View Full Version : KEF T33 tweeter replacement for 104/2


centaurus3200
07-23-2006, 09:47 PM
i did a search and found some good info, but am curious if anyone has any updates on their findings.

as many KEF owners with ferro-fluid cooled tweeters know, the gel hardens over 20 years and basically renders the tweeters useless. i recently traded my Bozak 302A Urbans for a pair of 104/2. should have hooked the KEFs up while the guy was here, but such is life. he's really nice and offered to give me cash to buy the KEF recommended replacements.

but, I've heard KEF's replacements are both overpriced ($160/pair) and don't even sound that great. as you know, the 104/2 has the tweeter mounted flush behind the mid/tweeter baffle. i do not want to alter the outside of the baffle, but have no problem tweaking it from inside to mount a suitable, if not better replacement. i mean $160 buys you some pretty fricken nice tweeters ;-)

so, what have you guys tried successfully? the tweeter is 1.25", but i can go smaller if necessary. i believe they are 4 ohm. overall sensitivity is rated at 92db at a 4ohm load.

specs: http://www.kef.com/history/1980/model104_2.asp

thanks,
Robby

kdlsoft
07-23-2006, 10:49 PM
One of the speaker companies in GB for a while was showing a Peerless tweeter as a screw-in replacement for the T33. For the life of me, I can't find that link now. I'll keep on looking.

Solen in Canada at the time had them for about $US 30-35 each.

T-33A's come up every now and then on that auction site......

I'll post again if I can find the replacement.

centaurus3200
07-23-2006, 11:28 PM
thanks you for your efforts!

does anything from madisound.com ring a bell?

Robby

One of the speaker companies in GB for a while was showing a Peerless tweeter as a screw-in replacement for the T33. For the life of me, I can't find that link now. I'll keep on looking.

Solen in Canada at the time had them for about $US 30-35 each.

T-33A's come up every now and then on that auction site......

I'll post again if I can find the replacement.

kdlsoft
07-24-2006, 11:47 AM
Shot a fast email to sales@wilmslowaudio.com (www.wilmslow-audio.co.uk) about the T33 replacement and got this reply:

"Robert
The replacement unit was a Peerless 811528 which has now been discontinued.
We have only one remaining unit in stock, the price would be 30 plus p&p Regards Terry"

Solen in Canada HAD them, don't know if they do now or who else might.

Solen part number 94DT2608 "international pricelist" $US 16.38. Don't know what their stock level may be (if any).

Bob

centaurus3200
07-24-2006, 02:46 PM
Robert
The unit that we have successfully used in the 104/2 is a Morel MDT29
at 26 each. This unit will operate with the front faceplate removed and will fit
into the same position as the original.
Regards
Terry

Madisound has them. is he just scrambling to think of something that will work or has he tried. odd being he never mentioned the morel in your email to him?

worth a shot though if you all think it will work. Morel makes some really nice drivers. what do you think would sound better in the 104/2? could just buy both and try them with alligator clips. return the morels if i decide on the peerless. how would both of these comapre to the T33 or KEF's replacement? i could buy a T33, but they are probably all shot now because of the hardened cooling gel.

Robby

centaurus3200
07-25-2006, 02:06 AM
crazy idea - a/d/s speakers are 4 ohm. what about their clasic tweeters from the 70/80's?

Robby

Nakdoc
07-25-2006, 09:52 AM
Another crazy idea. Why not clean the ferrofluid off with a solvent and use it without...? Dome tweeter diaphrams generally self center after the magnet is unscrewed.

centaurus3200
07-25-2006, 01:42 PM
i'm definitely gonna give it a try, but i think i will buy some suitable aftermarket tweeters from morel regardless. i've heard from people that have tried to clean out the tweeter, that it helps a lot, but still doesn't get them to have "like-new" output.

Robby

Another crazy idea. Why not clean the ferrofluid off with a solvent and use it without...? Dome tweeter diaphrams generally self center after the magnet is unscrewed.

