[Elecraft] Optimizing K3 Mini Speaker Gain with RemoteRig

[Mitch Wolfson, DJØQN / K7DX]

Note that the default RemoteRig setting in the control RRC gives a loud 
CW sidetone. This can be easily lowered by going into the keyer settings 
and change "side tone -db" to another number.

73,
Mitch DJ0QN / K7DX

Mitch Wolfson DJØQN / K7DX
10285 Boca Cir, Naples, FL 34109
Skype: mitchwo
USA: Home:+1-239-221-9600 - Mobile:+1-424-288-9171
Germany: Home:+49 89 32152700 - Mobile:+49 172 8374436

On 17.01.2016 11:10, Paul Christensen wrote:
> Since last May, I've been using a K3 Mini with RemoteRig.  Apart from one
> anomaly, operating the K3 Mini has been a great experience.  However, when
> using RemoteRig, K3 mini speaker audio is extremely loud and the CW
> side-tone is even louder.  However, receive audio and side-tone level in
> headphones is excellent.  If one tries to reduce CODEC gain in the
> RemoteRig, then headphone audio suffers and low-level digital artifacts
> start becoming detectable.
>
> The fix inside the K3 Mini involves replacement of two (2) "603" size SMT
> resistors at R39 and R40.  The stock values are 15K.  I changed these to
> 100K.  This results in a computed gain close to zero (Av = 1) for the
> speaker amp and allows it to be used as a current driver for the speakers.
> After the modification, speaker audio approximates headphone level without
> excessively loud receive audio and side-tone.  This change may affect
> operation of the K3 Mini when a RemoteRig is not used in some applications.
> However, probably most K3 Mini owners use theirs with a RemoteRig.
>
> Suggestion to Elecraft:  if there was a design reason for so much speaker
> gain, consider placing 0.100" headers on a future PCB revision to allow
> jumper selection of either the 15K resistors or 100K.
>
> Many thanks for a great product.
>
> Paul, W9AC
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to dj0qn at arrl.net
>