Frzninvt Posted March 24, 2005 Share Posted March 24, 2005 I would say that it is a polarity issue if the magnet is not oriented the way it was originally. Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted March 24, 2005 Share Posted March 24, 2005 Bob, Thanks. In case I have this problem, now I'm sure you'll be getting the tweeter for repair. Quote Link to comment Share on other sites More sharing options...
BEC Posted March 24, 2005 Author Share Posted March 24, 2005 ---------------- On 3/24/2005 3:39:20 AM DrWho wrote: ---------------- On 3/23/2005 10:53:30 PM BEC wrote: Extra credit question: Why would that be important? ---------------- Gotta keep the magnetic field going the right way to keep the tweeter in phase. Do I get a cookie now? ---------------- A winner!! You are awarded one virtual cookie. Turning the magnet over is the same thing as reversing the leads to the tweeter. Bob Quote Link to comment Share on other sites More sharing options...
BEC Posted March 24, 2005 Author Share Posted March 24, 2005 ---------------- On 3/24/2005 8:33:13 AM Frzninvt wrote: I would say that it is a polarity issue if the magnet is not oriented the way it was originally. ---------------- Just to elaborate on this a bit more. I have found a few of these things backward from the factory. The EV spec states that a positive voltage applied to the positive terminal of the tweeter should result in outward deflection of the diaphragm. Install the magnet backwards and the opposite will occur. Bob Crites. Quote Link to comment Share on other sites More sharing options...
Klipsch Employees Trey Cannon Posted March 24, 2005 Klipsch Employees Share Posted March 24, 2005 Very good post Bob! I have a box of 25 units that have slipped...can I send them to you? Quote Link to comment Share on other sites More sharing options...
BEC Posted March 24, 2005 Author Share Posted March 24, 2005 Trey, Send them on down, Bob Crites Quote Link to comment Share on other sites More sharing options...
BEC Posted May 30, 2005 Author Share Posted May 30, 2005 bump Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted May 30, 2005 Share Posted May 30, 2005 WOW, beautiful post and very elegant solution to a tough problem. One question though, how on earth does that pack of magnets and metal plates 'slip' to this degree? Thanks Bob. Nice extra credit DrWho!@ Michael Quote Link to comment Share on other sites More sharing options...
scriven Posted May 30, 2005 Share Posted May 30, 2005 ---------------- On 3/23/2005 10:47:54 PM BEC wrote: ... In the older alnico magnet tweeters, the top round plate had a welded ring on the back of it that the pole piece fit tightly through to center it... ---------------- Bob, Great post! Are the alnico versions susceptible to the same problem? If so are they reparable? Quote Link to comment Share on other sites More sharing options...
BEC Posted May 30, 2005 Author Share Posted May 30, 2005 A weld would have to break for the alnico tweets to have this problem. I have never seen it in other than the K-77M or EV-T-35A (ceramic magnet) tweeters. Bob Quote Link to comment Share on other sites More sharing options...
BEC Posted July 16, 2005 Author Share Posted July 16, 2005 Bump Quote Link to comment Share on other sites More sharing options...
Timmikid Posted July 17, 2005 Share Posted July 17, 2005 Thanks for the reply and the bump, Bob. I'll give it a try... Tim. Or... does anyone have one or two tweeters with new diaphrams for sale? Quote Link to comment Share on other sites More sharing options...
djk Posted July 17, 2005 Share Posted July 17, 2005 "A weld would have to break for the alnico tweets to have this problem. I have never seen it in other than the K-77M or EV-T-35A (ceramic magnet) tweeters." I've only seen it one or twice over a 10+ year period, it's mainly a K77M issue. If I had an alnico one with a magnet problem I would pick up a spare. Quote Link to comment Share on other sites More sharing options...
fini Posted July 19, 2005 Share Posted July 19, 2005 I had this problem with both tweeters in my first Cornwalls. A Brown Soun charged me an arm and a leg to fix 'em, too. Like, $250. Now I see what a PITA it is. Thanks for the great post, Bob! Quote Link to comment Share on other sites More sharing options...
