For anyone not reading our original post a little background. The repeater-builder article on the TK690H mentioned that the black KMC35 mic gave better sounding audio than the OEM grey KMC27 mic supplied with the radio. This is noticeably the case, but there seemed to me that a little more highs would be an improvement even on the KMC35 mike replacement, which is the OEM mike supplied with the TK8180 and some other Kenwood mobiles. Therefore I removed chip cap C10 on the mic pc board which works as a low level low pass filter in the 600 ohm mic input to the radio to partially cut off above about 2200-2500 cps. The result was a somewhat improvement in passing some more speech highs, with no noticeable effect on mike lows, so probably? worth removing 0.068 uF C10.? The comment was made that that should not be necessary as audio was quite good with the KMC35 mike as stock. Then I realized that the TK8180 audio input response is flat to 2800 cps, but only to about 2200-2500 cps on the TK690H? radios tested.?
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John
