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Seeking Advice on Rehabbing Kappa 6.1’s

Discussion in 'Infinity Loudspeakers' started by Natertots, Jul 18, 2018.

  1. Natertots

    Natertots Member

    Messages:
    70
    Location:
    Portland, OR
    FYI this will be my first real speaker repair attempt.

    I am looking for some guidance on testing and repairing some Kappa 6.1 Series II’s that I just acquired. I picked them up off of Craigslist for $50. As one would expect from speakers at that price, the surrounds are shot, the grills aren’t great, the cabinets are a bit rough and one of the binding posts is broken off. I have been doing some reading and I feel I have a grasp on most of the repairs but there are two main issues/questions I have.

    First: I haven’t tested the speakers and I want to know if it is safe to do so. My concerns revolve around the bad woofer surrounds and my power source.

    - The surrounds are completely gone on the woofers. Is it safe to play them at low levels to test them, or should I get new foam on them first?

    - I understand that Infinity’s like these take real power to run properly and they are low ohm speakers. At present I only have a pioneer sx-750 (50 wpc) and a Sony AVR (100 wpc), both only rated for 8 ohms. Would it be safe to test these speakers at low levels using either reciever?

    Second: One binding post has broken. It snapped off where the hole was drilled perpendicular to the post. I have done a brief search and haven’t found a replacement crossover. Do I just keep looking until I find one or can this be repaired?

    As I mentioned at the beginning this will be the first time I have done any work on a set of speakers so any guidance you all can provide is appreciated. Thanks in advance!
     

     

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  2. StimpyWan

    StimpyWan AK Subscriber Subscriber

    Messages:
    4,157
    Location:
    Blue Ridge Mountains!
    Welcome!

    Nice find, and a great price. For what you paid, the 6.1's deserve some additional cash flow.

    As to the woofers, with the surrounds totally gone, I would not play them. Even at minimal power. You could cause a voice coil rub, which could permanently damage the woofers. So, for the sake of sanity, at least check the impedance of the 2 woofers. If they match, the woofers are most likely OK.

    Now, binding posts. Not hard to upgrade with new posts. Though, I believe the posts are under a crossover board, making them hard to get to. I think I have a pair of 6.1 crossovers in my parts bins. I'll check them this evening, to see how hard it would be to access the posts, for repair. I'll update with what I find.
     
  3. swechsler

    swechsler Frog Whisperer

    Messages:
    5,231
    Location:
    7th row center
    I'll be watching this because I too have a Kappa 6.1 with one broken post. In theory the crossovers (see pic below, stolen from eBay) should come apart when you remove the 6 screws on the circuit board. I don't see any evidence of the posts being soldered directly to the board. However, it's difficult to remove the crossovers with the drivers installed, because the wires are too short to allow enough clearance to work on them.

    [​IMG]
     
    Bobbyd38 likes this.
  4. Natertots

    Natertots Member

    Messages:
    70
    Location:
    Portland, OR
    Thank you for that. Any insight into the process would be great.

    I have basically no experience with the fixes I need to execute (soldering, refoaming, etc), so while I am fully willing to put in the effort I want to have as much info as possible before starting.

    If I am going to be working on the crossover do you think it’s worth recapping while in there? Or are the caps they used in the Kaapa’s not as prone to breakdown as some other speakers?
     
  5. Natertots

    Natertots Member

    Messages:
    70
    Location:
    Portland, OR
    Thanks for the pic.

    I read the same thing about the difficulty pulling the crossover in another thread. It sounds like it is possible the speaker leads are soldered too. While that may not be an issue for some, I have only soldered one other project and don’t have my own equipment so it adds another wrinkle for me.

    I hope we both get some good answers. I am pretty excited to rehab these guys, even though I don’t have the right gear to really use them yet.
     
  6. swechsler

    swechsler Frog Whisperer

    Messages:
    5,231
    Location:
    7th row center
    You're probably going to have to do some soldering to remove the old post and add the new one, but it shouldn't be difficult soldering and I'm sure there are tutorials on Youtube. You can get a cheap soldering iron and a roll of solder at Harbor Freight; if there's none near you, try Wal Mart (or here's a kit on Amazon for $7.75, shipped free without Prime).

    If all your drivers are original, the wires to them should just be held on by clips (I'm guessing; I haven't yet opened my 6.1s, but in my 7.1s the wires are not soldered). You can remove each driver, disconnect the wires (make note as to which wire attaches to which terminal), then you should be able to remove the crossover and carefully pull the wires (pull the wire itself, not the crossover) out through the hole that the crossover was mounted in, not all the way (since the midrange is in a subenclosure, its wire won't come out all the way anyway), which should give you enough slack without having to cut or unsolder anything. Then you can remove the screws holding the crossover circuit board to the connection plate and see what's involved in replacing the post.
     
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  7. StimpyWan

    StimpyWan AK Subscriber Subscriber

    Messages:
    4,157
    Location:
    Blue Ridge Mountains!
    I took a look at my 6.1 crossovers. It doesn't look like it'd be too hard to swap out binding posts. It fact, I think it could be done without dismantling the boards. All the posts are near one end, and could probably be reached with needle nosed pliers, or open ended wrenches.

    20180718_174603.jpg

    20180718_174635.jpg

    My crossovers already look modded too. There's some poly bypass caps in there, that don't show in swechsler's picture. That could be an easy way to mod yours too.
     
    Last edited: Jul 18, 2018
    Natertots likes this.
  8. swechsler

    swechsler Frog Whisperer

    Messages:
    5,231
    Location:
    7th row center
    It will depend on how long the wires are that connect the posts to the circuit board. You'll probably need a couple of inches of slack to be able to pull them out and work on them.
     