BEC Posted July 19, 2005 Author Share Posted July 19, 2005 ---------------- On 7/19/2005 8:39:06 AM fini wrote: I had this problem with both tweeters in my first Cornwalls. A Brown Soun charged me an arm and a leg to fix 'em, too. Like, $250. Now I see what a PITA it is. Thanks for the great post, Bob! ---------------- Guess I need to raise my prices, I have been doing that way too cheap. Bob Quote Link to comment Share on other sites More sharing options...
Deang Posted July 19, 2005 Share Posted July 19, 2005 If a tweeter does not have a factory mark -- is there a way to tell + from - Quote Link to comment Share on other sites More sharing options...
BEC Posted July 19, 2005 Author Share Posted July 19, 2005 ---------------- On 7/19/2005 1:05:02 PM DeanG wrote: If a tweeter does not have a factory mark -- is there a way to tell + from - ---------------- Yes, with some difficulty. You would need to know both how the magnet is oriented and how the diaphragm is installed. You can check that the magnets are oriented the same between two tweeters (K-77Ms anyway) by holding them back to back. The magnets should repell if they are oriented the same. To detemmine proper phase on one tweeter, you would have to remove the diaphragm and place it back in the magnet gap just bare without its housing. A voltage (about 1 volt) applied to the two leads correctly (+ to + and - to -) should cause the voice coil to pop out of the magnet gap. That would then comply with the EV spec that says " A positive voltage applied to the positive terminal shall cause outward deflection of the diaphragm." Bob Crites Quote Link to comment Share on other sites More sharing options...
fini Posted July 20, 2005 Share Posted July 20, 2005 ---------------- On 7/19/2005 8:51:26 AM BEC wrote: ---------------- On 7/19/2005 8:39:06 AM fini wrote: I had this problem with both tweeters in my first Cornwalls. A Brown Soun charged me an arm and a leg to fix 'em, too. Like, $250. Now I see what a PITA it is. Thanks for the great post, Bob! ---------------- Guess I need to raise my prices, I have been doing that way too cheap. Bob ---------------- Well, I have to tell you, I was not happy about the price, since I could buy functioning tweeters on eBay for less. They did not inform me of the cost before repairing them... Quote Link to comment Share on other sites More sharing options...
Deang Posted July 20, 2005 Share Posted July 20, 2005 Bob, O.K., that's a start. You see, there's this company called B&K Sound, and their factory mark is coloring the positve solder tab. This other company, Crossoverupgrades -- likes to wipe down solder lugs and tabs with alcohol before they solder. I cleaned the tabs on one of the tweeters and sat it down. When I did the tabs on the other one, I was actually looking down on it while I was doing it -- and saw the coloring come off the tab. I put a scratch on it with a small screwdriver, sat it down, and then pick up the other one. Sure enough -- no red on the tab. Sooo... Quote Link to comment Share on other sites More sharing options...
BEC Posted July 20, 2005 Author Share Posted July 20, 2005 ---------------- On 7/20/2005 9:55:23 AM DeanG wrote: Bob, O.K., that's a start. You see, there's this company called B&K Sound, and their factory mark is coloring the positve solder tab. This other company, Crossoverupgrades -- likes to wipe down solder lugs and tabs with alcohol before they solder. I cleaned the tabs on one of the tweeters and sat it down. When I did the tabs on the other one, I was actually looking down on it while I was doing it -- and saw the coloring come off the tab. I put a scratch on it with a small screwdriver, sat it down, and then pick up the other one. Sure enough -- no red on the tab. Sooo... ---------------- Now I see the problem. The company Crossoverupgrades is incorrectly soldering on a slip on lug and since this lug is attached to plastic that melts very easily, B&K Sound would certainly like to discourage anyone from soldering on it. Soldering wires on those was never a good idea and is a really bad idea now that the plastic housings are no longer in production. Bob Quote Link to comment Share on other sites More sharing options...
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