Search:

Type: Posts; User: DHL; Keyword(s):

Search: Search took 0.06 seconds.

  1. Replies
    3
    Views
    4,279

    Thanks guys. Much appreciated. Also discovered...

    Thanks guys. Much appreciated.

    Also discovered during my testing why I was seeing that large turn on exotherm. JBL uses a NTC thermistor in the bias network to head off thermal runaway of the...
  2. Replies
    3
    Views
    4,279

    L212 Sub amp rebuild

    My L212 sub amp starting sounding weak (lower output at the same sound levels for the satellites), and after having an Al electrolytic failure in one of my TEK 576 curve tracers (which use the same...
  3. Thread: L112 refurb

    by DHL
    Replies
    4
    Views
    4,734

    I rebuilt the crossovers in my L212 using Dayton...

    I rebuilt the crossovers in my L212 using Dayton polypropylene film caps and it sounds great. I did use values as close as possible to the originals (within 5 - 10%). IMHO polypropylene films sound a...
  4. Replies
    8
    Views
    6,112

    Pull the cover plate (two screws on the front and...

    Pull the cover plate (two screws on the front and a number underneath) and look. The power supply caps are the four large silver cans sticking out of the board. Don't attempt to remove these without...
  5. Replies
    8
    Views
    6,112

    I am in the process of repairing/upgrading my...

    I am in the process of repairing/upgrading my L212 bass energizer as well. I am using 4 x 27,000 mfd Panasonic 63V THA caps on a separate PC board, and an outboard bridge rectifier. Removal of the...
  6. Replies
    8
    Views
    6,112

    You can but need to provide the EQ for the...

    You can but need to provide the EQ for the driver. Look at the feedback loop in the original. Was considering this route for my L212 bass unit, but considering the added complexity of summming L and...
  7. Thread: crossover upgrade

    by DHL
    Replies
    9
    Views
    7,428

    Along these lines, maybe the coupling capacitor...

    Along these lines, maybe the coupling capacitor failed short (unlikely, but possible) and there is an excessive amount of low frequency energy being fed to the driver?
  8. Replies
    88
    Views
    54,335

    Mr. Widget: Actually, the JC1/JC2s make my...

    Mr. Widget:

    Actually, the JC1/JC2s make my L212s sound amazing. Brings them up to the levels of my B&W 803ds which cost almost 10X the JBLs (maybe less than that in today's $). I was amazed at how...
  9. Thread: Which inductors??

    by DHL
    Replies
    11
    Views
    9,079

    I vote for the air core inductors. Yes they are...

    I vote for the air core inductors. Yes they are big. Yes, they are heavy. Yes they are expensive. But they sound better than iron core alternatives and I don't want to worry about exactly what power...
  10. Replies
    14
    Views
    25,638

    Thanks. I just hooked them up to my reference...

    Thanks.

    I just hooked them up to my reference system (Cambridge Audio CD/Bryston BDA-1, Parasound JC2 line preamp, JC1 monoblock power) and disconnected my B&W 803ds.

    WOW is all I can say....
  11. Replies
    14
    Views
    25,638

    You can get both the boards and "turrets" from ...

    You can get both the boards and "turrets" from

    http://www.tubesandmore.com/

    Look under "Hardware and Terminal Items", then "turret boards". Both the boards and turrets should be listed. Note...
  12. Replies
    11
    Views
    7,796

    I agree with other posts that removing the grills...

    I agree with other posts that removing the grills will sound best. Esp if the grill material was not provided by JBL, but an EBay seller. Who knows what the acoustic characteristics are?

    I am...
  13. Replies
    14
    Views
    25,638

    I think we went round and round on crossovers for...

    I think we went round and round on crossovers for the L212 sometime back. All I was able to determine was that the main components were pretty much the same for all versions, except for some changes...
  14. Replies
    14
    Views
    25,638

    The simplest method to use, without a lot of...

    The simplest method to use, without a lot of experimentation, is to align the rear of each cone (or the spider position) to the same plane. That should get you pretty close. I had a pair of L100s (or...
  15. Replies
    14
    Views
    25,638

    Modded and restored JBL L212 speaker system

    After many years of collecting dust, I have finally completed the restoration and modification of my JBL L212 system. It was originally purchased by me in the late '70s. After many hours of sonic...
  16. Replies
    18
    Views
    13,919

    Yes, that is still the goal. Building new cross...

    Yes, that is still the goal. Building new cross overs. I was checking the values in the published schematic to see if they matched the published spec of cross over points of 800 Hz and 3000 Hz. If...
  17. Replies
    18
    Views
    13,919

    4313B: "Too bad. That could have been fun. You...

    4313B: "Too bad. That could have been fun. You could have whipped up some nice 24 dB/octave LR active filters, put some nice little amps behind them and possibly ended up with something rather...
  18. Replies
    18
    Views
    13,919

    Sorry, I don't have either the L-pads or the...

    Sorry, I don't have either the L-pads or the cross overs.
  19. Replies
    18
    Views
    13,919

    If this is true, then what were the "standard"...

    If this is true, then what were the "standard" resistive loads used as substitutes for the drivers? 8 Ohms? If you use 8 Ohm resistors you will not get the response in the 1977 plots with the values...
  20. Replies
    18
    Views
    13,919

    Please look at the attached data: ...

    Please look at the attached data:

    http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=17989&stc=1&d=1157029720

    This is a voltage (not SPL acoustic) BODE diagram of the L212...
  21. Replies
    18
    Views
    13,919

    I have never heard of the term "acoustic...

    I have never heard of the term "acoustic crossover" when discussing passive component crossovers. Every design guide and speaker building document refers to the electrical cossover points in the...
  22. Thread: DIY Crossover Help

    by DHL
    Replies
    7
    Views
    4,834

    You can also use "TAG" boards, that are popular...

    You can also use "TAG" boards, that are popular with the tube amp builders. These are already built as you suggest, with a parallel row of pins.

    See, for example,
    ...
  23. Replies
    18
    Views
    13,919

    I just got schematics via EMail from HCG customer...

    I just got schematics via EMail from HCG customer support. I also was able to see the tech papers posted here under the technical info section for the L212.

    The one "error" that I note between the...
  24. Replies
    10
    Views
    6,773

    I like to use the products containing beeswax and...

    I like to use the products containing beeswax and lemon/orange oil. This product has a paste like consistancy and is easier to apply on vertical surfaces than a straight oil. You wipe it on like a...
  25. Replies
    18
    Views
    13,919

    L212 crossover schematics

    I am restoring my L212 speakers, and I need the schematics for the cross over networks. I tossed the crossovers years ago when I was planning to tri-amp the L212 with active cross overs, but never...
Results 1 to 25 of 25