I had a bent speaker frame on K2 S/N 1289 when I built it several years ago. The problem showed up very clearly as a "fuzzy" addition to what should be a clear audio tone. This is caused by the voice coil touching the magnet.
Several of us discovered them at that time. Elecraft immediately replaced any upon request. I fixed mine instead. I did it as follows: I tuned in a station like WWV that produced a clear beat note in the speaker (or should have). The sidetone might work too, but the early K2's, at least, do not have a clean sine wave sidetone and so it's harder to hear the "fuzz" on it. Using a wide blade screwdriver, I placed it between the frame and the edge of the magnet, and twisted it just enough to move the edge of the magnet slightly while listening to the tone. If no change, I released the pressure and moved on to a new spot. At one point moving the magnet caused the tone to clear up. Twisting the screwdriver a little harder put a permanent bend in the frame to hold the voice coil in the clear. Just try it in small steps, twisting a little farther each try until the tone stays clear when you let go. Don't press hard on the screwdriver. You don't want it to slip through the gaps in the frame and punch a hole in the cone! I fixed mine several years ago and I've not had any trouble since. I suspect that it takes a huge "whack" to make the magnet bend the frame even though it is a fairly heavy magnet and a simple stamped metal frame. It was probably bigger "whack" than the kit would experience being shipped, but it could have happened at any time before Elecraft got the speakers, or they could even be something not being caught at the factory. If I recall correctly, the speaker in my K2 came from China. Ron AC7AC -----Original Message----- To check for a twisted speaker, carefully move the cone in and out by hand. Just push straight down on it gently, and then let go. The cone should move perceptibly, but the voice coil should not rub. K3UJ _ _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
