qls1 xo work

Discussion in 'Infinity Loudspeakers' started by InAp, Apr 16, 2018.

  1. InAp

    InAp Active Member

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    183
    Hi, Thinking about upgrading the xo's in my qls-1, I have 2 sets of these speakers, the xo on the right is from a set I bought brand new in 1978, the one on the left are from an older set I bought second hand 20 yrs ago , which has the front full cover. I would like to build them external in a box and eliminate a lot of the crap and make it half way between settings on midrange and up. What are your thoughts on this, external makes it simple to try different caps and components with ease.
    Thanks Al
     

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  2. tubed

    tubed Lunatic Member

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    Why not.
    Especially when you can rid them of those ridiculously difficult speaker terminals.
     
  3. Bucky Badger

    Bucky Badger You can tell a curd by it's squeak. Subscriber

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    I need to work on my X-overs as well.
    GLWYoverhaul.
    :lurk:
     
  4. InAp

    InAp Active Member

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    Has anyone seen the early xo , did it have caps and resistors on the v1 and v2 coils?
     
  5. pauljh

    pauljh Active Member

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    Absolutely go ahead and make the crossovers external. That's what the PS Audio folks did when they rebuilt their IRS V system.
     
  6. tubed

    tubed Lunatic Member

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    ???
    :dunno:
     

     

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  7. pauljh

    pauljh Active Member

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    If the woofer has two voice coils, it is a Watkins woofer and it certainly will have capacitors and inductors in series with both voice coils.
     
    Last edited: Apr 17, 2018
  8. InAp

    InAp Active Member

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    183
    What I should have said is, did the early xo have all the black caps? as in the pic above on first post. I know the tin can caps are stock on the later as I bought them new, just curious if the early ones were upgraded before I got them.
    Thanks Al
     
  9. tubed

    tubed Lunatic Member

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    Both early and later QLS-1 probably used the black caps. It's believed the caps were not of the highest quality.
    I have a pair of "later" ones with the black caps which I quickly replaced with some Bennics.
    Perhaps I bit too quickly as I could have made the crossover a bit prettier.
    Picture 2180.jpg
    Picture 2191.jpg
     
  10. slimpikkins

    slimpikkins Super Member

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    My pair of xo looked like yours. My black/red caps measured ok but still replaced them with bennics. I have a pair of Quantum 2 which had the black caps and were split and a sticky mess...fell apart when I removed them.

    Looks like yours (one on left) have a value of 1600uf on the 4ohm coil. Mine did and my woofers would bottom out. Infinity changed that value to 1100uf and also change the coil on the newer models. When I removed my old caps I replaced the 1600 value for 1100 and the woofers no longer bottom out at high playback levels.
     
    Last edited: Apr 18, 2018
  11. InAp

    InAp Active Member

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    Tubed, What are the values of the blue caps? and are they electrolytic as well?
     

     

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  12. tubed

    tubed Lunatic Member

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    Electrolytics.
    1400uf to vc #2
    1100uf to vc #1
     
  13. cdfac

    cdfac AK Subscriber Subscriber

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    My advice: make the crossovers match official schematics. That represented the upgraded crossover version, and in my experience that sounded fantastic rebuilt. Use all new capacitors and resistors, including bypass caps on any electrolytics. I reused used all of the larger inductors, though, only replacing the smallest one or two.

    I think you're pretty safe choosing a median range value for the resistance of the pots, instead of keeping the pots operational.
     
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  14. tubed

    tubed Lunatic Member

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    I did bypass the pots, completely, as I preferred the highest setting anyway.
    Also, I went a single larger value capacitor for the tweeters, as I used the highest setting.
     
  15. chef free

    chef free AK Subscriber Subscriber

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    Don't lose the pots, what resistance values work for one room will sound weird in a different room. The pots come apart without tools for easy cleaning.
     
  16. tubed

    tubed Lunatic Member

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    Pots are still there, simply bypassed.
     
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