[Elecraft] K2, Audio Hiss

[Rob Locher W7GH]

Idiom Press makes an external SCAF-based audio filter that does an  
excellent job of eliminating hiss, among other things.  The web site  
http://www.idiompress.com has demo .wav files.

The Standard Disclaimer does NOT apply in this case...

73,
- Rob W7GH
K2 #5004


On Fri, 17 Mar 2006 10:02:45 -0800, Howard W. Ashcraft  
<hashcraft at hansonbridgett.com> wrote:

> I was listening to 40 meters late last night (virtually no one there so
> I had some time to fool around with the rig) and noticed the level of
> audio hiss in the K2.  With RF gain off completely and AF gain fully
> advanced, there is a fair amount of hiss.  This is also noticeable at
> operating levels and is a distraction from listening to weak signals.
> (obviously the operating af gain is set much lower and the hiss is also
> less obvious.  Since I usually use a very good set of in ear buds, I
> normally have the AF gain way down)
>
> All audio amps will create hiss at some gain level because you are
> amplifying noise that is inherent in the components.  But I'm wondering
> if anyone has tried to mod the K2 to create a quieter audio amp?  This
> appears to be an areas where some improvement is possible and it would
> make the K2 more pleasurable to use and weak signals more easily heard.
> I seem to recall from way back that we used to mod Dynaco stereo preamps
> by replacing carbon resistors with low noise equivalents (usually wire
> wound at the time) replacing potentiometers with gang switched low noise
> resistors, etc.  Some semiconductors and ICs also have low noise
> equivalents.




-- 
Idiom Press supplies the world's finest Morse Code keyers,
computerized antenna rotator controls, audio filters for serious hams,
books of interest to DX'ers and more.  http://www.idiompress.com