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Thread: jbl 2245 H

  1. #91
    Administrator Robh3606's Avatar
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    The aluminum shorting ring doesn't move at all it's burried under the gap. SFG magnet shorting ring not Dual Differential Drive, it works but helping to stabilize and make the flux equal on both sides of the gap top and bottom.

    Rob
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  2. #92
    Senior Member ivica's Avatar
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    Quote Originally Posted by Robh3606 View Post
    The aluminum shorting ring doesn't move at all it's burried under the gap. SFG magnet shorting ring not Dual Differential Drive, it works but helping to stabilize and make the flux equal on both sides of the gap top and bottom.

    Rob
    Interesting reading about the influence of the "short ring"
    http://diy-audio.narod.ru/litr/Farad...lImpedance.pdf

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    Quote Originally Posted by Robh3606 View Post
    The aluminum shorting ring doesn't move at all it's burried under the gap. SFG magnet shorting ring not Dual Differential Drive, it works but helping to stabilize and make the flux equal on both sides of the gap top and bottom.

    Rob
    That's the construction on newer drivers, not the 2245. How could there be rubbing marks on the aluminum ring on my old 2245 if it did not move with the voice coil? Believe me, it moves. Maybe it's incorrect to call it a shorting ring but I don't know what else to call it.

  4. #94
    Administrator Robh3606's Avatar
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    That's the construction on newer drivers, not the 2245.
    It doesn't matter. The aluminum flux ring is in the same location. Have a read of the attached link

    http://www.audioheritage.org/vbullet...ume-1-Number-9

    How could there be rubbing marks on the aluminum ring on my old 2245 if it did not move with the voice coil?
    Without the outer foam ring the whole cone tilts and rubs. The rub marks could easilly be from the former rubbing against the top plate and pole piece. The aluminum you can see is part of the VC form not the stabilization ring. The voice coil form obviously moves.

    Rob
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  5. #95
    Senior Member Eaulive's Avatar
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    Quote Originally Posted by dr_gallup View Post
    That's the construction on newer drivers, not the 2245. How could there be rubbing marks on the aluminum ring on my old 2245 if it did not move with the voice coil? Believe me, it moves. Maybe it's incorrect to call it a shorting ring but I don't know what else to call it.
    That's where the misunderstanding comes from, the part that has the rubbing marks is not the shorting ring, it's the voice coil former, so of course it moves

    The shorting ring is deep into the magnet structure and is fixed, coincidentally your VC former is also made of aluminum, that's the confusion
    My avatar: 4520 loaded with 2225H on E140 frames,
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  6. #96
    Senior Member ivica's Avatar
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    Quote Originally Posted by dr_gallup View Post
    That's the construction on newer drivers, not the 2245. How could there be rubbing marks on the aluminum ring on my old 2245 if it did not move with the voice coil? Believe me, it moves. Maybe it's incorrect to call it a shorting ring but I don't know what else to call it.
    As seen from E120 technical data
    http://www.audioheritage.org/vbullet...l=1#post148781
    there is seems some kind of aluminum foil in the former, I expect mainly to reduce coil inductivity (Le) that would become of importance on higher frequency (over 1kHz), but concerning that 2245 is LF driver, such aluminum former had mechanical and electrical "purpose",
    but on the figure of 2245 cone kit aluminum foil is not visible
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  7. #97
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    Quote Originally Posted by Robh3606 View Post
    It doesn't matter. The aluminum flux ring is in the same location. Have a read of the attached link

    http://www.audioheritage.org/vbullet...ume-1-Number-9



    Without the outer foam ring the whole cone tilts and rubs. The rub marks could easilly be from the former rubbing against the top plate and pole piece. The aluminum you can see is part of the VC form not the stabilization ring. The voice coil form obviously moves.

    Rob
    Thanks for that link, it really explains what's going on.

  8. #98
    Senior Señor boputnam's Avatar
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    2245h

    Revisiting an old thread...

    In the past few months, the response of the 2245H's in my 4345's (stock) seem to have improved subtly, yet wonderfully. I've not changed a thing in my system for a number of years; and, I'm not a heavy user, being as I'm frequently out on tour. So, maybe this "extended break-in" is just that. Whatever it is, their tonality is ever-more remarkable.

