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Thread: Upgrading an L-200

  1. #1
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    Upgrading an L-200

    I have a very good working pair of L-200's, but after reading this and other forums, I decided to experiment with upgrading it. I have purchased:

    - a pair of 136A woofers that the seller said came from L-300's,

    - a pair of 2405 slot drivers, and

    - a BBE Max-X3 2-way stereo electronic crossover.

    I like to replace the L-200's LE-15A woofers with the 136A's, keep the LE85 driver with the H91/L91 horn/lens combo and then add the 2405's in an outboard box made especially for them.

    I would use the crossover to feed the upgraded L-200's frequencies below say 7KHz (I would use the single L-200 inputs, not the bi-amp ones), and feed the higher frequencies to the 2405's. The crossover has separate gain controls for the high and low frequencies, so I can match the efficencies of the L-200 and 2405.

    I have some questions:

    1) Am I setting myself up for disaster, or is this a good plan?

    2) I've never pulled the drivers out of the L-200 cabinent before. To remove the LE-15A, do I just unscrew the 8 bolts around the periphery of the surround and then pull the speaker outwards, or do I need to go into the back of the cabinent first?

    3) I see that the L-300 has only one port and the L-200 has two. Should I stop up one of the L-200 ports?

    Thanks

  2. #2
    Senior Member duaneage's Avatar
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    I would run the two woofers througha box design program first and see what it says. Boxplot is a free progam that let's you see what changes in volume and tuning do and the price is right, just download it from here

    http://www.diamondcut.com/boxplot.htm

    and see what will happen before you take things apart. The driver TS parameters are available from the JBLPRO.com website under technical library and driver parameters/

    My gut instinct tells me that you would be better off leaving the 200s alone and building new cabinets for the 136a woofers.

  3. #3
    Dang. Amateur speakerdave's Avatar
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    Hi,

    I think the L300, like my 4333A's, crosses over at 800 Hz and therefore uses a different horn, the longer H92/2312. Total depth may be too long for that cabinet, so if you are looking to be exactly like the L300, there's a problem. I also think, going from the LE15 to the 136 you may not be happy with the existing crossover frequency, because the 136 will not be as good up there as the LE15. You might consider just adding the super tweeter. Or you might consider building your own cabinets and selling these off. LE85's are not hard to find.

    David

  4. #4
    RIP 2011 Zilch's Avatar
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    Standard LF driver in L200 is LE15B (cloth surround), not LE15A (lansaloy surround), and the crossover frequency is 1200 Hz. I last calculated the internal volume as 4.9755 cuft. It' different every time I do it.

    136A's will play nicely in that box with one of the ports closed for extended bass (~25 Hz), or both open for tighter, punchier bass (~35 Hz). I'm using 2235H's in them right now, with proprietary port closure technology so's I can choose bass tuning as desired.

    You'll want to move the crossover frequency down to 800 Hz with, say, 3110 crossovers. The rear panel crossover cutout size is the same.

    However, as stated above, if you're thinking L300, you'll not be fitting the longer horn in there unless you're willing to punch the LE85 out the back, a mess.

    The long horn may be optimum, but JBL used the short one down to 500 Hz in the "legendary" S7 system.

    L200B used the shorter horn crossed at 800 Hz with 136A woofers, and several members have successfully added 2405 UHF to them using 3106 crossovers. It can be cut into the baffle space above the present horn if you want to forego the external box.

    There is no biamp input on L200 that I'm aware of, but you should be able to use your active crossover. Feed everything below 7 kHz to the 3110's, and the VHF to the 2405's.

    The 8 bolts will remove the woofer, but it may require gentle persuasion to come free if it's not been removed before. Lay the cabinet on its back to work on it.

    There's no "going into the back of the cabinet" option available.

    See my avatar for an alternative formula for L200 upgrade if you want to get radical....

  5. #5
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    Thanks for the feedback. I've looked at the L-200's again and I see:

    - The woofer does have the cloth, accordian style surround, so that makes it an LE 15B.

    - I would use a GAS Grandson (40 wpc) amp to drive the 2405

    - The L-200 crossover is an LX-16 which has three stereo sets of inputs, a) one marked "Input" which is the way that I have connected the speaker to the amp (a 200 wpc GAS Ampzilla, BTW), b) one marked "LF", and c) one marked "HF".

    I am assuming that input option a) takes the full spectrum audio signal and splits it between the LE 15B and LE85 drivers at 1200 Hz and that b) and c) are for biamping with an external crossover and separate amps, i.e. the LCR passive crossover circuitry of the LX-16 would be bypassed.

    I will have to live with the short 1200 Hz H91 horn and hope that the 136A can reach that last half octave between 800 and 1200 Hz.

    An alternative is if the LX-16 crossover allows for biamping, then I can run two BBE Max-X3 electroinc crossovers in 3-way mono mode and cross the 136A at 800 Hz and the 2405 at 7KHz using the Max-X3's. I would have to run 3 amps. I have a GAS Son of Ampzilla (80 wpc) and a GAS Grandson (40 wpc) to do this so the amps will be of the same "family" of circuitry topology.

    I will plug up one of the ports as I really do want lower extension. I'll let you know how things turn out.

  6. #6
    RIP 2011 Zilch's Avatar
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    b) and c) are merely the wires going to the drivers. I you want to drive them directly, you have to disconnect the leads entirely from the crossover for use.

    Trust the Zilchster on this, now: If you aren't going full active triamp, spend about $100 on eBay and get a pair of JBL 3110 (800 Hz) crossovers to replace the LX16's. You don't need 3110A's since you're using a separate tweeter.

