[Elecraft] K3 Line In hum

[Björn Mohr]

On 7 jul 2009, at 18.53, DM5TI Gerard Jendraszkiewicz wrote:

> I wonder if anyone else experienced this type of problem and has a
> possible solution ?
>
> Independent of any connectiions I found out a 50Hz hum on my Line-In
> audio. After a long investigation I figured out
> it was a coupling with other transformers external to the K3.  The
> transformer of my ampliflier ( 10" away from my K3 ) couples an  
> audible
> 50hz hum into the Line-In input.

I do have the same problem of my K3 picking up line noise from a SPE  
1K-FA amp. Bypassing the input trafos as suggested seems to have  
helped some. I also tried the TX equalizer as suggested, but it did  
not make a difference in my case.

Another way to reduce the hum is to use the TX noise gate (Config  
Menu: TX GATE) which will effectively kill the hum between words. It  
won't solve the source of the problem, but it will minimize the effect  
of it as most of the line noise is amplified by the compressor between  
words. I have set my gate to 10.

73 de Björn,
SM0MDG
SE0X