Nakdoc
07-25-2006, 06:25 PM
The fluid supposedly improves the efficiency a bit. There used to be a source for ferrofluid. In the Manchester NH airport there is a ferrofluid exhibit placed there by the company that makes the stuff. Why not ask them?

centaurus3200
07-26-2006, 01:58 PM
it's done, i've made my choice and im sticking to it ;-)

Well, after some research, i tend to agree that both the T33 was never that great and that the KEF replacement is both overpriced and underwhelming. so, i bought a pair of Morel MDT30 tweeters. hopefully they will mate well. wimslow audio uses the MDT29, but the folks at madisound said the 30 will fit the same and sound even better.

yeah, i read lilke 7 reviews on the 107 and 107/2 on stereophile online and all said that the tweeter detracted from an otherwise incredible loudspeaker.

besides, madisound has a great return policy, so worth a shot.

Robby

ARRAY
08-25-2006, 10:02 PM
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centaurus3200
08-25-2006, 11:22 PM
if they sound decent, just use them. it was quite obvious on mine that there was little output coming from them. the ferro-fluid hardens over time and kills the tweeter output. this condition worsens if they have been blasted on many occasions.

i bought some Morel MDT30 but they have a rear chamber and did not fit. i sent them back and have some MDT29 on route. the MDT29 has been tried many times by terry at wimslow audio in the UK with great success. he even says they sound much better than the T33.

the morels are 8ohms at 89 db. the T33b is 92 db at 4 ohms. when the KEF group questioned terry, he said he did not have much faith in KEF's sensitivity measurments. plus, from my knowledge, 89db at 8 ohms is equivelelnt to 92db at 4 ohms. terry stands by the morels.

Robby

Paul C
08-25-2006, 11:45 PM
I think Parts Express had ferrofluid.

If the T33b is 92 db at 4 ohms, 1 watt, that is 2 volts.

If the Morel is 89 db SPL, 8 ohms, that is for 1 watt. One watt into 8 ohms is 2.83 v.

If you put 2 volts into an 8 ohm load, it would produce only 1/2 watt. Half power into the Morel would then produce 86 db. So, the T33b would make 6 db more sound for the same voltage input.

For a 4 ohm driver to have the same output at 2.83 v as an 8 ohm driver, the 4 ohm driver's SPL should be 3 db less than the 8 ohm driver's SPL.

centaurus3200
08-26-2006, 01:07 AM
we'll see. i'll trust terry. i have no choice. from my experience on the KEF forums, the T33b are not repairable. any attempt to clean out the hardened ferro-fluid and put new fluid in has resulted in better performance, but still not original output.

i thought that an 8 ohm speaker that is 89 dB/watt efficient also has a sensitivity of 89 dB/2.83 volts. But a 4 ohm speaker that is 89 dB efficient will have a sensitivity of 92 dB, because 2.83 volts into a 4 ohm load is 2 watts instead of 1 watt. 2.83 volts is the constant, not the variable.

so, true the t33b would be 92 db sensitive, but at 2 watts at 2.83 volts. the MDT29 would be 89 db efficient, but at 1 watt for 2.83 volts. so, they would be 3 db down, but require half the power, therefore be the same sensitivity. i have the spec sheet on the T33b. it's rated at 92db at 4 ohms. so, you are saying i'd need an 8 ohm speaker that is 98db at 8ohms? that's not going to happen.

but, hearing is believing. there are not many 4 ohm tweeters that will work because you have to remove the flange to fit behind the baffle in thw mid/tweeter enclosure in the 104/2. if the tweeters sound soft, then i'll have to revise the crossover. i'm pretty sure the MDT29 is the only tweeter that will fit with out any modifications to the enclosure. the only 4 ohm tweeter is KEF's suggested replacement which is like $240. they sound really hot and sibilant in 104/2 from what i hear.

again, i am not sayng you are wrong. in fact, i'm probably wrong. but either the morels sound acceptable or i'm selling the 104/2. life's too short to endlessly fart around when i have other speakers to listen too. i do find it totally absurd that KEF has left their loyal customers with true classic KEF gear hanging.

