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IMF owners thread!

Discussion in 'British Audio' started by canuckaudiog, Mar 18, 2013.

  1. dyche01

    dyche01 "Buy high. Sell low" Subscriber

    Messages:
    1,414
    Location:
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    I just joined the IMF owner's club, with a beautiful pair of ALS40-II's. You can read some of the details in this other (high traffic) thread:
    http://audiokarma.org/forums/index.php?threads/hk-730-meets-imf-als-40ii.752099/#post-10224071

    I am driving the speakers with a sweet little McIntosh 754 power amp, and using a NuForce DAC as a pre-amplifier. The combination sounds really good and, as many of you have noted, these speakers produce an amazingly rich and detailed bass. I am, however, a little disappointed by the upper midrange. When I pulled the covers, I found that the foam surrounds on the midrange drivers had hardened and cracked. From what I have seen on the web, this appears to be a common problem. I have re-foamed drivers before, but I am away from home and would prefer not to sink the time into repairing components, so I will play a long shot. Does anybody here have a pair of re-foamed midrange drivers for sale? If so, would you take my pair in partial trade?

    Mac_IMF_system.jpg
     
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  2. dyche01

    dyche01 "Buy high. Sell low" Subscriber

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    Here are a couple more pics.
    IMG_0273.JPG

    IMG_0274.JPG
     
  3. JoshHendi

    JoshHendi vintage audio student Subscriber

    These I believe are the 80, the Xovers in my 80IIs are quite different... interesting :)

    Welcome to the club dyche01 !!
     
  4. dyche01

    dyche01 "Buy high. Sell low" Subscriber

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    Thanks! I like the English theme you've got going here in clubhouse. The deep leather armchairs and the snooker table are great. I wish the cupboard had more than just Battenburg cake, but I am not complaining.

    I'll just pop a Westminster onto the Garrard and give this IMF stack a test drive.
     
  5. mech986

    mech986 Text ↓ optional Posts:>18,000 Subscriber

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    Dyche01, you might consider getting the recommended Monacor replacement midrange from Falcon Acoustics along with a set of new Non-Polar electrolytic Alcap crossover caps for your ALS40IIs. That's going to be your easiest option to refurbish the IMF sound without a refoam kit (from Euro sources). It will also clean up the tweeter section as well. Best though to access the crossovers to confirm the layout and cap / resistor values in list and pictorial form for Falcon so they can be sure to send the correct parts. Don't forget any part on the back panel if your speakers have any switches on the back panel.

    http://www.falconacoustics.co.uk/drive-units-1/imf/monacor-msh-115-imf-midrange.html

    http://www.falconacoustics.co.uk/re.../imf-als40-mk2-replacement-capacitor-set.html
     
    Last edited: Jan 31, 2017
  6. dyche01

    dyche01 "Buy high. Sell low" Subscriber

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    Thanks for the links! The choice on the midrange is whether to spend more TIME on the refoam or more MONEY on the replacement. With a four-month-old baby in the house, time is a precious commodity, so I might just cough up money for the replacements.

    As for the caps, I am ordering them today!
     

     

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  7. mech986

    mech986 Text ↓ optional Posts:>18,000 Subscriber

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    If you order the mids, saves on separate shipping. If you don't like the Monacor mids, I would buy them from you.

    The foams cost about $5 each plus shipping from the Netherlands. You would need to pull the ELAC mids out to get the model number off them or compare them to the pics in the below link to get the correct ones. Would be good to scrape off the old surround and then take measurements of the cone OD and the frame mounting OD and the space between the two, they seem to have some which look similar but are listed a little differently. Send them a before pic as well so they can see the way the surround and roll are shaped. Some IMF mids have a wide surround that seems to have the inner roll edge glued directly to the cone inboard of the cone edge, others have a more classical thin roll with an inner shelf which glues onto the cone. Importantly, you have the midrange with the outer cardboard circle gasket glued to the frame.

    You can buy direct from speakerrepairshop.nl or via ebay.

    http://www.speakerrepairshop.nl/index.php?action=search&lang=en&srchval=Imf#.WJD4H3476rU
     
    Last edited: Jan 31, 2017
    dyche01 likes this.
  8. c-atle-79bay

    c-atle-79bay Super Member

    Messages:
    2,592
    Location:
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    I will say the moncors in my Studios create a rich to bit over rich i.e. too much mid range when compared to other speakers...........they sound great though, but was an adjustment going to my TDLRSM's which are much flatter.
     
