EasyWriter Posted January 25, 2019 Report Share Posted January 25, 2019 I am attempting to restore my college-era KLH17 speakers, largely relying on advice and wisdom from this web site. This project is pushing the boundaries of my knowledge, which is good but challenging. I'm sure it's my fault and not yours, but it's not going well. I replaced the three capacitors on the first speaker, and my tweeter is silent. The woofer works. The capacitors are from Dayton Audio and specs are visible in attached images. I left the leads at full length and used a metal clip for a heat sink between the capacitor and solder point. I think my solder joints were good. I covered the bare leads with heat-shrink tubing. I didn't remove the existing resistors, so their configuration is unchanged. I've drawn an amateurish diagram of my resulting wiring. I have a multimeter, but I'm new to it, too, and not sure what I should be testing. Thank you very much for your help. I'd come mow your lawn, if I could, to show my thanks. Link to comment Share on other sites More sharing options...
JKent Posted January 26, 2019 Report Share Posted January 26, 2019 Hmmm... I don't see anything wrong but maybe someone else will. Schematic attached below. Are you sure the tweeter works? btw, I'm reading Springsteen's autobiography now and cracked up at the Monkey Man reference. Link to comment Share on other sites More sharing options...
EasyWriter Posted January 26, 2019 Author Report Share Posted January 26, 2019 @Jkent, Thank you so much. You're the patron saint of my project. I'd wondered whether the tweeter might be bad, but I don't know how to test beyond the circumstantial evidence. Is it possible that the 8.2uf capacitor is bad? I have voltage going into it but not coming out. The voltage jumps with the music, it seems, so I can't give you a specific reading, but it's generally about 0.5mV, it seems to me. Except it's 0 on the speaker side of the capacitor. I'm glad you enjoyed the Monkey Man reference. That song starts running through my head whenever I work on this project. Link to comment Share on other sites More sharing options...
JKent Posted January 27, 2019 Report Share Posted January 27, 2019 You can hook up the tweeter directly to the signal source at very low volume and you should hear the music but very tinny. I asked Roy to take a look at this. He knows far more about crossovers than I do. Hang in there. Link to comment Share on other sites More sharing options...
lARrybody Posted January 27, 2019 Report Share Posted January 27, 2019 You might check that the insulating washers around the binding post are installed properly because it could be grounding out on the metal plate. Definitely check the tweeters with the ohms function of your multimeter. I have seen several 17 tweeters come to life when the caps were replaced. Check your solder joints again, evan the ones at the tweeter terminals. Always look at the simplest things first. You will be successful. Link to comment Share on other sites More sharing options...
EasyWriter Posted January 27, 2019 Author Report Share Posted January 27, 2019 That tweeter is dead. Thank you for your suggestions for what to test. I started with the tweeter because my soldering skills are good, even if I don't understand the circuit. ? It zeroed out on the ohmmeter, and connecting it directly to the terminals yielded nothing but the sound of silence, and I don't mean the Simon & Garfunkel song. I'm determined to revive these speakers, so now I'll be shopping for some 4-inch, 8-ohm tweeters. Recommendations welcome. And you don't know how much I appreciate your help. @jkent @IARbybody Link to comment Share on other sites More sharing options...
JKent Posted January 27, 2019 Report Share Posted January 27, 2019 10 minutes ago, EasyWriter said: I'm determined to revive these speakers, so now I'll be shopping for some 4-inch, 8-ohm tweeters. Recommendations welcome. Good! Check ebay. Generally, if you find a KLH tweeter that looks like yours it will be right. Edited your photo Link to comment Share on other sites More sharing options...
EasyWriter Posted January 27, 2019 Author Report Share Posted January 27, 2019 Thank you and love the toe tag! Link to comment Share on other sites More sharing options...
EasyWriter Posted January 27, 2019 Author Report Share Posted January 27, 2019 How important is it to get KLH specifically? I see some other brands, especially Dayton Audio and Goldwood, that look good. Link to comment Share on other sites More sharing options...
JKent Posted January 27, 2019 Report Share Posted January 27, 2019 If you use a different tweeter it will no longer be a KLH Seventeen. AND you will probably need to make crossover changes. There is a lot of art and science to designing a speaker system and unless you know what you're doing you're better off not changing anything. These look like they may be right (I don't have Seventeens here to compare) https://www.ebay.com/itm/Klh-tweeters-fit-many-50s-70s-models/303042850572?hash=item468ec2ef0c:g:LVUAAOSwRfxcTiEy:rk:1:pf:1 Link to comment Share on other sites More sharing options...
EasyWriter Posted January 27, 2019 Author Report Share Posted January 27, 2019 I saw those, but it says they're 4 ohms. Don't I need 8? Link to comment Share on other sites More sharing options...
lARrybody Posted January 27, 2019 Report Share Posted January 27, 2019 Just a couple of questions. Is there a difference between the bright finished tweeters and the black finished tweeters. I have both kinds in different sets of 17's. Second question. Are the tweeters in my Model 20 speakers different because they are 4 ohm speakers? Link to comment Share on other sites More sharing options...
JKent Posted January 27, 2019 Report Share Posted January 27, 2019 Easy: The listing refers to DC Resistance, not speaker impedance. You can check your other tweet with an ohmmeter to be sure but 4 ohms DCR sounds about right. Larry: The paint color doesn’t matter. And the 17 and 20 are exactly the same except for the woofers. Tweets are the same. Link to comment Share on other sites More sharing options...
EasyWriter Posted January 27, 2019 Author Report Share Posted January 27, 2019 @jkent Thank you Link to comment Share on other sites More sharing options...
lARrybody Posted January 27, 2019 Report Share Posted January 27, 2019 Kent: Thanks for confirming that the tweeters are the same. Sort of like the AR3 phenolic dome tweeter also being used on the AR2a and early AR2ax speakers even though the later two are 8 ohm speakers. The KLH 17 and 20 woofers are the same except for their voice coil windings. Upon some further reading it seems that a lot of open Model 17 tweeters are caused by breaks in the tiny voice coil wire leads. If you can cut and pry off the mesh covers you might find something like this. Link to comment Share on other sites More sharing options...
EasyWriter Posted February 5, 2019 Author Report Share Posted February 5, 2019 Final report: Link to comment Share on other sites More sharing options...
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