Robby

Paul C
08-26-2006, 01:53 AM
16 ohm speakers are rated at 4 v (1 watt). Are you sure the KEF's are rated at 2.83 v? Or are they rated at 2 v? makes a difference.

centaurus3200
08-26-2006, 02:20 AM
their specs from various speakers on KEF's history section all seem to be 2.83 volt for their 4 ohm speakers. the specs for the 104/2 just say 92db. nothing else.

you know more about this than i, but being the other drivers are 4 ohm and the crossover is conjugate loaded. the tweeter will still be 8 ohm even on the 4 ohm tap. not sure what this means for their response though. for reference, i am using mcintosh MC60s tube amps. so, i can run the speakers on the 4 or 8 ohm tap. the back of the speakers say 100 watts at 8 ohms or 200 watts at 4 ohms. weird being if they are 4 ohm speakers, they should run on 4 ohms only, right? not that it would hurt the speakers on the 8 ohm tap.

an audioaslym member does use and enjoy morel MDT30 (90db) on his 4 ohm KEF C80. which are also conjugate loaded. teh C80 are 89db though at 4 ohms. which might make sense because when he pulled the dead T33 tweeters, his were rated at 6 ohms.

bah, my head hurts. i'll let you know how they sound with the MDT29. if they suck, i have 3 choices. keep searching, mod the x-over (which i don't know how to do) or just sell the fricken things ;-)

can you find a suitable tweeter? i don't think anybody makes a 4 ohm tweeter with a removable front flange.

Robby

ARRAY
08-26-2006, 02:33 PM
.................

centaurus3200
08-29-2006, 03:38 PM
Well,

i finally got some time to rig in the morel MDT29 tweeters last night. keep in mind that i have never heard stock 104/2. so, i just compared to my KEF Calinda.

well, there's a very good reason why terry only recommends the mdt29. it's literally the only thing that would fit. and it doesn't really fit. let me explain.

the T33 tweeter fits right between the two B110 midrange enclosures. it's held in place by a wooden plate on a track and a pressure bolt. anything with a magnet structure wider than 68mm will not fit as it has to wedged between the two enclosures. the height can not be taller than something like 26mm.

as it stands, the morel is 1mm too high, so the back of the magnet hits the metal thread on the wooden plate. so, i slid the plate over until the thread hit the magnet. used mounting double stick tape (heavy duty and thick). the tweeter won't budge.

i used alligator clips to listen. i can't solder, because once i do, i can not return the tweeters if i decide i don't like them.

so, now for the listening...

it was quickly apparent that my McIntosh MC60 tube amps did not have enough current to maintain decent dampening of the woofers on the 4 ohm tap. coupled with the fact that the 8ohm morels would be 3db down on the 4ohm tap, i quickly hooked the speakers up on the 8 ohm tap. ahhh, much better!

the morels are very smooth. a bit compressed sounding, but i think they will open up once they get broken in. they are not as bright nor as forward as the T27 in my Calindas. but the morels are extended and blend nicely with the B110 mids. are they a match made in heaven? no, mainly because the morels are 89db at 8ohm. i believe they are fairly closely matched to the other drivers, but they could stand another 1-2 db of sensitivity. still, compared to the comments ive heard for KEF's recommended replacement tweeter, the morels are 60% cheaper and much smoother.

so, where does that leave me? i have to listen more, but i am thinking of trying some 4 ohm 93.5db sensitive Vifa DX25TG05. i'm waiting to hear from madisound what the width is. it is not specified in the spec sheet. if it's more than 68mm, NO tweeter will fit. then i will just live with the morels. but the vifa DX25TG05 specs sound very close to the T33B.

other issues i noticed is that one of the mids distorts a little. not in a blown way, but in a voice coil rubbing way. it's minor. don't you KEF guys turn the drivers upside down to recenter the VC?

see ya,
Robby

ARRAY
08-29-2006, 05:32 PM
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Paul C
08-29-2006, 05:57 PM
More about ferrofluid. It does some damping of resonances, but the main thing is the "coolness factor"... literally. The fluid conducts heat out of the voice coil into the magnet structure and frame or basket. The whole tweeter assembly becomes a heatsink sucking the heat away from the tiny tweeter voicecoil.

I don't know if this is speaker grade ferrofluid:

http://www.forcefieldmagnets.com/catalog/product_info.php?products_id=102

centaurus3200
08-29-2006, 06:12 PM
as i stated before, replacing the ferro-fluid does NOT fix the T33 tweeter. i don't know why. but somewhere on DIY forums, someone wrote up a very descriptive story about his trials and trubulations with this cursed tweeter.