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  9. mech986

    mech986 Text ↓ optional Posts:>18,000 Subscriber

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    Sounds like an L-pad or a few small ohm resistors are needed to pad down the midrange a bit.
     
  10. c-atle-79bay

    c-atle-79bay Super Member

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    Location:
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    Thanks for the ideas Mech, the studio has Lpads for the mid range, and I normally turn them down, crossovers are fresh BTW sourced from Falcon. Granted it's not a bad thing, very warm and musical all the stuff associated with a bit rich mid-range and it does sound great. My misgivings were more when I got the TDL's I'd figured there would be some similarity of the sound, not so, and why should there be from a 1971 to a 1996 speaker, but I find my self missing or searching for some details best analogy would be the cow bell moved from the front of the stage to the back of the stage. Granted the trade off is 16hz bass that is fast rich and detailed and runs like an undertow. I'm actually about ready to pull the IMF's back out and compare though.

    The balance of trade-offs......
     
  11. Huib.

    Huib. New Member

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    Den Helder Nederland
     

     

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  12. Huib.

    Huib. New Member

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    hallo hier wat foto's van het filter DSC_0037[1].JPG DSC_0038[1].JPG DSC_0039[1].JPG DSC_0040[1].JPG DSC_0041[1].JPG DSC_0042[1].JPG
     
    mech986 likes this.
  13. Huib.

    Huib. New Member

    Messages:
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    Location:
    Den Helder Nederland
    sorry, mijn Engels is erg slecht hoop dat jullie het kunnen vertalen.
    heb pas een set IMF tls 50 mk2 a gekocht en waren nog maagdelijk wil de set opknappen en zal wat foto's met jullie delen DSC_0043[1].JPG DSC_0044[1].JPG DSC_0046[1].JPG DSC_0047[1].JPG DSC_0048[1].JPG DSC_0049[1].JPG DSC_0050[1].JPG DSC_0051[1].JPG DSC_0052[1].JPG
     
    mech986 likes this.
  14. K_50

    K_50 Active Member

    Messages:
    177
    Location:
    Copenhagen, Denmark
    Hey all . New member here with a pair of Compact Monitor II's.
    I'd like a bit more fullness in the midrange (that's just the way it goes with 2-ways, I guess), but they sound super sweet up top, and go very deep, and clean, for such small boxes!

    [​IMG]

    [​IMG]
     
  15. mech986

    mech986 Text ↓ optional Posts:>18,000 Subscriber

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    Hello Huib,
    Welcome! Translation from Dutch for you:

    "hi here some photos of the filter

    and

    New
    sorry, my English is very poor hope you can translate it.
    I just bought a set of IMF TLS 50 mk2 and was still virgin wants to refurbish the set and will share with you some pictures."

    Very nice pictures of your crossovers and of your drivers - you have the later ELAC supplied woofers and mismatched Audax (silk dome) and ELAC version (darker plastic dome) tweeters. Looks like you will need to refoam the midrange drivers which is common and typical. The Coles supertweeter microphone capsule has detached from the mounting plate - might be better to get replacement Coles 4001 G or K tweeters from Falcon Acoustics in UK.
     
  16. Huib.

    Huib. New Member

    Messages:
    4
    Location:
    Den Helder Nederland
    Hoi mech986, bedankt voor je hulp met vertalen.
    Ik ben hier nieuw en hoop wat meer informatie over de IMF's te vinden, het zijn de IMF tls50 MK2 A, heb het crossover opgetekend deze is toch wel anders als de mk2 heb ook een slordigheid gevonden waardoor de tweeter en super tweeter misschien wel kapot zijn gegaan van een kant, ik heb falcon gebelt voor wat meer informatie maar ze konden mij niet helpen wat de Coles tweeters betreft deze hebben een andere dc en z waardoor ik denk dat het kantelpunt teveel verschuift ik meet bij de originele een dc van 47 ohm en een z bij 13khz tot 20khz van 51 tot 57 ohm omdat het een iets ander filter is kun je volgens mij niet zomaar de condensator van het hoog, de 0.2 uf veranderen hierbij nog wat foto's voor de duidelijkheid ,alvast bedankt voor de hulp. DSC_0053.JPG DSC_0053.JPG mk2 a.png Naamloos.png DSC_0053.JPG mk2 a.png Naamloos.png gr Huib
     

