[Elecraft] K3S audio board for K3 upgrade?

[Jim Brown]

On Tue,3/22/2016 7:58 AM, Charlie T, K3ICH wrote:
>   There was a very pronounced peak in his
> audio around 300 hz and practically no energy past
> about 800Hz. No distortion, just a widely skewed
> audio passband.  It was a boatanchor radio, so
> there was something obviously wrong somewhere as
> everyone else sounded great.

Yes, this is one of the most common causes of lousy SSB audio. Here's a 
tutorial I wrote for the most recent issue of the National Contest Journal.

k9yc.com/ContestAudio.pdf

73, Jim K9YC