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<DIV>I pulled out the schematic for the SB104 after your last post. In the audio
chain between the MIC and the Tx mixer, the caps that determine the bass
response are C201, C202, C203, and C204. Of these the one that has the
highest corner frequency (meaning cuts off Bass at the highest frequency) is
C204 at about 1KHz, way too high. That's the one that was previously
suggested to change to a higher value to get better Bass response. </DIV>
<DIV> </DIV>
<DIV>C202 has a corner frequency much lower, about 30Hz. Changing it
shouldn't make much difference unless; (1) the value of the cap was not 0.1uF as
specified, or (2) somebody replaced the MIC GAIN pot or the VOX GAIN pot and put
in one with a much lower value.</DIV>
<DIV> </DIV>
<DIV>Anyway, glad you got the rig to work better. When I had a 104 I
too changed C204 even though I seldom worked Phone.</DIV>
<DIV> </DIV>
<DIV>BTW did you really find a 2.2uF Mylar cap at Radio Shack? Maybe
you meant 0.22uF? </DIV>
<DIV> </DIV>
<DIV>Chris, KL7DM </DIV>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN
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<P class=MsoNormal style="MARGIN: 0in 0in 0.25in"><SPAN
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face="Times New Roman">Recently, I changed C204 on the B Board (TX Audio) from
the original .01 disc ceramic to a .1 Mylar (RadioShack). Did help some, but
still had the mic gain 3/4 open to get enough TX
audio.<o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0.25in"><SPAN
style="FONT-SIZE: 9pt; mso-bidi-font-size: 18.0pt"><FONT
face="Times New Roman">I checked the schematic. C202, a .1 disc ceramic, is the
coupling cap between the two sections of the dual op-amp audio amplifier, just
before the mic gain control. I changed C202 to a 2.2 Mylar (again, plain ol'
RS), and now I have tons of audio with the audio gain about 1/3 open. Now,
that's more like
it!<o:p></o:p></FONT></SPAN></P></DIV></FONT></FONT></BODY></HTML>