    A primary reason JBL used the LE15B instead of the extended bass LE15A or 136A in L200 was because they don't play well to 1200 Hz. 2235's don't even do it; that's why 2234H is the recommended replacement, and even that is a compromise. JBL abandoned the attempt soon thereafter.

    Max recommended crossover frequency is 800 Hz:

    http://www.lansingheritage.org/image...2231/page2.jpg

    Note also, they soon published a mandatory modification for LX16, as well, to protect the LE85 drivers. The original L200 design was compromised in these several ways. Your upgrades will improve them substantially.

    http://manuals.harman.com/JBL/HOM/Te.../L200%20ts.pdf

    http://manuals.harman.com/JBL/HOM/Te...L200B%20ts.pdf

    [My proprietary port closure devices are 4" plumber's test plugs from the hardware store. Don't tell anybody, tho.... ]

  7. #7
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    Now I can really focus in. This is great.

    I just pulled the first L-200 woofer after noting that the green wire from the LX-16 goes to the red terminal on the woofer and the black wire goes to the black terminal. This answered my other question about biamping with the LX-16, the insulated colored wires go directly to the drivers and so you merely have to disconnect them from the push terminals of the LX-16 and connect them to the amp. That automatically takes the LX-16 out of the circuit.

    On the back of the woofer it says, "JBL LE15B, Impedence 6 -8 ohms". It's in great shape, BTW, the surround is in fine condition.

    I'm now going to pull the other LE15B, install the 136A's, implement the top secret port tuning device in one of the ports of each cabinent and see what is sounds like. More to come.

    I'll also be on the lookout for a 3110 crossover.

  8. #8
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    I'm now catching up on all of the links. The frequency response graph for the 2231 woofer (pro version of the 136A) shows that it is about +3 dB at 800 Hz and remains that way to about 1500 Hz before dropping off.

    The 2231 spec sheet does say that the highest recommended crossover frequency is 800 Hz, but the graph seems to support adequate output to at least the 1200 Hz crossover point of the LX-16. Does this seem to hold together?

  9. #9
    Senior Member Lancer's Avatar
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    That's on-axis response. Don't worry about it, just use it. You're facing a whole slew of compromises so it simply isn't going to matter much.

  10. #10
    RIP 2011 Zilch's Avatar
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    Quote Originally Posted by witoman
    This answered my other question about biamping with the LX-16, the insulated colored wires go directly to the drivers and so you merely have to disconnect them from the push terminals of the LX-16 and connect them to the amp. That automatically takes the LX-16 out of the circuit.
    That's fine for the woofers, but, until you're absolutely confident about your setup, you'll want protection capacitors in series with the mid drivers and tweeters. Normally, passive crossovers protect the drivers from turn-on (and turn-off) transients, excess amp DC output, etc.. 20 uF for the 16-Ohm mids, 4.7 uF for the 8-Ohm tweeters....

    Pairs of LE15B been going for up to $500 on eBay of late, but I'm holding off on selling mine 'til I try them in Z2 cabinets here compared to E145's.

    [They DO make tight, punchy bass....]

  11. #11
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    Done with changing out the L-200's LE15B woofers for 136A's. Plugged one of the two ports in each speaker with the amazing plumber's adjustable test plug, a perfect fit that just screws down to a tight seal.

    I'm out fiddling with the L-200's High Frequency Level control on the front panel to match the LE85's output to that of the 136A. I've turned the control down to -6 dB as the woofs are less efficeint with one port plugged.

    And now a slight confession, the 2405's that I wrote about are in transit to me right now from an eBay auction, 7338839423, but I do have mounting boxes for them as soon as they arrive. In the meantime, I've been using a pair of Heil Air Motion Transformer drivers from ESS AMT-3 Rock Monitors placed atop the L-200's. These are crossed over at 7KHz using the BBE external crossover, so I'm sending the LX-16 crossover on the L-200's only 7KHz and below.

    The GAS Ampzilla drives the L-200's and a GAS Grandson drives the ESS tweeters.

    How does it sound now? Well, the 136A's are *very* much smoother than the LE15B's. And plugging one of the ports does allow for deeper bass on the tracks that I've played so far. I've quite pleased that my L-200's (L-200B Primes?) sound a lot better. Lots more fiddling to do.

    Like, what would happen if I plug BOTH ports in each speaker, transforming them into acoustic suspension speakers ala Large Advents?

    Thanks for everyone's help on this project!!

  12. #12
    RIP 2011 Zilch's Avatar
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    Quote Originally Posted by witoman
    Lots more fiddling to do.

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    A photo of the project so far is at:

    http://velero-ii.com/Photos/JBL_L200...ter-WIT-11.JPG

    This is with the ESS AMT-3 tweeters on top. The 2405's are coming.

  14. #14
    Senior Member duaneage's Avatar
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    Pkugging both ports would cause the soofer to excurse a lot more than it does in a vented enclosure and that might not be OK for this woofer. The vent controls cone movement at Fb, although vented boxes do unload the woofer below Fc.

    Generally speaking (pardon the pun) vented boxes have vented speakers and sealed boxes have sealed speakers.

  15. #15
    Senior Member Lancer's Avatar
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    Running the 136/2231 sealed is fine. JBL spec'd them in 5 cu ft sealed volumes for sub duty back in the day before subs were so popular. Some people don't like sealed and think vented sounds better. For an L200 or L300 I'd leave them vented.

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