KEF 104/2 - The speaker gods have spoken

Discussion in 'Speakers' started by baco99, Apr 9, 2013.

  1. baco99

    baco99 AK Subscriber Subscriber

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    Haven't updated this thread in almost a year, but I wanted to share a story of ANOTHER 104/2 rebuild. A friend of mine picked up a set from an older guy who was downsizing. Apparently this guy had the woofers sent out and "professionally reconed" by a large and well-known service company in the middle-west (I won't mention the name because that would be uncouth.) In any case, I saw the invoice for the work that was done and almost fell out of my seat.

    When my friend got the speakers he wanted me to look at them because something didn't seem right. It took me a while, but I finally had a look. I was appalled at the horrors that I witnessed! Once I did a quick assessment I went to work undoing the work that they did, cleaned up the cabinets of some of the tools them left inside, reflowed the tweeters, and did a complete Falcon recap of the crossovers. Here are some pics.

    Pic on the right shows what the well-known repair shop did to replace the foam inner donuts on these drivers. As we all know, the early 104/2 used rubber outer surrounds, so those were OK. This shop decided, instead of taking the time and incurring the $10 expense to get the correct parts, to cut down a woofer spider and use that as the inner foam dust cap. ACK! Who does that. 2- things. 1) The fabric spider does not have the proper compliance for this driver, constricting the movement and reducing bass output. and 2) the fabric is not air tight so it was causing all sorts of air chuffing sounds, as well as compromising the sound quality of the bandpass enclosure.

    Correct foam donuts on the right getting installed after I cut out the incorrect ones.

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    Oh, and I found this inside the top of one cabinet while taking things apart found a 10 mm socket. OOPS!

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    The other issue with the woofers is the previous owner did not get proper instruction on how to reinstall them. The little silver grommets are used to spade the woofer properly to cabinet so the foam gasket gets a proper seal. Both woofers were canted at an angle, causing the upper drivers to leak air all over the place.

    [​IMG]


    Once I got the woofers all straightened out, I started working on the tweeters. The ferrofluid had turned completely to paste and the domes were hardly moving. I posted this on Facebook, but if anyone has KEF T33 tweeters from the 80s or early 90s, GET THE FERROFLUID REPLACED!!! It's not a matter of "they sound OK to me." The ferrofluid needs to be replaced. Period.

    [​IMG]

    [​IMG]

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    ALL CLEAN

    [​IMG]

    Last effort was to recap the crossovers. The hardest part of this job is actually removing the crossover. I don't have rubber arms. If you have rubber arms, this will be easy.
    With the crossover out, it was a matter of hunt and replace. The bag of parts from Falcon came in from the UK with all the perfect values.

    Reassembly was the opposite of disassembly.

    [​IMG]

    [​IMG]



    Now that these speakers are back together, they can sing again! My friend will be by to pick them up this weekend. He's going to be shocked at the difference in sound.

    I'll stand by my previous opinion that these are some of the best speakers, in terms of sound, ingenuity, design, and overall quality that I have ever seen or heard. Not just one of KEF's best products, but one of the best out there.

    [​IMG]
     
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  2. absolve2525

    absolve2525 AK Subscriber Subscriber

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    I got my 104/2 out of storage last week, and I forgot how damned good they sound. Even without the bass-eq box hooked up. Insanely good midrange and great smooth highs (of course with new ferrofluid). Very tuneful and full bass. I compared them to some highly regarded mini monitors, and they image just as well with even more liquid midrange. Definitely keepers! Great to see the refurb photos. I still have to order new crossover parts, but they sound great as-is currently.
     
  3. milanomike

    milanomike Active Member

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    I did the donuts and cleaned and re-fluidized (is that a word) the tweeters, these things sound sweet. I have not done the crossover but seen the kit from Falcon, not cheap, but they you get all the correct pieces without hunting around. You think this will make a significant difference? I agree, hardest part of job is removing the cross over.
     
  4. Paddy Garcia

    Paddy Garcia AK Subscriber Subscriber

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    As I've posted elsewhere, the Falcon kit is very nice, but I couldn't hear a difference on the 2 pairs of 104.2s I recapped. My recommendation is to replace foams and ferrofluid and enjoy :)
     
  5. Donkey Karma

    Donkey Karma AK Subscriber Subscriber

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    Top notch work AGAIN Brian! It's a shame to see some of the unprofessional work and shortcuts taken by some of the "pros" are still doing out there. Your friend is fortunate to have you in his corner..

    Yet to hear a pair of these. I saw a pair a cpl of weeks ago at a local Record store someone had brought in for repair. The owner of the shop told me they are impossible to work on and he was going to tell the owner they were worthless. I was already ears deep with work and the Macrophone rebuild. Maybe I'll stop by and see if they are still there and if the owner would like to sell them..? Least of all they the owner not to give up.
     
