In the past I complained about harsh receiver audio characteristics similar to some of the audio characteristics being posted recently. It got to the point that I stopped operating as the listener fatigue was so apparent. The effect seemed to be most apparent at CW filter bandwidths. I am apparently sensitive to something that was present, either high frequency trash or 3rd harmonic distortion. I have external rat shack book shelf speakers.
If you google audio fatigue you will eventually find that with some people even a tiny bit of 3rd order harmonic distortion can cause audio fatigue, 60 or 70 dB down. I have installed a beta version audio frequency low pass filter. It involved cutting two traces and soldering in a very small board that contains two SMT low pass filters for the two audio channels. The new board matches up with appropriate tie points on the DSP board (I think it was DSP anyway) for power, ground, two input and two output channels. I had to clear out some vias that were supposed to be solder-free but which were not on my K3. Except for clearing the vias the modification was straight forward. I should have remembered that a stainless steel needle pushed into a via after melting the solder with a soldering iron is the magic trick. The K3 became a different radio after the modification that I am quite pleased with. One of the problems we have is that no one who works at K3 can apparently hear the problem, thus no hurry or they think we are crazy. Mike Scott - AE6WA Tarzana, CA (DM04 / near LA) NAQCC 3535 K3-100 #508 / KX1 #1311 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