Robby

Nakdoc
08-29-2006, 06:31 PM
I believe the thing to do is try the Morels. Even a 3dB difference will be obvious. The impedance also affects the crossover frequencies. and 8 ohm tweeter has more coils of wire, hence higher inductance.

ARRAY
09-02-2006, 10:43 PM
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centaurus3200
09-03-2006, 10:06 PM
hey array, don't part them out!

have you heard them? do the tweeters sound like dead ducks? they should be fine. mine were obviously toasted

they don't suck by any stretch with the morels, but compared to my KEF Calindas with the T27, the HF response certainly does not break out of the box and make for a convincing sound stage.

i have a pair of Vifa DX25 on order. kind of a funky jobby. check them out at madisound. has an odd dome shape that contributes to nearly linear 40khz on axis response, but a sort of ragged 60 degree off-axis response. but who listens at 60 degrees off axis anyway.

so , here's the story for you. if you love your 104/2, the three options are

DX25
http://www.madisound.com/cgi-bin/index.cgi?cart_id=5441548.29862&pid=1365

audax - colin from the kef forum says the terminals are on the faceplate though:
http://www.madisound.com/cgi-bin/index.cgi?cart_id=4270451.14828&pid=2175

Vifa MG27 - madisound is not sure the flange is removable - but probably is:
http://www.madisound.com/cgi-bin/index.cgi?cart_id=5441548.29862&pid=1381

all fairly cheap and fun experiments for you 104/2 lovers. just buy all three and return the two you don't like. as long as you don't solder or scratch them, they will take the tweeters back if you pay for return shipping.

Robby

centaurus3200
10-01-2006, 11:27 PM
VIFA MG27!!!!!!!

fits perfectly and sounds awesome! I'm very happy!

i just got them up and running so i have to let them break in and listen more to give my absolute final evaluation. but i will says this. they sound light years better than the Morel MDT29 i was recommended as a direct replacement. the MG27 is 4ohm at 93.5db sensitivity compared to the MDT29 with 8ohm at 89db. the T33b is 4ohm at 93db.

now, i have never heard a working pair of T33b in a pair of KEF 104/2, so i'm just basing my thoughts against my other working speakers. KEF Calinda, Thiel 03A and JasZen Z-200. and all the the other speakers I've owned and listened to in the past. obviously the crossover was tailored for the T33, but the Vifas sound mighty nice as is. i'm sure you more knowledgable folks could tweak the crossover for the Vifas.

so, I've heard enough working stuff in the past to know if something sounded amiss with the Vifa MG27 in my KEF 104/2. they sound great so far. and at $22.10 apiece from madisound speaker components, you can afford to try them and see for yourself. just be sure to secure the dome to the magnet when you remove the flange. it's meant to be removable so you can replace thw voice coil if the tweeter blows. no big deal. the dome's mounting plate is notched in there pretty well, just a few strips of tape to make sure it doesn't fly off when mounting the tweeters and you are all set.

they fit perfectly between the two mid cavities. the wooden plate and pressure bolt slide perfectly over the back of the tweeter magnet. and the tweeter magnet even has a slot to secure the bolt in the center. it's like the MG27 was meant to be in there Wink

so, if you can live with Danish tweeters in your beloved British speakers, go or it!

see ya,
Robby

ARRAY
10-03-2006, 12:11 AM
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ARRAY
10-03-2006, 12:24 AM
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centaurus3200
10-03-2006, 01:20 PM
Hey Array,

thanks for the comments.

what do the foam doghnuts do other than keep crap from falling into the voice coils? mine aren't ripped, but i'm sure they are brittle from age. i was just going to leave them alone. my 104/2 are the early models with rubber woofer surrounds, so that's a good thing ;-)

see ya,
Robby

ARRAY
10-03-2006, 04:27 PM
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centaurus3200
10-03-2006, 04:44 PM
cool! do you have a link to the modded 104 site?

Robby

ARRAY
10-03-2006, 05:42 PM
Hey Robster, take a gander >>>

http://www.empiricalaudio.com/frTHE_Show_2004.html

bbbbq5555
02-13-2007, 08:36 AM
I just got a pair of 104/2 for free. the tweeters are blown, all doughnuts rot, cabinets in bad shape. it is still worth it even though I had to drive 110 miles round trip. I will try the Vifas to see how they sound.

