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Thread: My new JBL 4345 build.

  1. #31
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    4345

    Very nice. I have an orignal set of 4345s that I'm going to build a set of 3145 charged crossovers for. I have most of the parts ordered. I hope mine look as good as yours. I love vinyl.

  2. #32
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    Quote Originally Posted by Ricpan View Post
    Very nice. I have an orignal set of 4345s that I'm going to build a set of 3145 charged crossovers for. I have most of the parts ordered. I hope mine look as good as yours. I love vinyl.
    i was joking. i am only playing vinyl.
    i hope you ll let us know about your progress with the charged cc's.

  3. #33
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    update

    here is an update of my babies and my gear...

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  4. #34
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    Beautiful speakers Slavko!

    Quote Originally Posted by fencki View Post
    hi.
    i wanted to share my outcome of my 4345 project with you.

    still waiting for the 2122h to arrive (hopefully tomorrow)

    used drivers:
    2405 (original blue dia + alnico)
    2425j (original dia)
    2307 + 2308
    2122h (until now test with 2123h)
    2245h (original cones)

    i used the giskard schematic with biamp only and coupled caps.
    external crossover in external box.

    here are the photos:
    Attachment 76325
    Attachment 76326
    Attachment 76327

    greetings from vienna
    slavko
    Your 4345's look fantastic Slavko! Superb job! I'm starting my own build soon. What did you find to be the most difficult part of the project? Are there any recommendations you could make to a prospective 4345 DIY'er? Mario.

  5. #35
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    hi.
    it is a very FUN project.
    do you have all your drivers?
    if not the main problem will be to find the right crossover for the drivers.
    if all the drivers are original, you can find schematics here on the forum...

    the main problem for me was to find the 2122h. this was a real nightmare and a big search.
    the horns and lenses are also not easy to find, but much easier than the middriver.
    (this problems are here in vienna/europe)

    the best tip i can give is take your time and donīt rush. all the enclosure plans are here on the forum and you can follow them easily.

    i didnīt take my time for the finish of the speakers. so i will have to sand them again and lacquer them again.

    i made the crossovers outside the cabinet. it was easier for me to do it this way...

    feel free to ask me anything you want if needed.

    regards from vienna

  6. #36
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    Quote Originally Posted by fencki View Post
    hi.
    it is a very FUN project.
    do you have all your drivers?
    if not the main problem will be to find the right crossover for the drivers.
    if all the drivers are original, you can find schematics here on the forum...

    the main problem for me was to find the 2122h. this was a real nightmare and a big search.
    the horns and lenses are also not easy to find, but much easier than the middriver.
    (this problems are here in vienna/europe)

    the best tip i can give is take your time and donīt rush. all the enclosure plans are here on the forum and you can follow them easily.

    i didnīt take my time for the finish of the speakers. so i will have to sand them again and lacquer them again.

    i made the crossovers outside the cabinet. it was easier for me to do it this way...

    feel free to ask me anything you want if needed.

    regards from vienna
    Thanks very much Slavko.

    So far, I have the 2245h drivers and 2122h (actually 2123 re-coned with 2122 cones).

    I plan to also get originals for all the rest of the components, i.e. 2405's, 2307's and 2421B's (or 2425J's).

    Will I need to modify the crossover schematic because I'm using 2123 reconed to 2122?

    Mario

  7. #37
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by XRT22 View Post
    Will I need to modify the crossover schematic because I'm using 2123 reconed to 2122?
    A JBL 2122 cone kit in a 2123 is a 2122H in every way except for the label on the back.

    In collecting these components realize that a good DC reading does not guaranty that the driver is actually up to spec, and most HF drivers will need to be re-diaphragmned by an experienced professional if you are to have ideal performance.


    Widget

  8. #38
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    Quote Originally Posted by Mr. Widget View Post
    A JBL 2122 cone kit in a 2123 is a 2122H in every way except for the label on the back.

    In collecting these components realize that a good DC reading does not guaranty that the driver is actually up to spec, and most HF drivers will need to be re-diaphragmned by an experienced professional if you are to have ideal performance.


    Widget
    i agree in all points with mister widget.
    he is one of the pros here i trust whatever he says.

    regards

  9. #39
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    Quote Originally Posted by Mr. Widget View Post
    A JBL 2122 cone kit in a 2123 is a 2122H in every way except for the label on the back.

    In collecting these components realize that a good DC reading does not guaranty that the driver is actually up to spec, and most HF drivers will need to be re-diaphragmned by an experienced professional if you are to have ideal performance.


    Widget
    Thanks Mr. Widget!

