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Thread: D2430K compression driver information?

  1. #46
    Senior Member Mostlydiy's Avatar
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    Thanks for sharing this pos, its really interesting stuff. Similar measurements with the 476Be/Mg would be a real treat but I know they are hard to come by.

    /Mostly

  2. #47
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    Quote Originally Posted by pos View Post
    - The fact that the D2430K is a 32ohms driver (in 16//16 position) is a really nice feature as it will reduce the hiss (and distortion) coming from the amp (-3dB compared to a 16ohms driver, and -6dB compared to a 8ohms drivers). I wish more compressions drivers would be 32 or even 64 ohms devices, especially when used with active ...
    Thanks for the measurements. Did you pick these up from Ebay in USA? I had my eye on a pair!
    The 32 ohms may actually be a problem if the amp is specifically optimised for low noise.
    Have you made any measurements with the VCs in parallel rather than series?

    Best wishes
    David

  3. #48
    Senior Member pos's Avatar
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    Yes these come from ebay.
    I did not try the 8ohms setup, but I'd expect the measurements too look the same, once the noise floor of the amp has be taken off the equation (by the use of an lpad or an autoformer)

    What amp are you thinking of?

  4. #49
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    Quote Originally Posted by pos View Post
    Yes these come from ebay.
    Lucky I did not bid and raise your cost. Must check here next time I want a pair.

    I did not try the 8ohms setup, but I'd expect the measurements too look the same
    I think there is a coupled mode that can exist when the VCs are in parallel, that does not exist for series connection.
    Ideally the two sides are perfectly equal and there will be no excitation of that mode, the measurements will be the same.
    I wondered about the difference in reality. Would be an informative test, if the results are the same then the driver is close to theory.

    What amp...?
    I plan a dedicated compression driver amp of ultra low noise.
    Much better than a standard amp that has to be wastefully padded down
    I have mentioned it a few times in DIYaudio, where I see some of your posts too.
    Lower VC resistance alters some of the trade-offs in resistor noise, power loss in the feedback network etc.


    Best wishes
    David.

  5. #50
    Senior Member pos's Avatar
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    4313b posted the M2 technical manual in another thread.

    The manual clearly states there is no replacement diaphragm for the D2430K:

    Driver, High Freq.
    D2430K
    (5032754X)
    No Diaphragm Kit
    Driver Only
    This is quite choking for such an (apparently) fragile driver aimed at professional use.
    One advantage of this technology over big Be (or Mg) diaphragms is obviously the cost of the diaphragms themselves, so if one cannot buy replacements this is getting a bit silly.

    Then I checked the VTX25 tech manual, and it states the opposite:
    Compression Driver (3)
    D2430K
    (446213-001X)
    Diaph Repl
    D32RD2430

    The 32 ohms marking seems to indicate that the replacement kit is the pair of diaphragms, maybe already assembled as opposing rings?...
    That would be logical as matching between the two diaphragms is critical (for distortion canceling), and sealing is also probably a big issue here.
    Also interesting to note: the part list for the driver itself is different... (?!)

    That said, I have had a pair of D2430K in my hands and to be honest I do not even see how one is supposed to open the damn thing to install new diaphragms...
    Maybe under the foilcal, like the old ring radiators?

    Would anyone have information (price?) on these replacement diaphragms?

  6. #51
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by pos View Post
    )...I have had a pair of D2430K in my hands and to be honest I do not even see how one is supposed to open the damn thing to install new diaphragms...
    Maybe under the foilcal, like the old ring radiators?

    Would anyone have information (price?) on these replacement diaphragms?
    I wouldn't sweat it... I doubt you would ever be able to buy replacement diaphragms.

    The current direction JBL is going is free driver replacement while under warranty and buying a replacement driver after that until NLA... my real fear is that NLA may be sooner than would have been considered reasonable before everyone started sharpening their pencils scalpel sharp.


    Widget

  7. #52
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    JBL Pro took down their Transducer Parts List a while back, no more checking by the public to see if a replacement part is even produced anymore.

  8. #53
    Senior Member pos's Avatar
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    Well, I think I'll stick with the good ol' 1.5"/4" compression drivers: they are easy to service, can perform admirably (especially with Be), and beside JBL there will always good diaphragms for these on the market for a reasonable price (Radian, Truextent, etc.).

  9. #54
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    Quote Originally Posted by pos View Post
    M2 technical manual ...clearly states there is no replacement diaphragm for the D2430K:
    ...
    Then I checked the VTX25 tech manual, and it states the opposite:
    Quote Originally Posted by Mr. Widget View Post
    ...
    The current direction... is free driver replacement while under warranty and buy... a replacement driver after that until NLA...
    It seems JBL expects the M2 owners not to blow them, and if they do then to have the money to buy a complete replacement.
    But PA/tour operators are expected to blow out drivers so can buy replacement parts,
    That would almost make sense if the M2 driver is perhaps a selected/matched unit, perhaps why the different part number?
    Or is it just an assumption that M2 owners can be squeezed harder?
    A >$1000 driver that is a throw-away item would make me very reluctant to buy.

    Best wishes
    Dave

  10. #55
    Senior Member pos's Avatar
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    Quote Originally Posted by Dave Zan View Post
    That would almost make sense if the M2 driver is perhaps a selected/matched unit, perhaps why the different part number?
    That is exactly what I was told today by KW55 (he also told me the M2 exceeded by far everything he had listen to in his showroom )

    That makes sense indeed, as matching between rings and proper installation is probably paramount with this push/push distortion cancellation strategy.

  11. #56
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    Quote Originally Posted by Dave Zan View Post
    It seems JBL expects the M2 owners not to blow them, and if they do then to have the money to buy a complete replacement.
    But PA/tour operators are expected to blow out drivers so can buy replacement parts,
    That would almost make sense if the M2 driver is perhaps a selected/matched unit, perhaps why the different part number?
    Or is it just an assumption that M2 owners can be squeezed harder?
    A >$1000 driver that is a throw-away item would make me very reluctant to buy.

    Best wishes
    Dave
    The D2 is considered a replacement part rather than a finished good like other JBL compression drivers so it runs around $1.5k a pop instead of $2k a pop.

    Harman has gone to a whole driver replacement strategy.

    There were D2 replacement diaphragm kits, I would assume they are still available to JBL Pro Service Centers.

    Quote Originally Posted by pos View Post
    That is exactly what I was told today by KW55 (he also told me the M2 exceeded by far everything he had listen to in his showroom )
    The performance of the M2 isn't trivial. JBL was not blowing smoke when they called it a game changer.

    The only problem I have with the entire scenario is people having spent serious money on K2's and E2's... my very first reaction to the M2 was within the context of the K2 and E2. "Uh oh..."

  12. #57
    Senior Member pos's Avatar
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    What about the "selected D2" scenario for the M2?
    Have you heard anything along those lines?
    That would explain the difference in part number between the VTX25 and M2 spec sheets.

  13. #58
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    No, I have not discussed that with anyone.

  14. #59
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    VC diameter?

    Having seen conflicting info, I'd like to check my understanding...

    The 2430K uses 3" VCs, the 2415k 1.5" VCs. Correct?

  15. #60
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    Quote Originally Posted by pos View Post
    That said, I have had a pair of D2430K in my hands
    Can you please post an impedance curve of one with the resistor pad from the M2? (13 ohm series, 11 ohm parallel)

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