  6. darkblue94

    darkblue94 It wasn't me. Subscriber

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    It is now. :D
     

     

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  7. baco99

    baco99 AK Subscriber Subscriber

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    I would normally agree with you. However, in the process of recapping, I fixed about 4 solder joints that had gone bad. These inductors are iron core and heavy. Moving speakers around can cause them to shift and break the connection. Had it not been for the recap, these issues wouldn't have been addressed. Just throwing that out there.
     
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  8. baco99

    baco99 AK Subscriber Subscriber

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    They are actually remarkably easy to work on considering how complex they are.
     
  9. MCM_Fan

    MCM_Fan AK Subscriber

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    Exactly. Like any piece of fine machinery (in the days before planned obsolescence), they were designed with periodic maintenance in mind. The design and construction is unique, so unlike the standard monkey coffins, you cant just pull the woofer and have access to everything inside the box. Which is why KEF published and distributed a detailed set of disassembly instructions - like a Chilton's repair manual for speakers. Follow the very clearly written instructions and getting them apart is a piece of cake.
     
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  10. leray1

    leray1 AK Subscriber Subscriber

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    I saw your post on Facebook. Nice save!

    I changed the fluid in mine a few years ago. How long, typically, before they need it again?
     
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  11. nj pheonix

    nj pheonix AK Subscriber Subscriber

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    I bought a pair of these several years ago based solely on the gushing endorsement of this thread.
    I had them done over (surrounds, falcon caps, ferrofluid) .
    I never thought they made magic.
    I can only assume something wasn't right in them but they're gone now.
    Obviously I'd prefer to be gushing about them in the thread. I'm assuming even if they weren't my taste, based on the consensus mine never did what they were supposed to (at least while I owned them:dunno:)
    I do think mine were done right. Maybe the drivers were somehow damaged prior to me.
    Enjoy!
     

     

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  12. baco99

    baco99 AK Subscriber Subscriber

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    I'd say 10 years or so before they need to be checked on again? Hard to say. I did mine about 5 years ago according to this thread. LOL!
     
  13. baco99

    baco99 AK Subscriber Subscriber

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    I think I remember reading about your difficulties. I'm really not sure what it could have been. Could be personal taste. That's probably the #1 reason. But it could have also been some technical issue. As mentioned, there were a few bad solder joints on these particular crossovers that I never would have discovered had I not taken them apart. The work is methodical and meticulous and one mis-step can affect the whole system. For example, not sealing the drivers off properly will kill the bass. Getting the polarity wrong somewhere will definitely affect things negatively too. SO, could have been a lot of factors. Either way, I have faith you have found audio nirvana in a different way.
     
  14. nj pheonix

    nj pheonix AK Subscriber Subscriber

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    Indeed!:beerchug::D:music:
     
  15. BilboBaggins

    BilboBaggins AK Subscriber Subscriber

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    It is possible that the units weren’t done right, or they aren’t to your taste, or, perhaps you had the wrong type of amplification on them.

    A case in point.

    I had bought a really nice pair a few years ago, right at the same time I bought my Kef 105s. I already had a really nice pair of ESS AMT1aM towers. So for the next few months I ABed the three against each other using my two Bose 1801 power amps using my restored Bose 4401 for the preamp. My conclusion was that all three sounded as good with slightly different strengths. I kept the 105s which I still have and love. The ESS went quite quickly to Toronto. The 104s I sold to a good friend, who is using them currently with a 30 WPC Onkyo amplifier. They sound good, but they don’t sound great, like they do with a much bigger amp. I still hear them regularly whenever I go over there. No comparison.
     
  16. baco99

    baco99 AK Subscriber Subscriber

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    30 watts is WAY too little for these speakers. 70 wattt minimum at low volume. But really need 100 get some of the nuance out of them. I have this set connected to the NAD 2400s in bridged mode @ 200 watts each and 800 watts during transients. It's honestly the best combination I have ever heard.
     
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  17. baco99

    baco99 AK Subscriber Subscriber

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    As a further update, here's a video of Dan's 104/2 all done and sounding wonderful!

     
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  18. leesonic

    leesonic Hold on, here comes the bass. Subscriber

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  19. BilboBaggins

    BilboBaggins AK Subscriber Subscriber

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    I totally agree. These speakers need as much headroom as possible. I’ve reconciled myself to the fact my friend will never hear these speakers the way they should be heard.

    I was just throwing out possibilities with no knowledge about who had done the work or how it was done. No offence intended.
     
  20. BilboBaggins

    BilboBaggins AK Subscriber Subscriber

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    Interesting thing about this friend is that he used to be a musician, and was also very much into Audio, with high end Tannoys, a Nakamichi dragon, and some fancy class a amp I don’t remember. He replaced the huge Tannoys with a pair of Kef 104/2s. Then he fell on hard times and had to sell it all. This was in the mid to late 80s.

    When he heard I was selling mine, he told me I had a buyer.
     

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