ARRAY
02-21-2007, 10:12 AM
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centaurus3200
02-21-2007, 12:46 PM
are the surrounds foam or rubber? if rubber, the foam doughnuts can be bought and are not totally necessary. the rubber surrounds don't rot, so you are good to go there. the doughnuts mainly are there to keep crap from falling into the voice coil around the force cancelling rods. vifas are good and cheap and drop right in.

are you up to the task of refinishing the cabinets?

i would get them because thr mid/tweeter cabinet is very valuable. the B110 mids are chassis-less and are basically glued in place. you can not replace them if you blow a mid. you have to replace the entire cabinet

see ya,
Robby.

I just got a pair of 104/2 for free. the tweeters are blown, all doughnuts rot, cabinets in bad shape. it is still worth it even though I had to drive 110 miles round trip. I will try the Vifas to see how they sound.

bbbbq5555
02-23-2007, 10:27 PM
the woofer surrounds are rubber. the tweeters are easy to replace. i will leave the doughnuts as is. the main problems are the cabs. i would like to sand/remove the black paint and stain it or use some orange oil to restore the natural color of the veneer. it will be very time consuming. that is why i am thinking maybe i will just repaint them and use them as garage speakers. in fact the tops and bottoms have the worst shapes, the sides, fronts, backs and the mid/high panels are ok.
currently the infinity prelude pfr towers are my main speakers, along with a pair of thiel 04a. there will be no more room for the kef 104/2s. if they sound a lot better to the thiels i will put the thiels to the garage instead.
someone in the uk just sold a panel with working mids and tweeter for about $140 on ebay. too bad he only had one not a pair. also the shipping to the US is too much.
sure i can always part them out but i am sure i will be regret later if i do. also i can't get much in this condition.
i always wanted a pair and had two chances to buy them previously. the first time was in a thift store during a trip in reno. they sounded ok even they were connecting them to some crappy receiver. they were asking for $200. i didn't buy them then and the next day they were gone. the second time was right here in sf bayarea. someone sold them on craig's list for only $50 a pair!!! he said one of the mids sounded distorted. i was only a couple mins too late. i finally got them and this time they are free.

centaurus3200
02-23-2007, 11:52 PM
i live in oakland!

anyway, i had a pair of thiel 03a and the midrange on the KEF was much richer with an overall larger soundstage. the 104/2 is very coveted by KEF fanatics. as long as you have a high current amp to control the bandpass woofers, they are very impressive.

i take it they are black ash? mine are too. with out enough current, the bass may sound boomy, especially against a wall.

see ya,
Robby

the woofer surrounds are rubber. the tweeters are easy to replace. i will leave the doughnuts as is. the main problems are the cabs. i would like to sand/remove the black paint and stain it or use some orange oil to restore the natural color of the veneer. it will be very time consuming. that is why i am thinking maybe i will just repaint them and use them as garage speakers. in fact the tops and bottoms have the worst shapes, the sides, fronts, backs and the mid/high panels are ok.
currently the infinity prelude pfr towers are my main speakers, along with a pair of thiel 04a. there will be no more room for the kef 104/2s. if they sound a lot better to the thiels i will put the thiels to the garage instead.
someone in the uk just sold a panel with working mids and tweeter for about $140 on ebay. too bad he only had one not a pair. also the shipping to the US is too much.
sure i can always part them out but i am sure i will be regret later if i do. also i can't get much in this condition.
i always wanted a pair and had two chances to buy them previously. the first time was in a thift store during a trip in reno. they sounded ok even they were connecting them to some crappy receiver. they were asking for $200. i didn't buy them then and the next day they were gone. the second time was right here in sf bayarea. someone sold them on craig's list for only $50 a pair!!! he said one of the mids sounded distorted. i was only a couple mins too late. i finally got them and this time they are free.

bbbbq5555
02-24-2007, 05:54 AM
wow we live so close to each other! i will use the sony ta-e86b pre-amp and carver m-400t 205w/channel for the kefs. i think it should be enough. yes they are black ash and the paint is fading. the paint will come off if i rub the cab hard. do u have the kube also?

