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Any experience of IMF loudspeakers? I got a pair today!

Discussion in 'classic' started by beammeup, Apr 30, 2019.

  1. ToTo Man

    ToTo Man the band not the dog

    I don't have them to hand at the moment, but IIRC one of my pairs of 5/36 has Elac-branded tape wrapped around the circumference of the magnet. IMF used other Elac drivers so it's reasonable the 5/36 could've been made by Elac too.
  2. a.palfreyman

    a.palfreyman pfm Member

    Just spotted a pair of these on ebay. Would need a refoam though.
    No connection.
  3. Aural

    Aural Chris the Full Range fan

    Or the 3090s! Mine have been playing most of today-get surprised by bass, which goes down to 20 c/s. Not surprising, with the huge (ported) box and a 15 incher-actually 14 inch -Sandwich unit, bettter made than the 2075s.
    And yes, it has an isodynamic super tweeter, to match the Wharfedale Isodynamic headphones that -if you can fix up a set - I can recommend.
  4. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Actually transmission line. I've heard the Isodynamic headphones many years ago and I was impressed!
  5. Gervais Cote

    Gervais Cote Predator

    I have a pair of these IMF Super Compact 1 as well.
    The woofer is the original, I changed the mid driver for a Peerless and the tweeter for a Morel MDT 34 and updated the crossover with hi quality capacitors and new cabling.
    Hooked up to my Cambridge AR 60, Kenwood KT 8005 tuner : they sound wonderful !
    Definitely a keeper for me, this is my kit in the garage.
    Musiciseverything likes this.
  6. Musiciseverything

    Musiciseverything pfm Member

    They look lovely! I’ve been curious myself to hear a pair, and how they’d pair with my A&R Cambridge A60
  7. Gervais Cote

    Gervais Cote Predator

    They pair rather well with the A60 IMO, especially due to the fact the A60 has a good tone control for bass and treble. The original tweeter was a bit harsh but this is much better with the Morel MDT 34 I replaced with. If I was to do it again, I would go with a Wavecor tweeter instead to make it a bit softer.
    The A60 is very powerful despite its diminutive size and conservative power rating, produces a lot of deep bass with ease and never overheats even when pushed hard.
    I also love the wooden look of these two vintage items !
    Durmbo and Niel Blackwood like this.
  8. ff1d1l

    ff1d1l pfm Member

    Have a pair of them...the ear sponge has degraded.
  9. Big Tabs

    Big Tabs looking backwards, going forwards

    Just got my old IMF Super Compact II’s out of the loft (thank you Wife) and some stands and I am letting them warm up slowly. Not fired them up for years.
    The woofer on my speakers look different to the smooth (bextrene ?) woofers in my IMF ALS 40 II’s. They look original though as does the mid-range. The tweeters have been replaced with Kef units (I think??) before I got my hands on them.
    Good news is that there is sound out of all the speakers. Leaving them on with a c.d. playing on loop for a while.

    I will stick a photo up when I get around to it, maybe someone can confirm the Kef tweeters?
    Gervais Cote likes this.
  10. Big Tabs

    Big Tabs looking backwards, going forwards

    Here we go.

    Any idea on the tweeters?

    And that woofer!

    I have played them all day.
    They sound good for what they are.

    Supposed high efficiency I think. They are certainly loud at average levels.

    I think The Daughter is having them for a while, maybe.


  11. Big Tabs

    Big Tabs looking backwards, going forwards


    What are the tweeters?

  12. Bob Edwards

    Bob Edwards pfm Member

  13. snowman_al

    snowman_al pfm Member

    The tweeters are Peerless silk domes, cannot remember the type number, possibly KO10DT long out of production. They failed on a regular basis...
    The mid is an ELAC that IMF doped themselves.
    Strange bass unit in yours? Normally a KEF B200 8Ω as you can see from the recess cut out.
    Big Tabs likes this.
  14. jimmymcfarrell

    jimmymcfarrell pfm Member

    That’s the same bass unit that was in the earlier version of the ALS40s I had, can’t remember if my ‘40s had 2 woofers the same; I’m thinking not but I can’t remember what was different about the other one and if it was the top or bottom woofer that was the same as the one pictured above; however it definitely looks very familiar so I’m sure it’s correct for several models of IMF made at a particular point in the history of the brand.
    Big Tabs likes this.
  15. snowman_al

    snowman_al pfm Member

    I 'm sure they are original, but would guess it is a 'cross over' from the 8 inch KEF unit fitted originally to the 6.5 inch unit fitted to the next Compact which was a 2 way design.
    I understood the 3 way is a 'Super Compact' and the 2 way is the 'Compact II'.
    Big Tabs likes this.
  16. narabdela

    narabdela who?

  17. Big Tabs

    Big Tabs looking backwards, going forwards

    My IMF AlS 40 II’s have the shiny/glossy woofers (and subs),

    the woofers on the Super Compacts look like some one has thrown grit on the speaker then painted over it with rubber. They work well though!
  18. ToTo Man

    ToTo Man the band not the dog

    The specs stated in those two links are SPLs at 1 metre for 40 watts of pink noise.

    99dB or 100dB for 40 watts equates to 83dB or 84dB for 1 watt, which isn't high efficiency by any stretch.

    I owned a pair of Super Compacts and they weren't anywhere near as sensitive as my 95dB/1w Tannoys! I'd say they were around the same sensitivity as my JR149s, which fits with the 83dB-84dB extrapolation.

    AFAIK no IMF model was a particularly high sensitivity design, it simply isn't possible given the primary objective of a sufficiently extended low frequency response.
    narabdela likes this.
  19. narabdela

    narabdela who?

    I'd agree. I had a pair of ALS40s way back when. Great speakers (imo), but nowhere near the 98db sensitivity that that website's figures would suggest..
  20. Frizzy

    Frizzy Liberal anarchist

    I had tdl studio 0.5 as a student, awesome raw oomph. Not subtle but direct energetic and soaked up or destroyed weedy Brit amps. Need big current to control and tame.

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