Crossover part identification

Discussion in 'General Audio Discussion' started by Darby Crash, May 11, 2018.

  1. Darby Crash

    Darby Crash Active Member

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    Pulled the other crossover today and the little cap that was fried on the first one is good on this one so i can get the value from it. Also the Ohmites look great. Still dont understand why the posts were glued in the position they are in.
    11EC4837-FE1C-4C35-BEB7-DD8BF4C4687A.jpeg C686FA29-8DBA-4257-9767-F850366621A8.jpeg 84933622-2B82-4583-A27E-4EB6C29677BC.jpeg
     

     

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  2. woodj

    woodj Super Member

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    Yep.
     
  3. DaveVoorhis

    DaveVoorhis Super Member

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    They're likely set by the factory and then glued so the owner doesn't mess with them.

    You sure the Ohmites are 50ohm?

    Measure the resistance across the fixed (not the swept) terminals to verify.
     
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  4. EngineerNate

    EngineerNate AK Subscriber Subscriber

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    Those are some truly scabby crossovers.
     
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  5. Darby Crash

    Darby Crash Active Member

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    Will check resistance.

    50ohm .5amp

    34581C3D-85AB-4371-A002-14B766D0EEF8.jpeg
     
  6. EngineerNate

    EngineerNate AK Subscriber Subscriber

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    Stepped or smooth rotation?

    Any other letters printed on there?
     

     

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  7. Darby Crash

    Darby Crash Active Member

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    Smooth.

    Ohmite 0110 Model E 50 Ohm .5 Amp Rheostat

    The 2 from the first board, one is destroyed maybe from cap exploding. The other one is a little chared but rotates.
     
  8. Darby Crash

    Darby Crash Active Member

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    They seem to be set at the lowest range
     
  9. EngineerNate

    EngineerNate AK Subscriber Subscriber

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  10. toxcrusadr

    toxcrusadr AK Subscriber Subscriber

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    I wouldn't screw with those inductors, it's like replacing the wheels on a car just because it needs new tires. They are just about that durable. Plus the cost of all new inductors would be high compared to all the other parts.

    This may have been mentioned, but are you going to replace the input jacks? Some nice 5-way gold plated ones would be much better for very little $.
     
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  11. toxcrusadr

    toxcrusadr AK Subscriber Subscriber

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    BTW the reason that pot is 50 ohms is that when cranked up that high, it is capable of turning down the driver it's connected to by quite a bit.
    If those are set near the bottom end, you may not need that much range. Quite often speaker L-pads or pots are more like 8-16 ohms.
     

     

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  12. Darby Crash

    Darby Crash Active Member

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    2 are in great condition, the 3rd is a little chared but seems to work.
    I just dont understand why this range was used and what i can replace them with. E34BF81F-2957-4C6C-B4A3-BF67EED5BB9D.jpeg
     
  13. DaveVoorhis

    DaveVoorhis Super Member

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    These should do: http://www.radwell.co.uk/Shop/OHMITE/RJS50R
     
  14. Darby Crash

    Darby Crash Active Member

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    Location:
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    Thanks for responses. Yes i will be replacing binding posts. Im gonna build 2 boards, 1 for crossover and a separate 1 for L pads and posts instead of jamming them all on 1
     
  15. Darby Crash

    Darby Crash Active Member

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    50ohm isnt hard to find, but they all are watts not amps. So how does the .5 amps relate to watts
     
  16. toxcrusadr

    toxcrusadr AK Subscriber Subscriber

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    It's complicated... P=I squared x R in other words power in watts equals current in amps squared times resistance. To find P or I you probably need voltage...it gets complicated fast.

    For a handy pie chart google up "ohms law chart".

    But you don't have to know all that...if you're looking for pots for mid and tweeter, they only have to dissipate a fraction of total power, i.e. what you'd normally see going to that driver. What's the overall wattage of the speaker? Figure 1/4 of that goes to the tweeter or mid and the other half to the woofer. Something like 10W should be enough for tweeter and mid pots I would think.

    Actually those old ceramic ones look very well made and if they worked OK I would keep them, myself.
     

     

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  17. DaveVoorhis

    DaveVoorhis Super Member

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    Ditto. The ones I linked in post #33 are the modern equivalent, but they're not cheap. Wire-wound pots are designed to dissipate some heat and will sometimes discolour if they've run hot, but that doesn't mean they're necessarily bad. If they work -- i.e., they're mechanically sound and the wire hasn't burned up or broken -- they're fine.
     
  18. Darby Crash

    Darby Crash Active Member

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    174
    Location:
    Long Beach
    Thanks guys, im begining to understand. I have spent most of the day searching, researching and reading trying to figure out what to do with those damn knob thingys.

    Tweeters
    JVC ribbon
    HSW 1101-01A
    120w

    Mids
    Philips
    AD 02160 SQ8
    80w

    Woofer
    CTS 137
    10w18c

    If a L pad is 15 watts does that mean it will divert 15w range away from the speaker? If you look at the picture the pots are turned to the lowest position counter clock wise.


    I found the math
    Volts = amps x ohm

    Convert amps to watts
    Watts = amps x volts

    I think the bottom line is the pots i have marked 50ohm .5amp are rated at 12w
    I think i will be ok using these L-Pads from parts express 15w 8ohm.
     
  19. DaveVoorhis

    DaveVoorhis Super Member

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    No, it means it can continuously dissipate roughly 15 watts of energy before burning up.
    An L-pad is a specific arrangement of a pair of rheostats on one shaft used to control level whilst maintaining a specific impedance. See http://www.colomar.com/Shavano/lpad.html

    It looks like your crossovers use rheostats rather than L-pads.
     
  20. Darby Crash

    Darby Crash Active Member

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    Is there an emoji for “head exploding”.
    It seems like i will have to pick up a rheostat then.
     

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