i live in oakland!

anyway, i had a pair of thiel 03a and the midrange on the KEF was much richer with an overall larger soundstage. the 104/2 is very coveted by KEF fanatics. as long as you have a high current amp to control the bandpass woofers, they are very impressive.

i take it they are black ash? mine are too. with out enough current, the bass may sound boomy, especially against a wall.

see ya,
Robby

centaurus3200
02-24-2007, 12:54 PM
hey man,

no i don't have the kube, do you?

here's the deal, perhaps we can help each other out. we should get together and compare. I'm not overly sure I'm gonna keep mine because the most powerful amp i have is a modded Quad 405-2 (which is still being modded). it should rock a 4 ohm load without breaking a sweat when it gets back, whenever that is. my McIntosh MC60s have no chance running them on the 4 ohm tap, they sound okay on the 8 ohm, but the bass was really boomy and vague.

my stock 405-2 was better, but still boomy. I'd LOVE to try your carvers to see how they sound properly fed.

we can take off the mid/HF cabinet so you can see how to mount the tweeters too ;-)

i traded my beloved bozak 302A Urbans for them. i don't have any regrets. the bozaks were too big in our new living space. not only did they look goofy and out of proportion, they imaged in the kitchen! they are in a good place now. where they should be. in one of those mid-century eichler homes in San Rafael being powered by a restored fisher 500C. all the guy does is listen to soul and gospel. i gotta get over there sometime. i can't imagine a better system for that purpose!

lemme know. just send me a PM with your contact info.

see ya,
Robby

Bigyank
08-17-2007, 11:45 AM
So how did this saga end? Did centaurus3200 keep the 104/2's?
Did bbbbq5555 a newcomer to the site get a working pair of KEF's? Inquiring minds want to know! You left us hanging.

Also, though a very nice read :worthless

Yank

centaurus3200
08-17-2007, 12:40 PM
sold the 104/2, sold the 405-2, sold the quad 909.

i did like the 104/2 with the vifa MG27-04 tweeters. if you have 104/2 with dead T-33. just buy the vifas and call it a day. they melded perfectly with the other drivers but as good as the quad amps were, i still like my mac MC60s better. and the macs didn't have enough dampening for the 104/2's bandpass woofers.

that, and i happened to fall into a pair of minty Yamaha NS-1000M :-)

see ya,
Robby

So how did this saga end? Did centaurus3200 keep the 104/2's?
Did bbbbq5555 a newcomer to the site get a working pair of KEF's? Inquiring minds want to know! You left us hanging.

Also, though a very nice read :worthless

Yank

Saxplay
04-09-2008, 07:17 PM
Hi guys,

Well I have been on the hunt to replace my Kef T33 Tweeters for over a month and I finally came across a solution that I think will work. As mmany of you know the T33 replacement from Kef are discontinued. The Viva DX25 is one of the solutions that fit well but I went a little higher to the Vifa XT25TG35 which is used in many of the high end speakers today. They should be here tomorrow and I'll let you kow how they sound.

centaurus3200
04-09-2008, 07:38 PM
i tried those first - not a direct drop in - the magnet is too deep.

you can get it to work though.

Robby

Hi guys,

Well I have been on the hunt to replace my Kef T33 Tweeters for over a month and I finally came across a solution that I think will work. As mmany of you know the T33 replacement from Kef are discontinued. The Viva DX25 is one of the solutions that fit well but I went a little higher to the Vifa XT25TG35 which is used in many of the high end speakers today. They should be here tomorrow and I'll let you kow how they sound.

bbbbq5555
09-08-2008, 03:34 AM
sanded and repainted the cabs. replace tweeters with phase tech tweeters. didn't refoam the doughnuts though. sold them last year and kind of miss them now.

http://http://i72.photobucket.com/albums/i183/bbbbq555/100_1910.jpg

BillR mastering
09-08-2008, 03:58 AM
I second Robby's suggestion.

I saw this post moments ago for the first time and immediately before reading I thought "Dynaudio D28"..but since the Dynaudio drivers are under wraps, the MDT29 Morel is the obvious solution. if anything, it is possible it will have a little better clarity w/o issues than the T-33.