    We had dinner guests last night, and after all the social folderol, we got down to some serious listening. My neighbors had never heard such things as what the 2245H's produce - they left carrying their jaws. And, it was at maybe 75dB.

    Just sayin'...
    bo

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  9. #99
    Senior Member BMWCCA's Avatar
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    Quote Originally Posted by boputnam View Post
    Revisiting an old thread...
    they left carrying their jaws. And, it was at maybe 75dB.

    Just sayin'...
    Nice to see your name on a post.

    Sweetness happens.

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    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

  10. #100
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    Quote Originally Posted by boputnam View Post
    Revisiting an old thread...

    In the past few months, the response of the 2245H's in my 4345's (stock) seem to have improved subtly, yet wonderfully. I've not changed a thing in my system for a number of years; and, I'm not a heavy user, being as I'm frequently out on tour. So, maybe this "extended break-in" is just that. Whatever it is, their tonality is ever-more remarkable.

    We had dinner guests last night, and after all the social folderol, we got down to some serious listening. My neighbors had never heard such things as what the 2245H's produce - they left carrying their jaws. And, it was at maybe 75dB.

    Just sayin'...
    I think you had the same experience when you first heard them at Ken's place mate.

    How about a recent pic.

    Ian

  11. #101
    Senior Member ivica's Avatar
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    Quote Originally Posted by boputnam View Post
    Revisiting an old thread...

    In the past few months, the response of the 2245H's in my 4345's (stock) seem to have improved subtly, yet wonderfully. I've not changed a thing in my system for a number of years; and, I'm not a heavy user, being as I'm frequently out on tour. So, maybe this "extended break-in" is just that. Whatever it is, their tonality is ever-more remarkable.

    We had dinner guests last night, and after all the social folderol, we got down to some serious listening. My neighbors had never heard such things as what the 2245H's produce - they left carrying their jaws. And, it was at maybe 75dB.

    Just sayin'...
    I am afraid that "refoamimg 2245" would become soon, so be care not to destroy inner parts. I have almost the same experience with my 2231A drivers. Unfortunately there are no original refoam-kit for either 2245 or 2231 drivers. Most of the AF refoams do not sound as previous originals. Another problem: even the recon-kits do not sounds as originals....

  12. #102
    Senior Señor boputnam's Avatar
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    Quote Originally Posted by Ian Mackenzie View Post
    I think you had the same experience when you first heard them at Ken's place mate.


    Quote Originally Posted by Ian Mackenzie View Post
    How about a recent pic.
    Can do - but I'm headed off for a few days, so on my return. Not much has changed - I must have found a really nice high plateau...
    bo

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  13. #103
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    Quote Originally Posted by dr_gallup View Post
    That's the construction on newer drivers, not the 2245. How could there be rubbing marks on the aluminum ring on my old 2245 if it did not move with the voice coil? Believe me, it moves. Maybe it's incorrect to call it a shorting ring but I don't know what else to call it.
    From what I had in the past: two 12 inches that I did buy (cheap) but I hat to recone them (myself) with original parts from JBL. They had a Mass Ring, JBL did that for their studio woofers so the mass ring reduces efficiency a lot but makes the woofer going much lower than let's say a K-120 (guitar speaker). That mass ring was glued to the inner side of the voice coil, near the dustcap.

    Hope that it gives you some light

  14. #104
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    Reconing the JBL 2245H

    I know that it is considered blasphemy here to consider such things but ...

    Since JBL is no longer offering kits to rebuild the 2245H driver, does anyone here have first hand experience with the McKenzie kits? Assuming that a JBL kit is not available who is the preferred fallback vendor?

    http://reconekits.com/jbl2245h8ohmreconekit.aspx
    _____________
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    Carl Huff

  15. #105
    Senior Member grumpy's Avatar
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    JBL is no longer offering kits to rebuild the 2245H
    Is that, in fact, true? C8R2245H seems to -not- be NLA ($276 as of April 26)

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