts will be the standby. The ones that were on it were badly mangled poly and leaky as anything. Since I have nothing to compare them to-if I push on the cones of the mids, should they move in and out or hold firm? Before I removed the bad dust caps the one that was sealed had no play in the cone, but the three that were half on, the cone could move in and out. Not sure what I am going for.
As for the coating on the mids- I got 2 dust caps off without disturbing it, so one pod is good. The other pod, the coating came completely off. Seems like the hack before me crazy glued them on on that side. Its that pile of film like substance attached to the dust cap one one of my pics. I did a bunch of research and they used something called Platiflex, which is a PVA type adhesive. The correct method is to replace the dust caps then completely coat the cap and cone with it. Its definitely integral to the original design. The side that it stayed attached, I still need to coat the dustcap and blend it with the coating already on the cone. As far as what the modern equivalent of Plastiflex is-I have no idea. Will continue to research when I can.
Simplyspeaker has the parts u need . See if they still carry the speaker cone as they did not long ago . I rebuilt a pair of 104.2 . New voice coils , cones and surrounds and they sound beautiful .
Lou G
Super Member
KEF coated their drivers with a Plastiflex PVA (polyvinylacetate) coating. The coating on the front (single coat) was only used to make the central dust cap stick and be airtight. The coating on the back (multiple coats) did the real damping and was controlled by weighing the coated cone and is critical to the sound of the driver.
I don't think Plastiflex is available but something similar to the KEF formulation is actually Elmer's White School Glue, which is a PVA adhesive. The Borden Co (they started Elmer's Glue) actually supplied KEF the Plastiflex coating for their Bextrene speaker cones. The glue would have to be thinned down with water and is best applied by spraying on to get an even coat. It dries clear. I have used it as a spray diluted down (about 4 to 1) with water for model railroading applications. You have to play around with it to get it to the right consistency to spray properly. Any spray bottle works. if you did decide to use it, i would try it first on some practice pieces to get the coating right so you don't overdo it
I don't think Plastiflex is available but something similar to the KEF formulation is actually Elmer's White School Glue, which is a PVA adhesive. The Borden Co (they started Elmer's Glue) actually supplied KEF the Plastiflex coating for their Bextrene speaker cones. The glue would have to be thinned down with water and is best applied by spraying on to get an even coat. It dries clear. I have used it as a spray diluted down (about 4 to 1) with water for model railroading applications. You have to play around with it to get it to the right consistency to spray properly. Any spray bottle works. if you did decide to use it, i would try it first on some practice pieces to get the coating right so you don't overdo it
Crang
Well-Known Member
I wonder if using a poly dust cap then for air tightness would be better than felt and just skip the coating. I talked to a repair guy today at the Speaker Exchange looking for parts. They are an authorized KEF repair place. He said he doesnt put a coat on if its come off the front and they sound fine, but if I really wanted to there is no harm using a clear latex- said it looks like Elmers glue as well but dried clear. I may see if the uncoated ones are audibly different than the coated ones before messing around with it. I like your PVA suggestion better. But dust caps getting sealed sounds like the top priority. Thanks!
Anyone who's restoring their KEF 104/2 having trouble getting the bottom panel off? I'm trying to remove it to access the bottom woofer and replace the donut. Took all the screws out (obviously) but it is either jammed in or glued and it will not budge at all! Any thoughts or help would be greatly appreciated
Sometimes the bottom panel comes off. Sometimes it doesn't. If you really cannot get it off, you can replace the bottom inner donut by sliding the new one over the metal coupling rod. Place a couple quarters on the edge of the donut to hold it down while the glue dries. Make sure not to get any sold foam lodged in the woofer voice coil.
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darkblue94
The Devil made me do it.
The panels are not glued in by the factory. They are snug and not real easy to pull out. Pull the screws out of the blocks but not all the way out of the panel. Pull out gently with the screws alternating sides until the bottom panel is out.
I know someone with some KEF 104/2, I've never seen or heard them but they said his parents owned them and only ever used them occassionally and that they look brand new and sound good with no problems. He used to be asking $699 but said if I come get them to bring $250.
If I was to get them is it a high probability that I'll need to spend a lot of money on them to restore them.....the fluid, donuts, drivers, etc?
I'm excited about them but they are 1:30 away so I'll need to know I'm coming home with them no matter what. lol
If I was to get them is it a high probability that I'll need to spend a lot of money on them to restore them.....the fluid, donuts, drivers, etc?
I'm excited about them but they are 1:30 away so I'll need to know I'm coming home with them no matter what. lol
halkaloogie
The Jerk
I just wondered into a pair last week, and after I redid the tweeters they sing. That's a great price and If the donuts and surrounds are good, it's $20 and an hour of your time to do the tweeters.