Some very well respected loudspeakers (Quested) use that tweeter as well.

Go with it and be pleased. If not, you may have crossover issues that need addressing. When enough power enters a tweeter to damage it, the crossover should be carefully inspected.

statman122
07-13-2012, 08:19 PM
I tried the Vifa's in my 104/2, I have found them to be a bit to bright and harsh. I think I'm going to try the Morel MDT29-4 (4 ohm), but I'm told the excess plastic has to be trimmed off of the voice coil to get them to fit. How would one go about this?

dakmensa
07-14-2013, 02:43 AM
i did a search and found some good info, but am curious if anyone has any updates on their findings.

as many KEF owners with ferro-fluid cooled tweeters know, the gel hardens over 20 years and basically renders the tweeters useless. i recently traded my Bozak 302A Urbans for a pair of 104/2. should have hooked the KEFs up while the guy was here, but such is life. he's really nice and offered to give me cash to buy the KEF recommended replacements.

but, I've heard KEF's replacements are both overpriced ($160/pair) and don't even sound that great. as you know, the 104/2 has the tweeter mounted flush behind the mid/tweeter baffle. i do not want to alter the outside of the baffle, but have no problem tweaking it from inside to mount a suitable, if not better replacement. i mean $160 buys you some pretty fricken nice tweeters ;-)

so, what have you guys tried successfully? the tweeter is 1.25", but i can go smaller if necessary. i believe they are 4 ohm. overall sensitivity is rated at 92db at a 4ohm load.

specs: http://www.kef.com/history/1980/model104_2.asp

thanks,
Robby

Hello all,
This thread is pretty old, but I wanted to share my experience with the T33 ferrofluid problem.
I picked up a pair of KEF C60s for a very reasonable price. The seller said one speaker was reproducing no sound. That turned out to be operator error, but I found that one tweeter sounded as I assumed it should while the other sounded very muted. I switched drivers from cab to cab to eliminate the crossover or other internal wiring as the problem. It proved to be specific to the driver, and after a little research I took both tweeters apart and found that, as i had read, the coil and gap were both gummed up with old, dried ferrofluid. Removing the old fluid restored the output of the muted tweeter. It did not make a noticeable difference in the output of the other tweeter.
The procedure is very simple, and as long as you use a light touch you probably won't destroy anything.

1) Remove tweeter from cabinet, cut or desolder the leads (desoldering is not recommended, you will understand when you see the leads and posts on this tweeter) remove plastic trim ring (in this case a trim square) from tweeter. This is attached by the four screws closer to the center of the driver.
2) Gently pry the diaphragm/coil assembly from the magnet assembly. I used the blunt side of a "snap-off" knife and a flat tipped jeweler's screw driver, but anything sufficiently thin that affords you some control should be fine.
The diaphragm is attached to the magnet assembly very securely, on my drivers by way of double-sided tape on one, and a strong non-backed adhesive on the other. Working relatively slowly and in small increments will allow you to remove the diaphragms without bending or otherwise damaging anything.
3) Remove the dried ferrofluid. I used cotton swabs and 70% isopropyl alcohol on the coils and strips of craft paper (similar to rosin paper, but anything not exceedingly stiff should work) on the magnet/ gap area. In good light it's easy to see if there is anything left in the gap. For areas that did not come clean via the paper method, I scraped some flexible plastic shim material through the gap. I finished the gap area with 70% isopropyl alcohol on a thin, natural fiber brush. I was careful to use no more solvent than was needed to dampen the brush.
4) Reassemble the tweeters, reinstall in cabinets. The reassembly is made easy as there are tabs and indentations integral to the diaphragm and magnet assembly that allign the coil. I did not apply adhesive where it had previously been, but I am going to refill the gaps with new ferrofluid when it is back in stock at Parts Express.
Despite the lack of process photos, I hope this will prove useful to anyone with malfunctioning T33 tweeters. There is nothing mystical about the repair, (despite what some would like you to believe) and it costs nothing but your time (and if you wish, around 4 bucks for new ferrofluid from Parts Express). Give it a shot if you have T33 tweeters producing low output. Much cheaper than a new set of Morels.

Good luck,
David