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
<[EMAIL PROTECTED]> 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
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