  9. Natertots

    Natertots Member

    Messages:
    70
    Location:
    Portland, OR
    Thanks for the info. I started to look into things more thoroughly today.

    Pulling the drivers won’t help with the short wires issue. In my boxes the wires for the mid and tweeter are glued in where they pass through the mdf into the rest of the cabinet. Fortunately it looks like there is enough slack that I can get to the six screws holding the back plate in if I leave everything hooked up. Also, it looks like the binding posts are only bolted in, although I didn’t dig in far enough to be certain.

    My next question is, where do I get replacement binding posts? Is that just a Parts Express item, or should I check with Harman?
     
  10. Natertots

    Natertots Member

    Messages:
    70
    Location:
    Portland, OR
    Great pictures and good info. I did manage to get the crossover out far enough to get a decent look at it and I agree with you, looks like I just need to loosen some screws and nuts.

    Any suggestion on replacement binding posts?
     

    Attached Files:

  11. Natertots

    Natertots Member

    Messages:
    70
    Location:
    Portland, OR
    You were right about the speaker connections being clips.

    I do want to get a slider set up, but if I make a real hobby out of this I think I will pick up something decent from the beginning. I have done a little window shopping, but I am still unsure what to get. Any suggestions, maybe in the $50-100 range?
     

     

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  12. StimpyWan

    StimpyWan AK Subscriber Subscriber

    Messages:
    4,157
    Location:
    Blue Ridge Mountains!
    Thanks. I'm glad the pictures helped.

    Now, binding posts. I've used Parts Express 320-3375 mini posts. They should be the same length, and most likely, the same thread pitch. Unscrew one, and screw the other on.
     
  13. swechsler

    swechsler Frog Whisperer

    Messages:
    5,231
    Location:
    7th row center
    I have a Stahl soldering station, but I also have some inexpensive pencil irons for when I'm not working at the bench, and also a couple of vintage Weller soldering guns, for quick heat. The Stahl is great, but for working on large speakers I would probably use one of the pencil irons. It's not exactly delicate work, and it's much easier to bring a lightweight iron to the speakers than it is to bring some heavy speakers down to the workshop and risk damaging them.
     
    StimpyWan likes this.
  14. Listnnthdark

    Listnnthdark Well-Known Member

    Messages:
    502
    Location:
    West Lebanon NH
    Welcome and congrats . You have way more expert advice from others here . But since you mentioned your first time I will share that those face plates are a pain to get off . In my 1st refoam attempt on them I had already removed surround and cleaned the cone before the wrestling match began . I definitely did not want to crack them and around late third round I threw in towel and sent them out to millersound and happy I did . Was pretty cheap and my faceplates are intact . I think the way to get them off rather than elbow grease is by heating with a heat gun . ( Just what ive heard ) Best of luck ! :bye::thumbsup:
     
    mgkfifty likes this.
  15. Natertots

    Natertots Member

    Messages:
    70
    Location:
    Portland, OR
    I decided that since this would have been my first refoam that I would take them to a local speaker guy to refoam. I am going to get my feet wet on the refoaming with a set of 15” Mach 3 woofers. I bought them mostly to practice on, and if all goes well, pump noise into my fathers 49’x60’ shop. Woofers came back and looked good.


    As already discovered there was no soldering envolved in replacing the binding posts. I couldn’t get the Tweeter and Mid knobs to separate from the pots. Fortunately it was the lower binding post that broke and I was able to replace the binding post with little difficulty. The problem is the new binding posts are wider than the originals and the stock jumpers don’t fit. Now I am left with the scenario of buying another set of bingin post (I replace the matching pos and neg so things would be simetrical), modifying the original, or finding/making a replacement jumper.

    FYI I got mine from new posts from Madisound because they were shorter than the Parts Express set...

    So I got everything back together (jury-rigging the oversized binding posts for now) and hooked them up in my highly technical listening room. After playing with the crossovers I am not sure if any of the Mid or Tweeter level knobs work. So:

    Are these controls only functional when bi-wiring or bi-amping?

    If they should function when using a single set of wires and the jumpers, how do I test them?

    Thanks for all the help so far.
     

    Attached Files:

    Depecheduran likes this.
  16. Depecheduran

    Depecheduran AK Subscriber Subscriber

    Messages:
    90
    Location:
    Tucson, AZ
    Great find! It is always worth bringing quality speakers back from the dead. It is always worth learning something new. I am nearly done with my Kappa 7's. I hope yours sound amazing!
     

     

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  17. swechsler

    swechsler Frog Whisperer

    Messages:
    5,231
    Location:
    7th row center
    Don't worry about the jumpers, just use some wire to jump from the low to the high posts. Regarding the level controls, they have only a subtle effect on most Infinity models.
     
    Natertots likes this.
  18. mgkfifty

    mgkfifty Active Member

    Bill from Millersound is a good option if you are unsure of your skills or just don't want to tackle it yourself. It will be done right, quickly and at a reasonable cost. I have used his services many times and have never been disappointed.
     
    Depecheduran likes this.
  19. Bobbyd38

    Bobbyd38 AK Subscriber Subscriber

    Messages:
    91
    Give the Mid and Tweeter controls a couple shots of deoxit to lubricate and deoxidize pots or Lpads. Find an access from the rear and give then a couple shots, then work the controls back and forth.
     
  20. Natertots

    Natertots Member

    Messages:
    70
    Location:
    Portland, OR
    I did that on the crossover with new binding posts but haven’t done it on the other. I will do that for good measure, maybe tomorrow.

    I failed to mention earlier that the Tweeter co troll on the crossover I repaired “sticks” between 10 & 2 o’clock. When turning through that section it’s like there is some glue or other substance creating stiff resistance.
    It’s not so much resistance I was worried about breaking anything, but it is very noticeable. There was no change after two rounds of deoxit.
     

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