    Can you please tell me the difference between the 2421B and 2425J? I have found references to both in listings of 4345 components. Are these interchangeable without the need for crossover changes?

  10. #40
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    Quote Originally Posted by XRT22 View Post
    Thanks Mr. Widget!

    Can you please tell me the difference between the 2421B and 2425J? I have found references to both in listings of 4345 components. Are these interchangeable without the need for crossover changes?
    Also, what effect would there be if I was to use a 2420 instead of either a 2421B or 2425J? Would I need to modify the Crossover to accommodate this change? Thanks in advance!

  11. #41
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    Quote Originally Posted by XRT22 View Post
    Can you please tell me the difference between the 2421B and 2425J? I have found references to both in listings of 4345 components. Are these interchangeable without the need for crossover changes?
    The 2421B has an aluminum diaphragm which many feel sounds better, but this is not universal. The 2425J was created to mimic the 2421B with a ferrite magnet and JBL switched over to Ti diaphragms for greater reliability.


    Quote Originally Posted by XRT22 View Post
    Also, what effect would there be if I was to use a 2420 instead of either a 2421B or 2425J? Would I need to modify the Crossover to accommodate this change? Thanks in advance!
    I don't know the definitive answer to this, but it would likely work. The performance would not be identical to the system as designed. That said, virtually all LE85s and 2420s will likely need new diaphragms at this point and only the 2421B or 2425 diaphragms are now available.


    All that said, your asking such fundamental questions makes me wonder if it is smart for you to be taking on such a project without doing a lot more research and having a better understanding of the fundamentals of speaker design in general and of vintage JBLs in particular. You will be spending a lot of time and money on this project and there is no guaranty that you will be successful. Buying a new system such as the 4365 or a properly refurbished 43XX system will be a safer investment. I would not recommend your buying a JBL clone as you will never know if it is really an accurate clone or a "looks like" clone.


    Widget

  12. #42
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    Quote Originally Posted by Mr. Widget View Post
    The 2421B has an aluminum diaphragm which many feel sounds better, but this is not universal. The 2425J was created to mimic the 2421B with a ferrite magnet and JBL switched over to Ti diaphragms for greater reliability.


    I don't know the definitive answer to this, but it would likely work. The performance would not be identical to the system as designed. That said, virtually all LE85s and 2420s will likely need new diaphragms at this point and only the 2421B or 2425 diaphragms are now available.


    All that said, your asking such fundamental questions makes me wonder if it is smart for you to be taking on such a project without doing a lot more research and having a better understanding of the fundamentals of speaker design in general and of vintage JBLs in particular. You will be spending a lot of time and money on this project and there is no guaranty that you will be successful. Buying a new system such as the 4365 or a properly refurbished 43XX system will be a safer investment. I would not recommend your buying a JBL clone as you will never know if it is really an accurate clone or a "looks like" clone.


    Widget
    Thank you for a comprehensive response. Yes, will definitely need to do more research. Only reason I've asked about the 2420's is because I have been offered some which are in - what seems to be - very good condition and thought I could use these instead of buying 2421B's or 2425s. Perhaps I will start off using these until I can find a set of 2421B's or 2425's to replace them with. Thanks again for your assistance.

  13. #43
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    Quote Originally Posted by XRT22 View Post
    Thank you for a comprehensive response. Yes, will definitely need to do more research. Only reason I've asked about the 2420's is because I have been offered some which are in - what seems to be - very good condition and thought I could use these instead of buying 2421B's or 2425s. Perhaps I will start off using these until I can find a set of 2421B's or 2425's to replace them with. Thanks again for your assistance.
    i see no problem in try & error.
    i did it the same way...

  14. #44
    Junior Member Nixos's Avatar
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    beautiful work.. look like an original..I wouldn't pick it.. do you have any frequency response measurements?

  15. #45
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    Sometimes the older Alnico drivers loose a bit of magnetic properties and the throats maybe dirty.

    The newer Ti diapgrams are not an exact drop in fit in the older 24202470. The pin holes may need slight filing out.

    I would be careful of any old drivers as there are no guarantees.

    Mr Widget is right

    The scarcity of re cone kits and older drivers is a risk in terms of the original result.

    Talk to a JBL service agent like Jands in get them to check all your drivers.

    It will eliminate a lot of headaches.

    My advice is dont rush it. Its a really big job. Allow 6 months at least.
    If you have dont have background in electronics get someone to do the passive crossover, the discrete active crossover and wiring up (me-I accept donations like a case wine)

    Dont skimp on the active crossover if you have high expectations

    Setting then up can take a while.

    But when the are they give the newer systems a run for their money

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