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Thread: Does anyone have N1200 schematic with 16ohm

  1. #1
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    Does anyone have N1200 schematic with 16ohm

    Hello!

    I need N1200 schematic with 16ohm.
    Does anyone have N1200 schematic for 16ohm?

    Thanks

  2. #2
    Senior Member BMWCCA's Avatar
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    The information is found in the Links section of the forum under "professional links" "network schematics".

    http://www.jblproservice.com/pdf/Net...tics/N1200.pdf

    I believe they were all rated as 16ohm: http://www.lansingheritage.org/image...orks/page1.jpg
    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

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    In addition to BMW's link, G posted another different .PDF
    Look here

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    Senior Member BMWCCA's Avatar
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    Quote Originally Posted by BJL View Post
    In addition to BMW's link, G posted another different .PDF
    Look here
    I was looking for that one! Thanks. Should be put in the Links forum somehow, somewhere, I would think.
    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

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    Senior Member jcrobso's Avatar
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    Here are some alternitives.

    http://www.termpro.com/articles/xover2.html
    http://ccs.exl.info/cust_cr.html
    For those that want to get more in to the theory of crossovers look here.
    http://sound.westhost.com/lr-passive.htm

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    Old N1200s

    So, if you have very old networks, "in the gray container", the only way to know for certain what the cross over point is is to open them up.
    Correct?
    N1200.pdf (Posted by 4313B in another thread; Thank You!)

    Thomas

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    Dang. Amateur speakerdave's Avatar
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    Also, compare the 3120:

    http://www.jblproservice.com/pdf/Net...%20Network.pdf
    Attached Images Attached Images  

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    Senior Member jcrobso's Avatar
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    I have seen some on eBay labled 8 Ohm

    Quote Originally Posted by Wagner View Post
    So, if you have very old networks, "in the gray container", the only way to know for certain what the cross over point is is to open them up.
    Correct?
    N1200.pdf (Posted by 4313B in another thread; Thank You!)

    Thomas
    Maybe you could tell by looking a the value of the capacitors, if they are labeled.
    More info on X-over design.
    http://www.apicsllc.com/apics/Misc/filter2.html

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    Senior Member grumpy's Avatar
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    the only way to know for certain what the cross over point is is to open them up.
    Correct?
    No. You could measure them with proper loads, or measure and compare
    with spec's JBL provided when used with their specified load. Or let someone
    who knows what they are doing measure them.

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    Quote Originally Posted by grumpy View Post
    No. You could measure them with proper loads, or measure and compare
    with spec's JBL provided when used with their specified load. Or let someone
    who knows what they are doing measure them.
    Yes, understood.
    I meant for those of us who do not have the test equipment and relying only on schematics and values for identification.

    Thomas

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    Moderator hjames's Avatar
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    Quote Originally Posted by Wagner View Post
    Yes, understood.
    I meant for those of us who do not have the test equipment and relying only on schematics and values for identification.

    Thomas
    Of course, values marked on components are only accurate to the tolerance they were rated to, at the time they were made.

    Capacitors are known to age over time and change, which changes the performance of the network and the crossover points.
    Thus, old gear bought off ebay or similar sources is a wish, at best, and a bad joke worst case.

    Best approach is to create new crossover networks based on the original design.

    Of course, thats assuming you don't have tools or test gear to engineer new designs.
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    Senior Member Beowulf57's Avatar
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    Also note that although the test values show a Load Z of 8 ohms, that was I believe simply the standard test fixture used by JBL. The crossover may well have been used with a "nominal" 16 ohm driver. Often JBL specified the input impedance of the network and not the output load.

  13. #13
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    Quote Originally Posted by hjames View Post
    Of course, values marked on components are only accurate to the tolerance they were rated to, at the time they were made.

    Capacitors are known to age over time and change, which changes the performance of the network and the crossover points.
    Thus, old gear bought off ebay or similar sources is a wish, at best, and a bad joke worst case.

    Best approach is to create new crossover networks based on the original design.

    Of course, thats assuming you don't have tools or test gear to engineer new designs.

    Hi,
    Of course I understand the aging process, I was speaking to identifying which variant of N1200 one has.

    It is also interesting to note however, that in a number of threads I have read here, several folks have commented on the fact that they have rarely found a cap out of spec in any of the JBL networks they have examined when "rebuilding" was under discussion, including those over 30 years old.

    Thomas

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