With SLP=0 and THR=20 you have essentially *no* AGC action. That means nothing is protecting the audio amplifier from strong inputs.
I leave it to Wayne or Lyle to calculate the overall gain from noise floor to maximum DSP output but if one has set the audio for comfort on a S4-S6 signal the audio amp is running along at roughly 1.5W into the speaker. When that S9+10 dB signal comes along and you have no AGC even if the audio amplifier is expected to produce only 20 dB more power, the 3.1W amplifier is going to die when asked to produce more than 150 W of peak power. 73, ... Joe, W4TV On 2014-07-01 3:28 PM, Dave Hachadorian wrote:
I guess I've blown the speaker amp IC in my K3 again. This is the third time this has happened, twice in one radio and once in another. In this case, the radio had both the AF Output Mod Kit (pair of 470 ohm resistors) and the E85056 Audio Protection Assembly Circuit Board installed. I was operating on Field Day, with headphones, as I usually do, when some onlookers wanted to hear what was going on. I flipped SPKRS+PHONES=YES, then along came a strong signal, and poof! no speaker audio. AGC SLP was zero, and AGC THR was 020. Front panel AGC was FAST. This failure is really getting old, especially at $120 a pop to get it fixed. Dave Hachadorian, K6LL Big Bear Lake, CA . ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
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