     

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  17. mech986

    mech986 Text ↓ optional Posts:>18,000 Subscriber

    Messages:
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    Just so people are aware, I don't speak or know Dutch, but I do use Google translate:
    https://translate.google.com/


    "Mech986 Hi, thanks for your help translating.
    I'm new here and hope to find some more information about the IMF programs, it is the IMF tls50 MK2 A've crossover penned this is quite different from the mk2 have found an inaccuracy which the tweeter and super tweeter might be broken gone to one side, I falcon gebelt for some more information, but they could not help me the Coles tweeters concerns that have different dc and z so I think the tipping point too, I shift count in the original a dC of 47 ohm z at 13khz to 20kHz from 51 to 57 ohms because it has a slightly different filter you can not just think the capacitor of the high, change the 0.2 uf hereby some pictures for clarity, thanks for the help."

    Huib, we'll need a little clarification of what you're asking about.
     
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  18. Nashou66

    Nashou66 AK Subscriber Subscriber

    Messages:
    1,616
    Location:
    West Seneca NY
    Welcome K_50 !!!

    I just re caped a pair of those with Film caps from falcon.
    here is the post

    http://www.audiokarma.org/forums/index.php?threads/imf-owners-thread.509555/page-67#post-10238856

    I haven't had time to really listen to them much but they do go deep for a small box !

    Athanasios
     
  19. dyche01

    dyche01 "Buy high. Sell low" Subscriber

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    I haven't seen much about the ALS40 II's around here, so I figured I would share some experiences recapping a pair.

    I bought the replacement capacitor kit from Falcon Acoustics, which arrived in a timely fashion but, unfortunately, it was missing two of the necessary 4µF capacitors. I alerted Falcon but have yet to hear back from them.
    ALCAP_caps_sm.jpg
    For reference, a full recap of two ALS40 II speakers requires twelve (12) capacitors:
    4x 60µF
    2x 12µF
    2x 6µF
    4x 4µF

    The crossover network inside each speaker is divided into two boards, a large one located behind the upper bass driver (see below) and a smaller one located on the back of the terminal binding posts. Each of the large boards has four capacitors (2x 60µF and 2x 4µF) while the small boards have two (1x 6µF and 1x 12µF).
    main_driver_out_sm.jpg

    Here is the board behind the bass driver:
    crossover_insitu_sm.jpg

    This board is attached directly to the white foam, via some sort of brown, crusty glue. The foam peels away from the board relatively easily, especially if you use a plastic putty knife. Since I didn't have enough capacitors to do the entire job right now I didn't peel the boards off completely. Does anybody here have suggestions for an appropriate adhesive to re-attach the boards to the foam? I have some good contact cement and I was thinking of trying that. What do you guys use?

    Although I left the big boards alone for now, I did re-cap the small boards and clean the high frequency attenuator switch with contact cleaner. The through holes for the 6 and 12 µF capacitors are marked below.
    board_back_sm.jpg

    The ALCAP replacements are slightly bigger than the original ELCAP's but they fit just fine.
    switch_plate_sm.jpg

    I am not finished with these speakers, but I already notice a BIG difference in the sound. Before cleaning the switches and replacing the capacitors, both tweeters were essentially dead and the overall sound of the speakers was quite dark. Now the sound is much brighter and the authoritative bass that these speakers can pump out is balanced by a clear top end register.
     
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  20. dyche01

    dyche01 "Buy high. Sell low" Subscriber

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    The service department at Falcon Acoustics responded today regarding the capacitors. Apparently there is some variability within each model, and often models destined for export are different from those intended for domestic consumption. They very generously offered to send the additional capacitors.

    My advice (which echos a previous comment in this thread) is, if you are going to buy a re-capping kit, count the capacitors and send in a list with your order. It will help avoid problems with (often undocumented) variability.
     

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